MyRedTrek

What do you consider to be an acceptable variation for roundness with a mass-produced Bontrager AT-750 that comes on a Trek Verve2?

cxwrench

Pretty big. Maybe 1.5mm radial. I've seen 2-3mm lateral. They (whomever 'they' are) don't pay too much attention to those wheels.

hokiefyd 

If you can feel it in the ride (the radial hop), then it's probably too much. Otherwise, low-buck factory wheels like those are often not super round. I've had a set of AT-750s before on a 2015 Verve and the rear one had a bit of a hop to it...but I couldn't feel it riding, so I didn't worry about it.

MyRedTrek

So trying to make the runout on these rims essentially invisible the way I see on high end road bikes on Youtube would be an exercise in futility?

alcjphil

It is important to differentiate between rims and wheels. They are not the same thing. Rims can be somewhat out of round and still be built into wheels that are very close to almost perfectly round. A built wheel is different, its roundness depends on how skillfully it was built

cpach

Radial runout is more or less irrelevant so long as it's not felt while riding (so basically, never) except insofar as it infers equal spoke tension. On a lot of rims in particular, it is normal for the tolerance to be off at the seam I'd probably aim for within 2mm on that rim, but really I'd work the radial precision until it felt like I started needing to compromise on even tension.

hokiefyd 

It's probably an exercise in futility, yes. It really depends (at least in my experience) how the runout is distributed around the rim. If it's in a very small area of the rim, a quick "up and down" as you watch the rim spin, it's not likely that you can adjust the hop out with spoke tension work. It's possible, but unlikely. If the runout is spread over a larger area, a more subtle "rise and fall" as it spins, then that probably could be pulled in some with careful spoke work.

It may help to attach a fixed reference point close to the rim surface; if the bike has rim brakes, a brake shoe is good enough...if it has disk brakes, you can tie a small zip tie to the seat stay and have the tail pointing at the rim surface. Slowly spin the wheel and watch the rim surface in relation to your fixed reference point. With radial runout like you have, the radius of the rim will change as it spins. Mark with some painter's tape where the radial runout seems to start and then mark with another piece of tape where it seems to end (where the rim settles back to its average radius). If that's a fairly broad area (like a quarter or half of the rim circumference), then the runout may be fixable, or at least could be reduced.

zacster

As round as you can get the wheel you still have a tire to contend with and that is as likely to be out of round same as the wheel. Luckily air pressure evens a lot of it out. As others have said, if you can't feel it don't worry about it.

I just rebuilt a wheel and after applying even tension using a meter I found it a tiny bit out of round but not so much that the rim brake ever felt it. I just left it at that since it was laterally true and very even high tension.