I have the correct speedo transmission gear piece for my rear end and for stock IROC 16" rims. But the previous owner has some pretty "non low profile" tires on there. Consequently, they have a larger diameter than stock. Anybody know where I can punch in my new tire size and find out how much off the speedometer is? Any help would be much appreciated. Thanks.

 

Go to equations on the main page of thirdgen

 

When I put some Lo-pro's on my car, i just drove next to a friend and we matched speed and he yelled out how fast we were going. Hopefully his speedo reads correctly. It's not totally accurate, but you get an idea anyway. It also affects your odometer too. I didn't realize that at first, but now I know. Anyway, hope this helps some.

Tom

 

How does it affect your odometer? Thanks.

 

Odometer is running off the same gears as the speedo, thus like in my car when I go ~45 my speedo reads 65, so when I have gone 45 miles, my odometer will have counted out 65 miles. (Doh!) Oh well, I know my odo was off when I got the car since it had those 4.10's in it which I stripped out...now has 3.73's

 

if you know the outside diameter before and after it it easy. lets say you went from a 26 od tire to a 25, figure out circumfurence of both, then divide to get a ratio, then aply it to your speedo.

 

Go to this link
http://www.intercotire.com/calculators.htm
Change the tire size from metric first then use the MPH calculator.
Hope it helps.

[This message has been edited by Ozzy88GTA (edited May 20, 2001).]

 

Keep in mind that it isn't a specific number. It's a percentage. The faster you go the farther off it is. If it's 10 off at 50mph, it's 20 off at 100mph.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro