28 hole hubs - 2x or 3x drive side?

[Wayne77]

I am taking the plunge and building some wheels. I have 28h disc hubs (left flange 58mm, right flange 49mm on the rear hub) , Velocity Aileron rims, which are about 27mm deep. I was planning on 2x all around, but then got to thinking that I might be better off doing 3x on the drive side. I also heard that 2x is best on a 28h hub...something to do with the bracing angle.

What do you think? 2x or 3x on the drive side? (FWIW, I am 180 lbs)

[kramnnim]

2x, because of the bracing angle...is there any reason to go 3x?

[thirdgenbird]

My 28h wheels are 2x and were build by a trusted shop. The angle of the trailing spokes seems to match 3x on a 32h wheel but I haven't measured or done the math.

[xeladragon]

I took oldpotatoe's advice...

http://forums.thepaceline.net/showthread.php?t=151243

[Wayne77]

I took oldpotatoe's advice...

http://forums.thepaceline.net/showthread.php?t=151243

Thanks for the link - very helpful. So you went 3x front and back?

[Wayne77]

A couple other questions. For reference, here are the 28 hole hubs I'm using:

Front: http://www.bdopcycling.com/Hubs-D711SB.asp
Rear: http://www.bdopcycling.com/Hubs-D712SB-10.asp

- My hubs have larger flanges than the CX75 hubs. I see oldpotatoe's recommendation of 3x all around front and back, inside pulling for disc hubs. With the larger flanges, would I still be ok with 3x? Or should I stick with 2x?

- As mentioned, I'll be using the Velocity Aileron rim...which should be a little stiffer than a shallower section rim right? With the deeper rim, would 2x be ok? I want a durable wheel, but not sure if 3x will work on these larger flange hubs...

- Spokes...I was planning on Sapim Laser. I've heard some do Sapim Race on the rear, drive side. Since a disc hub has as much or more force on the disc side, should I do Race spokes on both sides, or stick with Laser on both sides?

- I checked spoke lengths 3 different spoke calculators with these hubs & Aileron rims..and get the same measurements (this is for 2x):

FL: 274.6 FR: 279.8
RL: 275.9 RR: 277

I assume I can round up on all these? Or round down? (I'll be using 12mm brass nipples), so I figure 275 for FL and RL, 280 for FR, 277 for RR.

...someone suggested using nipple washers, which I suppose would increase the ERD#, by 1.5mm. Correct?

[xeladragon]

Thanks for the link - very helpful. So you went 3x front and back?

Yep, just double-checked, 3x front and back. That's what the LBS recommended too. But for my weight and intended usage, I'm sure 2x would've been fine as well.

[thirdgenbird]

I should have said, mine are not disc.

[oldpotatoe]

I am taking the plunge and building some wheels. I have 28h disc hubs (left flange 58mm, right flange 49mm on the rear hub) , Velocity Aileron rims, which are about 27mm deep. I was planning on 2x all around, but then got to thinking that I might be better off doing 3x on the drive side. I also heard that 2x is best on a 28h hub...something to do with the bracing angle.

What do you think? 2x or 3x on the drive side? (FWIW, I am 180 lbs)

Well, the right side flange is fairly big but I would still do 3 cross both sides rear with the pulling spokes head OUT..to reduce the flange overlap of the pulling spokes.

[oldpotatoe]

A couple other questions. For reference, here are the 28 hole hubs I'm using:

Front: http://www.bdopcycling.com/Hubs-D711SB.asp
Rear: http://www.bdopcycling.com/Hubs-D712SB-10.asp

- My hubs have larger flanges than the CX75 hubs. I see oldpotatoe's recommendation of 3x all around front and back, inside pulling for disc hubs. With the larger flanges, would I still be ok with 3x? Or should I stick with 2x?

- As mentioned, I'll be using the Velocity Aileron rim...which should be a little stiffer than a shallower section rim right? With the deeper rim, would 2x be ok? I want a durable wheel, but not sure if 3x will work on these larger flange hubs...

- Spokes...I was planning on Sapim Laser. I've heard some do Sapim Race on the rear, drive side. Since a disc hub has as much or more force on the disc side, should I do Race spokes on both sides, or stick with Laser on both sides?

