XRAY - Model racing cars

Try reading this thread:

viewtopic.php?t=9023

It's for the 009, but the principles are still the same for Final Drive Ratio.

You do need to check the internal ratio of your 008 though, as there were two options produced, one with 38T diffs and 16T centre pulley giving an internal ratio of 2.375, or one with 34T diffs and 20T centre pulley giving an internal ratio of 1.7.

In case you are not sure, the FDR is than calculated as:

Spur gear / Pinion x Internal ratio

So, your original set-up is;

116 / 40 x 2.375 = 6.89 FDR (assuming the 34T/16T internal ratio)

Just one other point, if you are buying new spurs/pinions, you might like to consider going for 48dp rather than 64dp as personally, I think it's a bit easier to mesh 48dp and most people quote gearing assuming 48dp.

Hope that helps.