Nuts ‘n’ Bolts: Give Me a Brake

[[image:harv_brake_mini.jpg::inline:1]]In my constant mixing and matching of parts among a variety of bicycles, old and new, a recurring theme has been that of adapting various caliper brakes.

Published September 6, 2007 by C.I.C.L.E.
Contributed by Harv :: Photos by Harv and Leticia Z. 

In my constant mixing and matching of parts among a variety of bicycles, old and new, a recurring theme has been that of adapting various caliper brakes. Modern road brakes are such an improvement over older brakes; double-pivot, quick cable release, adjustable toe-in, etc.

However, you often cannot just bolt on a modern front brake to, say, a vintage lugged steel fork. First, modern caliper brakes use a long recessed nut tightened with a hex wrench. Old brakes just have a long bolt through the fork retained by a regular hex nut. At minimum, you have to drill out the back of the old steel fork to allow the recessed nut to enter. This usually involves enlarging the hole from 6mm to 8 mm. And you may have to either get a longer recessed nut, or add washers to the nut to effectively shorten it up, depending on the fork dimension. No big deal.

[[image:harv_brake2.jpg::inline:1]]A more challenging adapting problem would be having insufficient reach of the caliper; the brake shoes can fall short of the wheel rim. You may have some short reach calipers on hand and not want to purchase a longer reach set. Or visa versa. What to do? Faced with this problem, I devised an offsetting link to compensate for the disparity of reach. Using just standard hardware store items and common tools, you can make yourself a link and use a spiffy modern caliper on that old ten-speed frame or fork. This is similar in function to a 'drop bolt', but is a 'drop link'.

Starting with a chunk of 3/16 by 1 inch aluminum bar stock, you hack off about 1 1/8 inches of it for your link. Then chuck up a 1/4 inch bit into your drill press or drill motor and bore two clearance holes 14 mm apart on centers, symmetrically on the chunk of aluminum. This will give you a 14 mm increase in reach for your brake. You can't shorten this distance as there must be clearance behind the link for a 6 mm retaining nut. You can go over 14 mm if required but watch the caliper-to-tyre clearance. Try to calculate this distance so that your brake shoes end up in the center of the brake arm slots. But 14 mm should do the trick to adapt a modern short-reach road brake to a generic ten-speed lugged steel frame or fork. Unless you have a touring bike with room for fenders and/or centerpull brakes. Then a longer extension may be required.

[[image:harv_front_brake.jpg::inline:1]]You can shorten the effective reach of a caliper brake by flipping the link up instead of down. In this case, the link will have to be installed so as to stand off from the fork or frame to clear the protruding mounting bolt(s). Just add another nut or two between the link and the fork. This gets more complicated and you may have to cut short the brake mounting bolt to minimize the stand-off distance.

In addition to the aluminum stock, pick up the following hardware items to bolt up the assembly: a 6mm by 45 mm to 50 mm bolt, two 6 mm Nylok nuts, and two 6 mm washers. Just bolt the new caliper to the link, retaining with one Nylok nut and washer, then bolt the link to the fork with the long bolt and the remaining nut and washer. This procedure makes no permanent changes to the fork or frame and can be easily reversed if you want to go back to the original brake system.

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