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I AM THERE4 I JEEP
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Discussion Starter · #1 ·
I bought my 2010 JK with stock 225/75R16 wheels and tires. I upgraded to 255/75R17 and it looks like my speedometer is off by 5-6 mph. I asked the dealer when they switched out to the bigger tires if my computer needed to be set up for the larger size and they said no. Obviously, this is not true and I'm going to be contacting them again this week about calibrating the system but what I want to know is this.

When you get a shop or dealer to install bigger wheels and tires, is the calibration normally included in the install price?

If it needs to be done, then is that something that people usually have to pay for in addition to the install price? How much does this cost?

thanks-
 

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From what I been reading, the stealerships have the capability to flash the ecu to correct for oversized tires which will ultimately correct your spedometer. One thing you did not specify is if you have an auto or manual. Also, there are programmers available for purchase that allow you the flexibility to do this yourself, and so much more. However, any time you need to take the ride in for servicing, you may need to flash back to stock programming. I am in the same position, and I think I will coordinate for the dealership to do this so it is under their watch.
 

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:D If the dealer did the swap, they should do the "Flash" FREE !!




I bought my 2010 JK with stock 225/75R16 wheels and tires. I upgraded to 255/75R17 and it looks like my speedometer is off by 5-6 mph. I asked the dealer when they switched out to the bigger tires if my computer needed to be set up for the larger size and they said no. Obviously, this is not true and I'm going to be contacting them again this week about calibrating the system but what I want to know is this.

When you get a shop or dealer to install bigger wheels and tires, is the calibration normally included in the install price?

If it needs to be done, then is that something that people usually have to pay for in addition to the install price? How much does this cost?

thanks-
If you don't have it done (by them free) you won't be able to check your mileage/trip distance-speed !!

I did mine with the AEV Procal Module, which does a whole bunch of other things too--$139 bucks-

Good luck

:rofl::rofl: JIMBO
 

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I AM THERE4 I JEEP
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Discussion Starter · #4 ·
It's a manual transmission and the service guy who installed the new tires told me that because it was manual, there was no reason to do it? Does he mean because the manuals can adjust themselves automatically? If so, how long does that take?
 

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:rolleyes: Can't helpya with a manual tranny, but

That sys ain't gonna correct itself, call a diff. dealer. or get an AEV or "Superchip" and fix it yourself-

Your speedo is off close to 10% now and thats a BIG ERROR-this dealer you've dealt with should sell muffler bearings !!

:rofl::rofl: JIMBO
 

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I AM THERE4 I JEEP
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Discussion Starter · #6 ·
maybe it was just a misunderstanding with the one guy that I talked too. If I call the Monday morning and I get similar answers from others then they should sell mufflers. I'm just worried about getting a ticket because I think I'm going 50 in a 45 but really I doing about 56!
 

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Do a search for tire calculator and input stock configuration and then current sizes. The calculator will show you the calculated differences. To be safe, drive within those parameters for now until the speedometer is corrected.
 

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My Dealer installed my Khumo 33x12.5 tires and re-calibrated my speedodometer free. It was off by 3 miles per hour. Don't let them charge you.
 

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I AM THERE4 I JEEP
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Discussion Starter · #9 ·
Do a search for tire calculator and input stock configuration and then current sizes. The calculator will show you the calculated differences. To be safe, drive within those parameters for now until the speedometer is corrected.
Yeah already did that, this is why I know its off. Not to mention I'm passing most people doing the "speed limit" when driving. I've also used GPS while driving (not as accurate) but its showing about the same difference.
 

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Did you get the Transmission Temp recall done yet? I did the same exact tire swap as you and I was off by 6 mph. I had the dealer flash my comp for the tires while it was in for the recall and they charged me $19.00.
 

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Discussion Starter · #11 ·
Did you get the Transmission Temp recall done yet? I did the same exact tire swap as you and I was off by 6 mph. I had the dealer flash my comp for the tires while it was in for the recall and they charged me $19.00.
My JK is a manual so I don't think it was affected by the recent temp recall. I'm going to call them today to find out if they will do it for me. I'll update as soon as I know - thanks for the suggestions.
 

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:D If the dealer did the swap, they should do the "Flash" FREE !!






If you don't have it done (by them free) you won't be able to check your mileage/trip distance-speed !!

I did mine with the AEV Procal Module, which does a whole bunch of other things too--$139 bucks-

Good luck

:rofl::rofl: JIMBO
I'm in the same boat. went from sport 29in to Rubicon 32s... The dealer wants 113 bucks!!! Will the AEV void anything???
 

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I'm in the same boat. went from sport 29in to Rubicon 32s... The dealer wants 113 bucks!!! Will the AEV void anything???
Get the AEV Procal and do it yourself. The cost isn't that much more than you would pay the dealer and you'll have it for future use as well. No, the Procal won't void anything.
 

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Discussion Starter · #14 · (Edited)
This is a three year old thread but to answer my own question, it cost about $120 to recalibrate the speedo at the dealership. A pro cal is only $150 and a better use of the money by far.

Welcome kik and dtm. :thumb:
 

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I love how a stealership feels justified to charge $120 to reflag your ecu for tires when it takes all of about 30 seconds to plug in your new tire size and calibrate your speedo.
 

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What my dealership said

I think each dealership is different in what they say. Mine told me because of strick federal laws, Jeep couldn't adjust anything past a 285 tire. I don't know if this is the truth or not. I have 33's and my MPH was off by about 5 mph. This was at 65 mph per my GPS, my speedometer showed 60 mph.

Just go out and get a Pro Cal. It will adjust the speedo and a lot more and not void the warranty.
 

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I had mine recalibrated for $65 because I have 35's. Speedo was easily 10-12 MPH off. Now it's only off by 1-2 MPH. :/ Oh, well. I can live with that.
 
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