- I checked spoke lengths 3 different spoke calculators with these hubs & Aileron rims..and get the same measurements (this is for 2x):

FL: 274.6 FR: 279.8
RL: 275.9 RR: 277

I assume I can round up on all these? Or round down? (I'll be using 12mm brass nipples), so I figure 275 for FL and RL, 280 for FR, 277 for RR.

...someone suggested using nipple washers, which I suppose would increase the ERD#, by 1.5mm. Correct?

I would NOT recommend lasers for this disc wheelset. Particularly 28h..use Race..I don't think Lasers(or DT REVS) are stiff enough.

FL:275 FR: 280
RL:276 RR:277

Spoke washers or nipple washers. Unless the spoke holes in the hub are LARGE, like bigger than 2.3mm, not needed. For those rims, no need for nipple washers.

[Wayne77]

I would NOT recommend lasers for this disc wheelset. Particularly 28h..use Race..I don't think Lasers(or DT REVS) are stiff enough.

FL:275 FR: 280
RL:276 RR:277

Spoke washers or nipple washers. Unless the spoke holes in the hub are LARGE, like bigger than 2.3mm, not needed. For those rims, no need for nipple washers.

Thanks - very helpful. I wisened up a bit and changed my order to 32 hole hubs...(since these are disc wheels)

I'll do the classic build, 32h / 3x all around. This bike will be mostly used for commuting, with the occassional cross race. I'm completely new to cross and by no means a watt-monster, so hopefully this configuration will be adequate.

The reason I initially zeroed in on Laser spokes is I have an Amazon credit and right now Laser spokes / packets of 20 are priced even cheaper than DT Comps. Sapin Laser are not available on Amazon. Crazy excuse I know... I do like the idea of doing a little something to save on weight a bit, but I certainly don't want something that is going to break spokes all the time. I don't mind if the wheels are a bit livelier vs super stiff...as long as I'm not breaking spokes all the time.

With that said, do you think I'd be able to get by with Lasers with a 32h 3x build? Again, cross will be at most 2-3 races a year...most of this will be 32 mile commutes through the countryside to work, not alot of city stop and go.

Again, I sincerely appreciate anyone lending their hard-earned experience here!

[Wayne77]

Update:

So after a bunch more research...and listening to the sage advice here from oldpotatoe and others, I think I've settled on a build that is a good compromise:

WTB Frequency i19 rims 3X/32H, wheelsmith DB14 spokes - should come in around 1720 gr. The WTB rims are 23mm wide, 30gr lighter than the Velocity Aileron rims, and most reviewers state the finish is very nice, easy to build up. I've heard good reports of the Velocity Aileron too, so not sure how they would compare.

Hopefully this will be a good, durable wheelset for commuting and for cross. I've read a few scattered reports of WS spoke issues, but plenty more reports from builders who think they're fine. A bit lighter than DT Comps (butted secion is 1.7), but hopefully stiffer than DT Rev or Sapim Race.

[oldpotatoe]

Thanks - very helpful. I wisened up a bit and changed my order to 32 hole hubs...(since these are disc wheels)

I'll do the classic build, 32h / 3x all around. This bike will be mostly used for commuting, with the occassional cross race. I'm completely new to cross and by no means a watt-monster, so hopefully this configuration will be adequate.

The reason I initially zeroed in on Laser spokes is I have an Amazon credit and right now Laser spokes / packets of 20 are priced even cheaper than DT Comps. Sapin Laser are not available on Amazon. Crazy excuse I know... I do like the idea of doing a little something to save on weight a bit, but I certainly don't want something that is going to break spokes all the time. I don't mind if the wheels are a bit livelier vs super stiff...as long as I'm not breaking spokes all the time.

With that said, do you think I'd be able to get by with Lasers with a 32h 3x build? Again, cross will be at most 2-3 races a year...most of this will be 32 mile commutes through the countryside to work, not alot of city stop and go.

Again, I sincerely appreciate anyone lending their hard-earned experience here!

I would not recommend Lasers or DT Revs for disc wheels..just not a good idea in terms of reliability.

For above, WS spokes are fine, the 2/1.7/2mm version. But they won't be stiffer than Comps or Race..probably won't be able to tell any difference.

[Mark McM]

I would not recommend Lasers or DT Revs for disc wheels..just not a good idea in terms of reliability.

