Rear Caliper Position - Any Advantages?
 

I am building up a 9" rear, and since I'm welding on the brake brackets, I have some latitude on how I position the rear calipers - right at 90 degrees, slightly higher, etc.

For example, this guy has his clocked slightly higher than the centerline:

http://thegmr.com/wp-content/uploads...oser-12-52.jpg

And this guy's is slightly lower:

http://thegmr.com/wp-content/uploads/2012/01/024.jpg

And most pictures I see, where the caliper is behind the axle line, the caliper is clocked right at 90 degrees.

Are there any advantages to clocking the calipers other than the standard 90 degrees, other than modest packaging considerations? Clearly I would get into bleeding issues if I went too far either direction.

Thanks,

Jim

I think any benefit of position would be small. For example, putting them lower, moves the mass slightly lower, and probably gives them more airflow over the caliper but you aren't going to notice anything as a result.

The second picture is my rear end. The calipers arent actually mounted that low, they are just hanging there at that point, they actually ended up near vertical, in other words the bleeders are pointed straight up.

I have looked into this a little, and found no evidence supporting one position to be better than the other, in front of or behind the axle, or clocking the caliper either. Even with the caliper mounted horizontal, they can be bled by removing the caliper, installing a shim to simulate the rotor and bleeding normally holding the caliper in your hand......that is a pain in the arse, though.

Mount the calipers in a way that gives you the best clearance and easiest maintanence. After that I try to match the clocking of the front caliper for aesthetic purposes.

Thanks, guys.

Jim

I always wonder about the reaction load on the car.

Bryce, can you elaborate?

In side view, the caliper will load the axle housing through the caliper mounts trying to rotate the pinion down, that won't change. Would there be a different reaction between the caliper mounted front or rear?

If the caliper was mounted on the back side of the axle the load on the caliper would be in the vertical direction. the could reduce the load on the tire. The opposite would be true as well.

So you think that mounting the caliper in the front would load the tire under braking? The advantage would be minute at best, yes?

I visualize it the opposite but I doubt it plays out as they are both attached to the same component.

That part of the equation notwithstanding... Keep in mind that calipers can (and are) built as leading or trailing and are designed for that orientation - piston size / order. And FWIW I've run both leading and trailing and noticed no appreciable difference.