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I have a fixie and I'm finding the rear wheel slips forward when riding (horizontal dropouts), causing the chain to loosen and thus a sub-optimal riding experience. It's not enough to be critical, just annoying.
I have the bolts extremely tight on the frame with the chain taut, but it still slips a little when riding. I'm wondering if there are any tricks out there to solve this problem, or if I'm doing something wrong?
Search for chain tugs rather than a chain tensioner.
You want something to hold the wheel in place rather than to push the chain up or pull it down (
).
On a fixed gear, the latter will just break with the first back pressure on the pedals.
Some things to try:
*: Imagine your going up a really steep hill and your allmost at a stop. Regarless of anything else, the force appled to the bottom of your wheel must be constant to keep you from going in reverse. Now do a free body diagram on the wheel. In statics, we can sum the moments about any point, so choose the point which the chain connects with the rear cog. If A is the force applied to the wheel by the axel, G is the force applied to the wheel by the ground, r is the rear cog radius, D is the rear wheel diameter, Then summing the moments we have that A*r-G*(r+D) = 0, solving for A, we have that A = G + G*D/r, so as r is increased, the force at the axel is decreased. These results won't deviate much if a fully dynamics system were to be concidered.
**: Make sure the chain tugs that you get are beafy, small spindaly chain tugs are only designed to take the forces needed to properly position the tire in the drop outs and will bend or break if they need to take pedeling loads due to slipage of the rear axel.
You could look into getting some chain tugs which basically create a link between the axle and frame. Here is an example:
First make sure there's no grease lubricating the nut/dropout area. Also make sure you're using washers, not just bare nuts (or nuts with washers built in). If slippage is still a problem you have three choices:
In a little late on this forum question, but I’ve experienced this problem on a few aluminum frames that have stainless steel dropout sleeves. Your frame is likely using a stainless steel dropout. The stainless is as hard or harder than the axle nuts which prevents them from biting into the metal. The only solution is to abrade the dropout surface with sandpaper to allow more bite by the axle nut washer. Also check that the nut washer is still serrated to do the biting.
One pro-tip (per Sheldon Brown and fixed gear street riders and track racers alike): your chain tension should never be described as “taut”. You want at least one inch minimum of vertical up-down slack. Ideally, have the chain tension as lose as possible without chain jump. Your crank arms should register some play before the chain becomes taut. Also, When you stand the bike vertical on its rear wheel, you should see the chain has some side-to-side swing as well.
You can also take a few links out of your chain and move your wheel all the way forward so it has nowhere left to slide forward. This is probably the least desirable solution, I highly suggest getting a chain tensioner.
