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Bigger rotors and stopping power


banna
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I've got the old XT brakes on my AM bike and I want to increase the stopping power a bit. I've got 180mm rotor front and 160mm rotor back. If I change to 203mm rotor front and 180mm (or 203mm) back will that increase stopping power?

 

What about different brake pads?

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Gor for it.

I've been running a 203 / 180 combo on my Am bike for years and love the extra power.

Brake pads aren't an issue, what you need to swop out are the caliper mounting brackets.

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Don't know about the XT brakes, but normally a 180mm rotor is plenty enough. I replaced my worn organic pads with sintered ones and the improvement in grip was noteworthy.

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Gor for it.

I've been running a 203 / 180 combo on my Am bike for years and love the extra power.

Brake pads aren't an issue, what you need to swop out are the caliper mounting brackets.

 

Cool bananas thx. Re the brake pads, I was actually wondering whether a different brand or compound would provide a bit more "bite"?

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Don't know about the XT brakes, but normally a 180mm rotor is plenty enough. I replaced my worn organic pads with sintered ones and the improvement in grip was noteworthy.

 

Awesome will give that a go as well. The problem I have is that my XC bike has the new 2012 XT brakes on and they are significantly stronger than the old XT's. So I want to try to up the stopping power on the old XT's so that they feel more similar.

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I've got the old XT brakes on my AM bike and I want to increase the stopping power a bit. I've got 180mm rotor front and 160mm rotor back. If I change to 203mm rotor front and 180mm (or 203mm) back will that increase stopping power?

 

What about different brake pads?

I have just put 180mm front and rear from 160mm and the braking power is 100% better. Very happy with the change. I am sure the 203 would be even better.

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Ja look if that bike is used only for AM then go for it. Generally 203mm is complete overkill for SA terrain, unless you are a DH lunatic (with respect of course)...

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Make sure that your fork can handle a 203 Rotor. As most forks up to 150mm travel are only rated for use with up to 180

Edited by Mr Mulebar
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Why is bigger better here?

"Larger rotors provide greater stopping power by virtue of a longer moving arm for the caliper to act on. Larger rotors will also dissipate heat more quickly preventing brake fade or failure. Typically, downhill racers will run larger brakes to handle the greater braking loads and extended braking duration."

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It's all just mechanics.

 

Torque = Force x Distance.

 

The more torque, the greater your stopping power.

So how does one increase that torque. More force, or greater distance. (being the distance from wher the force is applied to the axis on which rotation is occuring)

 

More force means better (and most likely more expensive) brakes.

More distance means bigger rotors.

 

I run 203mm rotors on my DH bike (front and rear). Works very well.

When I had a FR bike I ran 203mm front, 180mm rear

and on my 4X bike I run a 180mm front, 160mm rear.

 

The smaller rear option is usually chosen because you need less stopping power in the rear. You don't want it locking up every time you brake slightly harder than usual.

 

Just look at superbikes. 2 massive rotors up front. 1 smaller one at the back. If that principle works for 2 wheels that do over 300kph, it'll work for our pedal powered machines

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Make sure that your fork can handle a 203 Rotor. As most forks up to 150mm travel are only rated for use with up to 180

 

Ja cool. Good point. I've got a Fox 36 160mm, so it should be able to handle it.

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Ja cool. Good point. I've got a Fox 36 160mm, so it should be able to handle it.

 

yup! a Fox 36 can handle a 203mm rotor. Just get the correct adapter and you're sorted :thumbup:

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It's all just mechanics.

 

Torque = Force x Distance.

 

The more torque, the greater your stopping power.

So how does one increase that torque. More force, or greater distance. (being the distance from wher the force is applied to the axis on which rotation is occuring)

 

More force means better (and most likely more expensive) brakes.

More distance means bigger rotors.

 

I run 203mm rotors on my DH bike (front and rear). Works very well.

When I had a FR bike I ran 203mm front, 180mm rear

and on my 4X bike I run a 180mm front, 160mm rear.

 

The smaller rear option is usually chosen because you need less stopping power in the rear. You don't want it locking up every time you brake slightly harder than usual.

 

Just look at superbikes. 2 massive rotors up front. 1 smaller one at the back. If that principle works for 2 wheels that do over 300kph, it'll work for our pedal powered machines

 

Ah, thank you Professor Patch ! That's the answer I was looking for. Off to the bike shop I go....

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It's all just mechanics.

 

Torque = Force x Distance.

 

The more torque, the greater your stopping power.

So how does one increase that torque. More force, or greater distance. (being the distance from wher the force is applied to the axis on which rotation is occuring)

 

More force means better (and most likely more expensive) brakes.

More distance means bigger rotors.

 

I run 203mm rotors on my DH bike (front and rear). Works very well.

When I had a FR bike I ran 203mm front, 180mm rear

and on my 4X bike I run a 180mm front, 160mm rear.

 

The smaller rear option is usually chosen because you need less stopping power in the rear. You don't want it locking up every time you brake slightly harder than usual.

 

Just look at superbikes. 2 massive rotors up front. 1 smaller one at the back. If that principle works for 2 wheels that do over 300kph, it'll work for our pedal powered machines

 

Glad you answered. The same comes to play on your axle. The bigger the rotor the bigger the forces on the axle. What axles are your using on the downhill bike? Thru axle type or normal QR axles. I think the OP should be warned about the possible danger for failure as well.

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Glad you answered. The same comes to play on your axle. The bigger the rotor the bigger the forces on the axle. What axles are your using on the downhill bike? Thru axle type or normal QR axles. I think the OP should be warned about the possible danger for failure as well.

 

Well, because the axle is running on bearings, the force would be exerted on the 6 rotor mounting bolts (or centrelock)... woudn't it? (I may be wrong?!)

 

But axle wise, my DH bike has a 20mm thru axle in the front, and a 150x12mm thru axle at the back (both Hope Pro II's)

Edited by patches
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