Hi Al. Final drive ratio is determined by the formula FDR = (S/P)*T where S is spur gear, P is pinion gear and T is internal ratio of the transmission. For the XXX cars it is 2.43, for Associated based cars it is 2.60.


Vehicle: Team Associated B4.1 Factory Team
Motor: Trinity/Epic Duo2
Motor Timing: 8
Gear: 31/69
FDR: 5.78
Track size: Medium/Large (~100' straight)

This setup is really good down the straight, but lacks the low end power that the Schuur Speed 17.5 has. The car is worn and the motor is old, but it is still within .4 seconds of my best lap with the X Factory X-6 Squared.


Vehicle: X Factory X-6 Squared (Associated transmission)
Motor: Schuur Speed 17.5
Motor Timing: 30
Gear: 33/72
FDR: 5.67
Track size: Medium/Large (~100' straight)

I don't want to change anything with this setup. If it weren't for other mechanical issues with my buggy I would have been solidly in the top half of the A main (after starting almost last in the B main). 3 stripped wheels and a broken CVD dog bone forced me to my backup car (B4.1 FT) for the A main, and then I broke that 2 minutes in. Bad night of RC even though my X was crazy good.


Vehicle: X Factory SCX-60CF (Associated transmission)
Motor: Tekin RS 17.5
Motor Timing: 12
Gear: 27/75
FDR: 7.22
Track size: Medium/Large (~100' straight)

With the Tekin motor I cannot gear it as high as I need to because of temperatures. At 27/75 I'm temping at ~140F, but at 28/75 or 27/72 I'm near 170F. This week I'll be trying out a new rotor (12.5mm stock legal high torque) which should give me more power with less timing, and with any luck it will be cool enough to add some gear. I'm getting killed on the straight but am making it all up in the infield (good enough for a podium finish my first run with a stock short course, anyway).