Car gear ratio question?

Question

K, im lookin to put some bigger rims on my car but im wondering, if I go from 13" rims (05 aveo...dont laugh I get 32mpg in the city) to 17" is this going to raise or lower my gear ratio? Actually, let me ask it another way..If my car with 13" rims goes 30mph in second gear at 3k rpm, will it go faster or slower at the same rpm/gear with larger rims?

And for the techies out there...If I do make a 4" rim increase is this going to mess with my ECM?

Answer 1

Bigger diameter wheels will make the car go faster than the speedo reading.   If if your car was doing 30 mph, it will actually do 34, 35, 36 (etc.) mph.

but the car will accelerate slower.

Good Luck...