I would like to know when you buy a new bike, why it comes with a larger front disc than the rear. I thought the larger the brakes the better?
The rear has less overall stopping power than the rear, as it tends to break traction. The larger rotor on the front balances out the point where traction breaks.
Rimmer - "There's an old human saying - if you talk garbage, expect pain"
The rear is limited with traction, thus large rotors are usable there only for heat managementon long downhills / heavy riders.
Front however can put much more traction during braking, and consequentailly, can take a bigger rotor.
It is a common practice to use a big front and small back - for example I use 203/160 on my AM bike.
Are serious downhill guys running 203 front and rear?
Front vs. Rear Brake Test
Take any bike with front and rear brakes. Stand next to the bike holding the handlebars with your hands on the brake levers.
-Squeeze the front brake and push the bike forward and than backwards.
(Notice how the bike skids in when pushed backwards).
-Squeeze the rear brake and push the bike forwards and backwards.
Notice how the bike skids going forwards and does a wheelie going backwards.
Rear brakes are useful for a few things, but front brakes stop the bike.
Rear brakes give you low brake power which is useful when:
landing a jump, altering with your front brake to minimize overheating, in case of front brake failure.
If you wear your rear brake pads out before your front brakes, your not a very knowledgeable rider and your skill levels are weak at best.