Originally Posted by andy (Post 127171)

can any body tell me what pinion to use on a trf501 with kit spur on a 10 turn brushed motor and 11 or 12 thanks,

Originally Posted by sosidge (Post 127291)

If this is an original 501X (16/36 pulleys, 96 spur), we were running a 19 or 20 tooth pinion with a 10x2 Much-More motor at the NERCR regional yesterday (around 11:1 overall), this was a medium/large grass track (25s lap), certainly the car lacked nothing in straight line pace to the other cars in the field.

If you are running a Worlds Edition car (38/17 pulleys, 91 spur, same as Durga), then we were running a 17 pinion with the same motor, spot on 11:1 overall ratio.

Indoors or on a smaller track you might want to go down a tooth.

Going up a tooth per wind is probably an OK starting point but you really need to look at the car on track, if it lacks pull out of the corners and up the jumps you probably need to go down a tooth, if it is revving out on the straights you probably need to go up a tooth.