Originally Posted by
ospower
hi everyone im starting to run this class my car is a cyclone s with a speedpassion 21.5 and a fdr of 2.43 i would like to know a combination of spur and pinion for a fair top speed, can anyone help me?
it's all going to depend on track size. what i run at my track may not work wel for yours.. a really low FDR (under 3.0) is not going to work on a track with a short straight away; and conversely, a high FDR (4.0+) won't work on a track with a mega long straight
but you'll probably want to shoot for a FDR or 3.9-4.0 for a start. I also think the 2.43 you stated above is the IR (internal ratio) of the chassis. you should be able to find some online charts that will break down what FDRs you'd get for X pinion and Y spur.
but from my experience for the HB TC, TCX and TCXX - you're going to want to use between a 90-100t spur and then the appropriate pinion(s) from there. also, my experience with the SP motors, is they need a little lower FDR to get all the power out of them - i've run a couple before and they are good, but i always had to go to a lower FDR when i ran that motor. i've since switched my last SP to my rally
