Bicycle Mechanics - Truing Wheels (Confusing Info)

I scored a nice used Park Tool TS-2 Truing Stand off Craigslist for a really great price. I am not a professional mechanic, but I am trying to be in a position to be totally independent of my LBS regarding service/maintenance.

The issue is this: When truing wheels, should one ever decrease spoke tension when fine-tuning true?

I ask because I have seen confusing information. I read, I think in Park's Blue Book that "newbies" should not attempt to decrease spoke tension to achieve trueness. That is to say, if your wheel is pulling to the left, just tighten spoke(s) leading to the right hub flange at the deviation center. I have seen contrary info that says to tighten on the right, but loosen opposite side spoke(s) by same amount of movement.

Which is recommended by experienced mechanics?

Thanks.

When truing wheels, should one ever decrease spoke tension when fine-tuning true?

Yes.
You should check the relative tension of the spokes in the area. If one at or near the area feels tighter, try loosening it. If it doesn't help, you can always tighten it again if you mark it & remember how much you loosened it (1/4 turn, 1/2 turn, e.g.).

Yes, decreasing tension is as important as increasing tension, and you should use either or both together depending on the situation.

Think of right spokes as pulling down and to the right, and left as pulling down and to the left.

If you have a longish area of the rim, spanning several spokes, displaced to the right and bring it to the left only by tightening left spokes, you'll also move it inward creating a low area. So to maintain concentricity, you'll tighten left to move it down and left, and loosen right for up and left, solving the wobble without creating a low spot.

There are other considerations such as working toward even tension. With practice, you'll develop feel and instinct, but limiting yourself to only tightening will limit your ability to align wheels effectively.

A broken spoke will increase the tension on adjacent spokes. Replacing the broken spoke may relieve some of this tension but it may not relieve it all.
I ping the spokes and try to come to a compromise between tension and trueness.

Repairing a wheel is invariably a messier process than building from new with all new components.

The only things I would add to this:

1. Get a tensiometer. It is debatable whether pinging spokes and going by "feel" are really accurate enough; it might be ok for an experienced mechanic but for a newbie you should learn to use a tensiometer. For more info: http://en.wikipedia.org/wiki/Just-noticeable_difference
2. Less is more. The amount of turn of the spoke wrench is probably less than you think. I spent a lot of time initially learning to true, turning the nipples far too much -- whole and half turns -- when really 1/4 and 1/8 were what was required. I wasted a lot of time and pulled out a lot of hair pulling the rim back and forth with a too-heavy-hand.
3. Get a tensiometer.
4. Worry about spoke wind-up. Especially when you're getting the spokes up into the higher tensions they need, wind-up becomes more of a factor and something you need to be concerned about. Spend some time putting stickers, pieces of tape, paper clips, whatever on the spokes when you turn the nipples to illustrate to yourself how much wind-up occurs. It is surprising, and it also teaches you how much relief (turning the wrench back) is required. Eg. Sometimes if a 1/8 turn is needed, you have about a 1/2 turn of just wind up before the nipple actually moves up the spoke threads. Then you have to turn back 1/2 to relieve that wind-up. So you tighten 5/8 of a turn and relieve 4/8 turn.

After you have some more experience, you'll find that when you're making final fine-tuning adjustments, you may not need to loosen the opposite spokes. This is after you've gotten the wheel mostly true, and you've gotten all of the spokes within 1-2 points of each other on the tensiometer, and you're making the final very small adjustments of like 1/16 turns, yes, in that case you can probably skip loosening opposite spokes.

A broken spoke will increase the tension on adjacent spokes.

Well to be more accurate it will increase tension on the spokes that are on the same side as the broken one and will decrease tension on the opposite side.

Well to be more accurate it will increase tension on the spokes that are on the same side as the broken one and will decrease tension on the opposite side.

If we're going to insist on accuracy on the forum, we might as well complete the thought. A broken spoke has an effect on it's neighbors (either side) only if the break results in a deflection in the rim. If the rim doesn't move, the lengths of the neighboring spoke are unchanged, and therefore the tension is unchanged.

