How do I calculate my gear ratios?

[Apples]

I have a 72 tooth and a 28tooth. So that is 2.57:1.

If I had a 28 tooth on the motor, then the 72 on the other end like before. Then if I added a28 tooth to the same shaft as the 72. Then ran a belt back the other way to another 72 tooth. What ratio would I have then?

Would it be 2 lots of 2.57:1.

So 2.57+2.57=5.14:1 ratio?

Apples
Australia

[fkaCarel]

(72 / 28) * (72 / 28) = 6.61 (also 2.57 * 2.57)

[Apples]

Thanks,

Quick reply too.

Cheers

Peter