View Single Post
  #2  
Old 04-21-2009, 10:04 AM
3100 3100 is offline
Banned
 
Join Date: Nov 2008
Posts: 1,034
Thanks: 0
Thanked 2 Times in 2 Posts
Re: Speedometer reading wrong???

what size are the front tires?

also the speedometer on most GM vehicles are of the air-core design. This is a moving needle operated by a magnetic coil. Since there is no direct mechanical connection, there is some variation in accuracy that cannot be eliminated.

here are some variations at different speeds

20mph variation 4
45mph variation 3
65mph variation 2

according to GM specs any air-core speedometer which reads within these limits should not be returned for service.
Reply With Quote