Why position a brake caliper in front or behind the disc?
Why position a brake caliper in front or behind the disc?
(OP)
Good day people,
I am wondering if anyone can tell me the science or engineering (other than the obvious cooling and contamination prevention reasons) of positioning a brake caliper (either front or rear) behind or infront or above the brake disc?
Any help in this curious matter would be very much appreciated.
Craig Critch.
I am wondering if anyone can tell me the science or engineering (other than the obvious cooling and contamination prevention reasons) of positioning a brake caliper (either front or rear) behind or infront or above the brake disc?
Any help in this curious matter would be very much appreciated.
Craig Critch.





RE: Why position a brake caliper in front or behind the disc?
I place my front calipers out front as it makes pad changes quicker but, they would work equally well on the backside. The rears depends on clearance and such. My current vintage racer has drums in the rear so it's not a problem.
Rod
RE: Why position a brake caliper in front or behind the disc?
It's certainly not uncommon to see calipers located near the top.
RE: Why position a brake caliper in front or behind the disc?
Rod
RE: Why position a brake caliper in front or behind the disc?
Stub axle and front suspension knuckle or upright flex can and this does cause the pads to be knocked back during cornering with substantial loss of braking efficiency next time they are applied. I had a car that had this problem because the calliper was probably from memory in about the 11 "O"clock 1"O"clock position. The so called fixes was to have quite a preload on the wheel bearings, but that resulted in front wheel bearing life of about 30,000 miles.
Also as Rod says, at 6"O"clock, the callipers collect retain debris, and cannot be bled. At 12"O"clock, they will interfere with the design of the suspension upright, and the calliper is in the most vulnerable position to boil the fluid.
3/9 "O"clock in front of the axle the calliper is most protected from debris, and gets most exposure to cooling air, but it shields the rotor from cooling air. At the back of the rotor increases exposure to debris, and hot air off the rotors.
I think there is nothing new here. These problems have been considered for over 50 years, and the designs are decided on for best overall compromise for the particular application.
Regards
pat pprimmer@acay.com.au
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RE: Why position a brake caliper in front or behind the disc?
In the front it will put extra load on the bearings on top of the vertical load of the car's weight.
On the other hand, the available space on the rear might be less on steered wheels because the inner wheel has a bigger steering angle.
Giel
RE: Why position a brake caliper in front or behind the disc?
F1 tried the brake caliper at 6oclock purely for CG reasons, but found the caliper body being "milled" down by the wheel flexing, requiring stiffer setups.
Another point can be yaw inertia of the vehicle, having the front calipers to the back of the disc and rear calipers to the front of the disc will reduce the inertia of the vehicle, expecially using those mostor 8 pots.
Jakub
RE: Why position a brake caliper in front or behind the disc?
Unloading the bearing under braking might not be a good idea if there is any clearance in the bearing. It may lead to shuddering of the wheel/brake assembly. The extra vertical load resulting from the caliper in front of the wheel is most likely small compared to cornering loads on the bearing and will help to stabilise the bearing.
Regards,
Jeff