How many spokes should be used when building a wheelset for a specific rider weight?

[NYCfixie]

I now that there are so many variables to consider when building wheelsets but what if you needed to build using the following parts:

H Plus Son Archetype rims (700c)
White Industries T11 hubs
Sapim CX-Ray spokes
Brass nipples
- mostly road use (90%), not racing, regular weekday and longer Saturday/Sunday group rides
- very very little gravel/dirt (at best maybe 10%)
- mostly 28mm tire, sometimes a 32mm


How many spokes would you use front/rear for these rider weights (and feel free to update ranges if it would better illustrate your answer):

200-190lbs
190-180lbs
180-170lbs
170-160lbs
160-150lbs

[Kontact]

This is the kind of question that should have a good, metric answer. But the answers you get will vary a lot.

- Some conservative builders don't see the rational for any "underbuilt" wheel, regardless of rider weight, and will avoid anything below 32 holes.

- Real world use varies tremendously, and some heavier people ride "light", and some lighter people could manage to break an anvil with their riding style.

- It takes a lot of builds and a lot of miles to establish the sort of real world baseline that could answer your question. Even guys who do nothing but build wheels for a living aren't going to have that kind of database built up about one model rim - especially if all their builds are conservative.

- Quality variations. After watching multiple expertly built DT RR415 rims crack at the eyelet holes for a light rider you start wondering if rim design is a lot more complicated than materials, shape and rim weight. Rims 30 grams lighter hold up much better, and DT is a good company, so what is the X factor? Design, QC? I dunno, but I wouldn't recommend that rim because of my personal experience, despite its specs, and I don't know how universal my experience is.


Sorry for the non-answer, but it may help you understand some of the answers you do get.

[cmbicycles]

My Archetypes are 32h built on Record hubs with laser spokes front and ND, and Race spokes on the rear with alloy nipples. I'm 190-200# depending on the season but I'm light on wheels. I've got a couple thousand trouble free miles on them and many more anticipated.

I could use lower spoke count wheels, but like kontact mentioned above, I'd rather the wheels be more reliable more than just having them a couple grams lighter.

[NYCfixie]

In general, I have heard...

32/32 for Over 200lbs
28/32 for 190 - 200
24/28 for 175 - 190
20/24 for 160 - 175

And that factory wheels in 16/20, 16/21, 18/24, 20/24 should really only be used by very light riders on race day.

Again, I know it is not easy to give general answers based on the info I mentioned above but I am looking for exactly that kind of information.

Fair or not, less spokes is about lower weight (not that it matters much for a heaver rider) and aero which can help all.

[zambenini]

I would agree with the above weight. Over 200 and go with 32 or 36, then downward from there.

That said, I have been on 28f 32r for years and I am now a big boy at 190 but have weighed between 165-185 on this wheels as much as at my heavier weight (push-ups I swear). Have not needed them trued 1x and I raced road for a few seasons on them and then made them gravel wheels. Rear was in a bad wreck with a car (front did get relaced then) and just got spikes retensioned and it was fine. Overbuilt with no regrets.

Only reason not to get fewer spikes in front is if you will load it up with gear for touring or something.

[ergott]

I'm also in the camp of "it depends".

Factors I think about:
weight
power output
riding style (masher, spinner, etc.)
prior experience (what has/hasn't worked in the past)
road conditions

probably some others I left out, but that gives you an idea of what can be involved.

[saab2000]

^^^


This guy just built me (last year) a set of wheels with Wheels Mfg hubs and Pacenti Forza rims for maximum strength. I went 28/24 with no hesitation at all and I'm currently no lightweight, between the 190 and 200 lb threshold. So far the wheels are fantastic and look really nice in my basement in these cold temps. Stiff, yet compliant.

I have been using 28 hole fronts for years with no ill effects. The front wheel takes about 90% less abuse than a rear wheel, so honestly, I think 24 would be OK with the usual "it depends" caveats.

[Ralph]

I've seen some rims so strong they almost don't need spokes except to connect the hubs. My daily rider 16/21 spoke Campy Zonda's kinda like that Rear wheel wider and thicker than front, etc.

So sure....it depends.....on a lot more than spoke count. I also think build quality (which you can't always see) is a big part. Some folks just build better wheels than other people. Some wheel problems we see on here involving rims and spokes look to me like a build issue many times.

You don't see many wheel problems from work done by our resident wheel builders on here.

[steelbikerider]

I have a set of DA hubs with archetype rims used for training with 28 front and rear. Fronts are Sapim Laser 2x, rear are Laser NDS, Race DS, 3x. I weigh 200 - 205 and haven't touched a spoke since I built them 18 months/ 9000 miles ago. I also have 2 sets of DA hubs laced to Belgium rims with CX-Rays, 28/28 and 24/28, again never touched a spoke in 1000's of miles. Last is a set of A force 33's in 24/28 with CX rays, again no adjustments but only about 1000 miles. Tires are Continental or Michelin 25mm. My only qualifier is that I have always been easy on wheels, spin at 85-95rpm with a smooth pedal stroke and have a power meter that always seems to read too low. ;)

[oldpotatoe]

I now that there are so many variables to consider when building wheelsets but what if you needed to build using the following parts:

H Plus Son Archetype rims (700c)
White Industries T11 hubs
Sapim CX-Ray spokes
Brass nipples
- mostly road use (90%), not racing, regular weekday and longer Saturday/Sunday group rides
- very very little gravel/dirt (at best maybe 10%)
- mostly 28mm tire, sometimes a 32mm


How many spokes would you use front/rear for these rider weights (and feel free to update ranges if it would better illustrate your answer):

200-190lbs
190-180lbs
180-170lbs
170-160lbs
160-150lbs

Tough to say because big guys can be easy on wheels and little guys can not be but...I wouldn’t use cxray on RH rear for anybody you mentioned(I’d use Race), BUT 170lbs U.P. 32h f/r, 150-170...28/32...remember 4 spokes weigh about 25 grams so a 20/24 is only 125 grams lighter than 32/32...on a 75,000 or so gram ‘package’..

Admittedly I am a conservative wheel builder..remember the French bridge builder...who s____d one ___k, he wasn’t known as French bridge builder but French ___k _____r...

