Originally Posted by BigDogRacing
Are you running with timing boost or no?
No boost- 13.5 in the 7.0-8.0 range and 10.5 in the 7.5-8.5 range
Those are just starting points.
If you don't know how to calculate your FDR then there's a section on rctech for newbies. You can find what you need to know there.
Those FDR-ranges is for boosted, right? Or else that it seriously undergearing.
I would say, if running no boost, then use a FDR of around 5 for 13.5 and around 5.5-6 for 10.5.
That would be a (if using a 84 spur with an internal gearing of 1.9) 31-32 teeth pinion and a 29 teeth pinion for 10.5