Usually a broken spoke will cause a change in the alignment, creating hop or wobble. Spokes that the rim moves toward have lowered tension, those the rim moves from have raised tension. The exact effect depends on the radial and lateral rigidity of the rim.

I understand what Park Tool is saying, but like others have said its not really a great rule of thumb to go by. In general, factory wheels that need a real quick true is best done by tightening spokes where the rim hits the caliper. But if the reason for the wobble in the rim is because of 1 specific spoke being tighter than the rest, and loosening that spoke is the most straightforward way to fix the problem, then loosening that specific spoke is definitely better than tightening up a bunch of others.


There are other considerations such as working toward even tension. With practice, you'll develop feel and instinct, but limiting yourself to only tightening will limit your ability to align wheels effectively.

+1. As you continue to true wheels you will build up intuition as to the reason for alignment problems in the wheel. It can be frustrating and infuriating at first but defintely becomes easier over time.

This is great information for a someone like me, I've never advanced beyond a brake pad true-adjustment.

Thanks.

This is great information for a someone like me, I've never advanced beyond a brake pad true-adjustment.

Thanks.

The best advice I can give you is to take it slow, and preferably work on front wheels first. As another person said, you'll be working in partial turns of usually 1/4-1/2 turns of a nipple at a time. It's better to work toward alignment by degrees doing the worst first then slowly bringing the whole wheel into alignment, rather than trying to bring each area to the center as you go along.

If you can find a junk wheel someplace that's better to get your first licks in with, rather than mugging your own wheels.

FBinNY (http://www.bikeforums.net/member.php/158672-FBinNY)

...thanks, I'll give it a shot. I have quite a few old wheels ...desperate they are for a quality truing.

All of this brings up a question I've had for some time. Can a flat spot be repaired, just by tensioning the spokes properly?

All of this brings up a question I've had for some time. Can a flat spot be repaired, just by tensioning the spokes properly?

If it was caused by impact - no, of course, as the spokes cannot push it back out. If caused by improper truing it's quite possible to fix by detemsoning the area, tensioning the rest of the wheel - focusing 1st on high spots and then evening the entire wheel tension.

All of this brings up a question I've had for some time. Can a flat spot be repaired, just by tensioning the spokes properly?

Simple answer is it depends. Pushing out flat spots in rims is like popping them out in cans by squeezing the sides. A long shallow flat spot will come up if you relax the spokes and let the comparatively greater tension of the rest of the rim push it out. Then you'll complete the alignment getting the tension as even as possible. More local flat spots require greater differentials of tension to overcome the distortion in the rim, and the stronger the rim, the harder it becomes, often impossible.

Back when we built light wheels with rims like Fiamme yellow label, or some Super Champions you could align just about anything because the rim offered so little resistance. Today's rims are much more rigid, making wheelbuilding easier if they're straight and round, but also making it much harder to correct local bends of any kind.

If we're going to insist on accuracy on the forum, we might as well complete the thought. A broken spoke has an effect on it's neighbors (either side) only if the break results in a deflection in the rim. If the rim doesn't move, the lengths of the neighboring spoke are unchanged, and therefore the tension is unchanged.

Usually a broken spoke will cause a change in the alignment, creating hop or wobble. Spokes that the rim moves toward have lowered tension, those the rim moves from have raised tension. The exact effect depends on the radial and lateral rigidity of the rim.


OK, FB - I think you're taking things a bit too far and yet not far enough. The only way for a broken spoke to not cause a deflection or a change in the tension of other spokes is for it to have no tension when it breaks. If it has any tension at all that tension has to be distributed among the remaining spokes. As the rim is elastic (in a physics sense) I would assume the overall tension would go down, so very few spokes would increase in tension.

OK, FB - I think you're taking things a bit too far and yet not far enough. The only way for a broken spoke to not cause a deflection or a change in the tension of other spokes is for it to have no tension when it breaks. If it has any tension at all that tension has to be distributed among the remaining spokes. As the rim is elastic (in a physics sense) I would assume the overall tension would go down, so very few spokes would increase in tension.

I agree with you but I think you missed my point. With rims that have high lateral rigidity compared with radial rigidity, and on tight high spoke wheels, a broken spoke will often cause more hop than wobble, that means that spokes on both the left and right see increased tension.

