wheel wobble issue - what to check?
10-21-08, 06:52 AM
#1
Senior Member
Thread Starter
wheel wobble issue - what to check?
I just built a new set of wheels, my third or fourth try at this.
Built the wheels up, tensioned and trued them. Went out riding them on the road and they felt great. Smooth and nice. Then I used the bike on my rollers and there is a noticeable (and annoying) wobble with each revolution. It is an up-down wobble (not a side-to-side), as if there is a piece of gum stuck to my tire. It happens with each revolution of the wheel.
The answer is pretty obvious here - likely it is out of round vertically, right? I have a homebuilt truing stand. It is kind of crude, but seems to work okay...yeah, right, not in this case. But, it is helpful in measuring side-to-side trueness, but not as precise for vertical.
Any suggestions on what to check? How to check it? I'm guessing the wobble isn't horrible, since it feels great on the road, but not on rollers. My other bicycles don't have this wobble on the rollers, so it isn't my cylinders that are out of round.
Built the wheels up, tensioned and trued them. Went out riding them on the road and they felt great. Smooth and nice. Then I used the bike on my rollers and there is a noticeable (and annoying) wobble with each revolution. It is an up-down wobble (not a side-to-side), as if there is a piece of gum stuck to my tire. It happens with each revolution of the wheel.
The answer is pretty obvious here - likely it is out of round vertically, right? I have a homebuilt truing stand. It is kind of crude, but seems to work okay...yeah, right, not in this case. But, it is helpful in measuring side-to-side trueness, but not as precise for vertical.
Any suggestions on what to check? How to check it? I'm guessing the wobble isn't horrible, since it feels great on the road, but not on rollers. My other bicycles don't have this wobble on the rollers, so it isn't my cylinders that are out of round.
10-21-08, 06:58 AM
#2
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Most truing stands have and indicator that lets the builder measure radial runout (aka "hop"). You should be able to rig something similar on yours.
Remove the tire and put the wheel in the stand and spin it with an indicator across the face of the rim beads and see how uneven the gap is as it turns. Hop is corrected by loosening a group of spokes (both drive and non-drive side) at the low spot and tightening a similar group at the high spot.
Remove the tire and put the wheel in the stand and spin it with an indicator across the face of the rim beads and see how uneven the gap is as it turns. Hop is corrected by loosening a group of spokes (both drive and non-drive side) at the low spot and tightening a similar group at the high spot.
10-21-08, 05:11 PM
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It could also be that the tire is not beaded correctly.Some tires don't fit as well as others.
You should be able to "eye-ball" the trueness on the bike.Just watch where the brake pads line up with the rim sides.
You should be able to "eye-ball" the trueness on the bike.Just watch where the brake pads line up with the rim sides.
10-21-08, 05:23 PM
#4
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Thread Starter
I thought of the tire issue as well. A few reasons why I don't think it is the tire:
1) I was using these tires on the same bike but on a different wheelset. No wobble. That was recently and the tires haven't seen anything but rollers.
2) The tires are seated properly. I checked that. They are older tires, hence why they are getting used on the rollers. Seated and snug. But, it isn't tire wear either, as I was using them 2 weeks ago on the other wheelset, no wobble.
3) I uninflated the tire and pumped it back up.
I did wonder if I overlapped the rim tape too much and that is causing it? But, the tube would probably take up this small seam.
I think I need to get it back in the truing stand and check out my hop. Thanks, HillRider!
1) I was using these tires on the same bike but on a different wheelset. No wobble. That was recently and the tires haven't seen anything but rollers.
2) The tires are seated properly. I checked that. They are older tires, hence why they are getting used on the rollers. Seated and snug. But, it isn't tire wear either, as I was using them 2 weeks ago on the other wheelset, no wobble.
3) I uninflated the tire and pumped it back up.
I did wonder if I overlapped the rim tape too much and that is causing it? But, the tube would probably take up this small seam.
I think I need to get it back in the truing stand and check out my hop. Thanks, HillRider!
10-21-08, 11:21 PM
#5
Senior Member
No, rim tape wouldn't cause any effects out by the tyre-tread. If you spin the wheel and look at the tread where it touches the roller, does it spin round with no up & down hops?
Post a picture of your truing stand. You should aim for radial-trueness of +/- 0.1mm, that's the standard spec for machine-built wheels. Humans should be able to do a better job than robots.
Post a picture of your truing stand. You should aim for radial-trueness of +/- 0.1mm, that's the standard spec for machine-built wheels. Humans should be able to do a better job than robots.