[msl819]

I have a set of DA hubs with archetype rims used for training with 28 front and rear. Fronts are Sapim Laser 2x, rear are Laser NDS, Race DS, 3x. I weigh 200 - 205 and haven't touched a spoke since I built them 18 months/ 9000 miles ago. I also have 2 sets of DA hubs laced to Belgium rims with CX-Rays, 28/28 and 24/28, again never touched a spoke in 1000's of miles. Last is a set of A force 33's in 24/28 with CX rays, again no adjustments but only about 1000 miles. Tires are Continental or Michelin 25mm. My only qualifier is that I have always been easy on wheels, spin at 85-95rpm with a smooth pedal stroke and have a power meter that always seems to read too low. ;)

^^^thats funny... I have been 200 (210-220)plus all of my riding life and have mostly been on 32 hole wheelsets with little problem outside of norm. In my mind it has much more to do with the road surface. When they started drilling and fracking around here and the truck tore up the roads, hitting potholes and other stuff got harder to avoid and wheels needed more attention, but so did my 135 lb riding buddies. I have a buddy who rides around 275, has quads like a power lifter, and rides 28 hole wheelset with little issue. Having an overbuilt set has always been more appealing to me, but that’s just my opinion.

[R3awak3n]

I think it depends on the rims used and what kind of spokes (but mainly rims).

IMO of course, unless you are touring, you are fine with 28 spoke wheels up to 250 lbs, maybe even more but I would say over 250 32 will be more reliable (again depending on the rims used).

I had a set of enve 45s, 20 front and 24 rear, I am over 200 and never had a single problem with them being true. At the same time I have had 32 h wheels that have come out of true. Oh who builds them also matters of course.

THis is one of those topics that I think people on PL are VERY conservative about.

[weisan]

I started building my own wheels about two years ago. I have used a variety of rims for my builds: Pacenti, Velocity, H Plus Son, DT Swiss, Kinlin, Mavic etc.
But one thing that is pretty constant is I tend to stick to 32h and 28h spoke count.

I am the kind of rider who wants to avoid wheel failure at all cost, especially when I am out riding. To me, there's nothing more frustrating than a ride cut short because of equipment failure especially the ones that are completely avoidable. I don't mind so much riding on "broken" frames because the ones that I ride on are actually far from any impending catastrophic failure, I am the one making that call of course.

I have built about 20-25 sets of wheels so far. None of them have needed any adjustment since I took them off the truing stand despite quite a few went through some really hard use like loaded touring, downhill MTB, gravel riding etc. I honestly consider my skill/experience as a wheel builder still very elementary and average but I think I got away with it largely because of choosing a higher spoke count for my builds.

I have weighed as much as 170 pounds, but recently has dropped to 152 pounds. Even then, I am still riding on my 32h wheels. I don't care.

[ripvanrando]

I did Paris Brest Paris on 21R/18F. I train on 20R/18F. I rode cross country on 28R/20F (xray spokes). I do have a set of overkill 32R/28F 650B wheels built by an Amateur (xray spokes, too).

Broke one spoke in maybe 45,000 miles.

But I like to live dangerous....am also light on the saddle despite 185-200 lbs range of body weight.

[NYCfixie]

This is what is so interesting to me. I have probably only ridden 36/36 and 32/32 spoke wheels my entire life up until about 5 years ago. Since then I have been on various low spoke count factory wheels and never had a problem but I did not keep any of them that long (I get bored of stuff easily).

The only time I can remember breaking a spoke was on a Backroads trip in Hawaii a few years ago. It was on one of their decently maintained Ti bikes with 32/32 wheels. I was lugging up a mountain (really a volcano) and heard the "ping sound". Pulled over, noticed the broken spoke on the rear wheel, called and waited for them to come swap the wheel, and no more trouble the rest of the trip.

I am not 200lbs but not a lightweight either and the only time I have ever broken a spoke was on a borrowed 32/32 wheelset. YMMV.

[msl819]

Part of it for me is if I break a spoke on 32 or 36, chances are I can get home on my own power. If I break a spoke on say a 20 I most likely will be calling for a ride. Not the end of the world but something to consider.

[ripvanrando]

Part of it for me is if I break a spoke on 32 or 36, chances are I can get home on my own power. If I break a spoke on say a 20 I most likely will be calling for a ride. Not the end of the world but something to consider.


Good point. The only spoke I broke in memory was on a 600K brevet and the rim rubbed brake pad the last 300Km. I was kicking myself for riding fast wheels but still finished

[NYCfixie]

In 30+ years of cycling on some really crappy roads (NYC, NJ, Boston area) I have only broken 1 spoke on a pair of borrowed wheels on a borrowed bike on a vacation trip in Hawaii.

I guess it depends on how often this really happens and your personal risk tolerance. I do not need ultra-weight-weenie wheels with almost no spokes but I have had slashed tires and mechanicals that could not be fixed road side ruin/stop rides more often than broken spokes.


Part of it for me is if I break a spoke on 32 or 36, chances are I can get home on my own power. If I break a spoke on say a 20 I most likely will be calling for a ride. Not the end of the world but something to consider.

Good point. The only spoke I broke in memory was on a 600K brevet and the rim rubbed brake pad the last 300Km. I was kicking myself for riding fast wheels but still finished in under 24 hours although the sledding was rough.

[msl819]

In 30+ years of cycling on some really crappy roads (NYC, NJ, Boston area) I have only broken 1 spoke on a pair of borrowed wheels on a borrowed bike on a vacation trip in Hawaii.

I guess it depends on how often this really happens and your personal risk tolerance. I do not need ultra-weight-weenie wheels with almost no spokes but I have had slashed tires and mechanicals that could not be fixed road side ruin/stop rides more often than broken spokes.

That’s the greatest correlation there is... borrow something and something is guaranteed to break!

[Ken Robb]

..

Admittedly I am a conservative wheel builder..remember the French bridge builder...who s____d one ___k, he wasn’t known as French bridge builder but French ___k _____r...

That is one of the all-time funny stories. Thanks for making me smile at the memory of my dead pal telling it with a hilarious Faux French accent. "Do zey call me Pierre ze bridge-builder? NON! But--------etc. etc. etc.:banana:

[jamesdak]

I've seen some rims so strong they almost don't need spokes except to connect the hubs. My daily rider 16/21 spoke Campy Zonda's kinda like that Rear wheel wider and thicker than front, etc.

So sure....it depends.....on a lot more than spoke count. I also think build quality (which you can't always see) is a big part. Some folks just build better wheels than other people. Some wheel problems we see on here involving rims and spokes look to me like a build issue many times.

You don't see many wheel problems from work done by our resident wheel builders on here.

