Can anyone verify a dealer can calibrate speedometer for 34.5" tires?

[wolfievtec]

I upgraded my 2021 Jeep JLUR to 34.5” tires and have been to my dealership twice for a proper speed calibration. I paid 125.00 for the "service contract" and they set my tire size to 33.5 because they insist their only options are 33.5 and 35.0, nothing in between. So.. my speedometer is still off 3MPH. Can anyone verify they had their dealer set the tire size to 34.5? Also, do I need to pay every time they calibrate or can they recalibrate again within my 2 month service contract window? I know I can just buy a Tazer or other programming device but since the Jeep is brand new I didn't want to risk voiding the warranty... thanks for any help!



Thanks for any help.

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[Cjanak21]

Not sure on the first half, but with the Tazer you can set it to what you want it at and if you bring it in for service you can always just "unmarry" it and nothing would effect your warranty because everything you changed would be brought back to factory spec... correct me if I'm wrong

 

[jaymz]

You aren’t going to void a warranty with a programmer. Cut your losses with the dealer now and buy one.

 

[calemasters]

I upgraded my 2021 Jeep JLUR to 34.5” tires and have been to my dealership twice for a proper speed calibration. I paid 125.00 for the "service contract" and they set my tire size to 33.5 because they insist their only options are 33.5 and 35.0, nothing in between. So.. my speedometer is still off 3MPH. Can anyone verify they had their dealer set the tire size to 34.5? Also, do I need to pay every time they calibrate or can they recalibrate again within my 2 month service contract window? I know I can just buy a Tazer or other programming device but since the Jeep is brand new I didn't want to risk voiding the warranty... thanks for any help!



Thanks for any help.

I installed Falken Wildpeak A/T3W LT315/70R17 which are ~34.5". The next day, I paid the dealer $125.00 for the "service contract" to calibrate the vehicle for the new larger tire size. Since then, I have checked my speedometer & odometer via radar, GPS and the interstate mile markers. The speedometer accuracy is within 2% of actual at 70 mph and the same for the odometer. I think this is as good as its going to get.

 

[gato]

You do realize that the difference between 34.5 and 35 is 1.5%, right?

That means that at 60MPH your speed will be off less than 1MPH.

Tell them to set it to 35" and be done with it. Your speedometer will be within 1%.

 

[wolfievtec]

You do realize that the difference between 34.5 and 35 is 1.5%, right?

That means that at 60MPH your speed will be off less than 1MPH.

Tell them to set it to 35" and be done with it. Your speedometer will be within 1%.

That's what I was thinking (set it to 35), I'm fine with it being that close. They tried to convince me that setting it to 35 was going to put a lot more miles on my Jeep. I think they just didn't feel like programming it again...

 

[wolfievtec]

I installed Falken Wildpeak A/T3W LT315/70R17 which are ~34.5". The next day, I paid the dealer $125.00 for the "service contract" to calibrate the vehicle for the new larger tire size. Since then, I have checked my speedometer & odometer via radar, GPS and the interstate mile markers. The speedometer accuracy is within 2% of actual at 70 mph and the same for the odometer. I think this is as good as its going to get.

Do you know if they selected 35” as your tire size?

 

[calemasters]

Do you know if they selected 35” as your tire size?

Yes they did.

 

[wolfievtec]

Just an update in case someone reads this thread. The dealer WAS able to calibrate my tires to 34.5 “ through a Mopar service contract. My total cost was $125 plus tax. I just had to keep bugging them until they looked into it and figured it out. I can verify it CAN be done.

 

[Twisted Patriot]

I know this is an old thread.. but I just called the dealer and he told me the biggest they can recalibrate for is 33's. Idk if this guy knew what he was talking about.. I need to recal to 35's.. (well.. probably technically closer to 34 as we all know most are not true 35).. but idk why he told me that.. gonna try a different dealer

 

[Dyolfknip74]

I know this is an old thread.. but I just called the dealer and he told me the biggest they can recalibrate for is 33's. Idk if this guy knew what he was talking about.. I need to recal to 35's.. (well.. probably technically closer to 34 as we all know most are not true 35).. but idk why he told me that.. gonna try a different dealer

Just use JSCan with a SGW cable and OBDII dongle. It's about $80 all said and done and you get a lot more options than just adjusting your tire size.

 

[1quick1]

I did the "service contract" and $125 for 34.5" tires on mine but this was over 4 years ago so could have changed. Mine is spot on with what the GPS says until 70mph + where I can see about .5-1mph discrepancy (so good enough for me).

 

[Twisted Patriot]

Just use JSCan with a SGW cable and OBDII dongle. It's about $80 all said and done and you get a lot more options than just adjusting your tire size.

I've never used any type of programmer on a vehicle.. any warranty implications with this as far as voiding anything?

 

[Dyolfknip74]

I've never used any type of programmer on a vehicle.. any warranty implications with this as far as voiding anything?

With JScan it's pretty straightforward. There shouldn't be any warranty implications at all as long as you don't leave the SGW bypass cable connected when she goes in for service. But even then, that's dependant on delaer. Mine knows I've changed my tire size and a few other things. They don't care.

 

[Twisted Patriot]

Has anyone used the ECRI device. Saw it on a [Banned Site] video and it caught my eye

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