rlefeve

Any experience out there going from stock 32's to 33's.
Would it be woth $150 to drop on the AEV Procal just for this change?
I do make several 4 hour highway trips north a year, pulling a small trailor.
I know I am screwed on MPG's but I am more concerned with performance.

DMoore5

I just made the change from 32 inch highway tires my jeep came with to 33 inch mud tires, I lost about 2 MPG, and a tiny bit of power up hill, barely noticeable, but off road performance is 100 times better and it looks better

jk_sea

Short answer: Yes.

The speedometer won't read correctly which is only a slight annoyance, but the important part is the recalibration of the ESP module. It makes decisions about when to brake each wheel based on multiple conditions, tire size being one of them. The only way it knows you have bigger tires is if you tell it--otherwise the increased size could biff the calculations in a loss of control. The Procal module does just that.

If you have an automatic transmission, the Procal will also adjust the shift points slightly with the larger tire size in mind.

The Procal isn't a tuner that ADDS power, it optimizes performance to fit changes you make to your vehicle.

Mobius1

truthfully with my real world experience I wouldn't buy the procal. Yeah the speedo is off but only 2 mph. Keep in mind results may vary depending on the tires because not all are created equal. My fuel consumption has remained unchanged I still average 17 mixed driving and recently went to and from Dallas a few times and averaged 20 on highway at 70mph. If you absolutely have to have the computer calibrated to the tires you are running I know the dealer can do it for 50 bucks, at least here in Abilene Texas that is. My current setup is a JKU auto with 3.73 gears, 33 inch BFG A/T 10 ply tires and stock 17 inch rims. Like I said this is just my real world experience and results will vary depending on maintenance of said rig and tires.

Kevin123

I am in the same boat, I'm going to a 33 and instead of buying a procal I'm going to get a tuner it does the same thing as the procal, but add the power + that you lost with the bigger tires. Now saying that I know the tuner option is more money, but if you ever plan on changing gears or modifying anymore you will be able to adjust for that. I can't decide if I wannt the new bullydog or the Intune.(JMO)

jk_sea

I think your experience is rare...I tried to have a Jeep/Dodge/Chrysler dealer calibrate the computer for slightly-larger than Rubicon-sized 32's on my 2009 JK, and they wouldn't touch it. Generally they are only able to program up to the Rubicon 32" BFG stock tire size, and even then, if the service writer is having a bad day he'll probably tell you to get lost.

The speedo being off will affect your mileage calculations if you're doing it manually. I don't know for sure, but the computer may calculate MPG (for those that have the display) based on the injector flow rate so that's probably more accurate in the scenario of an uncalibrated speedo and larger tires.

I'd do it, be done with it, rest easy knowing everything is dialed in. That's just me, though, and if tires are worth upgrading, it's worth it to do it right and take care of any ancillary problems they might cause.

btownjk

I'm running the.same tires but thespeed is off by about 5mph on off at2 10 ply

jk_sea

Say what, now?

rlefeve

Thanks, excellent input from everybody.

Kevin123, you have added another dimension to my question. Thanks.....I think LOL

rlefeve

I went down to AEV and picked up the Procal this afternoon.