Yep, I'm running 7 sets of Campagnolo/Fulcrum wheels on some of my bikes. Shamal, Zonda/Racing 3, and Scirocco/Quattro. Probably around 5000-6000 of my miles on the past two years on those wheels and haven't touched one yet. I've been in the 185-200 lb range unfortunately during this time and ride on rough chipseal. Too many factors go into building wheels to make it easy to say how many spokes are needed.

[bikinchris]

This is the kind of question that should have a good, metric answer. But the answers you get will vary a lot.

- Some conservative builders don't see the rational for any "underbuilt" wheel, regardless of rider weight, and will avoid anything below 32 holes.

- Real world use varies tremendously, and some heavier people ride "light", and some lighter people could manage to break an anvil with their riding style.

- It takes a lot of builds and a lot of miles to establish the sort of real world baseline that could answer your question. Even guys who do nothing but build wheels for a living aren't going to have that kind of database built up about one model rim - especially if all their builds are conservative.

- Quality variations. After watching multiple expertly built DT RR415 rims crack at the eyelet holes for a light rider you start wondering if rim design is a lot more complicated than materials, shape and rim weight. Rims 30 grams lighter hold up much better, and DT is a good company, so what is the X factor? Design, QC? I dunno, but I wouldn't recommend that rim because of my personal experience, despite its specs, and I don't know how universal my experience is.


Sorry for the non-answer, but it may help you understand some of the answers you do get.

^This. Also, how strong the rider is and if they ride hills and stand up a lot. I weigh 280 and can ride a 32 spoke wheel. I have ridden 32 spoke wheels for racing use like that for over 10 years without truing once. I had a set of personal wheels that I sold after 32 years of riding, I also have customers who are 150 pounds and can tear up 36 spoke wheels. I have others that I build 40 spoke wheels so they can go more than 5 years without trouble. So another point is how much maintenance the rider wants to perform.

So there is no easy answer.

[bigbill]

I bought some Zondas in 2008 because they were $300 from Ribble. I bought them with a Chorus 11 group. I figured I'd get a few seasons out of them and ten years later, still true. I'm a big guy but I'm also a diesel, I'm smooth on a bike and watch where I'm going. I cracked a rear Pacenti SL23 V1 but who hasn't. The Pacenti was replaced with an Easton R90 SL and it cracked after 18 months. Old Potato has those hubs and he'll lace them up to some DT511. I rode a set of Chorus/Open Pro wheels for 16 years with no issues. I've got a set of Cosmic Carbones from 1997 that were used in the Giro and I haven't broken those either.

There's no one right answer, but I'll always lean towards more spokes.

[jgarrett]

I’m 230 and drop down to about 215 mid season, and I have good luck with 28/32 wheels. My big question is, can I get away with a 60mm carbon wheel with 24 spokes since the spokes are shorter and the rim itself should be stiffer...we will see


Sent from my iPhone using Tapatalk

[mikemowbz]

While I'm completely 'off-the-chart' with regard to the weight ranges you posted as part of your inquiry, I will chime in to state that at 265-275lbs I no longer consider anything less than 36º for RR wheels for road use with a 25-28mm tire (assuming a trad alloy rim 450-500g such as an Archetype or TB14). I run a couple of 32/32º sets, and find that a 32º RR is much more likely, and quicker, to require some maintenance.

I don't ride particularly 'light', admittedly, and am quite happy with 32º for other applications where we're talking smaller diameter wheel, higher volume tire, and/or wider/beefier rim, but experience drives me to a conservative standard here.

I work in a shop, and typically advise 32º minimum RR for road riding to anyone over 175lbs or so looking to build up a trad alloy rim - and suggest to folks of all weights that a few more rather than a few less spokes makes more sense to me than the alternative. I guess I'm with oldpotatoe on this one...

[oldpotatoe]

I’m 230 and drop down to about 215 mid season, and I have good luck with 28/32 wheels. My big question is, can I get away with a 60mm carbon wheel with 24 spokes since the spokes are shorter and the rim itself should be stiffer...we will see


Sent from my iPhone using Tapatalk

The OP mentioned a rim so narrowed down this 'journey' of how many spokes partially but rim, weight, material, structure, etc...certainly goes into this equation. Those Shamals with 16 then 12 spokes? The rim wasn't light, in the 600g + range so yup, heavier rim(and a LOT of 'factory' wheels use heavier rims), you CAN use fewer and maybe thinner, spokes.
Although the whole thinner spoke gig, CX-Rays specifically, makes little sense to me considering they are just ovalized, thin(like a Laser) spokes and cost $3+ per, and 'support' a wheel like any, really thin, spoke. Lots of marketing going on there.

As for the question above? Depends on the rim. 'Shorter spokes' doesn't mean much..the 2 cross will make for a less strong wheel but '400g' or so carbon rims, are pretty heavy in the rim world. If built well, and you 'ride light', I think they could work. Don't use uber thin spokes..something like Sapim Race or DT Comp...

Gonna mention again..4 spokes weigh about 28 grams(CX-Ray/Laser), even less. Removing a 100-150 grams from a wheel, knowing it will be less reliable, makes little sense to me. When it's spinning, nobody knows(coffee shop points). When you ride it, a 24h won't 'feel' better than a 32h one, same rim. Another 'mistake' or 'trend is a marketing driven one..low spoke count wheels BUT much heavier rim, to make it reliable. See this on alot of bikesouttaboxes. Looks keen on the shop floor..ooo, ahh, low spoke count wheels..they take 150 grams off the wheel from spokes but add 250 grams to the rims to make them more reliable. Backwards way to make a lighter wheel..use a lighter rim and enough spokes..is the gig but that doesn't play well with the product managers.

IMHO, of course-'pal'

[jamesdak]

Well, sorta a side dilemma for me to the whole spoke thing is this....

In the past I've gotten several sets of handbuilt wheels at prices in the $500 to $1000 range. Williams Systems 30s, Zen Cyclery Siddartha's, November wheels, Pacenti SL23 laced to my Dura Ace hubs, etc. The only "cheap" set were some Velomine built Open Pros laced to Miche hubs and these were in the "heavy" 1700+ gram range.

Then I got my first set of Campagnolo Zonda's for a little over $300 and they were in the 1550 g range, low spooked (not that I care) and seem to work better than any of my handbuilts. No issues after lots of miles on them, comfortable, stiff, climb well, descend well, etc. Got Fulcrum 3s, same thing. Later picked up some heavier but semi-aero Scirocco's and they work so well at speed and feel lighter than they are in use. So everytime I get a new bike in (collect old steel but ride it all) it's hard to justify replacing worn, problematic rims with handbuilts from anyone when considering price. If I need a specific vintage look then maybe. But in terms of value for the money and performance it's hard to beat what you can get in certain Campagnolo wheels from the UK sites.

