changing gears

[Aero 9000]

Originally Posted by ihbuilder

well start playing around with different turn motors and pinion gears . Put in a grear reduction unit . There are a couple of options for those (GRU ) . In my heavy hual 5900i , I have a 75t lathe motor with a 4:1 GRU . In 3rd gear It'll just keep up to the other trucks in 1st . BUT , If your gona go that low you better beef up the input pinions on the axles when pulling weight (excess of 100#)

I'd want a multi speed GRU, to get lower gears and keep the high ones.
When you say "beef up the input pinions" in what way, different diameter or different material....?? Or change axles completely....??