Ty

I was just wondering about how much my speed is off now that I have 32's.

so anyone that has larger tires that would feel like chiming in...

05 super

maybe something on here for you ty.
http://www.oramagazine.com/pastIssue...-accurate.html
there is a formula part way down the page that might help

Scot

http://www.onlineconversion.com/bigger_tires.htm

Try this one.

LovetheTide

For me it's not more than 2 MPH according to my GPS.

JEFFSURE

I am running 35s for now, will be selling them . my speedo is roughly 5 mph off. it does seem the faster i go the more its off.

LovetheTide

^That's because the faster you go the more it is off.

calvin

try a speedo with a one less tooth

Bosaliniee

i like this site better than the other 2 mentioned.
http://www.miata.net/garage/tirecalc.html

by the way the speedo is not off by a certain mph its off by a percentage of the total speed, mine is off by about 9%

calvin

I would look into changing your speedo gear because this also controls your automatic transmission shifts.

GusA

I have a Ford f150 1999, 4.6L truck with 33" tires and 4:26 gears. My truck was about 25 mph off. I invested in a Hypertech Programmer and it corrected my speedo with the correct tire height and gear ratio. It also gave my truck more noticable power, once programming the octane used.