Wheel Truing Tolerances

Equipment
1

I just had my bike tuned up last week and when I dropped it off i was told I had a loose spoke and my wheels were out of true. Unfortunately, I assumed they were correct and told them to go ahead and true the wheels. I’ve done tow rides since getting the bike back and noticed that the rear [caliper] brakes no longer seemed to be braking evenly. Squeezing the brake relatively lightly resulted in squealing that had not previously occurred. This happened on the first ride. The second ride I could feel the brake unevenly appling pressure to both sides of the wheel. This was not the case before the tune-up.

I got out a feeler gauge and found that the rear wheel was about 0.5mm out of true. I read that when truing, one should shoot for between 0.1 and 0.2mm. My backup bike is currently being tuned up and I was going to take this bike back so they could look at this wheel again.

Does this seem like I’m being picky or not?

2

  • Can you clarify exactly how you measure this? It seems you are checking the gap between the brake pads and the rim.

  • If so, are you checking just at one point along the rim or the full circumference spun through?

  • I ask because a wheel can be true and still have an unequal gap to the brake pads on either side since the brake has separate centering adjustment controls.

  • If you spin the wheel and just watch the gap to the pads, is the gap changing or consistent through full rotation?

3

I spun the wheel looking at the gap on one side of the brakes. I saw that there was one high spot and a secondary high spot about 90° away. I rotated the wheel to create the minimum spacing between the brake pad and the wheel rim and then pushed the brake over to just close the gap. I then rotated the wheel to see where the maximum gap was and stuck a feeler gauge in the gap. The .46mm gauge just fit in the gap at the location with the maximum spacing. the gap does change as you spin the wheel.

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4

Then it sounds like this is worth showing the shop to see if they will address it.

5

I will do so and post feedback.

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6

Half a mm is nothing to be concerned about…but if they trued it they did an awfully lazy job of it. Or a couple spokes unwound a tad or something.

7

So I took the bike back today and one of the mechanics that has been there a long time took a look. He agreed the truing was not as good as it should be. He trued the rear wheel that had ~0.5mm wobble and also redid the front wheel that was not as bad but had room for improvement. He also adjusted the position of the front calipers that I had noticed were set a bit too far out on the diameter of the rim but had not mentioned. To top things off, he also gave me $20 in-store credit for having to bring the bike back for adjustment.

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8

Sounds like great service! Hooray for a solid LBS :smiley:

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