FIXX

iTrader: (2)

my 92 suburban was 5 mph off as well, 245/75/16 tires stock,went to 265/75/16 and it was spot on.next set of tires i put on was 285/75/16, at the time i had the upper hand before the warranty expired and also picked up 3 mpg (per gps miles) on the highway..


i think they do this so we have to buy a new vehicle before it time to buy.

IRONMAN

For radar to be close to accurate you must be headed on a path EXACTLY at the gun in all 3 planes so it should read slower then actual speed.
GPS will produce a better accuracy comparison for speedo testing IMO

Miami Law

This is absolutely correct. There are a few things that come in to play, everything from proper calibration to tire and wheel size, even vehicle size as well as proportion or location within whats known as the radar cone are all factors. Beware of the lazer radar, dead on accurate, and can target a single car within a pack...
Also beware they (radar boars) are constantly calibrated and infact in construction and school zones mainly, we will write tix using them, yeah you can put up an argument in court, but who has time for that shhhhhhht.
Hopes this helps.....if you must speed do it Midnights in Miami, I hate writing tix now, lmao.

CigDaze

Thanks guys. Good info on the radar. Makes perfect sense since it's nothing more than a Doppler signature reading, meaning it's non directional (distance only), and thus it traveling in a direction not directly towards or away from the source would yield less than actual travel speed. I'm going to give my GPS a go one of these days to see how it compares.

And the Honda note was interesting as well. I looked it up and you're right Mr3D, they did get busted on that a few years back. WHile I was digging, I found that Nissan was found guilty of doing the same.

Griff

The roadside radar signs are not calibrated on a regular basis.