Calibrate for 35s

[Mojito Mojo]

So I tested my speedo today. I have 315/70/R17 KO2’s on my JLUR. Haven’t done anything to calibrate but my digital speedometer matched the speed the waze app was showing on my phone exactly. Not sure what voodoo black magic is going on to figure out I’m running 35’s but I’d do that test before paying a dealer $150 to hook up your jeep to a computer for 5 min.

I was told that, at least on the Rubicon, that the ECM would automatically recalibrate itself up to a 35” Tire size.

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[BillyHW]

I was told that, at least on the Rubicon, that the ECM would automatically recalibrate itself up to a 35” Tire size.

Not sure why there would be any need to limit it to 35s or the Rubicon though.

 

[DanW]

I was told that, at least on the Rubicon, that the ECM would automatically recalibrate itself up to a 35” Tire size.

It doesn't do that. I wish it did.

 

[Mojito Mojo]

It doesn't do that. I wish it did.

I will try to clarify tomorrow with the dealer.

 

[DanW]

I will try to clarify tomorrow with the dealer.

Let us know what you find.

 

[Mattyp1214]

My dealer that is an authorized AEV dealer too, They do a good amount of lifts, told me they can't flash it right now. They are very familiar with flashing using procal as they flash all of the builds they do for the lot, jks of course. Said as of now they can't do it and wait for a procal release.
It is off by around 5% so the computer does not auto compensate for it. Mine is also sorta reaching for gears at lower speeds I feel like now with 35s, so I am pretty excited for them to get moving on a flash for it! Also the tire sensors are annoying. Hopefully someone will release something!

 

[Mojito Mojo]

Let us know what you find.

My question to the dealer this morning:

I have a question. When I stopped in the other day I believe I was told that the new JL Wranglers would automatically detect a larger tire, up to 35”, and recalibrate the speedometer and odometer to compensate.

Can you verify this with your service department?

The dealer’s response to me:

“Hi Doug. So yes that is correct. The speed sensors in the hub will recalibrate itself.”

 

[RonH]

My question to the dealer this morning:

I have a question. When I stopped in the other day I believe I was told that the new JL Wranglers would automatically detect a larger tire, up to 35”, and recalibrate the speedometer and odometer to compensate.

Can you verify this with your service department?

The dealer’s response to me:

“Hi Doug. So yes that is correct. The speed sensors in the hub will recalibrate itself.”

Nope...at least not on mine. 55 mph indicated on speedo, 58 mph via GPS which is right at the 5.2% for the increased tire size.

 

[MBurgJL]

I wonder how long it takes them to recalibrate, if the do?

 

[RonH]

I wonder how long it takes them to recalibrate, if the do?

I'd think sooner than this...I've got just over 400 miles on the 315's now...

 

[MBurgJL]

I'd think sooner than this...I've got just over 400 miles on the 315's now...

I agree

 

[DanW]

I agree

Yep, I've got about 1500 or so on mine. I'm convinced that dealer is full of

 

[Sschmittou]

I'e had the 315/70 on about 2 weeks and 400+ miles. Speedo say 45 gps app says 47/48.

 

[OnlyOne]

Yeah. It doesn’t work. Lol. Mine is about 5-6 mph off with 37’s

 

[Mojito Mojo]

My question to the dealer this morning:

I have a question. When I stopped in the other day I believe I was told that the new JL Wranglers would automatically detect a larger tire, up to 35”, and recalibrate the speedometer and odometer to compensate.

Can you verify this with your service department?

The dealer’s response to me:

“Hi Doug. So yes that is correct. The speed sensors in the hub will recalibrate itself.”

And I stopped in the dealership again Friday and told them about the pushback I was getting from this forum! The general manager, the head of the parts department and their head Jeep technician ALL said that tires up to 35” would automatically recalibrate, just like the engine would recalibrate for different fuel octane levels or adjust the fuel/air ratio for different altitudes. Has anyone ever tested their phone GPS against a stock tire combo? Are the GPS systems on the phone really that accurate? Just asking!

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