2-3mm out of round is enough to detect as a thump when you ride, especially if it is in a sudden single spot. In my experience, it's usually a 2-3mm low spot, not a 2-3mm bulge. I'll assume that's what you have.
If that's the case, then what you want to do is: 1. Mark the sidewall of the tire and the spot on the rim with a sharpie 2. Remove the tire 3. Remount the tire as best as you can but with the tire rotated 90 degrees from where it was 4. Check again for a low spot. Did you find one? 5. If yes, a. is it at the same mark on the tire? Maybe it's a bad tire b. is it at the same mark on the rim? Maybe there's a rim flaw c. is it at neither mark? Then it's probably the well known 'too-deep synergy rim well' documented all over the place. Build up the well with more rim tape. I use gaffer tape for this purpose. On Thursday, June 18, 2015 at 11:45:25 AM UTC-7, Michael Hechmer wrote: > > I am getting a thumping vibration from a front wheel at speeds above > 25mph. The wheel is nearly new with a White hub and Synergy rim. The tire > is a brand new Pari-Moto. It was on my converted Trek 620. I can't see > any obvious cause and here's what I've done so far. > > A visual inspection of the tire and wheel didn't show any obvious > anomalies, so I checked the head set and decided to tighten it just a bit. > That didn't have any noticeable affect on the thump. Then I swapped > wheels with my Saluki, which also has pari-moto tires. Rode both bikes over > the same short, hilly course. The thump definitely went with the wheel. > Next I took the tire off. Pari-motos go on very easily but are hard to > get straight.. I put the wheel in my little Minoura wheel stand. It is > perfectly round and nearly perfectly true. I carefully remounted the tire, > working to get it as perfectly straight as I can. Then I put the wheel and > tire up on the stand. The tire moves in and out about 2-3 mm away from the > side wall and about 2-3 mm away from round. I retested it and still got > the high speed vibration. > > ?? Michael > > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
