DARKSCOPE001

hey guys this is my first post but i was wondering if any of you could tell me a bit about the avid brakes. ok so first off right now i have some tecktro brakes that came on my bike (a 04 specialized hardrock ss) and i love how consistant the disk brakes feel over rims that i am used to back when i used to ride bmx but they arentnt quite powerfull enough. so i wanted to invest in a set of avid bb7 brakes. from what i understand they are the best mechanical disks you can buy. but i origionaly wanted to run big 203mm rotors all around my bike front and rear and the guy at my local bikes store said that this would be a bad idea because i would be constantly locking up my tires. so then i thought what about running a 160-180mm in the rear and a 203mm up front because i want alot more braking than what i have right now. i like to be able to slow the bike compfortabaly with one finger now have to reach out with my index and middle and pull the leaver back till it hits my ring finger. so if you guys can tell me what size rotors you think i should get. also what about leavers i was going to buy a pair of avids speed dials. so any suggestions on leavers would be mugh appreaceated and anything you guys can tell me on how to make my brakes silky smooth would be great also because i love the feel of hydros but not the thought of having them fail on the ride and not being able to fix it with a wrench.

THANKS GUYS
Sean Scott

FreeRidin'

Chances are you will be more then happy with 160s. Also, it is not the smartest idea to put 203s on a QR fork. The amount of braking generated from 8" BB7s could possibly snap your fork in two.

Raiyn

Or rip the wheel from the dropouts.

Set up properly (meaning instructions were followed) a set of 160mm BB7's has plenty of stopping power for the average XC'er. I'm not a small guy by any stretch, and my 160's (f&r) have never failed to to stop me when desired. Mine are set to lock at just past lever parallel to the grip. This gives me good modulation and power without the "binary" feel that inexperienced riders seem to favor.

Stacey

I'm running 160 (with a Shimano caliper) front & canti rear and feel I have plenty of stopping power as I have no problem lifting the back tire under MAX braking, yet I have excelent modulation.

One thing I don't understand, and I've seen it mentioned many times, is the negative concept of 203's and fork damage.

In my years of moto experience, I've found that larger rotors provide for cooler running rotors and less brake fade, and allow the use of larger four & six piston calipers. Never once has there been a caution about breaking forks due to 'too much stopping power'... Even when upgrading from pathetic single leading shoe drum brakes to highly effective twin disc setups.

I understand the math of a longer disc radius increasing the stopping power at a given braking power, but two things are preventing me from getting my head around this principle completly.

1. If a larger rotor has more stopping power (leverage on the hub/wheel), then wouldn't it require less lever pressure (effort) to bring the speed to zero? Therefore, if the same effort was applied to a lever on a 203 that was used on a 160 wouldn't you exceed 100% braking and lock the wheel before catastrophic failure of the forks or seperation of the Q/R interface?

2. Also, applying the same logic... Wouldn't a rim brake have an even longer braking radius than a 203 and exacerbate this condition?

Not trying to be controversial, just seeking clarification on this concept.

DARKSCOPE001

yea i agree with stacey i dont see why a 203 would rip the fork appart i mean it may be possible i dont know and its not like ima be ripping on the brakes im not that kind of biker im usualy realy smooth with the application of my brakes its just the tecktros that came on my bike are weak and dont stop me in the desitred distance. idk maby im just demading to much from my brakes i dont know what a good stoping distance is all i know is i dont like the way the feel. like when they where new they where realy nice and i loved them cuz as soon as the pad engaged with the rotor the brakes where very powerfull and worked great but as they grew older now i can tell when the pad hits the rotor but now i have to squeese them alot harder than i like and they have almoast a spungy feal to em. so i had my bike shop check em out and the guy said that they where a total hastle to adjust and when i got it back the braking was substantialy better but not fantastic. and he told me that avids where the way to go. so i figured my birthday was coming up why not ask for a set? and so i just wanted to see what everyones oppinion was. but it sounds like 160's will do fine. but no one is yet to answer my question about leavers. i herd a guy talking about his setup of bb7s and his speed dials and he said they where awsome but idk he may just be braging. anyways thanks guys for all the input.

LATER
Sean Scott

fjyang

I got 203mm front rotors and Avid BB7 mechanical on two of my bikes (160mm rear) and it work great. You can easily do stoppies with the 203mm wether intentional or not. Having that extra stopping power and peace of mind is hard to put a price tag on. You probably don't need 203mm and 160mm will do fine but I don't see the down side except a little extra weight.

What ever you do don't put 203mm on back it'll lock up your rear wheel too easily and fish tail you out of control unless your doing downhill racing. Also if you use to ride motorcycle...swap the brake lines so that the right hand lever activate the front and left lever activate the rear as during emergency braking, your instinct will take over from your motorcycle training and grab a hand full of right lever and lock up your rear wheel and spin out of control.

I use to ride motorcycles and upgrading rotor size is never a issue with regarding to breaking the fork or axel, and motorcycle are traveling at much heigher speed and way higher braking force on rotors and forks.

People want you to stay away from big rotors is that you probably don't need that much stopping power at the begining and as you skill lever and type of trials you ride becomes more techinical, upgrade as needed.

I sense most mountain biker are conservative bunch that stick with what they know and don't experiment too much unlike motorcyclist, which embrace change and technology and love to experiment their ride with new frame concepts, forks and rear suspension. Most mountain bike technology trickle down from motorcycles and race car suspension designs.