I’ve destroyed more than my fair share of ball diffs learning how to break in and set them properly. If you have been over-tightening your ball diffs, that could be bad news. Here’s a guide on how tight you should tighten your ball diffs.
How Tight Should You Tighten Your Ball Diffs?
There are many companies out there that tell you to tighten your ball diffs all the way down and back off 1/8 of a turn. I never do this as I am a proponent of tightening the diffs slowly, an hour turn or two hours turn at a time until I get the feel I want.
How tight the ball diffs should be will depend on how much rotation you want.The loosest you want to run diff is when it is tighter than the spot where it slips. It must be tight enough so that the diff does not slip.
The further the ball is forced down into the ring, the more contact patch there is. This results in more force and there is more surface area creating more friction, which is why the diff feels tighter.
I feel that it is dangerous to back off the pressure on a diff because the pressure on the surface area keeps everything rolling smoothly albeit tight, and backing off the pressure might cause the ball to slip or slide off at some point.
This is why I believe it is in your best interest to bring your diffs up to tightness slowly while you break them in. Once you have got the diffs broken in, try not to back them off unless you absolutely have to. And if you have to back off the pressure, only do so by a little – a little pressure off goes a long way in the feel of a diff.
Don’t forget – ball diffs need to be broken in and readjusted, either on the bench or during the first run. The balls will start to sit in the rings which loosens the tension and causing the diffs to slip more. In order to maintain its slip characteristics, it needs to be retightened.