Scangauge recalibration - Tire size increase

[taylorRichie]

Hey guys what's the percentage increase I need to set my scangauge to?

Going from Stock size, to 33" tires?

Thanks!!

Richie

(I searched the forums... really.. couldn't find anything)

[JoFotoz]

Hey Richie...

I've done measured mile speed/distance checks over a 4 mile section of f/way...

...and my 33's seem to give a little under 10% differential.


jo

[rowhard]

do the math: if the diameter of the original tires was 24
inches and the size of the new tire is 30 inches, 100x(1-(24/30)) = 20.
Setting the value to 20% will compensate for the tire size change.

right, the 10% Jo quotes sounds about right. My 31.5" tire is 6%

[taylorRichie]

Only problem is I don't know the stock tire diameter. I had a different size on my VX when I bought them.

It's printed on the inside door though if I remember.

[nfpgasmask]

I just asked this question like a month ago.

http://vehicross.info/forums/showthread.php?t=13532

I think mine comes out to be about 7% off. So, at 60 on my speedo, I am most likely going about 65. I need to set my scanguage up to calculate this, just haven't had the time to dig out the instructions. If you figure it out, post it up if you can....

Bart

[rowhard]

The stock tire is 30.5 inch dia. according to http://www.miata.net/garage/tirecalc.html