How is it even possible to build wheels like this?
 

I decided to pick up a new set of rain wheels and got some Alex Race cheap. When I noticed a noise while climbing in my lowest gear, I thought I'd bent my RD since I recently dropped the bike. Turned out one of the spokes was loose -- like finger tight type of loose.. Just for the heck of it, I checked the tension on the other spokes -- I don't think there were any two that were the same tension. How did they even manage that?

Curiously, the wheels seem to ride fine, but I haven't run them through the ringer yet. Still, I won't be crying when I wear these out...

Use a wheel building machine that is set to tighten only until a certain trueness is sensed. Do not stress relieve. Done.

No harm done if you have them retensioned, stress relieved and trued now before you fatigue them any more. They will last you a long time if you take care of the problem now. Otherwise you will never trust them to get you home.

i would, or have my LBS, loosen all the spokes and tighten uniformly (both wheels) and soon. i'm assuming the rim is true sans spokes.

Could have missed the final steps. The usual process (human or machine) is to string and set initial tension, then stress the spokes and do final tension and true. If it missed the stress/tension/true steps, that could explain your findings.

If the rim is stiff enough laterally, you can get a lot of creative spoke tension patterns. They'll all equal out to a "true" wheel, but if you were to measure the strain on the rim, it'd be an irregular wavy pattern. You know how if you break a spoke you can release the tension opposite and increase the tension on that spoke's neighbors to compensate? Same thing, but in spades and across the entire wheel. Also, because rims tend to be high profile these days (as opposed to a low profile box), the rims are extremely stiff in the radial direction, meaning the rim can absorb wildly differing radial spoke tensions and not really show roundness variations when put to a truing stand.

Don't just even out the tensions to fix. You'll go out of your mind chasing a moving target. De-tension the entire wheel and rebuild the tension all the way around from scratch.

I have seen machine built wheels de-tension themselves as soon as the tyre was installed and inflated... it sounds like someone running their fingers across a harp as they all lose tension because of wind up in the spoke that was not relieved.

Pre-built wheels can be a good deal as the sum of the parts is often less than what you have to pay for them singly... but they need to be checked.

For a while I would get wheelsets off of Performance that had Ultegra hubs and Open Pro rims for $200/set. I'd get them, retension them, and they'd be as good as a hand-built.

Then they raised their prices...

I hope you will permit me to correct a couple of misconceptions you exhibited in your post. First spoke unwinding is a serious problem, but it is not because it significantly loosens spokes. In most cases unwinding won't even be as much as a quarter turn, and that is hardly enough to noticeably loosen spokes. What it does is throw the wheel out of true. Still serious, but a different thing altogether.

Second, stress relieving spokes is a different process than releasing the windup in them. Both processes are important, but they are different. Stress relieving is done by squeezing pairs of partially tensioned spokes together to raise the micro areas of high stress above the yield point. Releasing spoke windup is done by compressing the rim in a fully tensioned wheel (in several steps around the rim) to temporarily loosen the spokes so they can unwind. When the rim is released, the spoke are pulled taut again. Then a final round of truing/tension adjustment and checking is required.

I mention this as it is important for novice wheel builders to keep these things straight. More information about it can be found by Googling "Sheldon Brown Jobst Brandt stress relieving"

If one spoke is wound up it will knock the wheel out of true... when 36 of them do this on a wheel that was probably under-tensioned to boot the effect is more significant.

These were on pre-built wheels that I had not checked... simply inflating the tyre caused them to become de-tensioned to a point where they would have tacoed under a rider.

When I build wheels I always do a final true and stress relieving with the tyres mounted and inflated... I have yet to have a wheel fail because of a build issue.

...careful with that. That's not 100% true. Also - many people other than Sheldon (RIP) and Jobst build wheels...well... I tend to find that stress relieving fully is one of the factors that has always set my wheel builds apart from every single other build we have ever come across. It's more than just the spoke.

You'd be amazed at how much windup is stored in some spokes in wheels that were machine built and never fully stress relieved...and yes stress relieving fully will release spoke windup.

