Hello. I have a 92 GXE and have noticed recently that the speedo is 5 mph off. This seems to be alot for instrument error. Is this a common problem with VG's?

Also, Has anyone actually built the VG Hybrid?

 

what size tires are you running

 

factory 15"

 

There are fact°ries and factOries: diameter differences between various 15" tires can cause errors up to 10%

 

Yea, what Wiking said. If you changed from the stock 205-65-15 tires, you would likely have affected your tire diameter and consequently your revolutions per mile, which equates into miles per hour. Some possible tire size errors are:

................. Speedometer ... Actual Speed ... Difference
205-55-15 ...... 60 mph ....... 56.2 mph ....... +6.3%
235-65-15 ...... 60 mph ....... 63.3 mph ....... -6.0%

You can use this clever Tire Calculator to find out how each change affects your mph: http://www.miata.net/garage/tirecalc.html

 

Thanks for the help. I just had new tires put on and I can't remember off the top of my head what size they are. It was whatever was in the computer at Pepboys. They are most likely the 205-55s based on your information. Thanks again.