Calibrate for 35s

[Riviera]

We just lifted a sport and put 35s on it, when you configure the bcm (that's how you change tire sizes on the JL), it won't let you select a larger size than the 285/70R17. I believe this is because of emissions/fuel economy standards. The same was true with the JK. Obviously, someone will surely make a "tuner", like the AEV ProCal to circumvent this. But the dealer cannot reprogram to a larger size with the tools that are provided from FCA. I do not work for FCA and I am in no way representing FCA or it's dealers. I'm just explaining what's possible and what is NOT possible, at this time

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[DanW]

We just lifted a sport and put 35s on it, when you configure the bcm (that's how you change tire sizes on the JL), it won't let you select a larger size than the 285/70R17. I believe this is because of emissions/fuel economy standards. The same was true with the JK. Obviously, someone will surely make a "tuner", like the AEV ProCal to circumvent this. But the dealer cannot reprogram to a larger size with the tools that are provided from FCA. I do not work for FCA and I am in no way representing FCA or it's dealers. I'm just explaining what's possible and what is NOT possible, at this time

Ok, we shall soon see, when I go in to have them flash it. Again, the dealer told me they do it by actual measured tire height, as AEV does with the Pro-cal, and not by tire size. Why? Because different brands of tires sized 285, for example, have varying actual height, especially with a load on them.

 

[Riviera]

That's very cool, and I hope they CAN do it, i'm must not understanding HOW they can do it. I upgraded my tire size as well, but it appears the difference is negligible, so I am not worried about it until i go to 275/70R18, which might be a while.

 

[DanW]

That's very cool, and I hope they CAN do it, i'm must not understanding HOW they can do it. I upgraded my tire size as well, but it appears the difference is negligible, so I am not worried about it until i go to 275/70R18, which might be a while.

Remember, too, I'm hearing this from a dealership. I may get up there and discover that it was a service rep who had no clue they used aftermarket programmers on the JK and assumed it could be used on the JL. I'll let you know when I find out. I also need to compare it to GPS speed, to see how far off it is. I suspect 3mph at 50mph. My buddy has a JK Rubi with 35's. His is off by six or 8 mph, at 65 to 70mph, going from the stock 32's. That's significant.

 

[Riviera]

Remember, too, I'm hearing this from a dealership. I may get up there and discover that it was a service rep who had no clue they used aftermarket programmers on the JK and assumed it could be used on the JL. I'll let you know when I find out. I also need to compare it to GPS speed, to see how far off it is. I suspect 3mph at 50mph. My buddy has a JK Rubi with 35's. His is off by six or 8 mph, at 65 to 70mph, going from the stock 32's. That's significant.

Well I do hope they have figured out a way of doing this as it would save us all some money if we didn't have to buy tuners to change tire size beyond OE options. However, the AEV is pretty inexpensive, so if something comes along on that price range, I wouldn't be too upset, personally.

Good luck and keep everyone updated!

 

[AZCrawl]

Are they being lazy, or are you being stupid? I believe the message says when you try to program 35" tires "unsupported tire size". There isn't a way for them to do it, Einstein. Just like you couldn't program anything larger than a 255/75R17 / 255/70R18 (32.06) on a JK. I understand you think everyone at a dealership is a crook or a moron, but it's a little more complicated than that.

Don't put words in my mouth Geraldo.

 

[DanW]

Well I do hope they have figured out a way of doing this as it would save us all some money if we didn't have to buy tuners to change tire size beyond OE options. However, the AEV is pretty inexpensive, so if something comes along on that price range, I wouldn't be too upset, personally.

Good luck and keep everyone updated!

AEV would be my preferred way to do it, but they told me six months, at a minimum. The guy said they have so many projects going on that this may get kicked down the road. I told him not to kick it too far, or people will look to competitors. SuperChips said very little other than to say they don't have one at this time. They would not elaborate.

 

[Riviera]

Don't put words in my mouth Geraldo.

I just reread it, and I did take a liberty. I see people bashing dealerships, like THEY KNOW how to do something. Some dealers are jerks, some are stupid, but none of them are miracle workers. I've seen "stealerships" help customers when they could have turned their backs on them. All of us who modify our rigs are at risk to get turned away for warranty repairs and need good relationships with the dealers. This is a brand new model, and not all the info is out. When we call people lazy without knowing the circumstances, WE are making quick assumptions that might not be fair.

 

[BillyHW]

Why isn't this just a setting you can enter in the EVIC? I thought it was the future already.

 

[Sschmittou]

I went to my local jeep shop (jeepers creepers) explained i was putting 315/70/17 on the jlu rubi, then moving the 285/70/17 to my 17 sahara and need recalibration.
they told me the only place that could possibly do it is a dealership. So i called 6 dealerships first 5 told me they can only program to the largest factory offered size, the 6th one the girl I spoke with put me on hold and went to speak to a lead tech. She came back 5 mins later and just said he can do both jeeps and asked to make a appointment.

She had no other info about cost or how they do it. Guess I'll find out if it is true or a misunderstanding of what I'm trying to do.

 

[MBurgJL]

I went to my local jeep shop (jeepers creepers) explained i was putting 315/70/17 on the jlu rubi, then moving the 285/70/17 to my 17 sahara and need recalibration.
they told me the only place that could possibly do it is a dealership. So i called 6 dealerships first 5 told me they can only program to the largest factory offered size, the 6th one the girl I spoke with put me on hold and went to speak to a lead tech. She came back 5 mins later and just said he can do both jeeps and asked to make a appointment.

She had no other info about cost or how they do it. Guess I'll find out if it is true or a misunderstanding of what I'm trying to do.

How did this work out for you?

 

[Sschmittou]

It didn't. I got there and was told they can only calibrate to biggest factory tire.

So both Speedos are off about 1 mph per 20 mph.

 

[AZCrawl]

It didn't. I got there and was told they can only calibrate to biggest factory tire.

So both Speedos are off about 1 mph per 20 mph.

Jeep better address this issue and soon! This is BS.

 

[JayV]

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.

 

[BillyHW]

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.

There were rumours that the JL would be self-calibrating, but I thought those turned out not to be true.

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