MTB - Why do you put a bigger brake on the front wheel rather than putting it at the rear?

Question

Would buying a bigger rotor help you brake better?

Answer 1

When you stop, most of the weight of the vehicle is shifted to the front, so a bigger brake in front is more important.

Answer 2

Theoretically, yes.  When you brake be it in a car or on bicycle or motorcycle, the weight is transferred to the front wheel.  The more stopping power on the front, assuming both brakes are applied with the same pressure, the better stopping power.  That is why front brakes in a car go out faster than the rear.  However, you do run the risk of flying over your handle bars if you only apply the front brake going at too fast a speed and you're leaning forward.

Answer 3

when you press the breaks most of the load gets pushed forward and thats where the FRONT breaks are. they get most of the load

Answer 4

The front wheel has more stopping power (which, as the others have stated, makes it feel like it takes more of the load).  While the rear brake doesn't have as much stopping power, it usually has more than enough to lock up the rear wheel and send it into a skid (even with v-brakes in good conditions).  

Although a lot of people think it's nuts to put a stronger brake on the front, thinking that it's a great way to send you over the bars faster, it's actually much smarter and makes it easier to slow down.   You should be using your front brake most of the time.....and when you use both brakes together, you normally want to put more pressure on the front because it does a better job.  Get in the habit of shifting your body weight rearward when you brake.  Unless you're really pointed downhill at a steep angle, you can grab a handful of front brake and not go flying.  

It's very popular to run a 7" front with a 6" rear.....it gives you better braking for decents (or just more grip for instant stops and tricky maneuvers).   The 6" in the rear is usually plenty.   People that have extended downhill sections or who are going very fast downhill like to use larger rotors than the normal 6" xc versions....they help to keep the rotors cooler (thereby stopping better without fading out), and they give more grip in wet conditions or for fast stops.  8" is overkill unless you're doing fast, long downhills.

Bigger rotors will help you brake faster, yes....not necessarily better.  "Better" depends on how you use them and your riding skills.   There's a lot more to good braking than just squeezing a lever.  

Hope this helps out some.   If you want to learn more, check out the "Mastering Mountain Biking Skills" book from Brian Lopes and Lee MacCormack.....awesome book and the only one I'm aware of that actually teaches mtb skills in useful ways, including the important details that other books never seem to include.

Answer 5

Because the front wheel does 70% of the braking.