I got a bullshit speeding ticket the other day - 58k in a 50 - the cop reduced it from he claimed 62k so I wouldn't lose points. Now I am sure I was only doing 55 as I almost always try to stay within 10k of the posted limit My question is as my 87 n/a has 15" wheels in place of the stock 14", can this screw up the speedo reading by as much as 10%? I know that taxis have to have their meters re-calibrated whenever they change a tire or wheel size.

 

It also depends on what size tires are mounted on those wheels.

For the speedo reading to be approximately the same, the wheel/tire combo must have the same (approx) diameter as the original. And that diameter, pretty much depends on the tire.

Refer to:

http://www.maitreg.com/Cars/tools/speedrpm.asp

http://www.maitreg.com/Cars/info/tirespecs.asp

 

BUMP

 

Whats the tire size of the 15s, and what was the size of the 14's they replaced?