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Unread 06-18-2003, 12:24 PM   #1
ILoveto4x4inNC
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Join Date: Feb 2003
Location: Raliegh, NC
Posts: 91
Speedo error range?

I got a ticket the other day(the idiot said I was doing 71 in a 55, my cruise was set at 57). I took the Jeep in to a shop to have the speedo checked. I'm only off 3mph. The dealer says that's within spec. They said that these trucks have a 2-5 mph margin of error. Is this true? Where can I get something in writing that shows that? If I was really speeding, I wouldn't have an issue with this, I'd just pay the fine and call it a day. Since I wasn't speeding, I'm gonna fight it. I just need to find all the info I can to try to prove my case. As always,

Thanks for the info.

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This aint your daddy's Jeep!

'98 ZJ with 5.2L
Stock except for Optima red top
bigger tires(30x9.50 15 BFG MTs)
Rancho RS5000 shocks
swapped in NV231
and Pioneer CD deck.

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Unread 06-18-2003, 05:32 PM   #2
Stocker
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Join Date: Nov 2002
Location: Jefferson State
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You're running 30/9.50-15s and only off 3 mph? Without doing the math, I'm surprised - I would have expected more. How were you clocked - radar? There are different types, each with possibilities for error. Some online searching may help educate you, and maybe someone here has specific information they can share with you.

I do know this - with the exception of laser, police radar fans out from the source, so its beam gets wider the farther away the target. Also, some radars tend to lock in on the fastest target, some the largest target. So although the officer saw 71 mph, it may not have been you. If you go to court, I believe you can request proof of his (radar) unit's last calibration.

I know this is somewhat general but there is plenty of info on this subject, both online and in books. May take some digging! Good luck!
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Unread 06-19-2003, 01:46 PM   #3
ILoveto4x4inNC
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Join Date: Feb 2003
Location: Raliegh, NC
Posts: 91
I was a little shocked that I was only off by 3mph too. What I need know is some documentation from Jeep that shows that I'm within the margin of error for my vehicle. Is that someting that I can get form the dealer or do I need to look some place else?

I've found all kinds of info showing how radars are prone to error. In the area that I got pulled over in, there are several cell towers, large metal buildings, and houses with attached garages. I'm tying to find somebody that has a fuzz buster I can borrow so I can see if anything around there will set it off. If it will set off a fuzz buster, it will cause interferance with the radar. With my 3mph error, and my cruise set at 57-58mph, I was only going 60-61mph. Something there was causing a false reading and since I was out by my self, I got the ticket.
__________________
This aint your daddy's Jeep!

'98 ZJ with 5.2L
Stock except for Optima red top
bigger tires(30x9.50 15 BFG MTs)
Rancho RS5000 shocks
swapped in NV231
and Pioneer CD deck.

White Jeep Club member #14
ILoveto4x4inNC is offline   Reply With Quote
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