BTW-Bikeman, I wouldn't have split hairs this way, but it was coming from you and you prefaced the post with "well to be more accurate". I consider you a knowledgeable credible source, so I hold you to a higher standard and responded to what I would have ignored from other people.

All of this brings up a question I've had for some time. Can a flat spot be repaired, just by tensioning the spokes properly?


If it was caused by impact - no, of course, as the spokes cannot push it back out. If caused by improper truing it's quite possible to fix by detemsoning the area, tensioning the rest of the wheel - focusing 1st on high spots and then evening the entire wheel tension.


Simple answer is it depends. Pushing out flat spots in rims is like popping them out in cans by squeezing the sides. A long shallow flat spot will come up if you relax the spokes and let the comparatively greater tension of the rest of the rim push it out. Then you'll complete the alignment getting the tension as even as possible. More local flat spots require greater differentials of tension to overcome the distortion in the rim, and the stronger the rim, the harder it becomes, often impossible.

Back when we built light wheels with rims like Fiamme yellow label, or some Super Champions you could align just about anything because the rim offered so little resistance. Today's rims are much more rigid, making wheelbuilding easier if they're straight and round, but also making it much harder to correct local bends of any kind.

I've heard one (very) experienced wheelbuilder say that he's given up trying to bring already-built wheels back into round. Even if he is building up a wheel and in the phase where he is increasing spoke tension and doing his first checks to make sure it is in round and it is not, he will just start over.

He told me basically "I know it should work; there are even formulas for how much tightening and loosening each spoke should get depending on how close they are to the out-of-round spot, and that you should be able to tighten the spokes on one side and loosen on the other and change the concentricity, and I've been trying to get it to work for years, but it just doesn't work"

Not saying he was right or wrong, but that's his take on it.

I've heard one (very) experienced wheelbuilder say that he's given up trying to bring already-built wheels back into round. Even if he is building up a wheel and in the phase where he is increasing spoke tension and doing his first checks to make sure it is in round and it is not, he will just start over.

He told me basically "I know it should work; there are even formulas for how much tightening and loosening each spoke should get depending on how close they are to the out-of-round spot, and that you should be able to tighten the spokes on one side and loosen on the other and change the concentricity, and I've been trying to get it to work for years, but it just doesn't work"

Not saying he was right or wrong, but that's his take on it.

I don't know about the very experienced, but it's doable and on repairs more a matter of what's achievable and what's acceptable. Aligning is usually harder than building, no matter the problem, because there's history, and local bends in the rim vs, a theoretically round new rim.

Concentricity is very easy to manage on a new build if you use a methodology that doesn't introduce errors. But remember that there's always some variation in spoke lengths and rim eyelets, so even if you've done a masterful job of counting turns, and doing everything uniformly, you'll still have to do some compensating for the natural variation. If done early on it's easy and fast, then it's only a matter of maintaining concentricity as you go along.

I think that most of the better wheelbuilders will tell you that the actual process of building and aligning wheels is something they do using the brains in their fingers not the brain in their head.

The only things I would add to this:
1. Get a tensiometer. It is debatable whether pinging spokes and going by "feel" are really accurate enough


Plucking spokes is plenty accurate for achieving relative tension. The Jobst Brandt method of achieving correct absolute tension works for box section rims with reasonable spoke counts. For deep section rims or unreasonable spoke counts the $50 Park tension meter is a fine idea (feel at a given tension varies too much depending on lubrication, nipple condition, and spoke thread diameter) because you'll have fatigue problems with the spoke bed before reaching the rim's elastic limit.

I got a Park meter before my last wheel rebuild since that's a faster path to correct absolute tension than the Jobst Brandt method of increasing tension and stress relieving until the elastic limit is reached (after which you back off half a turn) and I don't own any identical wheels I could compare.

The first front wheel I built stayed true for 12-14 years until I bent it. The bend took 136 and 75kgf on the adjacent spokes to make it ridable, but otherwise the wheel ranged from 104 - 120kgf or +9/-5% without a tire.

The last rear wheel built without a tension meter has been true since then (I think it got rebuilt when I crashed ~5 years ago) and measures 110kgf average +/- 5% on the drive side with a tire installed.

