F/R brake temperature?
 

How much difference there should be between front and rear brake temps after lapping session?
I have about 100 C. difference f/r. I understand that fronts work harder, but it is about 40% temp difference.
I wonder if I should get more aggressive pad for the rear to make them work harder.
Thoughts?

Convert your temperatures to Kelvin (or any other units where 0 is absolute zero) and the difference isn't all that much.

500F front and 310F rear.
Is it too much of a difference or not?

A lot of variables involved - pad composition, rotor material/construction - but 190F sounds reasonable to me. The fronts are doing a lot more work so they naturally get hotter, ie, you can't expect the temps to be all that close. You should be paying more attention to balancing the brakes and don't worry about the temps so much. If you are balanced now, more aggressive brakes will throw the balance off.

Indeed. To expand on that a bit; the ideal brake balance of the car is dictated by how much traction is available at either end of the car under maximum braking. The traction available is dictated by the tires, weight balance of the car, and the weight transfer that takes place at maximum braking. The amount of weight transfer is dictated by the wheelbase length, the weight of the vehicle and the rate of deceleration.


In effect this means that with grippier tires, more weight transfer will take place and the front brakes should be, and will be able to, do comparatively more of the braking work since they have more weight over their tires. Conversely, with less grippy tires or when its raining, at maximum braking, less weight transfer will take place (because you cant brake as hard) and a setup where there is less of a front biased braking force -still front biased though- will then provide the most overall braking ability. That's why, a bit counter-intuitively imo, racecars or cars with adjustable brake bias like mine need to run more rear bias in the wet than in the dry to maximize their braking capability.

If your not having brake issues then don't fix your brakes.

Well said one of the best explanations on brake balance I have read in a while.:tiphat:

Exactly! If you are not having any of the common issues like ice mode, brake fade or over cooking your brakes then you are good to go. I don't know what your skill level is but as you get faster you will need to add brake cooling and possibly more aggressive pads. As stated above at that point you will need to talk to someone with experience and find the combo that works best for you. I would also limit the number of experts you talk to as well as it will complicate things. I use a couple of different of speed shops for their specific specialty. Although I live by the premise, keep it simple stupid there is nothing simple about track car setup the better you get as a driver and you are able to exploit the limits of your car.

Run nothing less than Motul RBF or Castrol SRF brake fluid.

The most important temperature you need to be concerned with your brakes... is the Caliper temperature.

The rotors get 1000+ F with track use.

As long as the CALIPER (that holds the fluid) remains below the boiling point of your fluid, you're good. This is why TI shims behind your brake pads are so effective.

...Most people jump out of their cars to open the hood, or check tire pressure.
I, on the other hand, measure caliper and rotor temps. If rotors are still 700+ after cool down lap then i drive a mile around the paddock to cool some more.

You never want to park the car with smoking hot brakes after a session. The pads will transfer material to the rotors causing a high spot. When I park. I try to park on a slop. After about 10 minutes. I will drift the car forward about one half of a tire rotation. This puts the pads in a different spot on the rotors.

And don't put the e-brake on either. It may stick.

I've gotten the 'bono's hot enough to leak around the bleeders on both front and back.

:iagree:

I have exactly the same temperature on all calipers and I have Brembo GT-S 380mm/345mm combo which is 2 empty bar from the max on Brembo temp sticker. You should have the same temperature front and rear if the bias is correct.

No... don't think so.

70% of braking is done with the front wheels... it's the same reason the front rotors are bigger than the rears. Different inputs = diff temps.

The front brakes are about twice as big so they have about twice the heat volume. I sold many Brembo race kits here in Taiwan as well as the GT, GT-S, and GT-R kits on street cars and race cars, and they all behave the same.


iPhoneTapatalk

Just wanna add this little bit here via AP Racing’s website

https://www.apracing.com/Info.aspx?I...&ProductID=976

“In order to achieve optimum racing brake performance and prolong disc life it is essential that the brakes operate at the correct temperature. In general discs should run at similar temperatures front and rear and from side to side, dissimilar temperatures will lead to varying brake balance.”

Also wanna point out, Andy’s method of temp sticker indicates peak temp, where as Obender66 seems to be measuring temp after a cool down lap, so the different rates of heat dissipation may also cause a bigger variance than there is.

Another thing is, was Obender66’s temp taken after many successive laps where rotors and calipers’ temp were stabilized, or after just a couple quick laps?