Will taller tires decrease the gear ratio?
Is it a significant difference in performance?

thanks for any help!

 

Yes, and it all depends.....

tall skinny tires are way better in the snow

 

Going with shorter tires is said to be the poor man's gear change. I forget which summit issue, but there is a way to calculate your new gear ratio by changing tire sizes. By getting taller tires the gear ratio decreases numerically but you have a higher gear ratio, which will worsen you acceleration.

 

Just adding to Marks statement...in most cases it will increase top speed and gas mileage.

 

Just as a 3.08 is ten percent higher than a 3.36, a 27 inch tire is ten percent taller (and hence larger in circumference) than a 24.5.

Tire diameters can vary up to about .5 inch between companies. In some cases, you can change the net effect of a rear end ratio by approximately 5 percent by investigating the various tire options.

A 4.10 can be made to act like about a 3.9 with a little bit of work.