The new front wheel measured better when it left the truing stand but couldn't do a better job staying true.

I almost think they could have just as well said not to tighten any spokes, only loosen. I would feel handicapped either way.

Are there any other experienced wheelbuilders that can't true a wheel using the brake shoes?

Are there any other experienced wheelbuilders that can't true a wheel using the brake shoes?

I find it much easier with a spoke wrench. But yes, I agree. Tools help, but skill, and the judgment born of experience trump lots of tools. If buying the right tools makes you a good mechanic, then we'd all be able to fix anything simply by making an appropriate purchase.

I almost think they could have just as well said not to tighten any spokes, only loosen. I would feel handicapped either way.

Are there any other experienced wheelbuilders that can't true a wheel using the brake shoes?

The brake shoes work well enough, but sitting at the kitchen table with a truing stand five feet from my beer fridge is a lot more pleasant than doing it standing in the garage. Especially when I'm going to park my butt there long enough to build a wheel (long enough to drain my Masskrug which holds a full liter of ale).

I'm noticing a pattern here;
I never see Drew talking about wheelbuilding w/o mentioning beer.:D

I'm noticing a pattern here;
I never see Drew talking about wheelbuilding w/o mentioning beer.:D

Wheel building requires proper lubrication and while anti-seize works great on the wheel it's not the best thing for the builder.

I think that most of the better wheelbuilders will tell you that the actual process of building and aligning wheels is something they do using the brains in their fingers not the brain in their head. Quoth FBinNY

Boy, is that ever true! I used to build wheels for a living. Never used any measuring tools then or now. This winter, after 35 years of doing little more to wheels than touching up the true or replacing a broken spoke, I built up a pair. It was a good thing I didn't have to rely on my brain which, like a sponge, is both absorbent and porous. My hands, though, knew exactly what to do.

Practicing on unimportant wheels is good advice, provided the rims are straight and the nipples aren't frozen. Try loosening all the spokes first, then tighten & true.

As far as using a truing stand vs a bike, a good stand makes it a little easier, but has no effect on the quality of the job. The only tool absolutely required is a spoke wrench. And if you are a very careful masochist, you can even forget that and use a good adjustable wrench instead. But you shouldn't.

Wheel building (& truing) is not an art. It is a skill which is learned through repetition. Kind of like riding a bike...

Thanks for all responses.

Is it proper to assume that what Park Tool was recommending for newbies is reasonable vis-a-vis factory-built wheels? That is to say, the wheels are gonna come from the factory with almost equal and/or acceptable relative tension all around, and if the wheel goes out of true, it's b/cos a/some spoke(s) got unwound from their proper tension due to some impact.Then the job at hand is to find that wayward spoke(s) and tighten.

Reasonable assumption? Or the wrong way to think about this?

By the way, my wheels are Shimano C50 Clinchers and Mavic SSC and ES. And I am assuming these kinda wheels - given their provenance- come with almost perfect tension from these reputable manufacturers.

No?

No, factory machine built wheels often have very uneven and insufficient spoke tension. Some of the "high end" expensive wheels are OK, best bet is custom hand built wheels.

Can anyone confirm this advice from the Park Tool book? It sounds like terrible advice for any number of reasons.

The only advantage I can think of is that machine built wheels are often built with too little tension (or the tension drops when ridden due to insufficient stess relief), but just about the worst thing I can think of is to try to 'fix' and under-tensioned wheel by tightening up just a few spokes without regard to the overall tension.

Can anyone confirm this advice from the Park Tool book? It sounds like terrible advice for any number of reasons.

My copy of the Park Tool USA book says on PP54, CH. 4-1.1, under "Lateral Truing" "Tightening or loosening spokes at a section of rim can change lateral movements of the rim. However, inexperienced mechanics should generally tighten nipples when correcting deviations. Tightening the spoke tension will typically produce more rim movement while making these corrections."

While that statement does not appear to be sweeping, it is what I referred to in my original post. I think the statement was aimed at the possibility of a "newbie/inexperienced" mechanic making matters worse by loosening spokes without the aid of a tensiometer to ascertain that the spoke being loosened had lost some tension from where it was supposed to be.