What FDR?
 

Well I searched here and I searched google. I can't seem to find a calculator or a set of numbers to hit either.

I just got a TA05 and thought about putting my MM5700 system in it on 2s LiPo. I can't seen to locate a final drive ratio for this, or for the car with an epic 27 for that matter. I may go with either motor. I plan to race it in a local parking lot track so I need a ratio for a 6 minute race, not top speed or anything crazy.

I have a 100 tooth 64 pitch and 5 different pinions for that or a 70 tooth 48 and a few pinions for that as well.

Thanks guys - Tim.

I would suggest using 48P if you are in a carpark. Little bits of girt and stones on an un-prepared surface chew uot spursa like nobodies business.
w.r.t. FDR, the standard TA-05 has an internal ratio of 2.25. For the MM, the 70 spur will be way too small, you won't get a pinion small enough to get a gear ratio that works for racing.
For the 27 turn, i'd start with an FDR of 6.5 and work from there. That's what I raced on before brushless in my TA-05, but it depends on your track size.
For the MM, the FDR is going to be more like 8.5 to 9.5 to be in any way useable in a race.

Shouldn't that be a 17 or 18 tooth to get a 9.26 or 8.75? Are those too small to use?