holden7896

I have bigger than stock tires so wont my speedometer be off? Is there anyway to fix other than going back to stock tires?

Roughrider

Use this calculator...it will tell you how much your speedometer will be off and then you can decide what to do about it. http://www.miata.net/garage/tirecalc.html

To adjust your speedometer there's a piece that gets changed that the cable fits into. I think they're color coated and can be purchased from suppliers. They're really intended to compensate for different rear axle ratios since tire sizes on C3's was pretty fixed.

7T1vette

You need to use a GPS (navigator) or time mile markers to find out what speed you are actually going when speedo is set at 60 mph. For every 3-4 mph that you are 'low' of actual speed, you should reduce 1 tooth from whatever speedo drive gear you remove from the transmission. For every 3-4 mph that you are 'higher' than actual speed, you should add 1 tooth to that gear.

Street Rat

Check out this link...

http://chevelleengineer.home.comcast...eer/speedo.htm

holden7896

Thanks guys. I think for now I'll just subtract the number it's off by when I can drive it as I have other things to pay for on it and I will probably work my way to stick size tires

7T1vette

Changing the speedo gear is lots cheaper and easier than changing the tires....

69 Chevy

It's a plastic 'driven' gear that costs a whole 10 bucks and takes 5 minutes to R&R once you get the car up in the air.

http://corvette-parts.zip-corvette.c...en%20Gear&rk=7

holden7896

Oh that is cheap. Might as well fix it then

PRNDL

Easier to just let some air out of your tires.

7T1vette

Hey, that works, too!!! [until they blow out...]