Originally Posted by
svines1972
Scottrik - I think I get it. If I go with 64 pitch, I come up with an 88 spur, 40-41-42-43 spur I would have a range of 4.09-4.40. Sound about right for the Novak GTB - 13.5 SS. Will these combos fit in the TC5R?
Well...you appear to have nailed using GearChart. Excellent.
Not sure how you picked the 88t spur, hopefully it wasn't from trying to convert your existing spur to 64p...though your existing spur is WAY bigger than it needs to be. You'd need pinions in the upper 50's to get down to the FDR you say you want so I don't think that would fit. You'd have a MONSTER spur gear combined with an equally monstrous pinion (though I have pinions up to 60t...gotta be able to hit 90mm rollout for 17.5 1/12 on longer tracks).
Just for checking your math...your 87t 48p spur matches a 116t 64p spur.
I'm pretty sure an 88t spur would fit fine with pinions in the low-40's.