Originally Posted by Robudda723
Trying my hand in on road and have picked up a TC3. I am running a 17.5 Brushless. The GT Sedan class I am running in has a 3.5 FDR rule. However the instructions for that car do not show a Brushless system. Any recommendations on the spur and pinion to come up with the 3.5 FDR with a 17.5 Brushless system? And what is the proper math to get the FDRs for the TC3?
Can't guarentee you can reach your FDR without a slight mod to the chassis in order to make room for larger pinions but try it first and then do the mod if needed. FDR is simple. internal drive ratio of the tc3 is 2.5 if i remember correctly.
So...spur tooth count / pinion tooth count = ? then ? x 2.5 = FDR
EX: 72 / 40 = 1.8 then 1.8 x 2.5 = 4.5 FDR.
. should help.