Why? Sapim Laser and DT Revolution spokes are only thinner in the middle - they are the same thickness (and strength) at the ends as other spokes. Disc brakes add torque loads to wheels, but spokes don't fail due to torque loads.

[oldpotatoe]

Why? Sapim Laser and DT Revolution spokes are only thinner in the middle - they are the same thickness (and strength) at the ends as other spokes. Disc brakes add torque loads to wheels, but spokes don't fail due to torque loads.

I never mentioned spokes breaking but how stiff the 2 wheels would be all else being equal.

Since they are thinner in the middle, they don't support the rim as well as 14/15, 1.8mm center. More flexible at same tension.

[krismac23]

2x both sides. PT hubs have the same 57mm flange diameter. I had a customer who once wanted a 28h 3x/2x wheel. The 3x pulled the spoke over the spoke head, not a good idea. and 28h 2x gives you a better bracing angle. Not by much, admittedly but it does give a better bracing angle.

Only reason for 3x on a 28h is if you wanted the better torque transfer. I do a lot of 28h 3x/R builds for road wheels that are Alu rimmed. 28h carbon usually get's the 2x/2x treatment or the 3x/2x depending on flange height.


I am taking the plunge and building some wheels. I have 28h disc hubs (left flange 58mm, right flange 49mm on the rear hub) , Velocity Aileron rims, which are about 27mm deep. I was planning on 2x all around, but then got to thinking that I might be better off doing 3x on the drive side. I also heard that 2x is best on a 28h hub...something to do with the bracing angle.

What do you think? 2x or 3x on the drive side? (FWIW, I am 180 lbs)

[Wayne77]

2x both sides. PT hubs have the same 57mm flange diameter. I had a customer who once wanted a 28h 3x/2x wheel. The 3x pulled the spoke over the spoke head, not a good idea. and 28h 2x gives you a better bracing angle. Not by much, admittedly but it does give a better bracing angle.

Only reason for 3x on a 28h is if you wanted the better torque transfer. I do a lot of 28h 3x/R builds for road wheels that are Alu rimmed. 28h carbon usually get's the 2x/2x treatment or the 3x/2x depending on flange height.

Per a suggestion earlier in this thread pulling spokes heads out would rememdy the spoke over spoke head issue, no? BTW, this makes me sound even more novice than I already do, but can someone explain bracing angle to me? why is a better bracing angle...better?

[oldpotatoe]

2x both sides. PT hubs have the same 57mm flange diameter. I had a customer who once wanted a 28h 3x/2x wheel. The 3x pulled the spoke over the spoke head, not a good idea. and 28h 2x gives you a better bracing angle. Not by much, admittedly but it does give a better bracing angle.

Only reason for 3x on a 28h is if you wanted the better torque transfer. I do a lot of 28h 3x/R builds for road wheels that are Alu rimmed. 28h carbon usually get's the 2x/2x treatment or the 3x/2x depending on flange height.

Are the latest PT hubs 57mm, the ones I have seen are 70mm(?)...

My determining factor is spoke over adjacent spoke head also but if it's not, 3 cross for 28h, inside pulling, is a better idea, IMHO.

[Mark McM]

I never mentioned spokes breaking but how stiff the 2 wheels would be all else being equal.

Since they are thinner in the middle, they don't support the rim as well as 14/15, 1.8mm center. More flexible at same tension.

While that is all true, how is this different for disc brake wheels? For a wheel with fewer spokes, thinner spokes may indeed make the wheel too flexible. But for a wheel with many spokes, the sheer number of spokes can make up for the flexibility of each individual spokes - whether or not it uses a disc brake.

[oldpotatoe]

While that is all true, how is this different for disc brake wheels? For a wheel with fewer spokes, thinner spokes may indeed make the wheel too flexible. But for a wheel with many spokes, the sheer number of spokes can make up for the flexibility of each individual spokes - whether or not it uses a disc brake.

Right...so I wouldn't use thin spokes on a disc wheel. I mentioned, 'all things being equal'...32 spokes...32 isn't 'many spokes'..40h is

[Mark McM]

Right...so I wouldn't use thin spokes on a disc wheel. I mentioned, 'all things being equal'...32 spokes...32 isn't 'many spokes'..40h is

I think you misunderstood. All other things being equal, it doesn't matter whether it is a disc brake wheel or not. If you believe otherwise, please state why.

