Originally Posted by Aristo

Gearing

If you have worked out your required roll out and irrespective of internal ratio. You have settled on in 64 pitch 38 tooth pinion to 88 tooth spur. What are the advantages/disadvantage in using the above as opposed to using 45 tooth pinion to 104 tooth spur?

Putting it another way what advantage/disadvantages in using small pinions and spurs as oppose to larger pinions and spurs with the same ratio. Or does the internal ratio influence this as well? That is; if you were to have a 1.75 internal ratio and or a 2.13 internal would you use the smaller pinion/spur combination with the smaller internal ratio or vice versa to get the same roll out?
Aristo

Originally Posted by ray_munday

A couple of things to consider Aristo:

- The weight distribution will change if you use large gears vs smaller gears as the motor will move forwards / backawards. In 2wd off road this makes a very big difference, not sure about TC.
- bigger pinions and gears will have higher inertia, reducing acceleration.
- very small gears (below 16 teeth) tend to be less efficient than larger gears, but by the sound of it you are well away from those sizes.

If you are running a stock class with limited power I would probably go for the smallest gears possible to reduce the inertia and have maximum acceleration.

Ray