Any speedo calibration tricks available on 944S?

109er · 08-18-2003, 07:07 AM

I got nailed on 295 outside of Richmond last Friday, and intend to get the speedo calibrated before my appointment with the Hanover County traffic court; I saw about 90, the cop said he saw 102 (!) and obviously that would make a difference in the fines levied. So, beyond the obvious ("don't speed like an ass on 295"), has anyone here run into situations like this, and are there any little adjustments that can be made (i.e. different speedo drive gear, etc) to improve the situation a bit?

Thanks in advance-

Lynn

TMH · 08-18-2003, 08:27 AM

Lynn,

I can't answer your question regarding calibration tricks, but I too have had questions about the accuracy of my speedometers. I bought a little GPS unit for less than $100 and have used it to confirm whether my speedometers were accurate (they both ended up being close, and reading a little high, so I should be safe).

The speedometers in fire engines are notoriously inaccurate. In some cases I have made a small chart which I place somewhere in sight, which shows indicated speed vs actual speed. Sometimes speedometers are less inaccurate at lower speeds than at higher speeds, and you want to know your speed accurately in that radar'ed school zone just as much as you want to know it on the open highway.

Just a couple of thoughts,
Tom

ronin · 08-18-2003, 08:50 AM

not sure about how to calibrate the speedo, but German cars' speedos are usually optimistic instead of slow like yours. both my P-car and BMW will read a few miles over actual speed when I get into the 70s and beyond. someone told me once that German car manufs. do this to keep your speed down. not sure if that's true. question I have though is did you change wheels and end up with an increase in diameter? that could give you the difference (and ticket!) you ended up with. assuming, of course, that the cop was correct.

rammstein · 08-18-2003, 09:17 AM

According to an article in C&D, Germans make their speedos read high because it is against German law for your speedo to ever read low. All speedos will have some type of variance, so they have to average on the high side. In the U.S. its something like +/- 5 mph allowed.

ronin · 08-18-2003, 09:24 AM

ahaa, that would make sense. at least I got half the story right.

as for the variance in the u.s., it all depends on the jurisdiction you get popped in