Inboard braking / Torsen stubs

[agosling77]

So we are considering an F1 style dual inboard braking system for our rear end.

One seemingly simple concern I have is that we are using the stock Torsen housing, but I see of no way of stopping the inboard stub axles from moving in and out of the diff unit using the stock housing.

Also, do the stub axles need to be supported with bearings inside or outside the housing?

Just looking for some insight to some of my drivetrain issues.

[agosling77]

So we are considering an F1 style dual inboard braking system for our rear end.

One seemingly simple concern I have is that we are using the stock Torsen housing, but I see of no way of stopping the inboard stub axles from moving in and out of the diff unit using the stock housing.

Also, do the stub axles need to be supported with bearings inside or outside the housing?

Just looking for some insight to some of my drivetrain issues.

[oz_olly]

The Torsen diff is designed to use snap rings to retain your stub shafts. You need to machine a groove in the end of the shaft. To determine how big this groove should be you need to first choose a diameter for your snap ring. In 2007 we made our own out of some high tensile wire and bent them around a piece of round stock. The groove in the end of the shaft should be deep enough to allow the snap ring to compress in its groove below the minor diameter of the stub shaft spline. The snap rings look like a a wire ring with a segment cut out. Once you line up the splines on assembly you just tap it in gently. To remove it you usually need to make or use some sort of slide hammer that can pull it out so make sure your diff housing can react the slide hammer loads or you may never get the stub shafts out again.

If you are worried about the stub shafts plunging into the torsen spline use a bearing or bushing shoulder to limit that axial motion.

And lastly yes you do need to support your stub shafts outside of the housing because at any angle where the axles are not parallel there is a resultant torque that needs to be reacted (do the vector sum of your drive line torques at max angle and load combination to determine what this moment to be reacted is). You will then see to react this resultant moment the shaft should be supported in two places. You can use the torsen splines to do one reaction and a bearing on each stub shaft to do the other (the way you are planning to mount your discs, I imagine the torque from the eccentricity of the brake disc may be larger than that due to the drive shaft angularity (check both cases).

I hope I understood your question correctly, if not sorry for over simplifying.

Cheers

Olly

[Hector]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">And lastly yes you do need to support your stub shafts outside of the housing because at any angle where the axles are not parallel there is a resultant torque that needs to be reacted (do the vector sum of your drive line torques at max angle and load combination to determine what this moment to be reacted is). You will then see to react this resultant moment the shaft should be supported in two places. </div></BLOCKQUOTE>

I may not understand your post oz, but why do the bearings need to be outside the housing?

Seems to me like any bearing (inside or outside) of the housing should serve to handle the moment just fine.

[oz_olly]

Hey Hector,

Yeah sorry, there was a lack of clarification in my post. You are dead right the bearing can be in or out of the differential housing provided they are correctly supported and constrained. What I meant was you need to have bearings outside of the actual torsen housing that holds the side gears unless you make your own custom one with all the bits integrated.

Cheers

Olly

[Hector]

Awesome - thanks for the response.