Correct caliper brake/wheel alignment
 

I've got a very old 10-speed roadbike (1971 Motobecane) with side-pull "Weinmann Symetric" caliper brakes and those "non-speed-release" hubs — you know, the kind which requires 30+ minutes of fiddling around with how the wheel sits in the frame until it sits exactly vertically and horizontally parallel to the frame. However, I have problems with my rear brake flexing the top half of my rear wheel to the right side by about 1-2 millimeters when I brake. The wheel is as parallel to the frame as I can get it and it is (more or less) true; likewise, the distance between the rim and each caliper is roughly equal.

Does this mean that the brakes need adjusting?— if so, then how do you "center" the pull on these side-pull brakes? From what I can see (see attached photos), there doesn't seem to be any adjustment facilities besides for the caliper-rim distance, adjusting the brake shoe in relation to the caliper, or simply "pushing" the calipers to one side or the other. However, doing the last option doesn't seem to make any difference at all— in fact, it seems like they "automatically" get "pushed" back to their original position during braking.

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errantlinguist, There is a nut on each side of the brake stay. Use the nut between the caliper and the brake stay to align the caliper and the nut on the front of the brake stay to tighten. This may take a few attempts, but once right and tightened should stay as adjusted.

Brad

Hi,

Lubricate the brake pivots, sounds like one is sticking.
There aren't two nuts, just the rear.

rgds, sreten.

Actually there is. It's used to retain the brake assembly on the pivot bolt. It can be a standard hex shape, have only two flats or star shaped.

Brad

Actually you are both incorrect as to how to center that caliper, although lubrication is a good first step. The OP has a very rare Weinmann Symmetric brake (ironic name considering the problem). See the 4th pic at this link for closeups of the construction. It's been at least 20 years since I worked on one but I believe you just need to loosent the binder bolt, clamp down the brake with the lever and retighten. Alternatively just loosen the bolt slightly and shift the caliper by hand until the arms come back evenly.

Yes; the Weinmann "Symmetric" was one of the first dual-pivot brakes on the market, but unlike modern dual-pivot brakes it doesn't have that handy caliper centering bolt so you need to center it using the mounting bolt as described above.

Thanks for the correction!

Brad

Hi, would you care to point out what I said that was incorrect ?, rgds, sreten.

Hi, No there isn't for that brake, rgds, sreten.

Thanks: this did the trick. It's a real nightmare trying to hold the calipers in place while tightening, but I think it works now...

Lubrication is not the way to center that caliper, though it may help. IF that is the only solution given and it does not work it's only a partial answer - so wrong was perhaps to strong - merely incomplete.