[bikinchris]

It needs to be said that these low spoke count wheels have a much higher spoke tension than the old style normal wheels. Total spoke tension must be higher than the load on the wheel. If not, the wheel fails. Catastrophically.

[Ken Robb]

It needs to be said that these low spoke count wheels have a much higher spoke tension than the old style normal wheels. Total spoke tension must be higher than the load on the wheel. If not, the wheel fails. Catastrophically.

Hey Chris, are you saying that there is a formula for weight vs. tension or just suggesting that heavier loads will require higher tension in general?

[echelon_john]

Depends. Spoke tension is limited by the rim, and best practice is to build up to, but not exceeding, the rim manufacturers' recommended spoke tension.

That recommended tension number doesn't change on a HED Belgium rim, for example, whether it's 32H or 20h. You wouldn't build a 20H C2 Plus to a higher tension than a 32H C2 Plus. This is true for every example I can think of of a rim that would be built by a custom builder. Proprietary *system* wheels may well use higher spoke tensions, but they're beefing up the rim to make that possible.



It needs to be said that these low spoke count wheels have a much higher spoke tension than the old style normal wheels. Total spoke tension must be higher than the load on the wheel. If not, the wheel fails. Catastrophically.

[Kontact]

It needs to be said that these low spoke count wheels have a much higher spoke tension than the old style normal wheels. Total spoke tension must be higher than the load on the wheel. If not, the wheel fails. Catastrophically.

Aside from '80s super light box tubulars with lots of spokes and low tension, I don't think tensions vary that much between spoke counts in various wheels.


I could be wrong, but I'd like to see some tensiometer readings that demonstrate otherwise.

[bikinchris]

Aside from '80s super light box tubulars with lots of spokes and low tension, I don't think tensions vary that much between spoke counts in various wheels.


I could be wrong, but I'd like to see some tensiometer readings that demonstrate otherwise.

Except that f you build (for an extreme example) a 20 spoke and a 48 spoke wheel with the exact same tension, then the tension of those 48 spokes will destroy the rim.

You cannot exceed the strength of the rim, but you can spread the load out over more spokes using more crosses in the spoke pattern. So a 48 spoke wheel with 5x will spread the load out over almost the entire lower half of the rim when loaded, whereas a 20 spoke wheel will load only 2 or 3 spokes. Therefore the 20 spoke wheel would HAVE to have more tension to avoid wheel failure. The 48 spoke wheel has much lower tension, but the load will be spread over about 20 to 24 spokes (with 4 being loaded primarily and they will be 'leaning' on 3 to 4 each to help them from going slack), therefore it can actually hold a higher load.

[Kontact]

Except that f you build (for an extreme example) a 20 spoke and a 48 spoke wheel with the exact same tension, then the tension of those 48 spokes will destroy the rim.

You cannot exceed the strength of the rim, but you can spread the load out over more spokes using more crosses in the spoke pattern. So a 48 spoke wheel with 5x will spread the load out over almost the entire lower half of the rim when loaded, whereas a 20 spoke wheel will load only 2 or 3 spokes. Therefore the 20 spoke wheel would HAVE to have more tension to avoid wheel failure. The 48 spoke wheel has much lower tension, but the load will be spread over about 20 to 24 spokes (with 4 being loaded primarily and they will be 'leaning' on 3 to 4 each to help them from going slack), therefore it can actually hold a higher load.

"The rim" doesn't have a set maximum total load. Each spoke is pulling on a specific spoke hole, and each spoke hole's strength is independent of every other spoke hole. Those individual spoke holes pull the rim into compression, so you are implying that the rim will somehow implode. But since the sections of rim between the spokes get shorter as the spoke count goes up, they are stronger on the 48 vs the 20 spoke, so I imagine it is something of a wash. In other words, you can put considerably more compression on a 1" section of rim than a 2" section before that section is crushed by compression.


I certainly could be completely wrong, but I don't see where you got this idea that a rim has a total loading limit and would need to see some sort of explanation how that would play out.

[bikinchris]

"The rim" doesn't have a set maximum total load. Each spoke is pulling on a specific spoke hole, and each spoke hole's strength is independent of every other spoke hole. Those individual spoke holes pull the rim into compression, so you are implying that the rim will somehow implode. But since the sections of rim between the spokes get shorter as the spoke count goes up, they are stronger on the 48 vs the 20 spoke, so I imagine it is something of a wash. In other words, you can put considerably more compression on a 1" section of rim than a 2" section before that section is crushed by compression.


I certainly could be completely wrong, but I don't see where you got this idea that a rim has a total loading limit and would need to see some sort of explanation how that would play out.

You can do this experiment. When you are building a wheel, you regularly grab the parallel spokes and squeeze to help the spokes settle in and build a more stable wheel. If the spokes are too tight, the rim will take a set and start to take a taco shape. That's what proves you can overload the rim.

[Kontact]

You can do this experiment. When you are building a wheel, you regularly grab the parallel spokes and squeeze to help the spokes settle in and build a more stable wheel. If the spokes are too tight, the rim will take a set and start to take a taco shape. That's what proves you can overload the rim.

I don't think anything will taco if I squeeze some spokes, and I don't think that has much to do with what you're talking about.


You've basically suggested that a 48 spoke wheel has to have less than half the spoke tension of a 21 spoke wheel or the rim will do something bad. What are you predicting a 48 spoke wheel at normal tension is going to do?

[bikinchris]

I don't think anything will taco if I squeeze some spokes, and I don't think that has much to do with what you're talking about.


You've basically suggested that a 48 spoke wheel has to have less than half the spoke tension of a 21 spoke wheel or the rim will do something bad. What are you predicting a 48 spoke wheel at normal tension is going to do?

I'm not predicting idly. I am going on the experience of building hundreds of wheels. So NO, it wouldn't be half the tension for twice the number of spokes or twice for half.

There is some leeway in exactly how tight the tension can be. You can load a 32 and 36 spoke wheel with the same spoke tension and you will have a stronger 36 spoke wheel, but when you go all the way to a 48 spoke wheel, you cannot tension all of the spokes to say e.g. 100kgf. That would be too much.

So no matter what spoke count a wheel has, the tension needed cannot exceed the maximum load the rim can support. Nor can that tension be so low that the spokes become un-tensioned. Lateral and vertical forces both have to be included in the total load.

