do you have the bb5? yes, i've heard a lot of complaints about that brake. the positive reviews say that you have to adjust it before every ride. the bad reviews say that after a few rides it stops working completely. i don't know what to say but when i buy my next mountain bike i will have the lbs swap for bb7s and pay the difference.

sam, as you said, he should definitely get the rear brake fixed up. he needs it as a weak back up in case for whatever reason the front brake fails. i'm surprised you stopped from 30 mph with only 15 ft. i guess i'm a wuss after my endo accident when closelined by a dog leash. luckily you and the OP probably don't weight as much as me (220 lbs). if i tried to stop in 15 ft going 30 mph downhill on my hybrid (low handlebars), no matter how good my technique was to brace myself against the handlebar, i'd flip over the handlebars catastrophically. i think doing such a big stop is very risky. maybe your geometry was different than mine (higher up handlebars).

i like biking but i've come to realize that a bike has no protective mechanisms at all. you can't brake too hard at high speeds or else it's endo. if the brakes fail (like the OP's rear) at an intersection...scary! so i make sure that i ride cautiously and that my breaks and components are in excellent working order.

edited for careless spelling mistake on "brake".