[QUOTE]Originally posted by Barry WY Silver/Black '01
[B]Come on guys!

 

I had an officer check my speed a few months ago before I got my new wheels and tires and it was reading 2 mph fast at 45 mph. After I got my 18's, which are a slightly larger diamater with the tire, I had the same officer radar me and it was only 1 mph fast. I think most cars (in my experience) have optimistic spedo's.

Andrew

 

Use a stop watch and mile markers on the Interstate. Check it 4 or 5 times because sometimes mile markers are slighlty misplaced. Mine reads 83 at a true 80. Remember also that error will change with tire wear. If your speedo reading is optimistic (as most are) it will become more optimistic (by about 2 percent) as tires wear from full tread to no tread.