On Oct 14, 2011, at 1:49 AM, Rex Kerr wrote: > didn't solve my problem with the Al fenders moving from side to side and > rubbing on the tire during climbs
I can't think of any mechanism that would cause the rear fender to move when climbing, unless you're getting a huge amount of frame flex. I have seen situations where the front fender hits the tire due to fork flex, usually right at the front end of the fender. My hunch is that this is occurring when you climb standing. If it's the rear wheel, I think what was happening is that your fender is too close to the tire (there should be 8-10 mm clearance from the tire at its closest point) and that as the wheel flexes while you climb the tire rubs. The point of contact is probably on the left (non-drive side) near the brake bridge. Rear wheels flex is a slight potato chip shape as we climb standing; we rock the bike which introduces side loads and the pedaling torque on the drive side spoke tightens the trailing spoke and slackens the leading spoke, causing the rim to move. This can cause the rim to hit the brake pad, usually the one on the left, and a fender if the fender is too close. This is less likely to happen with a tight wheel (but a tight wheel is more likely to crack the rim around the spoke holes, since rim design has been drastically dumbed down in the past 15 years; a tight rear wheel may make a bike less likely to shimmy, as well). Back in my racing days on climbs you'd hear this "vrrrt vrrrt vrrrt" noise as the peloton climbed from rims hitting brake pads due to wheel flex. The became more prevalent after the introduction of dual pivot brakes which need to have the pads set close to the rim. Pro cyclists will sometimes reach back and release the rear brake when doing long climbs to prevent this. Campy came out with a dial pivot front/single pivot rear brake setup a few years back which I think was intended to prevent this problem. -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en.
