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caa0428 01-23-2010 10:59 PM

Speedo Recailibration for WJ
Does any one know how to recailbrate or if there is a specific tool like the one Hypertech has to recailbrate the speedo on a wj. Just put on the new wheels and a two inch lift. Will post new pics soon.

RobClarksJeeps 01-31-2010 12:31 PM

Re: Speedo Recailibration for WJ
I have an 8.5 inch lift and 35 inch mud tires on an 04 Grand Limited. I changed my speedometer using a Superchips 3875. When you put in the tire size, you have to play with a little to get it right, the tire size alone won't equal perfect calibration. (my 35's = 32.5 on the superchip)

Use a Garmin GPS and cmopare it to the speedometer until it matches. This worked perfectly for me.

josef15111 01-31-2010 06:50 PM

Re: Speedo Recailibration for WJ

Use a Garmin GPS and cmopare it to the speedometer until it matches. This worked perfectly for me.
funny some one brought this up

ok my garmin and my friends garmin both say 2 mph less thatn what the speedo says. it does this in my old avenger my 01 gc and his 2000 explorer. whats of the gps's or the speedo's i havent tried in any other car yet but its been of by two on all three of them

RobClarksJeeps 02-03-2010 09:35 PM

Re: Speedo Recailibration for WJ
Let's just say that I work with radar and drive alot for a living.

I can say that by far, no one's speedometer is perfect, not even close. On average, they are all off to some degree, typically by 2 or 3 miles per hour in either direction. Something as minor as tread wear or inflation can affect the speedometer.

Speedometer errors also tend to exagerate at higher speeds. For example, 2 mph different at 35mph can equal 10mph error at 65 mph.

However, GPS is not 100% accurate either because it does not acount for elevation, only map speed. GPS isn't affected by temerature, tire preasure, tread wear, or gear wear.

With all of this in mind, I have compared GPS to radar, and at speeds of about 150mph, I can honestly say that the radar and GPS speeds were almost identical, which is actually quite impressive.

No, GPS isn't perfect, but on flat land, I would trust it before trusting anyone's speedometer.

josef15111 02-04-2010 10:41 AM

Re: Speedo Recailibration for WJ
ok sweet thanks for the info man helps out alot, i was rather confused as to why the speeds didnt ever match lol.

Thanks Again

pinguino50 02-27-2010 03:58 PM

Re: Speedo Recailibration for WJ
Dealer reflash, superchips 3875, and superlift truspeed 33002.

206WJ 02-27-2010 04:13 PM

Re: Speedo Recailibration for WJ
The only bad thing about the dealer re-flash is they will only go up to the max factory tire size. I think it's 245/65/16 or something like that. I use the superchips.

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