Engage

I have an 81 running 255-15 tires.
Notice the speedometer is showing 110 kph when it is actually doing 100 kph
Anyone corrected the error? If so how?

Thank you... Barry :confused:

Stingy74

You need to indicate what the aspect ratio of your tires are, ie: 255-60-15. If you have a tire shorter than stock it will rotate faster giving you an incorrect reading on the speedometer. I like to drive beside someone with a new car where you know the speedo works and I read my rpms.

figment3

if you can find a friend with a g.p.s you can find out exzacly how fast your going and to where :D

Shutdown1

Barry,


I don't think there is anyway you can correct your speedometer for the error. 10 kph speedmeter error is not that uncommon at all in lots or cars. I have a similar problem to yours, except my car reads too slow on the speedometer. This is because I had to go to 235/15 tires (smaller) so as not to rub up against my Hooker sidepipes as they come out of the rear of the wheel well. In your case I think I would just keep in mind a 10 kph difference when I'm driving, rather than change the tires. Regards


'74 Turbocharged 350, "Molested to Perfection" , class of '71

gerry c

Speedometer error can be corrected two ways.

First, a different drive gear. The drive gear is on the end of the speedometer cable where it goes into the transmission. You can get coorect gears at any chevy dealer. If you are off 10%, pull your gear, count the teeth and go to your Chevy dealer and get one with 10% less teeth.

Second way is to go to a speedometer repair shop and get a corection box. It goes between your existing cable and the transmission. The gear from chevy is cheap and easy