My speedometer is off. I'll be doing sixty-65
and it will say like 75-85. It really didn't bother me till yesterday when I got a ticket . How do I fix this or recalibrate it

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speed is a good thing,
more speed is a better thing

 

If you've changed your tire size or rim size from what you had on the car originally, this will make your speedo inaccurate. Changing rear end gears to a different ratio will also throw your speedo off. You can either go back to your original tire or rim size to correct it, or go to the GM dealer and have them help you pick the right speedo gears to make it accurate again. You have to get the gears with the right number of teeth for your application to correct the speedo. They have a chart on the computer at the dealership to help you figure out what speedo gears you will need. I had to get new speedo gears for my car when I changed the rear end gears from 2.73 to 3.42:1, and it's still not perfectly accurate because I'm running 70 series tires instead of the factory 60 series tires. Hope this helps.

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."