Rotor size-braking power ?

[patches]

so why does my road bike take so long to stop, as I usually wonder about this before hitting the tree/signpost/curb/car/other rider in front of me.

 

 

 

 

 

 

ya ya breaking, brake force and all that nonsense

 

 

yup! you nailed it right there... road bike calipers don't exert nearly as much force as a hydrolic system.

 

...so yeah, rim = good radius to maximize torque... but the force from the brake is inadequate. Look at trials riders. Some run discs, but many run those Magura hydro rim brakes because they need to know that their wheel isn't gonna budge an inch when they're hopping about on 1 wheel.

Edited May 31, 2011 by patches

[schmoose]

This whole 180 front and 160 back really irks me, I've suffered from a lot of brake fade over the years, funny thing is its ALWAYS the back that fades first, 180 front 160 back looks cooler thou.

 

With regards bending 180 rotors you need to be very careful which rotors you get, those cheap light jobs always bend even if you don't bash them.

 

One other thing to bear in mind is that rotors also wear out, especially the thin XC ones, i've often remedied my fade by just throwing on new rotors.

[Tumbleweed]

This whole 180 front and 160 back really irks me, I've suffered from a lot of brake fade over the years, funny thing is its ALWAYS the back that fades first, 180 front 160 back looks cooler thou.

 

 

Then stop using your back brake so much?

[patches]

This whole 180 front and 160 back really irks me, I've suffered from a lot of brake fade over the years, funny thing is its ALWAYS the back that fades first, 180 front 160 back looks cooler thou.

 

With regards bending 180 rotors you need to be very careful which rotors you get, those cheap light jobs always bend even if you don't bash them.

 

One other thing to bear in mind is that rotors also wear out, especially the thin XC ones, i've often remedied my fade by just throwing on new rotors.

 

Sure, some people do it because it looks cool... but there is a purpose behind it.

 

The front brake is the one that will stop a bike more efficiently. It's physics. On the other hand, when a rear brake is locked up, it's very in-efficient, as the rear wheel loses traction, because the weight is being shifted to the front.

 

So some people put a smaller rotor on so that the same breaking force (at the finger) can be applied, but the rear wheel won't lock up as easily.

 

As for bendy big rotors... just get some Hope floating discs I run 203's on one of my bikes and those things are stiff as hell!

Edited May 31, 2011 by patches

[TNT1]

Then stop using your back brake so much?

 

+1

 

I know it's not exactly the same, but on the motard, I have changed front pads and discs on the front a lot over three years, and never once on the back.

[dirtrider]

Where at the 3 towers did you need to brake that much ?

[schmoose]

As for bendy big rotors... just get some Hope floating discs I run 203's on one of my bikes and those things are stiff as hell!

 

Till the rivets come loose?

[patches]

Till the rivets come loose?

 

Haven't had that problem (touch wood)... it does sound a tad concerning though. Has it happened to you?

[schmoose]

Yes, but its not a critical failure. Basically in the stand the rotors are fine but as soon as they warm up a bit the theres about 2mm movement in the rotor between the floating bit and the steel rotor. I've carried on using the rotor without any severe problems, I probably shouldn't but it matches my wheels.

[Nobody]

So what is the consensus here if you change just the rotor from 160 to 180?

Definitely better?

 

I changed from a 180 in front to a 160 (nothing to do with stopping power, just easier to keep all the same size.)

[Dubber88]

dubber: lolwut?

smaller rotors cause faster wheel lockups? That's interesting cos the thread's about bigger rotors creating more stopping force.

185mm heats up quite quick? compared to...?

bends easier? More problems? Sounds like you bash your rotor alot. Did u also swop to single speed rear end due to bashing your rear mech?

 

 

 

Now that I think of it, probably had more to do with the condition my rotor was in, swopping it for a new 160mm, with regards to the lockup theory.

 

With the 185 at the back I had that typical high frequency vibration noise after some braking, which i presumed was caused by the heat build up.

 

Did not give this one allot of thought

 

 

If I were to rephrase : I won't use a 185mm rotor for the back after my experience...

Edited May 31, 2011 by Dubber88

[Guest Omega Man]

 

So some people put a smaller rotor on so that the same breaking force (at the finger) can be applied, but the rear wheel won't lock up as easily.

 

 

Wait. So I run a 203 on the front and a 180 on the rear. Does that mean i apply the same force with both fingers? Cos that's what i think i do but I had no idea it was cos of a 203 front and 180 rear.