storytyme

iTrader: (20)

I run a 2wd buggy. The ideal FDR for the 2wd according to http://www.comeseethis.com/gearing/Default.aspx is 8.1. I understand how FDR works and what a higher and lower FDR mean, but how about using different combinations of spur and pinion to get the ideal FDR. Will I see any difference. If I want a FDR of close to 8.1 I can do the following:

spur/pinion
87/28 = 8.08
84/27 = 8.09
81/26 = 8.10
78/25 = 8.11
75/24 = 8.13
72/23 = 8.14

So will I even notice a difference in these combinations if the FDR is always going to be at 8.1 or close to it?? I know some of these combos won't fit as they are too small to mesh together (72/23) or too big to mesh (87/28). I was going to go to the track to test out these combos but thought I would post here to get any thoughts

t0p_sh0tta

iTrader: (35)

http://www.rctech.net/forum/electric...ifference.html

On-road, but it still applies

Not to derail, but I have a similar question. Is there a set rule of thumb as to where to being when picking your FDR?

Comeseethis.com lists an ideal FDR for each car and motor. Is this ratio dictated by the motor manufacturer (e.g. 7.1 for a 13.5), or is there some golden rule for gearing that I've never heard of?

I'm not sure if that question was clear, so I'll post an example: I swapped my 7.5 motor (87/22) for a 10.5 (87/24 to start) the other day. How would I know where to begin with my gearing? Trial and error? Start with the recommended FDR ratio from the motor manufacturer?

-Lamar

bob o

iTrader: (2)

A smaller pinion will spool up faster, slightly less weight to get spinning.
Bob O

storytyme

iTrader: (20)

I would start with the recommended FDR. For tracks with long straights go with a lower FDR. With tight infields go with a higher FDR. Not sure than stay with the recommended FDR. Good luck.

t0p_sh0tta

iTrader: (35)

Thanks