can the speedometer be re-calibrated?

[new jeep owner]

just wondering when every one lifts their liberty, and goes to taller tires how much it throws out the speedometer.?
I put my winter tires on, stock size 225-75/16
and just for fun compared my speedometer to my gps.
the speedometer now reads 7 kph / 4.3496 mph faster then I'm actually going.
well according to the gps any way.
never thought to check it before with the summer tires.

 

[Porkchop]

A Hypertech can do it, or the correct scan tool can , you can also go to the dealership.

 

[tommudd]

Have to go to the dealer
and then it seems only certain years

 

[Luke]

I can only tell you that my 05 cannot be re-calibrated. I just used the following to calculate the correction factor.

Car / SUV / Van / Light Truck Tire Calculations

 

[Luke]

duplicate post

 

[martin_metal_88]

Nice little tools you have here.

 

[rockymountain]

I recallibrated my 04. need to do it again. About 3-4 MPH off on the highway. It cost me $25 at the dealer. Hopefully they do it again for that price.

 

[J-Thompson]

Place GPS in Jeep
Go 60 mph on GPS
Note reading on speed O in Jeep
Drive faster or slower based on that

Now every one who uses this method please send me a check
for $12.50 which is 1/2 what the dealer would charge

 

[flair1111]

mine is off by 5mph and more the faster i go. its an 06. i figure when i get bigger tires itll correct it.

 

[rockymountain]

I did it for proper shifting and correct gas mileage calculations. Really worth $25 to not rely on a gps or doing calculations to get a good estimate.

 

[tjkj2002]

Place GPS in Jeep
Go 60 mph on GPS
Note reading on speed O in Jeep
Drive faster or slower based on that

Now every one who uses this method please send me a check
for $12.50 which is 1/2 what the dealer would charge

That does not fix the trans shifting issues resulting in the speedo being way off.

 

[new jeep owner]

should I be concerned about shifting issues with stock size tires?

 

[Cardhu]

should I be concerned about shifting issues with stock size tires?

Run a gps,if its on your fine. the larger tire sizes throwing it off etc.

 

[tjkj2002]

should I be concerned about shifting issues with stock size tires?

No,even if your speedo is off as the PCM is programmed to see what it is seeing with stock tires and how the speedo is currently set.

 

[HoosierJeeper]

Mine is almost dead on after the larger tires I think. Checked it against the GPS last summer.

 

[Ry' N Jen]

Speedos never dead on.
Even with the pinion reset done.
Air your tires down for high speed dirt roads and its off again.
Checked it against GPS and code reader computer and at some speeds it very close and at other speeds its way off!
Typical speedo.

 

[Dave]

That does not fix the trans shifting issues resulting in the speedo being way off.

Yeah, I noticed a difference in the rpm's and ****** shifting. I experimented a little and it seems like if I lock out o/d on the country roads where speed is 45-50 the ****** works better.(stays in drive and doesn't shift around) Then shift to o/d on the highway. Seems to work better since I do not want my ****** shifting around and heating up. Kind of a "work-around" until a 4.10 gear change.

My speedo is off around 4mph at highway speeds according to my gps.

Dave

 

[rockymountain]

I do the same thing Dave.

 

[TwoBobsKJ]

X3

Bob

 

[Ry' N Jen]

Even though we had the pinion reset/speedo recalibration done we still drive with the overdrive off in some cases.
Our KJ just drives better. Especially on high speed dirt.