Ring and Pinion Backlash, What's everyone doing? Options

[Matt Romanowski]

For the folks who are rebuilding their own transmissions, what are you using for a backlash measurement? The manual says around .007, but that seems a little tight. We're trying to get some temperature out of the transmission and were thinking about running a little looser. Anyone tried that?

[Dr Evil]

I disagree. When it comes to the 901 pinion, more teeth takes away from the overall girth of the pinion base with smaller/thinner teeth. They would definitely put this in a box that was not intended to handle crazy tq. These weaknesses become evident when high tq is passed through a box not built for it. When keeping in with parameters speced for the boxes, the number of teeth is not an issue.

Your mention of the change made to gain an extra tooth on the 915 supports what I am saying. Increased size was mandatory and that box handles more tq/hp than a 901. All parts are thicker in that one.

[Jon B]

More teeth increase the gear's load bearing surface and help decrease material fatigue. That is a fact. Each tooth surface bears less sustained load per cycle, as time spent in contact is briefer. And having a slightly taller ratio, the 8:35 pinion has fewer cycles per mile as well.

We can disagree.

In any case it's really not a viable solution for anyone, as sets are both scarce and expensive.

Jon B.