Thursday, February 28, 2013

Brakes | Traditional Cantilever vs Direct-pull


Brakes | Traditional Cantilever vs Direct-pull  

This topic is not to argue which one is better or pro's & con's of either system, but rather to simply point out the differences between the two systems which becomes critical when shopping for replacement brake shoes or even replacement brakes.  
Traditional, cantilever brakes used two cables in tandem to create the brake force; a main cable running from the lever and bike, to a second, "transverse" cable which connects both arms of the cantilever units, one on each side of the wheel.  As the main cable lifts/pulls upward on the middle of the transverse cable, causing the cantilever arms to rotate inward, applying pressure on the rims to slow the bike.
"Direct pull" brakes, while also a type of cantilever, are also commonly known as "V-Brakes" (a Shimano trademark).  V-Brakes offer a cleaner design by using only a single cable from the brake levers to you brake arms.  So unlike the canti-brakes that use a cable-cable-arm system, V-Brakes offer a cable-to-brake are system, hence "Direct-pull" and as you squeeze the brake lever, the cable initially pulls the right-side arm until it meets the rim and then the left arm is pulled inward to the rim, together squeezing against the wheel to slow you down.

While those are the basic variances in the two systems, both systems use levers on the handlebars, cables and cable housing to protect both the frame and cable from rubbing, as well are mechanical arms that pivot from the frame to push against a rim that provides friction to slow the bike down. 
This is a very simplistic article as there are many, many complicated designs of each system on the market, some include hydraulic-lines in place of cables, multi-pivot designs to offer maximum braking force, weight savings and more... 

Note: Often important to note which brakes you own, at least by brand name and by the type of pads installed for when you need replacement parts. Your local bikes shops are usually pretty friendly, so you can always bring the bike to them so they can see in person what you own, or make is simple, just snap a photo with the old cell-phone.