Gearing advice

[eda]

I need some pinions for the following combinations in my BJ4WE:

Novak GTB + 10.5T Nosram Dragon (manual recommends 20/78 = 9.75:1 F.D.R)

Novak GTB + Novak Velociti 6.5R (manual recommends 16/78 = 12.19:1 F.D.R)

Do these pinion sizes sound about right? Will be used mostly on medium size astroturf track for club racing.

[Richard Lowe]

They both sound a bit undergeared to me, when I used to run a Novak 5.5R in my BJ4 I geared it on 19/81, so for a 6.5 that would be more like 21/81.

I've never run a 10.5 so I'm not sure how you'd go about gearing that I'm afraid