Just received my Yusa on road car and was wondering what to do about the 2 speed center trans. I would like to keep the two speed and was wondering how to gear it. I know that mike makes a 2 speed adapter to use the losi mod1 screw-on gears. How do you determine which pinion gears to use together. I will list the stock gear sizes when I have a chance, but I understand that the two pinions have to be specific sizes for each to mesh correctly with the spur gears at the same time.
I would say use BrianG's gear calculator to determin the diameters of the stock pinions & spurs, and the ratio between them, then apply that knowledge to picking new pinions.
That sounds like what I came up with. The gear sizes are 17 and 21 on the pinion and 44 and 48 on the spur side. Guessing that this has buggy ratio diffs, 43/13. With those ratios it should be quick with my aveox/mgm combo. With about 38k motor rpm it will do about 65mph in 2nd gear!