Originally Posted by jcr
what a pain trying to find something that will mesh together with the motor mount restrictions. I am guessing you're using all three screws to mount the motor?
Yeah, once you find a gear combo that meshes well you will be all set. Spur gears in the 90 range seem to be a good fit and offer a variety of pinions for tuning a good FDR. I was wrong to say start in the 80s since they are a little too small and won't mesh right, my bad.
Just settle on a spur gear size for now and then adjust only the pinion from there to get a good FDR. Let's make it easy and start with 96 for a spur, that leaves you a good range to choose from for pinions, from 44-55 and maybe a few more. Run laps for 5 minutes and check the temps and lap times and then just switch the pinion out from there to adjust and find the sweet spot.
3Racing makes some nice inexpensive gear sets too so you can stock up on a wide selection.