[Kontact]

I'm not predicting idly. I am going on the experience of building hundreds of wheels.

There is some leeway in exactly how tight the tension can be. You can load a 32 and 36 spoke wheel with the same spoke tension and you will have a stronger 36 spoke wheel, but when you go all the way to a 48 spoke wheel, you cannot tension all of the spokes to say e.g. 100kgf. That would be too much.

So no matter what spoke count a wheel has, the tension needed cannot exceed the maximum load the rim can support. Nor can that tension be so low that the spokes become in-tensioned. Lateral and vertical forces both have to be included in the total load.

What kind of rim did you collapse?

[bikinchris]

What kind of rim did you collapse?

Oh, that was very early in the learning process of wheel building. Probably a Trek ISO tubular rim about 35 years ago. No, not collapse, but taking a 'set' during the process means your tension is too high. As you come above a tension where you can true the wheel both laterally and vertically, you grab parallel spokes on both sides at the same time and squeeze hard. This beds the spokes into the hub and makes the process much quicker to a final wheel. The rim taking a set is very different than finding out some of your spokes unwound and reduced tension. When you reduce tension, then you can true the wheel and it is good to go.

[Kontact]

Oh, that was very early in the learning process of wheel building. Probably a Trek ISO tubular rim about 35 years ago. No, not collapse, but taking a 'set' during the process means your tension is too high. As you come above a tension where you can true the wheel both laterally and vertically, you grab parallel spokes on both sides at the same time and squeeze hard. This beds the spokes into the hub and makes the process The rim taking a set is very different than finding out some of your spokes unwound and reduced tension.

I understand. I have also built wheels professionally. I was just wondering what high spoke count wheel you were basing your comments on.

[Mark McM]

Hey Chris, are you saying that there is a formula for weight vs. tension or just suggesting that heavier loads will require higher tension in general?

After building a great many wheels with different rims and numbers of spokes, and also using Jobst Brandt's method of finding highest allowable tension, I actually have found a relationship between rim weight & tension (& number of spokes). This relationship is:

Tension = (Rim coefficient) x (Weight of rim ) / (number of spokes)

The Rim Coefficient will vary, depending on rim material and design, but typically is in the range of 8 - 9 Kgf/gram.

So, for example for a 420 gram rim and 32 spokes and Rim Coefficnent of 8 Kgf/gram, the maximum tension would be:

Tension = (8 kgf/gram) x (420 grams) / (32 spok = 105 kgf

If 28 spokes were used, the tension would increase to:

Tension = (8 kgf/gram) x (420 grams) / (28 spokes) = 120 kgf

The relationship holds well for lightweight rims and large numbers of spokes. However, as the weight of the rim increases and the number of spokes decreases, other factors come to denominate, and this relationship no longer holds. So, while this relationship will work great for 350 gram tubular rims built with 36 spokes, it will not work for deep section 600 gram rims with 16 spokes.

[Mark McM]

Depends. Spoke tension is limited by the rim, and best practice is to build up to, but not exceeding, the rim manufacturers' recommended spoke tension.

That recommended tension number doesn't change on a HED Belgium rim, for example, whether it's 32H or 20h. You wouldn't build a 20H C2 Plus to a higher tension than a 32H C2 Plus. This is true for every example I can think of of a rim that would be built by a custom builder. Proprietary *system* wheels may well use higher spoke tensions, but they're beefing up the rim to make that possible.


Unfortunately, in many cases you may have to take the manufacturer's spoke tension recommendations with a grain of salt. Frequently, rim manufacturers will recommend the same maximum tension for all their rims. That's right, the same maximum tension for their strong, heavy rims as for their weaker, lighter rims (and for all numbers of spokes). That's physically impossible. I strongly suspect that the rim manufacturers do not actually do any type engineering to determine the actual spoke tension limits on their rims, and simply use some arbitrary number that "seems to kind of work, at least a lot of the time". I'll bet if you asked a rim manufacturer how they arrived at the maximum tension recommendation that is specific for a particular rim, you'd just get a blank stare, and maybe some vague non-comittal hand waving.

Am I claiming that I'm smarter than the rim manufacturers or know something they don't? Not at all - I have no way of knowing what the actual maximum tension should be for a particular rim. What I'm saying is that it is highly likely that the manufacturer doesn't, either.

[Mark McM]

You cannot exceed the strength of the rim, but you can spread the load out over more spokes using more crosses in the spoke pattern. So a 48 spoke wheel with 5x will spread the load out over almost the entire lower half of the rim when loaded, whereas a 20 spoke wheel will load only 2 or 3 spokes.

There seems to be a lot myths about the role of spoke crossing and improving wheel strength, and the above is just an example. Many wheel myths should have been put to rest when Jobst Brandt published his book "The Bicycle Wheel" over 40 years ago, but it appears that few have bothered to read it. Everything in that book still applies today, and its basic principles have been confirmed and re-confirmed many times since its publication.

Crossing spokes definitely has a an affect on the wheel torsional strength/stiffness, but it has almost no affect on vertical or lateral strength or stiffness. Crossed spokes do not "share the load" between them, or transfer loads to different parts of the rim. This is discussed in "The Bicycle Wheel", and was further confirmed in a research study by Henri Gavin. Gavin built otherwise identical wheels with different numbers of spoke crossings and instrumented the spokes with strain gauge. He then measured the actual stress/strains in the spokes while the wheels were ridden. His measurements show that the spoke crossings has virtually no affect on the stresses/loads experienced by the spokes.

Therefore the 20 spoke wheel would HAVE to have more tension to avoid wheel failure. The 48 spoke wheel has much lower tension, but the load will be spread over about 20 to 24 spokes (with 4 being loaded primarily and they will be 'leaning' on 3 to 4 each to help them from going slack), therefore it can actually hold a higher load.

The 20 spoke wheel will need more tension to support the same load, but it has nothing to do with spoke crossing. And the number of spokes bearing the load is much smaller than you indicate. When a load is applied to the wheel, the rim is loaded in bending, whereas spokes are loaded in tension, so the rim is much more compliant that the spokes. Therefore, when a load is applied to the rim, it will transfer that load primarily to the spokes in the small area around the load point, called the LAZ (Load Affected Zone). The LAZ is relatively small, and only encompasses a small portion of the rim (perhaps 1/16th to 1/8th of the circumference). There are typically only a small number of spokes in the LAZ. But the more total spokes the wheel, the closer together the spokes will be, and therefore the more spokes there will be in the LAZ, bearing the load. The finite element analysis in "The Bicycle Wheel" illustrates the LAZ and how few spokes actually bear the load.