The number of spokes that are 'many' is dependent on a lot of factors. For example, I recently built up a wheel with an 80mm deep carbon rim on a high flange hub (the spokes were only about 220 mm long). Even with CX-ray spokes (same stiffness as Laser spokes), with 24 spokes it was still a very stiff wheel. With an Open Pro rim, 32 spokes is might be 'many' for a hub with wide flange spacing and a smaller rider. For a narrower spaced hub and a larger rider, 32 spokes might not be 'many' for the Open Pro.

[oldpotatoe]

I think you misunderstood. All other things being equal, it doesn't matter whether it is a disc brake wheel or not. If you believe otherwise, please state why.

The number of spokes that are 'many' is dependent on a lot of factors. For example, I recently built up a wheel with an 80mm deep carbon rim on a high flange hub (the spokes were only about 220 mm long). Even with CX-ray spokes (same stiffness as Laser spokes), with 24 spokes it was still a very stiff wheel. With an Open Pro rim, 32 spokes is might be 'many' for a hub with wide flange spacing and a smaller rider. For a narrower spaced hub and a larger rider, 32 spokes might not be 'many' for the Open Pro.

So you are saying the stresses on a rim brake wheel and disc brake wheel are the same?

I'd say the 80mm carbon rim and 220mm spokes may be why it's 'stiff'.

[Mark McM]

So you are saying the stresses on a rim brake wheel and disc brake wheel are the same?

Well, similar magnitudes, anyway.

Let's start with the assumption that both front and rear wheels used crossed lacing. If you take a read through Jobst Brandt's book The Bicycle Wheel (poehali.net/attach/Bicycle_Wheel_-_Jobst_Brandt.pdf), it shows that stresses due to torque loads are small compared to stresses from radial (weight bearing) loads:

EFFECTS OF TORSIONAL LOADS
Pedaling causes nonuniform torque that varies during the pedal stroke and with rider effort. A hub brake, on the other hand, produces uniform torque, but its torque still causes dynamic changes as the wheel rolls. For a small-flange hub, torque from strong pedaling or braking causes tension changes as large as plus and minus 5 %. This is about the same as the effect of tire pressure, except that torque is a dynamic load and tire pressure is static.

The reason that torque loads produce relatively small stresses is simple - torque loads are distributed amongst all the spokes, whereas radial loads are concentrated on a small number of spokes near the LAZ (Load Affected Zone).

It is interesting to note, that with small gears and high pedaling pulses, drive torque can actually match the largest torques from braking. Afterall, popping a wheelie (lifting the front wheel off the ground) using just pedal force produces a similar torque as doing a stoppie (lifting the rear wheel off the ground) from braking.

So, stresses due to disc brake torque are a consideration, but they are only small consideration.

I'd say the 80mm carbon rim and 220mm spokes may be why it's 'stiff'.

Exactly. Rim stiffness and flange spacing play a major role in selecting the number and thickness of the spokes. There is no single number or thickness of spokes that is 'correct' for all wheels.

[oldpotatoe]

Well, similar magnitudes, anyway.

Let's start with the assumption that both front and rear wheels used crossed lacing. If you take a read through Jobst Brandt's book The Bicycle Wheel (poehali.net/attach/Bicycle_Wheel_-_Jobst_Brandt.pdf), it shows that stresses due to torque loads are small compared to stresses from radial (weight bearing) loads:



The reason that torque loads produce relatively small stresses is simple - torque loads are distributed amongst all the spokes, whereas radial loads are concentrated on a small number of spokes near the LAZ (Load Affected Zone).

It is interesting to note, that with small gears and high pedaling pulses, drive torque can actually match the largest torques from braking. Afterall, popping a wheelie (lifting the front wheel off the ground) using just pedal force produces a similar torque as doing a stoppie (lifting the rear wheel off the ground) from braking.

So, stresses due to disc brake torque are a consideration, but they are only small consideration.



Exactly. Rim stiffness and flange spacing play a major role in selecting the number and thickness of the spokes. There is no single number or thickness of spokes that is 'correct' for all wheels.



Except revs or lasers on disc wheels is dum....