i have searched the forums and found alot of people describing thier tires that they run on thier cars. now to describe my situation is my speedo is off about a steady +15mph. when i leave from a stop it almost instantly jumps to 20 mph. so my question is im running 205/40/17's and would that be enough to through it off that much. or does this sound like more a vss problem. also the car appears to have been converted from a/t to m/t. im trying to fix all the problems with that before i swap my tires for more reasonably sized tires like a 45 or 50 series. any suggestions would be appreciated.

Your tire size is not the problem.

Originally posted by Babbz413
Your tire size is not the problem.

Correct. Accoring to the miatanet tire size calculator you should be about 3mph slower when the speedo reads 60.

I have heard of guys taking the needle off and going down the road holding a steady pace using GPS to measure the speed then sticking the needle back on at the correct speed. That might fix it. Otherwise you probably have an issue with the gauge cluster or the speedo sensor.

Had the exact same problem happen in my avenger years ago. It was randomly one day 15mph faster then actual. The heat gauge was messed up too so I swapped it for a different one and all was well.

Originally posted by Babbz413
The heat gauge was messed up too so I swapped it for a different one and all was well.

The what?

Originally posted by Babbz413
Had the exact same problem happen in my avenger years ago. It was randomly one day 15mph faster then actual. The TEMPERATURE gauge was messed up too so I swapped it for a different one and all was well.