spoke tension question

[bitt3n]

How do I know what spoke tension I should be aiming for if I'm using a HED Belgium Plus Rim and Sapim Race round 1.8mm spokes?

I managed to get my wheels dished and trued to within about a 0.25 mm both horizontally and vertically but I think the spoke tension is way too high at 170 KGF on the drive side and 100 KGF on the disc side on the rear wheel and 150 KGF disc and 100 KGF non-disc side for the front (according to the Park TM-1 and Park Wheel-Truing App).

Also there's considerable variation between the tensions of spokes on the same side of the same wheel, which I imagine is a sign of incompetent wheel building.. It looks like I need to get them within 20% of one another?

[ergott]

Too high. Use 120 drive side (left is whatever it is to get rim centered) and 100-110 front.

Make sure you are consistent with how you use the Park tensiometer. I'd try to keep all the spokes closer to 5-10% variation.

[bitt3n]

Originally Posted by ergott

Too high. Use 120 drive side (left is whatever it is to get rim centered) and 100-110 front.

Make sure you are consistent with how you use the Park tensiometer. I'd try to keep all the spokes closer to 5-10% variation.

10% seems rather close to the tolerance of the TM-1 tensiometer. For my spokes, a reading of 22 corresponds to 117 KGF and 23 corresponds to 131 KGF, which is roughly 12% more. I guess I'll try to keep all the drive-side spokes between 22 and 23.

In retrospect I guess I should have built my wheels by slightly tensioning all the spokes, then tensioning the drive-side to ~120 KGF while adjusting the non-drive side so that the wheel stays true/dished. Is that more or less the way you do it?

[classtimesailer]

Yes. Round and round we go. Little by little. Checking dish and trueness along the way. And then all is good. I'm not a pro but it seems to me that plucking spokes is a credible guide to even tension and works as well as my TM-1.
Roger Musson's ebook is highly recommended.

[foo_fighter]

I'm a bit surprised you were able to get upto 170Kgf. Brass nipples and good 3 sided spoke wrench?

[sales guy]

If you went high tension and did it quickly and not gradually on both sides, you could've broken the backbone of the rim. If that happens, they'll never stay straight or tensioned.

You need to bring the tensions up gradually on both sides at the same time. It makes it easier to dish and keep the hops and flat spots minimal if any(until you do those specifically) and it also keeps the rim from warping.

We had someone at AMC who would just jack the tension up and his wheels never held. They would always come back for rebuilds. We tasked him to do 10 wheels once for a bike company for review to see about OEM use. Of the 10, 1 was spot on, the other 9 were all off. Tensions. Up and down, side to side. He actually told us he wanted to be paid to fix the problems. That he was paid to just build them. NOT to fix the problems. We were like ***??? He ended up getting let go and I had to redo all 10.

Slow and steady wins this race.

[bitt3n]

Originally Posted by foo_fighter

I'm a bit surprised you were able to get upto 170Kgf. Brass nipples and good 3 sided spoke wrench?

aluminum nipples lubricated with linseed oil and a cheap spoke wrench.

Originally Posted by sales guy

If you went high tension and did it quickly and not gradually on both sides, you could've broken the backbone of the rim. If that happens, they'll never stay straight or tensioned.

You need to bring the tensions up gradually on both sides at the same time.

I increased the tension only gradually over the course of truing/dishing but it appears I ought to have paid more attention to how much tension I was applying. My tension was way to high and there was way too much variation between the tension of different spokes.

I've seen a bunch of videos of people building wheels without using a tensiometer so I figured it wasn't that vital but Ergot's suggestion tells me that the tension needs to be attended to more carefully than I realized.

[R3awak3n]

the park tool apparently reads very conservatively so you probably did not have 170kgf on that wheel and why it didnt brake anything because that is a crap load of tension.

[oldpotatoe]

Originally Posted by bitt3n

aluminum nipples lubricated with linseed oil and a cheap spoke wrench.



I increased the tension only gradually over the course of truing/dishing but it appears I ought to have paid more attention to how much tension I was applying. My tension was way to high and there was way too much variation between the tension of different spokes.

I've seen a bunch of videos of people building wheels without using a tensiometer so I figured it wasn't that vital but Ergot's suggestion tells me that the tension needs to be attended to more carefully than I realized.

Agree with ERGOTT and altho the Park tool is a decent consumer tool, the Wheelsmith one is more accurate. People who use 'c above middle F' type stuff for wheels make me scratch my head. Or those who say their 'hands' can feel proper tension..the path to poor wheels, IMHO.

