Bike Forums - When to true wheel?

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When to true wheel?

I'm talking about lateral trueness here. I have a set of Hed Kermesse wheels. I actually have never checked their trueness in a year. I put the bike upside down and adjusted the brake pads in until I heard some rub and then adjusted them out just a bit. I used a feeler guage to measure the lateral out of true at the widest gap and it looks to be about .1-.2mm at the widest point. Should these brought in to the shop to get lateral runout to .00? I am annoyed I never checked these when new to have something to compare it to. These wheels have about 6000 miles on them.

.1-.2mm is nothing to worry about, and is commonly acceptable with brand new wheels if it allows the spoke tension to be more even. Peter White does a good job explaining this.

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How true will your wheel be?

That depends on how true the rim is. "WHAT?!?!?!?", you say!

Well, some rims are better than others. And the sad truth is, that in order to keep prices under control, some rim makers are not as particular about the straightness of their rims as they roll out of the factory as I would like them to be. When I build a wheel, I want to end up with a wheel that is round and true. It shouldn't have any perceptible hop or wobble, and the spoke tension should be the same for all of the spokes on each side of the wheel. Most rear wheels will have higher tension on the right side spokes than on the left side, that's normal. But a perfect wheel would have all of the right side spokes at exactly the same tension, and the same for the left side spokes.

But sometimes I can't get a wheel to be both round and true, and have perfectly even tension all around. That's because of irregularities in the rim itself. If the rim isn't perfectly round and/or true, the spoke tension cannot be even, and end up with a round and true wheel. In order to have a round and true wheel in that case, the spoke tension must be uneven. In that case, I have a decision to make. If the rim is so out of true that the wheel cannot be built with adequate tension in all of the spokes, I cut out the spokes, get another rim and start over again. But if the rim is just a little bit out, and I can correct it with moderately uneven spoke tension, I'll finish the wheel. As long as I can build it so it stays true, I'll do it. And it may end up with a slight vertical hop or dip, but not enough to notice while riding.

This is a compromise. But it is a necessary one, since not everybody can afford the best rims. And not everyone can afford to have a builder spend hours testing each rim from the factory and building and rebuilding the same wheel looking for the perfect inexpensive rim.

So how does all this shake out in practical terms? Top quality rims from Velocity and Mavic are generally perfectly round and true. The most I ever see is a slight vertical dip (1mm) at the joint on some of the Mavic rims, and an occasional hop at the joint of the Velocity Deep V. It rarely happens and it's almost never enough to affect the wheel in any way. Since they are expensive rims, my standards when building with them are very high. If there's a small defect, more than 1MM vertical deflection, I'll start the wheel over again with a new rim. But don't be surprised if when you look closely at the wheel while spinning it, there's up to 1m of vertical runout near the joint. You'll never feel that while riding.

But inexpensive rims from Sun have to be treated differently. Sun rims are remarkably strong, quite resistant to warping or denting. But Sun's quality control, frankly, leaves a bit to be desired. They often have crooked joints and slight warps right out of the box. But very often they will build up as perfectly as a Velocity or Mavic rim. And there's really no way of knowing before hand.

Where rims are concerned, you really do seem to get what you pay for.

But don't worry, if I can't guarantee it, I won't sell it.

So is this normal and leave it be?

Does it make a pulsating in your braking or a bumpy ride feeling? At 0.2mm I'd be shocked if it did and you'd have to change your screen name to PrincessAndThePea. Since it's a factory built wheel, it wouldn't hurt to have the spoke tension checked, but that may require your wheel to be more true or less true.

Really, it's not necessary to true a wheel until it starts rubbing something, but most of us are more anal than that. Having handbuilt wheels, I never have to true them unless I crash or hit something really hard.

1 mm is what I would expect from a new wheel or one that just came back from a mechanic. But, you can probably ride on as much as 5 mm and not notice it. So, 0.2 mm is nothing.

You might want to check radial run out too. Again, <1 mm is totally normal.

Also, this is just the nitpicky engineer in me, but I doubt you can measure the runout to that kind of precision by listening for rubbing and using a feeler gauge. Use a dial gauge if you really want to get a precise measurement. Of course, if the wheel is so close to true that you're even reaching for the feeler gauge to try to measure the runout, it's entirely within any sane spec and it's a purely academic exercise at that point.

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Originally Posted by urbanknight (Post 11461918)

.1-.2mm is nothing to worry about, and is commonly acceptable with brand new wheels if it allows the spoke tension to be more even. Peter White does a good job explaining this.

Thanks for the Peter White post, helps explain what I see when truing or building up my wheels. Agreed that .1-.2mm is well within the tolerance of metal in general and wheels specifically.

So I guess I can leave it be for now?

Quote:

Originally Posted by urbanknight (Post 11461987)

Does it make a pulsating in your braking or a bumpy ride feeling? At 0.2mm I'd be shocked if it did and you'd have to change your screen name to PrincessAndThePea. Since it's a factory built wheel, it wouldn't hurt to have the spoke tension checked, but that may require your wheel to be more true or less true.

Really, it's not necessary to true a wheel until it starts rubbing something, but most of us are more anal than that. Having handbuilt wheels, I never have to true them unless I crash or hit something really hard.

:thumb:

-Jeremy

Quote:

Originally Posted by urbanknight (Post 11461918)

.1-.2mm is nothing to worry about, and is commonly acceptable with brand new wheels if it allows the spoke tension to be more even. Peter White does a good job explaining this.

I'd never found that post, but that's a superb bit of information! Thanks!

I don't think I could spot .1 or .2mm... I usually have my wheels trued when I spin them and the amount of hop annoys my sensibilities. I'd guess that happens close to 5mm. It's definitely before it becomes difficult to adjust the brakes to not rub.

IMO how much out-of-true you can stand your wheels being depends mostly on how fast and/or hard you corner. If you're leaning hard in a corner, you can REALLY feel your wheel as it wobbles from side-to-side. If it's bad enough, you can feel the wheel lose traction at times. I suspect a badly-enough out-of-true wheel can cause you to wreck in a turn.

I true my wheels when I'm bored and am in the mood.

They generally don't need it, but I can tighten up the front brake slightly, which I like. It's also enjoyable for me, I like truing wheels. I've never built any, and I don't know that I ever will, since most of the race wheels I want just come pre-built (like HED or Reynolds).