pingman77

So my dealer mounted/balanced my wheels tires and installed the rc 2.5 pucks on my 2013 jku. They told me they recalibrated my speedo. Im wondering if they actually did? Im also wondering if I need to purchase a procal. If they actually did recalibrate, would there be any benefit of purchssing a procal or is it even possible? Im only wondering all this due to a couple things dealer promised and never came true.

Billbikes

What size tires? As far as I know, if the tires are larger than a stock size(255's), the dealer can't recalibrate to correct this. You would need a procal for this. It also lets you change your tire pressure settings if you want.

Jk kris

They said say to me. I'm showing 7 under at 60 mph. So I just keep that in mind. If it shows 65 I'm really running 72

pingman77

I have 285/70/17. Im real suspicious they didnt recalibrate. I checked with gps phone app. My speedo said 72 and phone gps read 74. So, does the procal benefit transmission in anyway?

ToolManTimTaylor

Keep in mind a dealer can not program any tire size larger than what comes on a Rubicon as that is the largest tire size Jeep offered wranglers with. A ProCal or Flashpaq or any programmer that offers gear and tire programmability is able to make changes. Very important for automatic transmission wranglers to have gear ratios and / or tire sizes installed on the jeep be programmed in

Billbikes

With an auto trans, it'll recalibrate the shift points. With 285's, there is very little change over stock, as long as you had 255's already. You would notice a little improvement.

pingman77

Ok.. Is it worth the investment as my jeep is now?

second2none

After using the procal, my speedo was dead on with my 35's. Had the cop that works in my building put the radar on me. It was also nice to use it to turn off the TPMS system off.

m25red

Seemed to help with shift points for me. My mpg's have also improved. I ran across one of those speed detection devices which show you how fast you are going. Was spot on. Procal well worth it to me.

ToolManTimTaylor

Yes the reason is that the Jeep looks at throttle pedal position , road speed and adjusts fuel and timing curve to get you down the road at that break neck speed we all know the jeep has . It also uses that info to properly calculate and make your shift points and lockup the torque converter for fuel mileage and heat reduction.

Now by altering say just gear ratio, tire size or both your road speed VS RPM in a certain gear is now changed. The throttle position now does not match what was expected from the factory program at a given speed or load. Performance suffers and shift points are now skewed. Trans damage long term from heat will wind up being the result. The torque converter lockup clutches may be unnecessarily slipping (Being chrysler went to a progressive lockup setup in the torque converters) when the clutch solenoid should be in total lockup at an expected speed and pedal position instead thus creating alot of heat.