Gear ratio calculations

[Anorak_ian]

I'm a little curious as to what my final gear ratio is,
So I've been on the internet trying to look up how to calculate my ratios (with little success).

I got as far as, engine & clutch 36x68 (1.89:1), gearbox and back wheel sprocket 17x38 (2.24:1).
The back wheel / tyre is a 16 inch Avon sm mk2, 500 s.

Does anyone know how to calculate this to the final ratio?

Cheers Ian

[Crazymanneil]

I always liked this calculator -

http://www.rbracing-rsr.com/gearspeed.html

I think one of the members on this site is something to do with that site actually.

N

[Anorak_ian]

Thanks for the link, well that's given me something to think about.

Top speed 17 tooth 78mph,
18 tooth 82,
19 tooth 87mph.

She pulls away badly up hill with a 21 tooth so it looks like 19 tooth is the max for her.