Here is a short video I made that documents what seems to be a frame issue with regard to the seating of the bearings. Hopefully you can get a good sense of the problem from watching this, and I suggest turning up your volume so you can hear the “knocking” sound at the end of the video.
A big thanks to Josh for shipping out another frame, which hopefully will solve the problem.
(As of 12:35 pm, PST, the video is viewable, but not fully processed, so the video quality will not be optimized until fully processed.)
Josh has been strong addition at UDC since he started, because he used to be a senior bikeshop mechanic and thus has a good perspective from the more mainstream bike industry, with respect to repair/maintenance.
Just to cover all the bases, I decided to remove the bearings, and put on a new pair I had as replacements. I was immediately struck by how easily the bearings came off, using my usual pitman puller method. When I last changed my MUni bearings, I remember just how incredibly tight they were pressed on.
So I thought the 36er bearings that came with it might be the culprit, since they came off so easily, maybe they were the source of the free play. So I put the new spare set on, and they went on like my MUni; with great resistance! I thought for sure I had found the problem. I put everything back together…and the free play was STILL there!
So, just as Kris and Josh already suspected, it is that at least one of the frame bearing housings were machined too small. Oh well, a new frame will be tested and then shipped to me, so that’s good news! Thanks again to Kris and Josh!
Gee thanks Terry . . . . you’ve got the same uni I’ve been waiting a month for in your living room : P (the orange nimbus) . . . just feeding my desire. . . . soon, it’s coming soon. I know that’s your spare, but . . . I WANT IT!!! D:>
edit: oh . . . and : ) glad you got it all worked out. I’m looking forward to seeing it on the trails.
Actually the only nimbus parts on that MUni are the frame and hub. The saddle and seatpost are kh, as are the moment cranks. It also has the surly large marge rim and 24x3 intense tire. Basically like my regular every day MUni, except for the frame.
I’ve had it about 3-4 weeks but only have maybe 4 hours on it. I originally noticed the “knocking” sensation only when reversing direction while riding (e.g. stopping, idling, etc). I haven’t yet tried readjusting the bearing holders but I didn’t have to tighten them all that much more than I normally would (just a bit more) to eliminate it.
I took my new kh 36er into the LBS to have the spokes tightened, and when I got it back a few hours later, I noticed that the wheel was barely rotating! The bearing caps had been grossly over tightened, and it had been sitting at the shop like that for several hours. After I eased them back to normal tension, I took it for a test ride and immediately noticed the “knocking” sound was all but gone!
I then checked the wheel and the free play that was there before, and that was also pretty much gone! Apparently, the over tightening of the bearing caps-in Josh’s opinion-had caused the frame caps to become “cold seated” to the bearings! Josh and I agreed that over tightening your bearings like that is NOT recommended, but in my case, it had a silver lining, and the bearings came out unscathed.