Gearing advice

[jono83]

hi can some one give me a starting point for a sintered 7.5 wth a 83 spur gear around oswestry its a tight astro/grass track. thanks in advance

[stegger]

I'd go with a 21,22 pinion fella but somebody from there may have better knowledge

[bigred5765]

21-22

[jono83]

cheers guys

[jono83]

Also how about a 6.5 around the same
track. With an 83 spur.

[mikeyscott]

What was the FDR of the 7.5?

20 for a 6.5? Not sure as I'm about to do the same 7.5 >> 6.5