How will tire diameter affect gear ratio???

[98ls1blackbird]

I've got a question, I'm going to buy BFG drag radials for my 98 TA A4 with 2.73 gears. I see they make a 205-40-17 that is 23.5 inches in diameter. I want a shorter tire to help out the 2.73 gear a little. How will that change the effective ratio campared to a 26.1 inch diameter of a stock size tire. I don't know how to figure it out. Having a brain fart I guess. Any help is appreciated. Thanks.
John

[0rion]

Not sure how accurate it is but I found a calculator that said you're new actual ratio would be 3.03.

I'm pretty sure the calc is ( old tire/new tire)*axle ratio= new ratio so 3.03 would be accurate but like I said, I'm not positive.

[98ls1blackbird]

Thanks, thats the info that info I was looking for.