All cable housing, shift and brake, was spiral-wound before the days of indexed shifting - which, as you are aware, can compress. Unlike shift-cable housing, which is coaxial (its steel strands are longitudinal), brake-cable housing is spiral-wound to preclude its own compression. Also, there is very little friction in liquid moving in a hose compared to a cable sliding in a metal tube, so your cables and housings must be low-friction and your cable routing needs smooth bends to minimize friction. You’ve also glimpsed why the braking performance we’re used to on road bikes with high-performance rim brakes will be hard to come by using discs without adding considerable weight and aerodynamic drag.įirst, liquids are essentially incompressible, so a hydraulic brake will push essentially equally hard, no matter how long the hose is.
You’ve knocked the lid off the reasons that cable-actuated disc brakes generally don’t stop as well as hydraulic ones - the cable and what pulls on it. I’ve heard from others the burn-in period was really long on their road bikes, so maybe they will continue to improve. I’m wondering if the longer cable pull of the new Shimano levers doesn’t match the calipers well - maybe the standard BB-7 calipers would be better? I could also try different pads or a larger rear rotor.
I’m planning to replace the housing with something compressionless. They seem to be short on stopping power the MTB versions I’ve tried have been much stronger. Readers can send brief technical questions directly to Zinn.ĭo you have tips for setting up disc brakes on road bikes? I’m using Avid BB-7 road calipers with XX 160F, 140R rotors with stock pads and standard cables/housing with Ultegra Di2 brake levers. you can find the original article via the Velonews website here:Įditor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. As always, Lennard is thorough in his research and offers some insight into this subject. This FAQ to Lennard Zinn of Velonews caught my eye and discusses some of the specific problems associated with discs on a road bike setup. I receive many questions about road disc brakes and the pros and cons of such.