Proper and even tension, along with the other 3 variables being proper, at the same time=long lasting wheels.

[staggerwing]

Originally Posted by R3awak3n

the park tool apparently reads very conservatively so you probably did not have 170kgf on that wheel and why it didnt brake anything because that is a crap load of tension.

This is NOT what I found with my Park tension meter. Built a calibration fixture (dead weight/lever arm), and found it read 2-4% low over a variety of spokes, from 2.0mm straight gage, 1.8mm swaged, and aero bladed (CX ray) spokes.

Pretty darned good for a simple device.

Relative pitch can be useful for finding an outlier. However, I couldn't possibly tell what the proper pitch for a specific tension would be.

[ColonelJLloyd]

That's pretty damned high. If it were me I'd start over with new nipples.

[Hindmost]

Originally Posted by bitt3n

aluminum nipples lubricated with linseed oil and a cheap spoke wrench.

I am surprised the nipples didn't visibly deform.

[11.4]

For any particular rim there's a particular tension where everything settles in very nicely. Below that tension, you won't get consistent spoke tension; go much above that tension, and you'll have that problem again. When you reach the right tension you should be able to get about 3% variance or less per spoke, and I've seen people do better than that -- after stress relieving. That's the kind of consistency that leads to the longest-lived and most problem-free wheels.

While someone may say that there's an arbitrary tension to reach, you'll find that one rim may consistently have a certain optimal tension but it can be higher or lower than another rim. The Hed Belgium is an incredibly strong rim and not only is likely to true ideally at a slightly higher tension, but it also can explain why you didn't run into problems with excessive tension.

[bitt3n]

Originally Posted by 11.4

For any particular rim there's a particular tension where everything settles in very nicely. Below that tension, you won't get consistent spoke tension; go much above that tension, and you'll have that problem again. When you reach the right tension you should be able to get about 3% variance or less per spoke, and I've seen people do better than that -- after stress relieving. That's the kind of consistency that leads to the longest-lived and most problem-free wheels.

While someone may say that there's an arbitrary tension to reach, you'll find that one rim may consistently have a certain optimal tension but it can be higher or lower than another rim. The Hed Belgium is an incredibly strong rim and not only is likely to true ideally at a slightly higher tension, but it also can explain why you didn't run into problems with excessive tension.

Is there a good resource for getting the optimal spoke tension for a given rim? I tried searching for HED Belgium Plus and all I found was some guy on bikeforums claiming he read on some other guy's blog and it said the max acceptable spoke tension for this rim is 163 KGF..

[11.4]

Originally Posted by bitt3n

Is there a good resource for getting the optimal spoke tension for a given rim? I tried searching for HED Belgium Plus and all I found was some guy on bikeforums claiming he read on some other guy's blog and it said the max acceptable spoke tension for this rim is 163 KGF..

Not really. Individual lacing methods, choice of spokes, even different batches of spokes, can bring about differences.

Don't bother with BikeForums. Their information is so suspect as to be useless. And anyway, even an acceptable spoke tension of 163 kgf doesn't say much about how the rim will respond or what you actually did to the rim. These are brutally tough rims and about the best that you could have chosen to learn on.

You'll find that with most tensiometers, there can be 10% or even 20% inaccuracy in measurement. The better ones are at least consistent spoke to spoke. If you use the DT one, which is the most accurate and the most reproducible in my experience, you'll find that if you gradually up the tension as you get close, with repeated stress relievings, you'll find that after relieving you end up with scattered variances and then get to where you're bang on target on virtually every spoke. You may have a glitch in any rim that causes one spoke to be off a bit, but if it's just one spoke that measures low and the wheel is still round, try tightening that spoke up to match the tension of the others. The stress will distribute itself much more effectively when the rim is at the right tension, and that makes the wheel building much easier and also makes for a much better wheel.

It's important to stress relieve adequately. Most people don't begin to do so enough, which is why their wheels move a bit with use. I've heard people object to approaches that really mash the wheel but frankly, I've seen relieving improve the wheel and remove issues in just about every instance with modern rims. With a rim like the Belgium, in a reasonably dense spoking, I don't hesitate to lay it on its side and put some pressure on the spoke crossing to force a flexing. Or to use a 1" dowel to twist and flex the spokes significantly. We build hundreds of track wheels and I don't think we've ever had to retrue one, despite banking stresses, high tire pressures, the nature of the events themselves, and periodic crashes. I'd never do this with older style rims, but new style rims are designed to be self-supporting and don't rely on the spoking for stability. Ditto for most carbon rims.