Scangauge recalibration - Tire size increase

[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

[tom4bren]

Richie,

I'm running 33's. TomTom tells me the speed is off 'zackly 10%. I'd start there & adjust as necessary.

Tom

[etlsport]

my stock tire size is 29.5... 245/60/18

[Kenny]

Stock tires on the 00, 01 are 245/60 R18 = 29.6"
(all sorts of neat info on the Federal Sticker in your drivers door frame.)

Mine are 265/70 R17= 31.6"

My Garmin tracks me at 10% error. Doing 66mph by GPS when speedo says 60mph.