Brake Mounting location

[Forspeedrs]

Would someone explain what determines where to mount a brake caliper, ie. why should the brake caliper be mounted on the front side of the rotor rather than the rear, and vise versa.

 

[CoryPad]

For racing vehicles or passenger vehicles?

Some considerations include: packaging (e.g. avoiding the steering link), stress on the upright, polar inertia moment (racing only).

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Forspeedrs]

From mostly a racing point of view, basically the inertial affects. For example, would it be true that placing the brake caliper on the front side, the reaction force from braking would put the suspension in jounce? How much affect does it have, and is it worth doing over better packaging.

 

[GregLocock]

would it be true that placing the brake caliper on the front side, the reaction force from braking would put the suspension in jounce?

No


Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Forspeedrs]

Greg,

Could you eloborate, what affect does it have, if any?

Thanks

Lou

 

[GregLocock]

There is no net vertical force on the suspension due to the brake, because there isn't one. How can I explain the absence of something?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Forspeedrs]

Sounds good, this is what I thought, but I had peers of mine trying to tell me it was different, thats why I asked the almighty Greg Locock... any idea as to what CoryPad was driving at?

Thanks

 

[CoryPad]

The inertia effects I mentioned are at the entire vehicle dynamics level and are concerned with yaw and pitch response. If mass is located more distantly from the centroid (e.g. with front brake calipers mounted towards the vehicle's front), the polar inertia moment is higher. This is not necessarily a large effect, but still a concern for some racing applications.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Forspeedrs]

I gotcha Cory,

Thanks

Lou

 

[evelrod]

Having a choice, I put my calipers on the front facing forward simply to facilitate pad changes. On many cars ,e.g. Cortinas, Anglias, etc., the front struts can be mounted so the calipers are forward or rearward. I've tried them both ways and I prefer forward. On the rear disc braked cars I have built, it did not seem to matter so I mounted them whichever way gave the most clearance for other suspension bits.

I suppose cooling could be a factor. I use ducting to the brakes in any case.

Rod

 

[2SlowJoe]

Mounting the caliper at the front or back rather than the top or bottom can help reduce "knockback".

Under cornering loads, the wheelbearing flexes which causes the rotor to be at an angle relative to the pads. This spreads the caliper. The next time the brake is applied, their is a dead pedal band as you bring the pads back to the rotor. This is worse with certain types of calipers. (opposed piston)

-Joe

 

[oab]

With motorcycles, the caliper is mounted at the rear, to bring their mass in line with the steering axis. When they are mounted at the front, they add to the steering pendulum effect.
Not so important on cars.

Harvey.

 

[lemans]

looking at the side of the car .calipers should be inbetween frt.and rear tire.to keep calip. wt. closer to the cg. old f1 trick.

 

[hemipanter]

Mounting the caliper to the rear of the disc is cancelling out iternal loads in the spindle. I cant go in to it to much without making some drawings for a good explanation.
But you may think of it as a cowbar acting from the tiregrip to the spindle axle and caliper. We like to keep those loads as low as possible bot not to the extend of changing load direction in the wheelbearings during hard braking. In such case the caliper location could be mowed clockwise in the right direction.
I am not saying this is important, only that the fhenomenon exsist and that it could be uset to the advantage.
Goran Malmberg
Hemipanter