when are your brakes to big ?

[darkling]

so i asked the question on a different thread but not to many responses anyone know the true answer .

does weight of the car come into factor when choosing your brakes ?

does wheel and tire size also factor in other then the diameter you can fit inside the rim ?

[corvettekid1973]

I'm not a authority on this by any means but I do think that yes weight should be a factor in brakes. Also the bigger and wider the wheels the more rotating mass you have there for the more work on the brakes. All of that will cause a lot of heat in your brakes.

[darkling]

hmm having a hard time putting my total question into words . i have noticed most larger american cars have had alot of lock up in turns wondering if that is really caused by to much braking surface .
lets say like a 3000 lbs car with 17 inch rotors and 6 piston calipers might it be the fact that the 1500 or so lbs on the front rotors isn't enough to allow the brakes to get some slippage thus causing a total lockup .
not factoring in driver fat foot error .
hope that helps

[regal454]

lets say like a 3000 lbs car with 17 inch rotors and 6 piston calipers might it be the fact that the 1500 or so lbs on the front rotors isn't enough to allow the brakes to get some slippage thus causing a total lockup .
not factoring in driver fat foot error .
hope that helps

The friction between the tire and the road is what stops the car, not the brakes. In the case above, you would need a bigger tire or softer compound.

[CFster]

When you can't fit anything bigger!

[badazz81z28]

I feel there is no such thing. Obviously you can go bigger than what's needed, but nothing negative about it. Go as big as the wheels will allow and call it a day

[Todd in Vancouver]

When you can't fit anything bigger!

That looks AWESOME !

[SLO_Z28]

I feel there is no such thing. Obviously you can go bigger than what's needed, but nothing negative about it. Go as big as the wheels will allow and call it a day

The exact opposite is true. You have a large mass spinning at thousands of revolutions per minute on a larger axis than you originally had. It increases sprung weight, unsprung weight, and decreases steering responsiveness, and has negative effects on the tires traction. Big is heavy, heavy is bad.

[darkling]

but due to the clamping force of a huge brake kit on a light front end won't it be harder to find the sweet spot between tire traction and lockup . i know pedal feel has alot to do with that . and maybe using a adjustable proportioning moving more of that pressure to the rear might help ?

i just keep seeing lockup over that over i really just want to solve this before i drop 2k on brakes and find issues

[rustomatic]

Look at what they use on a new car that stops in a very short distance. Look at an economy car, then drive one, if you haven't recently. My 2012 Honda stops like hell, and has single-piston calipers on not-very-large rotors in front; it has (small) drums in back (they only give you rear discs with the cosmetic options package that includes alloy wheels--you can see the discs through them). The science of effective application is not found in bolting on the biggest and blingiest things you can find.

By the way, the Honda (Civic) weighs more than my 1963 Falcon; I surely do not need 14-inch rotors to stop as well in the old car...

[TLWiltman]

You only need a rotor large enough to get rid of the heat produced by the brakes during heavy use. Anything larger is extra weight and generally cosmetic. Keep in mind the ubiquitous NASCAR stock car. 15" wheels and just shy of 13" rotors (actually, I think they have a short track setup with 13" rotors nowadays).

[corvettekid1973]

He could go with 10'' rotors and single piston calipers on all four corners and it could stop great, but those breaks would fail if he ever decided to track his car with those brakes and larger wheels. It depends on his intended use of his car. Do bigger brakes add weight? Yes but that's what's needed for heat dissipation, which helps with reliable consistent braking. Its works the hell out of brakes when people put those 20" wheels on brakes that was meant for a 15" Wheel

[darkling]

i'm actually looking at the 12.88 wilwoods 6 piston on my nova in the front with 18's but not to sure how to set up the back i'm going to be using a strange 9 inch was thinking that just the 2 piston would even be overkill

[Paul Huryk]

Like others have said, the important thing is the tire friction to the ground that matters - and that 65% of the braking friction is generated through the front tires and brakes. One of the best things you can to in terms of stopping power is put a wider and/or stickier tire on the front of a car.

Don't get me wrong, if your ride is 20+ years old (and still has OEM brakes), it would be better off with better brake systems. As an example, I'm in the process of putting on a 13" Wilwood FSL system on my 1989 Trans Am (10.5" front brakes stock) - rears are the 12" (and are more than enough). I already moved up to 275-40-17 tires from 245-50-16 and that made a difference with stock brakes. My Baer 13" 2 piston kit stops my Camaro from 60 in 105ft - you don't need a 15" 6 piston race system to stop anything short of a 6000lb SUV.

Actually you can over brake a car - if you don't have ABS and can lock up the tires without being 90%+ on the pedal, you have too make brake for your tires. Sure some cars need more thermal capacity to not cook the brakes, but cooling and better rotors can solve that issue most of the time. A lot of the newest cars with huge brake systems use the ABS as a crutch in terms of modulation - not many can out stop the right systems on an retrofitted car without ABS in anything other than a wet turn.

[LowFast]

You only need a rotor large enough to get rid of the heat produced by the brakes during heavy use. Anything larger is extra weight and generally cosmetic. Keep in mind the ubiquitous NASCAR stock car. 15" wheels and just shy of 13" rotors (actually, I think they have a short track setup with 13" rotors nowadays).

This is true, however they use very thick vented disks to disapate the heat and monster calipers as well. I would actually like to see manufacturers provide NASCAR type brakes with thick disks and overall smaller diameter for those who do not want monster wheels.

[cornfedbill]

Big brakes are really most beneficial in the dissipation of heat. Small brakes overheat more rapidly than large brakes.

If they lock up too easily, the pressure can be reduced by changing to a larger master cylinder piston diameter or smaller brake caliper pistons. You can also change the pad compound.

It is true that small brakes can stop just as quickly - once. But repeated stops will cook the small brakes.

Is this for track use? Autocross? Cruising? An honest assessment of the goals may help you to decide how much brake (mass) is too much for you. I am sticking with 12" x 1.25" rotors. I am not planning on hard track use. They will be enough for some track use, autocross and more than enough for the street.

Remember that rotors are flywheels that suck power to accelerate and make it harder to stop. Rotating mass carries much more inertia than mass that is not rotating.

[Quickboat]

When you can't fit anything bigger!

Bet those dont stop so well with that brake line and banjo bolt lying on the ground like that...LOL....

[TheJDMan]

When you can't fit anything bigger!

Agreed!

[SLO_Z28]

This is true, however they use very thick vented disks to disapate the heat and monster calipers as well. I would actually like to see manufacturers provide NASCAR type brakes with thick disks and overall smaller diameter for those who do not want monster wheels.

Everyone brings up NASCAR but that is not the series to get brakes from, the cup cars have absolutely terrible brakes. The biggest problem I see is that no one asks the right question here, which is what brake PAD you should run. Pad matters MUCH more than rotor diameter, and caliper piston count. Getting a pad that has the right feel to the drive, in the heat range the driver is used too, is more important than brake size.


Brian Hobaugh won every single event at Run To The Coast, smoked everyone on the road course, autocross, and speed stop, by a lot. Brian is on bone stock brakes.

[a67]

Everyone brings up NASCAR but that is not the series to get brakes from, the cup cars have absolutely terrible brakes. The biggest problem I see is that no one asks the right question here, which is what brake PAD you should run. Pad matters MUCH more than rotor diameter, and caliper piston count. Getting a pad that has the right feel to the drive, in the heat range the driver is used too, is more important than brake size.


Brian Hobaugh won every single event at Run To The Coast, smoked everyone on the road course, autocross, and speed stop, by a lot. Brian is on bone stock brakes.

OK, I'll bite, what pads was he running?

Bob