In our Master Mechanic classes we teach everything possible, but due to time and payroll constraints some things get less attention. I’d like to take just a moment and show a small but critical difference between two brake levers.
In ~1995 the Dia Compe PC-11 brake lever was available. It’s designed for Cantilever brakes, which have a short caliper arm, so the leverage is “high”. We can see this by looking at the distance between the cable path and the lever pivot, it’s about 0.65 inches.
The Shimano BR-M739 brake lever has a cable path-to-pivot distance of about 1.27 inches, a dramatic difference from the Dia Compe lever. This lever is made for use with V-brakes only, with a little adjustment possible in it’s “low” leverage design.
I’m no engineer, but I can see that the Shimano lever will pull much more cable with lower force than the DiaCompe. I’m not going to calculate that with the angle of the brake lever, but it’ll be “more”. As a mechanic I can tell these levers can’t be swapped from these pictures, and have any quality of function.
Today, bike functions and parts are getting mixed more than ever. “Flat bar Road Bikes”. “Road Bikes with Disc Brakes”. “BMX bikes with V-brakes”. We’re seeing demands for greater braking power on many bikes, and we may get requests with good intent and bad execution. Regardless of the reason, brake parts within a category are made to work together. Mixing low-leverage systems (Modern V-brakes, mechanical disc brakes) and high-leverage systems (Cantilever, basic side-pull, U-brakes and all modern road bike brakes) in any form can only result in compromised performance or loss of safety. There are very few exceptions to this, please contact any Bike Trainer in our company for details if needed.
It can be tempting to dismiss the value of training, but we discuss things similar to this in all of our classes. Whether you've hired a "Pro Racer" or absolute "newb", they need to go through Sport Chalet Bike Dept training.
Be Safe!
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