How to set the ball diff?
 

Hi was wondering what is the correct tightness for the rear ball diff?

The setting I do is, to set it so the hex driver is hard to turn. then i like to back it off around 1.5 to 2 full turns. Is this too loose? Will it wear the ball diff prematurely?

I dont like it when it is tight as per the instruction sheet coz it makes the car feel like its rear wheel drive. Hard to get rear traction and good holeshots

You put the diff in the car, lock off the slipper and set the diff according to feel, the front should always be set tighter than the rear, which is probably why you find it tail happy on power.

i have front one way. i have set the rear diff 2 turns out from tight, and it feels nice like that.

but reading the instructions it pretty much says you have to have it tight or you will wear it out.

i'm worried this setting would be too loose.

is it so long as if you hold the spur and spin one wheel, if the other wheel rotates the other direction without any slip then it should be ok?

No, you lock the slipper, put a driver in one diff half and spin the wheel on the other side, you need to put in a reasonable amount of force the be able to make it slip. If it's too easy, then the diff is too loose.
Make sure the slipper isn't engaging when you do this or you wont be able to set it properly. You should always check the diff after 1-2 runs after a full rebuild as the balls would have seated by then, thus loosening the diff slightly.

2 full turns out from tight is far, far too loose!

I start with a setting that is hand tight on the screw (don't force it as you may slightly deform the plates and balls), then slacken off between 1/8 and 1/4 of a turn.

Fine tune your setting in the car, basically the diff should turn smoothly without slipping if you hold one wheel and the locked spur gear and try and turn the other wheel.

thanks heaps. now my setup is more stable i'll try a tighter rear diff. :bom: