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Ive notice my speedo is off from the factory. Im sure its from the gearing but you think they would have fixed that. :?
 

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I've noticed the same thing too, using my GPS.

At 60 mph on the speedo the GPS reports 57 mph.

There are some who have installed 33" tires and say it reads right on with the bigger tires.
 

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I've heard that guy with 33" and factory programed speedo for 31" is correct. I know I had them calibrate mine for 33" and it is off, how much I don't know, I need to borrow my brothers GPS.... Jerry
 

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I also have heard what Medic said several times.
 
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I have an automatic and I have been wondering if keeping the computer set for 31'' tires while running 33'' would cause any problems. I don't have 33s yet but they are in the near future. Would the shift points be off? How would overdrive act on the highway or in town?
 

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won't cause any mechanical problems but your odometer will be off. On the up side it will be out about 6% in your favour. You will actually have more mile on the JP then what is displayed so it gives you a little more warrenty milage... :D
 
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I read other posts that this may be a recall issue!!!!!! If the milage is in my favor you wont dee me at the dealer!!!!
 
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Mine is fast 8 mph so it is going back and they can fix it until it is perfect, I wonder if this how they get away with such a good waranty?
 

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I don't think it will be a recall issue.. It may make it to the TSB classification. If you are running stock it will not work in your benifit. 35" and up it will.

The only other problem is with the police. It is hard to explain to them that the speedo is off and a even bigger PITA to prove it to the courts.
 

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I don't think I have ever seen a Wrangler speedo that was accurate!
Like Griz ...mine have always been a bit slow on stock set up...
That is 3 jeeps...'97 TJ...'00 TJ and the Rubi... GPS is the way to find out how fast your going..... mike
 
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I'm stretching my memory here, but I think there is a Federal Law about the speedometers could not come from the factory reading lower than actual speed, so the manufacturers intentionally set them a little high to ensure that they pass this inspection point. Generally this should work out to about 2 or 3 mph high at 60. Now I would think that if it was greater than this there would be a problem.

Now my head hurts...

Ron
 

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I'm runing 265/75R-16 MTR's and just by the neighborhood police speed checking trailer, I'm really close. Even when I get up next to people with digital speedos, I seem to be reading about the same as them. So it seems that 32-33" is about right.
 

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My speedo is off too. When my speedo says 60 mph I am doing 64 mph. This is checked by gps and also the radar units set up in the construction zone . I thought jeep would have it right since mine is bone stock as far as tires and wheels but it ain't. I believe the gps. As long as you know about it you can cope but it ticks me off that a factory jeep aint right.
 

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Biker Mike said:
My speedo is off too. When my speedo says 60 mph I am doing 64 mph. This is checked by gps and also the radar units set up in the construction zone . I thought jeep would have it right since mine is bone stock as far as tires and wheels but it ain't. I believe the gps. As long as you know about it you can cope but it ticks me off that a factory jeep aint right.
Just think you get more milage out of your warranty that way..That is why I haven't changed mine...
 
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I have driven many different cars because I travel constantly on business and rent a different car at my destination each week. I usually take a GPS with me, and have found that it is the rare vehicle that displays speed and distance accurately (maybe 1 in 20). I have never had one that had an indicated speed lower that actual. The error varies from 0 to 5%. I just use the GPS to get a quick calibration and travel at the indicated speed that yields the correct actual speed. My Rubi's error is 3.6%.

Dan
 

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PBR Stitch said:
I'm stretching my memory here, but I think there is a Federal Law about the speedometers could not come from the factory reading lower than actual speed, so the manufacturers intentionally set them a little high to ensure that they pass this inspection point. Generally this should work out to about 2 or 3 mph high at 60. Now I would think that if it was greater than this there would be a problem.

Now my head hurts...

Ron
I have seen lots of customer complaints about speedos reading a little high, and yes the factory does run a 5-10% overage depending on the vehicle and the tire size. Of course DC engineering or Tech line will not confirm or deny this fact.
 
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Mine is off too. However mine is racking up more miles than I actually travel. So I am anxious to get the bigger tires on.
 
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The 33"'s got mine lots closer, the 35"'s seem dead on. I also checked it with a GPS by the by.
 

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I told the dealer I was racking up extra miles since the speedometer is off by 4% they told me it has to be off my more than 10% before DC will cover re-calibration, by the time I get the 35's on my speedo will show 20,000 miles and I will have a little over 19,000 actual miles :x I guess I’ll have to put 37’s or 39’s on to make up for my loss :D
 

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My speedo was off with the stock 31's, speedo always read several mph faster than actual. Now with 33's it is right on
 
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