Originally posted by hondatech
I don't care what motortrend says, I hooked up a honda pgm tester to my civic and my speedo was fast only by 2 mph then actual. So I still don't see how you got 127 at 140.
the margin of error on most if not all speedo goes up as the speed increases.
i know in my car at 60 i'm doing about 59 but around 120 indicated is more like 110-112 ish.
also a cheaper way to find out the speedo accuracy (well cheaper than getting clocked by a police car :exnbp: ) is to borrow a GPS. most decent ones will give you the speed read out and it's 99% accurate.