[Kontact]

Unfortunately, in many cases you may have to take the manufacturer's spoke tension recommendations with a grain of salt. Frequently, rim manufacturers will recommend the same maximum tension for all their rims. That's right, the same maximum tension for their strong, heavy rims as for their weaker, lighter rims (and for all numbers of spokes). That's physically impossible. I strongly suspect that the rim manufacturers do not actually do any type engineering to determine the actual spoke tension limits on their rims, and simply use some arbitrary number that "seems to kind of work, at least a lot of the time". I'll bet if you asked a rim manufacturer how they arrived at the maximum tension recommendation that is specific for a particular rim, you'd just get a blank stare, and maybe some vague non-comittal hand waving.

Am I claiming that I'm smarter than the rim manufacturers or know something they don't? Not at all - I have no way of knowing what the actual maximum tension should be for a particular rim. What I'm saying is that it is highly likely that the manufacturer doesn't, either.
I don't see why it is "impossible" for a rim maker to have a range that is neither so flexible that low spoke counts work yet has the strength on heavy rims for a large number of spokes all at the same tension.

This is not the same as saying "all rims of all descriptions can take the same tension in any possible drilling". It is saying that a company's lightest 400 gram rim can use the same tension for 20 to 32 spokes and the 600 gram rim can use that same tension for 32 to 48 spokes. Is anyone producing a single rim that is available in every drilling from 20 to 48, or are the light rigid rims the ones with few spokes and the the heavy rims the ones with many spokes?

[Mark McM]

"The rim" doesn't have a set maximum total load. Each spoke is pulling on a specific spoke hole, and each spoke hole's strength is independent of every other spoke hole. Those individual spoke holes pull the rim into compression, so you are implying that the rim will somehow implode. But since the sections of rim between the spokes get shorter as the spoke count goes up, they are stronger on the 48 vs the 20 spoke, so I imagine it is something of a wash. In other words, you can put considerably more compression on a 1" section of rim than a 2" section before that section is crushed by compression.


I certainly could be completely wrong, but I don't see where you got this idea that a rim has a total loading limit and would need to see some sort of explanation how that would play out.

Again, this is all covered in "The Bicycle Wheel" by Jobst Brandt. This book should be read by anyone who wants to claim that they are a wheel "expert".

The spokes all pull inward on the rim. All this net inward pull results in a high circumferential compresson on the rim. If there are a large number of spokes at high tension, this compression can be quite large. For example, 32 spokes each tensioned to 220 lb (100 kgf) will result in a circumferential compression force on the rim of about 1000 lb. If you double the number of spokes and keep their average tension the same, the rim will have circumferential compression of 2000 lb.

On a lightweight rim with a large number of spokes, it is very easy to tension the spokes high enough to buckle the rim in circumferential compression. For lightweight rims with many spokes, this circumferential buckling force becomes the limiting factor for spoke tension. In fact, in the "The Bicycle Wheel", Jobst Brandt presents a method for determining maximum spoke tension based on tensioning the spokes just high enough so that squeezing pairs of spokes results in minor rim buckling, and then backing off the tension.

Of course, the stronger the rim and the fewer the spokes, the greater the tension required to buckle the rim. For many modern wheels with deep, heavy rims and a reduced number of spokes, it may be virtually impossible to tension the spokes high enough to buckle the rim. In these cases, maximum spoke tension will be based on other factors.

[Mark McM]

I don't see why it is "impossible" for a rim maker to have a range that is neither so flexible that low spoke counts work yet has the strength on heavy rims for a large number of spokes all at the same tension.

This is not the same as saying "all rims of all descriptions can take the same tension in any possible drilling". It is saying that a company's lightest 400 gram rim can use the same tension for 20 to 32 spokes and the 600 gram rim can use that same tension for 32 to 48 spokes. Is anyone producing a single rim that is available in every drilling from 20 to 48, or are the light rigid rims the ones with few spokes and the the heavy rims the ones with many spokes?

While it would certainly make sense to make deep heavy rims available for small spoke counts, and shallow light rims available in large spoke counts. But in many cases, manufacturers make both their deep heavy rims and shallow light rims available in the same spoke counts. For example, the Kinlin XR200, a 380 gram, 22mm deep clincher rim is available in spoke counts of 20,24,28 & 32, whereas the Kinlin XR380 rim, a 550 gram, 38mm deep clincher rim is also available in spoke counts of 20,24,28 & 32. Do you really believe that both rims, in all the available spoke counts, should use the same tension?

Now, the 20 spoke version of the XR380 might get away with only 100 kgf tension. But it can surely take more tension, and the wheel would be even stronger due to it. I actually built a 20 spoke XR380 with 150 kgf average spoke tension, and it is holding up fine. I don't think I'd try the same tension for the 32 spoke version of the XR200.

[Kontact]

Again, this is all covered in "The Bicycle Wheel" by Jobst Brandt. This book should be read by anyone who wants to claim that they are a wheel "expert".

The spokes all pull inward on the rim. All this net inward pull results in a high circumferential compresson on the rim. If there are a large number of spokes at high tension, this compression can be quite large. For example, 32 spokes each tensioned to 220 lb (100 kgf) will result in a circumferential compression force on the rim of about 1000 lb. If you double the number of spokes and keep their average tension the same, the rim will have circumferential compression of 2000 lb.

On a lightweight rim with a large number of spokes, it is very easy to tension the spokes high enough to buckle the rim in circumferential compression. For lightweight rims with many spokes, this circumferential buckling force becomes the limiting factor for spoke tension. In fact, in the "The Bicycle Wheel", Jobst Brandt presents a method for determining maximum spoke tension based on tensioning the spokes just high enough so that squeezing pairs of spokes results in minor rim buckling, and then backing off the tension.

Of course, the stronger the rim and the fewer the spokes, the greater the tension required to buckle the rim. For many modern wheels with deep, heavy rims and a reduced number of spokes, it may be virtually impossible to tension the spokes high enough to buckle the rim. In these cases, maximum spoke tension will be based on other factors.

I don't think you're getting my objection. We don't build 290 box rims with 16 spokes, and we don't build 400 gram A section rims with 48 spokes. The kinds of rims with few spokes at a "modern" tension are considerably more rigid than those old tubular rims, and the rims we build with 48 spokes are quite heavy, and could accept both few spokes or many at higher tensions.

When is it that we have to choose to lower the tension with modern rims lest they pringle? Is that not limited by the available drillings as much as the engineering of the rim.


