Why are the front brakes better then the rear brakes?

You'll find this on most cars. It's due to physics - when decelerating the weight and energy transfers to the front of the vehicle, as a result front brakes are larger since they have more energy to cope with, and that extra weight also gives the front wheels extra grip and thus more braking ability.

Anyone feel free to correct me :)
 
fbc said:
You'll find this on most cars. It's due to physics - when decelerating the weight and energy transfers to the front of the vehicle, as a result front brakes are larger since they have more energy to cope with, and that extra weight also gives the front wheels extra grip and thus more braking ability.

Anyone feel free to correct me :)

Spot on correctamondo, no correctioning required :thumbsup:

and if you want to pick me out for making up words, i claim shakespeare did it and so will i ;)
 
If you want a quick reason why:

Download the LFS demo. Get on the drag strip or any long straight, with really strong brakes and a really high rear bias. Get to top speed, then brake hard.

Let me know how that works out for you.
 
FATMOUSE said:
If you want a quick reason why:

Download the LFS demo. Get on the drag strip or any long straight, with really strong brakes and a really high rear bias. Get to top speed, then brake hard.

Let me know how that works out for you.
I was just going to point that out. Look at motorcycle brakes (specially sport models) where the weight transfer (and the difference between front/rear) is even more pronounced: You have a rather small rear disc brake and two huge discs in the front.
 
fbc said:
You'll find this on most cars. It's due to physics - when decelerating the weight and energy transfers to the front of the vehicle, as a result front brakes are larger since they have more energy to cope with, and that extra weight also gives the front wheels extra grip and thus more braking ability.

and IF you set up the rear brakes equal to the front brakes, the rear brakes would lock up under (medium)hard braking (granted there's no ABS), which you don't want either
 
The front brake are bigger than the rears because the brake balance is more biased towards the front. When front brakes > rear brakes the car tends to understeer more into a turn. When front brakes < rear brakes the rear of the car will lock up first and cause the backend to slide around (oversteer). The former is safer for road cars. Since the front brakes do more work they are bigger (or "better").

Race cars have a more neutral balance because race car drivers demand a tiny bit of oversteer while turning in. (watch the Australian GP practice sessions!) Also, race cars have manually adjustable brake balance valves. Drivers can change the balance during the race.
 
Z Draci said:
The front brake are bigger than the rears because the brake balance is more biased towards the front. When front brakes > rear brakes the car tends to understeer more into a turn. When front brakes < rear brakes the rear of the car will lock up first and cause the backend to slide around (oversteer). The former is safer for road cars. Since the front brakes do more work they are bigger (or "better").

Race cars have a more neutral balance because race car drivers demand a tiny bit of oversteer while turning in. (watch the Australian GP practice sessions!) Also, race cars have manually adjustable brake balance valves. Drivers can change the balance during the race.
But even race cars have bigger front brakes, because they should be stronger due to weight transfer, right? Please correct me if I?m wrong.
 
Redliner said:
Z Draci said:
The front brake are bigger than the rears because the brake balance is more biased towards the front. When front brakes > rear brakes the car tends to understeer more into a turn. When front brakes < rear brakes the rear of the car will lock up first and cause the backend to slide around (oversteer). The former is safer for road cars. Since the front brakes do more work they are bigger (or "better").

Race cars have a more neutral balance because race car drivers demand a tiny bit of oversteer while turning in. (watch the Australian GP practice sessions!) Also, race cars have manually adjustable brake balance valves. Drivers can change the balance during the race.
But even race cars have bigger front brakes, because they should be stronger due to weight transfer, right? Please correct me if I?m wrong.

Yes, you're correct! Even if the static weight balance from front to rear is a perfect 50:50 when the car is braking that weight balance can shift biased towards the front. So the front brakes need to have a higher braking force relative to the rear. That's why the front brakes are bigger in all cars and motorcycles.
 
Also, the cross-drilled merc brakes are usually brembos up front and the rear....well its just normal merc brakes. Why are they cross-drilled? Prob to make them "look" agressive....cross-drilling really doesn't do much compared to normal vented...
 
The holes in cross-drilled rotors vent the gas produced from the brake pads. If the rotor is solid, the gas can act as a layer between the pad and rotor surface--which people claim can reduce braking force. Most people now say that cross-drilled rotors can cause uneven rotor wear and has problems with uniformity (causes vibrations and uneven braking force).

This is why slotted rotors are the norm for evacuating brake pad gases. Also, street driven cars do not necessarily need cross-drilled or slotted rotors. It is only useful during periods of strong, prolonged braking where brakes can fade due to overheating.

For street cars they usually use slotted or vented rotors just for looks.
 
Drilling front rotors weakens them and can cause cracks. Some have shattered, and it's not worth it because there's also less surface area and friction for stopping power. It doesn't make up for the supposed "weight savings".

If you want performace rotors, get slotted. I have them. Sounds cool when stopping too. Flings water out the channels as well.
 
wahaha said:
Drilling front rotors weakens them and can cause cracks. Some have shattered, and it's not worth it because there's also less surface area and friction for stopping power. It doesn't make up for the supposed "weight savings".

If you want performace rotors, get slotted. I have them. Sounds cool when stopping too. Flings water out the channels as well.

That's only in very poorly designed discs. If it's all modelled correctly before being made, there is no reason why the disc should shatter. Also...the holes are there for lightness.....as stated they're there for getting rid of the dust ;)
 
current pad technology doesn't have the issue with outgassing that older brakes used to have even in racing applications so at this point cross drilling and venting is somewhat useless beyong getting rid of brake dust and heat disipation

TF
 
Its the same with my DH bike :D
 
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