Inboard Rear Disc Brakes - Plausibility

[tom'72]

My mother has an '85 Citroën 2CV that has stock inboard brakes, never thought they would be better in any way then regular brakes really.

[Steve C]

Hi

The old Audi 100s had inboard discs. Its a nice idea but I feel its not worth the effort.

Steve

Audi 100

[CPRcubed]

I did my college senior project by putting inboard rear disks on a '69 Baja. I used 914 calipers, Type III rear hubs, and machined the other parts (rotor hats, rotors, and mounts). Caliper mounts bolted to the transmission side cover studs. Rotor hats mounted to the tranny CV flange (using longer CV capscrews). The setup saved about 14 lbs unsprung weight per side. The brakes worked well, although since all braking force is now transmitted through the CVs and axles, it is very hard on those components. I ended up breaking one of the CV "bearing cages" due to the constant loading (I imagine applying the brakes is like launching the car from a dead stop all the time). Caliper orientation is also limited under there. I could not get them oriented to where the bleeder was at the high point. I had to unbolt the calipers to bleed them correctly. My calculations showed a very small improvement in suspension reaction with the reduced unsprung weight which probably is not worth the cost and effort associated with such a conversion. Cheers!

[Wally]

Originally Posted by Steve C

Hi

The old Audi 100s had inboard discs. Its a nice idea but I feel its not worth the effort.

So did the Alfa 155 models over here. I am sure other Alfa's used them as well.
Its a very good idea IMHO.
I don't really get the airflow concern for cooling? :
Airflow is much better at the trannny ends than encapsuled inside a big wide wheel

The service issue is probably the reason for most factories not to use them.

[dd-ardvark]

Have you guys had a look at http://www.transworks.biz/ before. Seems that they may have come up with a new way of skinning a cat.

On their site, they machined IRS type1 side covers to accept outboard bearings to carry the weight of the carrier and output shafts, that by doing this it stopped stub axle breakage associated with IRS high HP type1 trans applications..., and consequently their running Inboard brakes as well.

Have a look, it's under FLANGE BEARING RETAINER, here's the link http://www.transworks.biz/TWP.html http://www.transworks.biz/brakes1.jpg

dd-ardvark / David