How To Set A Gear Mesh

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by Joe "Noose" Neumeister


I posted this in SlotBlog and thought it would be good to add to the IRRA site.
It works for me and it sure does help prevent motor and bushing burn-outs! I have never lost a gear and always have smooth gear meshes with both hypoid and non-hypoid set-ups.  This is all meaningless if your chassis is weak in the back and you slam into someone/something or visa versa. Minimizing the chance of a bent bracket will always ensure the gear mesh stays good.

Note: This applies to the most commonly used Parma crown gears which are plastic. It won't hold true for metal gears.

1. Make sure the axle spins completely free in the bushings or bearings.

2. I make sure the fat end of the angled pinion is towards the motor and the tapered end is toward the crown gear. The teeth of the crown should touch the pinion just ahead of the rear of the pinion (the fat part) . Some like it in the front but I have seen more guys blow gears that way.

3. Set the crown against the pinion and lightly lock the set screw.

4. Turn the axle to see if there is some play all around. Almost all of the Parma crown gears are a bit out of perfect roundness. You need to find the high spot and that is the spot you want to make sure is set with the right amount of play.

5. The crown should just move slightly in this spot. If not, use your hand to turn the crown away from the pinion a bit and check again until you feel you have it right.

6. Lock the crown down and check the play all around again.

7. With a power pack hooked up, turn up the power until the motor starts to turn over slowly. Take a lighter and put the flame along the teeth and pinion for a short period of time. You can literally hear the the sound get quieter.

Do not overheat of course or you are going to melt the gear.

Another tip:
I keep my gears separate. gears used in hypoid position with Pro Slots or Falcons are kept separate from those aren't and separate from those used on TSRs, which turn the opposite way.

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