Originally Posted by
surreal
dude, whatever else you decide, you really do want a front brake. The oft-quoted figure is that 70% of your braking comes from the front. I don't know if that's exactly true, but the front brake is definitely the more important one for most riding disciplines. Leave it on, i say. Or, just get the bb7s, front and rear.
YES, if he's going to only get one disc-brake, put it on the front where it will make the biggest difference.
The percentage of braking depends upon the level of deceleration desired. Stopping from 5mph at 0.10G can have 100% of the braking be from the front
or the rear brake. As you try to decelerate quicker in shorter distances, more and more of the weight shifts to the front tyre (increasing front-grip & decreasing rear-grip). At the maximum deceleration rate of about 0.85G, 99.99% of the braking-force will be coming from the front brake. People try and argue the difference between 99.99% versus 100% all the time, but the reality is that in all-out maximum-deceleration braking, the front brake is much, much more important than the rear.
Kinda ironic situation occurs all the time on bicycles and motorcycles. A lot of people are fearful of the front-brake and use only the rear. In a panic situation such as a car pulling out in front of them. The rear-brake only bike requires 10x longer braking distance and you see an arcing locked-up tyre-mark on the ground as they slide. Adding insult to injury, they end up crashing and getting run over by the same car they were trying to avoid anyway. The front-brake users will stop in plenty of time and watches in horror as their buddy gets crushed.