You're more than welcome to send a wheel you've built to me at any time. I won't touch it other than to stress relieve it fully and return it to you. You'll think FedEx dropped it off a cliff.

I hear you, but I suspect most of the problem was the original under-tensioning. Even every spoke unwinding 1/4 turn would only reduce the average tension by what, 5-10 kgF? You would have to be right on the edge of loose (especially on the NDS) for that to matter. Wheels like you describe are rarely built with windup prone Revolutions or Lasers which are saved for the primo builds. I can't see a heavier gauge spoke winding up more than 1/4 turn.

Ever driven a spoke with a power tool?

http://www.bikeforums.net/showthread...e-I-want-this!

The thing that I find scary about this is that these wheels began as the stock wheels from someone's bike. I would logically infer that means a lot of people buy brand new bikes that have wheels like this...

Yup. That's what lead into the "new wheels are the best upgrade you can make....." stuff. Yes, the new wheels will almost undoubtedly be lighter and maybe more aero. But all the original wheels may have needed was somebody giving them a hand finish with full release and they would have been fine for many miles.









Get your mind out of the gutter.

You just made me like wheel building more...

It's always good to enjoy ones work, I always say.

[QUOTE=Psimet2001;16506509]Ever driven a spoke with a power tool?

QUOTE]

Nope. Interesting video. Thanks. Is the robot not capable of over-turning the wrench and backing off to limit (not eliminate completely perhaps) windup? Do you routinely see more than 1/4 turn of windup of a spoke in a machine-built wheel? On every spoke? With substantial spokes? Just wondering.

umn... Am I understanding correctly that the "grasp spoke pairs firmly"- method is not sufficient? what does it even mean to fully stress relieve?

Before we go any further, are you a cop?

Here is the problem. I don't doubt that you have procedures which produce a superior wheel, and that they may be other manipulations besides squeezing pairs of spokes and compressing the rim. I don't doubt they accomplish stress relieving (of the micro stresses in the spokes) as well as allowing or forcing the spokes to unwind. Maybe you relieve other kinds of stresses as well. And seat the nipples and spoke bends in a better way. You are choosing to call a wheel treated with the compendium of procedures you use as "fully stress relieved". But I think you have hijacked the term "stress relieved" and applied to all of the things you do which are actually true stress relieving as well as other things. No doubt they are beneficial, even necessary, but you can't just properly call something what it isn't.

My statement that you say isn't 100% true (what IS 100% true) adheres to the terminology used by the referenced authorities on the subject. And I think it helps the inexperienced builders to understand the several different manipulations which will be required to produce a good wheel so that they are not thinking they are doing one thing when they are really doing another. That is all I am trying to accomplish.

Correct.

If you simply squeeze together adjacent spokes you will leave the wheel assembly with residual internal stresses. These stresses will "spring" or allow the wheel to change (rim change position, spoke(s) change tension) once large loading forces are applied to the wheel in use.

Sheldon was a good guy. Very knowledgeable.

Jobst did a really poor job (IMHO) of handling the subject back when everything was a weak, low tension carrying box section rim and 32 or 36 spokes. Indeed he didn't believe in stress relieving and believed if it had any merit at all it was solely to overcome localized grain boundary stresses in the stainless steel of the spoke induced from tensioning. In that regard he saw little to no need for it.

IMHO - Gerd Schraner is WAYYYYY more competent and more of what I would consider to be a subject matter expert. All that being said I have been in talks to bring the wheel building books of our forefathers into the modern era. In that regard I do consider myself to be a subject matter expert.

If you build your own wheels and have your own techniques and have been happy with the outcome then what does it matter.

Just built my first wheel with CX-Ray spokes. I thought using the special gadget to hold the spoke while tightening the nipple was very cool. Then I thought, why not lay a set of round spokes down in a fixture and paint a line down one side of all them?

You don't need to paint them. You can just put little flags made out of masking tape all pointing the same way on the round spokes, either parallel to the rim or perpendicular to it. You will see clearly when the spoke winds up. When the wheel is finished, just remove the tape.

Wow, that video is impresive but more impresive is the brain of the man who built it !! I wish my little brain could do something like that!!