And I've read Brandt, but I don't know if the principles he developed to explain why a 290 gram tubular needs less tension is necessarily applicable to modern rims. Not because the principle isn't true, but because the modern rims are pushing maximums in any of the configuations available. In other words, do we know that any of these modern rims we are talking about actually would exceed Brandt's formula?

[Kontact]

While it would certainly make sense to make deep heavy rims available for small spoke counts, and shallow light rims available in large spoke counts. But in many cases, manufacturers make both their deep heavy rims and shallow light rims available in the same spoke counts. For example, the Kinlin XR200, a 380 gram, 22mm deep clincher rim is available in spoke counts of 20,24,28 & 32, whereas the Kinlin XR380 rim, a 550 gram, 38mm deep clincher rim is also available in spoke counts of 20,24,28 & 32. Do you really believe that both rims, in all the available spoke counts, should use the same tension?

Now, the 20 spoke version of the XR380 might get away with only 100 kgf tension. But it can surely take more tension, and the wheel would be even stronger due to it. I actually built a 20 spoke XR380 with 150 kgf average spoke tension, and it is holding up fine. I don't think I'd try the same tension for the 32 spoke version of the XR200.

You are talking about what I'm getting at.

The XR380 is rigid enough to not collapse due to large gaps between spoke holes on 20 hole drillings when riden, but also has the "rim coefficient" to take the compression of 32 spokes at that same spoke tension.

But it isn't offered in a 48 hole version, so we don't have to worry what happens above 32 spokes. We just have to know that the rim has enough rigidity for the minimum spokes and enough rim coefficient for the maximum, and it isn't absurd to think that one rim could have that range. Just as one heavy rim might have the range to accept 32 to 48 spokes.

The average spoke tension used today is not just about wheel strength, it also has to be at a level where the spoke holes don't crack and the hub flanges don't burst, regardless of what is happening in the rest of the wheel. So it really isn't realistic to talk about jacking up the tensions on 20 spoke wheels for overall structural reasons when the specific attachment points aren't built for it.

[Mark McM]

You are talking about what I'm getting at.

The XR380 is rigid enough to not collapse due to large gaps between spoke holes on 20 hole drillings when riden, but also has the "rim coefficient" to take the compression of 32 spokes at that same spoke tension.

Ah, but what about the other end of the product line, the 380 gram 22mm deep XR200? I think you'll agree that this rim should be built with more than 20 spokes, and 32 spokes for the rear is probably a good idea. I'm pretty sure that with 32 spokes this rim could be buckled with excessive spoke tension.

(By the way, the "buckling" of a rim isn't the same as for eccentrically loaded columns. The rim is too well braced by the spokes for that. Rim buckling is primarly from yielding under compression. Therefore, the main factors are the secion area and yield strength of the rim - the shape of the cross-section doesn't play much of a role.)

The average spoke tension used today is not just about wheel strength, it also has to be at a level where the spoke holes don't crack and the hub flanges don't burst, regardless of what is happening in the rest of the wheel. So it really isn't realistic to talk about jacking up the tensions on 20 spoke wheels for overall structural reasons when the specific attachment points aren't built for it.

Well, that's why I said that for heavier rims and fewer spokes, factors other than rim buckling limit the spoke tension.

By the way, I also believe that the role of static tension is exaggerated in regard to rims and hubs cracking. Clearly, rims don't crack and hub flanges don't "burst" purely from static tension. If they did, they'd break when the wheel was being built and stress relieved. In use, most wheel loads result in decreases in spoke tension, so some of the highest tensions the spokes ever see are during stress relieving. Other evidence that rims and and hubs don't break from momentarily overload can be found by examination of cracked components. Overloads result in localized yielding around the break, but cracked rims and hubs don't show this yielding. The cracks are caused by fatigue, which are caused by cyclic loads, not by static loads.

You might argue that high static loads decrease fatigue life, which is true. But even here the affect is exaggerated. High static loads have their greatest affect on low cycle fatigue life, and its affect decreases for high cycle fatigue life. Wheels are a case of high cycle fatigue - a wheel under goes a million load cycles in just 1,200 miles.

Instead, I believe that most cracked wheel components are a result of cyclic loads, instead of static loads. In other words, the wheel was under-designed for its dynamic loading, typically either with un-relieved stress concentrations, too few (or too thick) spokes, or with a too flexible rim.

I've been a professional wheel builder, and always used high tensions (120 - 150 kgf weren't uncommon). As far as I know, other than as a result of crashes, I think only one of my wheels ever had a cracked rim (a GL330), and only maybe 4 ever had broken spokes, and none of them had a broken hub flange. On the other hand, all wheels were well stress relieved and generally weren't underbuilt in regard to rim stiffness or spoke count.

It's interesting to note that many low spoke count "prebuilt" wheels use standard components, such as hubs and spokes, and often standard rims as well - just with fewer spokes than when the components are available separately. I know that this was certainly the case with many Campagnolo wheels. And yet, the Campagnolo technical manuals specified relatively high tensions - sometimes as high as 150-170 kgf. How is it that these components suddenly got "stronger" when they were pre-assembled in the factory?

I suspect that it is because the "recommended" maximum tensions for un-assembled are just spit-balled, or are a kind of 'catch-all' maximum that covers the worst case scenario. Similar to how many carbon fork makers all specify a maximum of 40mm of spacers, as if all steerers where the same strength, or all riders were the same weight. (Do the fork makers really think that a steerer that won't break with 250 lb. rider using a 150mm stem and 30 mm of spacers, will suddenly break when a 100 lb. rider with an 80mm stem uses 50 mm of spacers?).

Or, maybe low maximum spoke tensions are really way to dodge warranty service? (This was Mavic's standard way to deny warranties for cracked rims: "Your warranty is denied because you used too much spoke tension!" "Wait, I didn't even tell you what tension I used!" "Well, the rim broke, so the tension must have been too high!").

As a side note, a few distributors actually managed to get some 38mm deep Kinlin XR380 rims with 16 holes, so I procured one and built a front wheel. While many rim manufacturers have blanket maximum tension recommendations of 100-110 kgf, I don't think I've ever seen a pre-built 16 spoke wheel with spec.-ed tension this low. I built mine with 160 kgf.

[Kontact]

Ah, but what about the other end of the product line, the 380 gram 22mm deep XR200? I think you'll agree that this rim should be built with more than 20 spokes, and 32 spokes for the rear is probably a good idea. I'm pretty sure that with 32 spokes this rim could be buckled with excessive spoke tension.

