Good morning all,

I'm having a dull moment. Based upon a tire comparsion calculator I know it will make a difference on the MPH, if I change sizes. Now I'm wondering does it make a difference on the odometer too?

Thanks

 

Yes, of course it will.

 

Yup, but not by any significant amount for the first few tens of thousands of miles.

 

Gas station to my house with 195/50-15 tires: 2.7 miles.
Gas station to my house with 195/55-15 tires: 2.6 miles.

I haven't done any testing but I would think it's a good guess that going somewhere for 270 miles on 50 series tires would make it look like 260 miles on 55 series tires.

 

Yes, and it sucks because it will never be the actual odo mileage of the vehicle.

 

It's a simple game of percentages. If your tires are 4% smaller than stock, your OD will read 4% high (you haven't gone as far as the OD says). If your tires are 4% bigger than stock, your OD will read 4% low (you've actually gone further than your OD says).

BTW: Your speedo wasn't accurate to begin with. They typically read 5mph high compared to what the computer is reading from the speed sensor + any % difference in your tire setup. Your best bet is to memorize a few speed/rpm steps from a gearing calculator (like M-factory's). I like to know true 65mph and 45mph cause those are typical "regulated" speeds. It's good to know what rpm to be at in 5th should you see a cop speed-checking people.

Here is my old stock Civic CX D15B8 setup compared to the ITR swap setup on (both on 205/40/16):
http://www.teammfactory.com/gearcalc...ission+1+%26+2

Here is my ITR swap on 205/40/16 (4.2% smaller tire) compared to a stock ITR with 195/55/15 (23.44" diameter):
http://www.teammfactory.com/gearcalc...ission+1+%26+2