In the fall when I get new tires, I would like to jump up a little to a 265/75 tire. My question is just how much will it effect my speedo? It can't be much going up just one size but I'm still curious. It's about an inch difference in height all together. 30.5" to 31.5" give or take a little since it's not a perfect conversion.

 

You have a superchips don't you? It doesn't matter then since you can change it haha if you dont try one of the tire calculators out there to see the difference i'm guessing at least 2-3 mph

 

Here's a link I found searching the forum:

http://www.4lo.com/calc/gearspeedo.htm

 

http://www.miata.net/garage/tirecalc.html best tire size thing i have used.

if your going from 265/70 to 265/75 spedo will be off 3.4% 60mph on the dash will be 62 actual

 

i went from a 265/75 R16 to a 235/85 R16 and I have no difference in size, just a little skinnier.

 

Mine was off about 5 mph with 31x10.50's but fixed it with my superchips

 

Yeah I don't have it anymore. I sold it. It didn't really do a lot for me being a manual and didn't think it was worth it. I sold it for $10 more than I paid for it too.

 

Ahh...gotchya - yeah I know what you mean about the not feeling to much from being standard its the same way in mine, I basically have it for the tire size difference and as a code reader.

 

Yeah if I didn't need the money I would have kept it just for those two things as well but at the time I needed the money so I sold it.