(By the way, the "buckling" of a rim isn't the same as for eccentrically loaded columns. The rim is too well braced by the spokes for that. Rim buckling is primarly from yielding under compression. Therefore, the main factors are the secion area and yield strength of the rim - the shape of the cross-section doesn't play much of a role.)


That's the thing - you're "pretty sure", but since you don't have the rim coefficient it is just supposition.

I don't follow what you're saying about cross section. The shape, composition and heat treatment are all factors in the yield strength of a structure, rather than the yield strength of a material alone.



By the way, I also believe that the role of static tension is exaggerated in regard to rims and hubs cracking. Clearly, rims don't crack and hub flanges don't "burst" purely from static tension. If they did, they'd break when the wheel was being built and stress relieved. In use, most wheel loads result in decreases in spoke tension, so some of the highest tensions the spokes ever see are during stress relieving. Other evidence that rims and and hubs don't break from momentarily overload can be found by examination of cracked components. Overloads result in localized yielding around the break, but cracked rims and hubs don't show this yielding. The cracks are caused by fatigue, which are caused by cyclic loads, not by static loads.

You might argue that high static loads decrease fatigue life, which is true. But even here the affect is exaggerated. High static loads have their greatest affect on low cycle fatigue life, and its affect decreases for high cycle fatigue life. Wheels are a case of high cycle fatigue - a wheel under goes a million load cycles in just 1,200 miles.

Instead, I believe that most cracked wheel components are a result of cyclic loads, instead of static loads. In other words, the wheel was under-designed for its dynamic loading, typically either with un-relieved stress concentrations, too few (or too thick) spokes, or with a too flexible rim.



I don't think anyone believes that the issue is static loads. But the cyclic loads at higher tensions, even at lower amplitude, are going to do more "work" on the components.

Additionally, the stiffer the rim the more localized the spoke hole stress.



Personally, I own two XR200 wheelsets that I built, one 24/28 and the other 20/24 (triplet rear). I've only had them three years but the 20 has stayed in true, and the 28 hasn't imploded, despite all built at the same spoke tension. We'll see, I suppose.

[bob heinatz]

Enjoyable thread. My experience is that it is more importance who builds the wheel than spoke count. A good light rim built by a professional wheel builder is the way to go for me. That also means I depend on their opinion on the build.

[Mark McM]

That's the thing - you're "pretty sure", but since you don't have the rim coefficient it is just supposition.

I don't follow what you're saying about cross section. The shape, composition and heat treatment are all factors in the yield strength of a structure, rather than the yield strength of a material alone.

As you are pointing out, there are many factors that can affect column buckling. For long slender columns, the cross section shape (as represented by the radius of gyration), the curve of the column, and the eccentricity of the load can make a big difference. On the other hand, for short, fat column shapes, yielding (deformation) is primarily a matter of area and yield strength. In other words, long slender columns bend and buckle, whereas as short fat columns just get "flattened". Since the is well braced by the spokes against radial and lateral deflection, it's yielding is less like that of a long slender column, and more like that of a short, fat column.

Of course, it's not quite as simple as that, but the primary factors in the yielding of the rim under circumferential compression are the yield strength of the material and the cross sectional area. Since the all rims for the same wheel size are approximate the same diameter, and since the density of aluminum alloys are all close to the same, the cross sectional area of the rim will be nearly proportional to its weight.





I don't think anyone believes that the issue is static loads. But the cyclic loads at higher tensions, even at lower amplitude, are going to do more "work" on the components.

That's true, but consider that: A) spokes are tensioned at well below their yield points; and B) the primary reaction of spokes is tension reduction. While a high static tension will have an affect on fatigue life, by far the largest factor remains the magnitude of the cyclic loads.

Additionally, the stiffer the rim the more localized the spoke hole stress.

Just the opposite is true. The stress in the rim hole of course will be proportional to the load on the spoke. But a stiffer rim will distribute wheel loads across more spokes, reducing the portion of the load each individual spoke must bear, thus reducing the peak spoke loads.


[QUOTE=Kontact;2295596]Personally, I own two XR200 wheelsets that I built, one 24/28 and the other 20/24 (triplet rear). I've only had them three years but the 20 has stayed in true, and the 28 hasn't imploded, despite all built at the same spoke tension. We'll see, I suppose.

Well, you didn't mention what the spoke tensions were. For a Rim Coefficient of 9 (Kgf-grams), a 380 gram rim with 28 spokes could easily operate with an average tension of 122 kgf without danger of buckling. Modern rims are made with stronger alloys than those of yesteryear. Kinlin rims are made with a particularly strong Niobium alloy, so the Rim Coefficient of these rims may be much higher than for older rims.

(Anecdotally, I once built a 32 spoke wheel with an Araya CTL-370 rims, which weighed about 375 grams. The alloy on this rims must have been particularly soft, as I couldn't get more than about 90 kgf average tension without the rim yielding during stress-relieving.)

[Kontact]

Additionally, the stiffer the rim the more localized the spoke hole stress.

Just the opposite is true. The stress in the rim hole of course will be proportional to the load on the spoke. But a stiffer rim will distribute wheel loads across more spokes, reducing the portion of the load each individual spoke must bear, thus reducing the peak spoke loads.

It does distribute it across the rim, but that only happens because a small area around the spoke hole is taking those stress variations rather than a whole section of rim moving.

And really, that's the 'forest for the trees' problem in this discussion - you can't just treat spoke tension as something you can add as necessary. "Good" spoke tension is whatever is sufficient (rather than optimal) for wheel strength while not overloading the localized anchor points. Because the life of wheel is limited most by the number of work cycles the spoke holes can take more than any other factor.


Well, you didn't mention what the spoke tensions were. For a Rim Coefficient of 9 (Kgf-grams), a 380 gram rim with 28 spokes could easily operate with an average tension of 122 kgf without danger of buckling. Modern rims are made with stronger alloys than those of yesteryear. Kinlin rims are made with a particularly strong Niobium alloy, so the Rim Coefficient of these rims may be much higher than for older rims.

I don't recall what tension I was using other than that is was 'typical', so let's say it was 120 kgf, right in the middle of Velocity's recommended range of 110 to 130 or right at Enve's number. Regardless, I used it across all the spokes, because I wanted spokes that would maintain very low amplitude of tension change while not overloading the spoke holes. And that seems to be the way rim manufacturers also look at the problem.

[casparwhittey]

I built mine up 32h because I don't want to cut out any of the resale market when I go to sell them on the classifieds ;)