Bicycle Mechanics - How untrue is too untrue?

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RazorWind
05-04-04, 10:53 AM
I was cleaning up my bike yesterday/this morning, and after I had removed the wheels and cleaned them as thoroughly as I can in my bathtub, I noticed that my front wheel at least has about 1 to 2 milimeters of runout, causing it to rub against the brake pads if I set them to be really close together. (For a really short brake handle throw)
Is there a tolerable amount un-trueness? The bike in question is a 2003 Diamondback Sorrento, with Weinmann ZAC 19 double wall wheels, which are the stock wheels so far as I know. The riding I do is over paved terrain exclusively, and unfortunately, I have to ride over curbs every once in a while, which I expect is what caused the problem. I guess what I'm asking for here is some advice as to how bad the runout can be before it becomes a serious issue. Is it OK to keep riding it like that for a while, or should I go have the wheels retrued before I ride it again?
As you may have guessed, I'm a n00b. Thanks in advance. :)
Avalanche325
05-04-04, 03:24 PM
It depends on the type of riding and bike. 1-2mm isn't bad on anything. If you are rubbing with 1 - 2 mm you have your brake pads REALLY close. Remember that wheels do flex a little while sprinting and under hard cornering. I keep my road bike as close to zero as possible, my MTB gets a little more slack. If you can see it, it is probably a little worse than 1 or 2.
Get a spoke wrench and tweak a little. A wheel that only needs one or two spokes tweaked 1/4 of a turn is the best place to learn.
I concur with Avalanche. For a minor true, hang the bike from a bungie cord so that one wheel is off the ground, then turn the wheel slowly, watching or feeling for high spots. Use either the brake pads or a thumb resting on one of them as a guide. Quarter-turn adjustments are indeed appropriate. Work slowly, take your time, and pay attention to what you are doing, and you should be able to get a good result if the rim is only a bit out of true. You can leave the tyre mounted on the rim for a lateral adjustment, but you really should remove it for an optimal radial adjustment.
Retro Grouch
05-04-04, 10:40 PM
I was cleaning up my bike yesterday/this morning, and after I had removed the wheels and cleaned them as thoroughly as I can in my bathtub, I noticed that my front wheel at least has about 1 to 2 milimeters of runout, causing it to rub against the brake pads if I set them to be really close together. (For a really short brake handle throw)
Is there a tolerable amount un-trueness? The bike in question is a 2003 Diamondback Sorrento, with Weinmann ZAC 19 double wall wheels, which are the stock wheels so far as I know. The riding I do is over paved terrain exclusively, and unfortunately, I have to ride over curbs every once in a while, which I expect is what caused the problem. I guess what I'm asking for here is some advice as to how bad the runout can be before it becomes a serious issue. Is it OK to keep riding it like that for a while, or should I go have the wheels retrued before I ride it again?
As you may have guessed, I'm a n00b. Thanks in advance. :)
If you're only 1 to 2mm out of true, make your adjustments in 1/8 turn increments. Honestly, I wouldn't bet on an inexperienced mechanic getting those Zac 19 rims any closer than that because they're on the flexy side.
roadfix
05-04-04, 10:53 PM
How untrue is too untrue?..... Well, that depends on how picky you are. If a couple of mm's bug you, then tweek a few spokes.
I just resurrected a similar rim that was 1-2" out of true today! You're fine but watch it in case it gets worse.
redfooj
05-05-04, 01:09 AM
i personally couldnt tolerate anything more than a MM
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