[SG-1]

I have a GT hybrid with an unusual problem that I am not 100% sure of.

During speeds of 14MPH or less, the tires are smooth as glass. Above 14MPH, the wheels feel like they are out of round; almost as if the tire is 1/2 inch high at 12 o'clock on the rim and 1 inch on the 6 o'clock position. I've let the air out of the tires, loosened the bead, squeezed the tire all over, and re-inflated, same result.

It is a bit hard to tell, but it appears to be a defective rear tire, as the rim does not seem out of round when I spin the wheel by hand.

Unfortunately the bike is 3 years old, so I can't take it back to the LBS, even though the bike has less than 300 miles on it.

Thoughts before I get a new set of tires?

[wild]

Do you have sealent in the tupes, slime . Or it could be tire liners maybe.

[photosbymark]

Well a few things that you should think about. First of all your local bike shop should work on it, even if it is out of warranty. It probably needs a pro set of eyes. It acts like something is out of balance. First thing to check is to make sure that the wheel is all the way in the drop outs on both sides. IF the wheel isn't quite all the way in on one side, it might create such an issue.

Second just because it looks round doesn't mean it is round. The best way to know for sure that the wheel is ok is a truing stand. The local bike shop should be able to do this for you without a big expense, but they should do it. The truing stand can measure round in different ways other than side to side. Spoke tension is important, and adjusting it might be the solution to your problem.

Other possible problems that are less likely with a 300 mile wheel, but potentially more dangerous is bearing problems in the rear wheel or something else internally that could be a bigger problem with a total failure. I don't think its likely but if a bear seizes on the rear wheel, well better you than me. grin Still I just think you likely need the wheel trued

[SG-1]

Some of the folks over at the LBS know me, so I will bring the back wheel in for inspection.

Here is a pic of the bike in question, my commuter:

[photosbymark]

Let us know what they find

[SG-1]

Did not have time to visit LBS today, but after my 14 mile ride this morning on the GT, I was able to look down and watch the wheel & tire at 15MPH. The tire is obviously out-of-round. I used my rear triangle as a visual reference and watched the rim & tire, the rim doesn't move, but the tire was moving slightly out of my focus.

Will take the wheel off and leave it in my car so that I can stop by the LBS during the week.

[SG-1]

UPDATE:

Forgot about this thread. I took the wheel to the LBS and they trued it. It was out of round. After I put it on the bike and went downhill, hitting 26MPH, it is now smooth as glass.

Amazing how being 2mm out of round can make a huge difference.