Ask the Editors: Fluid Shear Braking Lesson
Dear ATVC:
In my mechanics class we were discussing fluid shear brake systems. Can you explain how these work and have they ever come on an ATV?
A “traditional” braking system works by turning friction into heat energy- in the case of your average ATV, a disc rotating with the wheel stores the energy of motion, pads (being squeezed by a caliper) make contact with the disc and hence introduce resistance (friction) which transfers kinetic energy into heat.
Fluid shear is quite a different principle whereby the torque generated by shearing fluid between multiple friction discs absorbs the heat of engagement and dissipates it through a housing where it cools and is recirculated.
The recirculating of this fluid minimizes wear to all of the components involved and on a physical level, oil shear braking is typically smoother, quieter and more cushioned than what we experience with dry friction.
Indeed Kawasaki (with the Prairie) was the first ATV to come equipped with a fluid shear braking system (commonly called a “wet brake”) though the system has yet to gain mass appeal presumably due to the commonality of dry braking system components.
