Keith, at 12:53 on Apr 23 1995, you wrote to Bill Grimsley...

BG> Most speedos are purposely made to read 6%-10% fast at 100km/h, to 
BG> compensate for increased tyre diameters due to centrifugal force 

KR> back in the old days, when coppers had to follow you for some 
KR> distance to book you, 

In Australia, it was 3/10 of a mile (or it was in NSW).

KR> instead of getting an instantaneous reading on a radar, the law was, in the 
KR> uk, that he had to check his tyre pressures and record whether they were in 
KR> tolerance. it was a nifty little let out for those who knew of it, cos' the 
KR> cops rarely bothered to.

Good trick!  Even radar units are not unbeatable either.  Have you ever
wondered why they're not used in wet weather?  Coz the water droplets on
the surface of the vehicle being checked present a greater (varying)
surface area to the doppler beam, and cause it to read high.  

Knowing this (as the coppers already do), if you ever pass through a radar
trap, and suspect that you may have been over the limit, immediately hit
your windscreen washers, so that by the time you are pulled over, your
windscreen is covered with water droplets, then argue that you weren't
speeding at all.

Caveat, I've never tried this, so you may need to be prepared to go to
court if the copper books you anyway (unlikely, I'd suggest), and you'd
then need to bone up on your doppler-shift theory in order to impress the
magistrate.

BG> That said, I once took the VL (bog-standard 3.0l Nissan EFI 6) to 
BG> an indicated 210km/h, but that was on the 1st Moonbi Hill, 

KR> i am reliably informed that there is a straight bit of road just 
KR> south of gympie where twin cam corollas have been seen doing 
KR> speeds in excess of 190k/h (from the tacho)   (:

I have also been reliably informed about this very same piece of road, by a
copper friend of mine who is still looking for this "lunatic pommy
bastard with a Corolla and NSW plates".  |-)

Regards, Bill
@EOT:

--- Msgedsq/2 3.10 alpha