Recalibration issue

[BDinTX]

If I’m reading your sheet correctly, they put in the CALTIRE350 option which is the value for a true 35” tire.

An internet search says that tire is actually 34.76” tall but it’s probably closer to 34.5” with the weight of the vehicle sitting on them.

So CALTIRE345 is probably a more accurate option but if my math is right that 350 option should only be giving you -1 MPH discrepancy at 70 MPH.

You might try calling the selling dealership. If they do a lot of wheel changes they may be able to call your closer dealership and explain how to program correctly.

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[beaups]

If I’m reading your sheet correctly, they put in the CALTIRE350 option which is the value for a true 35” tire.

An internet search says that tire is actually 34.76” tall but it’s probably closer to 34.5” with the weight of the vehicle sitting on them.

So CALTIRE345 is probably a more accurate option but if my math is right that 350 option should only be giving you -1 MPH discrepancy at 70 MPH.

You might try calling the selling dealership. If they do a lot of wheel changes they may be able to call your closer dealership and explain how to program correctly.

The speedo is reading 6-7% too low. It’s obviously still set for 33’s.

 

[Crownline]

We thought that at first too, but they swear it's set it to 35s. And I know they did something bc my setting for the chirp when you lock the doors from the remote was back on. Maybe they didn't do something right, though. Who knows! It's just frustrating.

I think we're just going to get a taser. It's not worth getting the original dealer involved when the dealer here could call the MVP line and get directions if they needed help. Just don't understand how they can send it out the

 

[beaups]

We thought that at first too, but they swear it's set it to 35s. And I know they did something bc my setting for the chirp when you lock the doors from the remote was back on. Maybe they didn't do something right, though. Who knows! It's just frustrating.

I think we're just going to get a taser. It's not worth getting the original dealer involved when the dealer here could call the MVP line and get directions if they needed help. Just don't understand how they can send it out the

They def did it wrong. Although, I wonder if the changes were entered and just not properly “committed” as the tazer has a reboot process it runs through when you make tire size changes. Will be interesting to see what the tazer shows as your current size once you get it. It’s a great device nonetheless.

 

[jeepoch]

@Crownline,

I invested in a Tazer JL Mini just for this reason. The dealership quoted me $128 to reprogram the tire diameter (size) calibration after installing 35x12.5x17 Goodyear Duratrac All-Terrains. Since the true diameter doesn't always match this sidewall number (35" in this case), I didn't trust the dealership to get this right.

My stock tires were Michelin 235/55R18 (31.5") about 3.5" difference in diameter from my new larger rubber.

Using the Tazer, I kept incrementally adjusting the Tire Diameter calibration over several iterations until I eventually got as close as possible to comparing the speedo to my phone's GPS speed when traveling about 5 miles over both highway (70mph) and neighborhood (25mph) roads. My final diameter value turned out to be around 34.8".

Again, it is my belief that the dealership would have simply only entered 35.0" without ever dynamically checking anything. The Tazer at least allowed me to experiment and get it right.

I've never owned a fast car (typically only 0 to 60 in about a half hour) type of thing. Not that bad, I'm certainly exaggerating a little bit, but I've never received a speeding ticket since 1985. I certainly don't want my newly lifted on much larger rubber JL, indicate a much lower 'indicated' speedometer velocity than the vehicles 'true' speed, especially at highway conditions where the difference in readings would be the greatest.

With the change in these two tire diameters when driving at 70mph 'indicated' would yield approximately 87mph 'true'. This would certainly likely cause a few speeding tickets.

So I too took this issue rather seriously. While the Tazer was almost twice the cost of the one time dealership charge, I now have the capability of recalibrating my tires as often as I care to check. As they wear over milage driven, or as I change them with newer ones at some point.

In hindsight, I should have only purchased the Tazer JL Lite, which did not have all the bells-and-whistles type of really cool features and which was also considerably less expensive since I find that I never use any of it's 'Live' features. Once the speedometer is accurate I then remove the Tazer but still leave it 'Married'. The tire size calibration remains in tact until I want to recalibrate yet again.

Still, a very good investment. It gives me complete control with zero dealership intervention.

And no, I do not work for Z-Automotive and own none of their stock. Though I do enjoy fiddling around with my Jeep.

Jay

 

[mwilk012]

They’re just flat out doing it wrong. The size change isn’t saving for some reason, your values you are describing are exactly what happens when the stock calibration has 35’s installed. Get a programmer and do it yourself.

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