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Discussion Starter #1
Well I installed new tires a few days ago.
The specs are 315/70/70. They are 33.5 mounted.
Load D
Hercules terra trac ATs

Now here is the tricky part. I purchased a new Flashcal to adjust the tire size. I put in the new size but shifting was a bit off.
I saw a lot of people have luck with putting the size down to 31-32.5 with the flash cal. Shifting was better but speedo was off by 5-7mph.

Can anyone help out with this ? Ideally what is the RMP suppose to be at per shift point of 1st ,2nd , 3rd etc ?

I am running 3.73 gears and it's automatic.
I don't mind the speedo being off by 1-3. Just trying to avoid putting excessive wear on the Transmission
 

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You may want to check that your flashcal even changes your trans program. I'm pretty sure it only re calibrates the speedo. Larger tires definitely has an affect on your trans shifting points.
 

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You may want to check that your flashcal even changes your trans program. I'm pretty sure it only re calibrates the speedo. Larger tires definitely has an affect on your trans shifting points.
Hold up, so the darn flash cal just changes the speedo ? Not shifting points ?
 

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FlashCal changes the shift points in an auto.
 

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That's what I understand is that pretty much all you can do with flash cal is adjust for larger tires and different gears. Oh and turn your fogs on with hi beams.
Hmmm. Perhaps because I also regeared? Mine seems to shift appropriately.
 

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Hold up, so the darn flash cal just changes the speedo ? Not shifting points ?
Latest Flashcal features. Nothing changes your trans shift points.

KEY PRODUCT FEATURES:
• Corrects speedometer for tire upgrades between 26” - 42”
• Speedometer recalibration for gear /axle swaps up to 5.38
• Locking axle options with transfer case in 4-Hi & 4-Low (2007-16 Rubicon only)
• ESP stability optimization (2011-16 automatic transmission models only)
• Engine idle adjustability for winching
• Daytime running light options (2007-16 models only)
• One touch lane change
• TPMS Options (Download required)
• Accessory delay options (2011-16 models only - Includes adjustable delay for radios, accessory lights, and other aftermarket accessories tied to the same fuse)
• Headlamp delay options (2011-16 models only)
• Horn chirp and exterior lighting flash options when locking doors with keyless entry
• Reads and clears diagnostic trouble codes
• Internet updatable
* Results and feature set may vary based on vehicle make, model, and aftermarket upgrades. Read all instructions before installation and/or operation of this product use.


In order to get the shift points back to optimum you need to re-gear.
 

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Discussion Starter #9
Latest Flashcal features. Nothing changes your trans shift points.

KEY PRODUCT FEATURES:
• Corrects speedometer for tire upgrades between 26” - 42”
• Speedometer recalibration for gear /axle swaps up to 5.38
• Locking axle options with transfer case in 4-Hi & 4-Low (2007-16 Rubicon only)
• ESP stability optimization (2011-16 automatic transmission models only)
• Engine idle adjustability for winching
• Daytime running light options (2007-16 models only)
• One touch lane change
• TPMS Options (Download required)
• Accessory delay options (2011-16 models only - Includes adjustable delay for radios, accessory lights, and other aftermarket accessories tied to the same fuse)
• Headlamp delay options (2011-16 models only)
• Horn chirp and exterior lighting flash options when locking doors with keyless entry
• Reads and clears diagnostic trouble codes
• Internet updatable
* Results and feature set may vary based on vehicle make, model, and aftermarket upgrades. Read all instructions before installation and/or operation of this product use.

In order to get the shift points back to optimum you need to re-gear.
Thanks for that buddy. I just read up everything.
I can deal with the shifting. It's nothing
too bad and I still have to get use to it. Thank god I live in a flat terrain city though.

I'm working with the F4 version and I am having issues with downloading the tpms tune. I also don't have the ESP option either
 

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I went with the same in 275/70/17 C hoping to avoid just this issue.
They measure just over 32" mounted on 8.5" AEV's and weight ~ 81lb/
My theory was to keep the weight down and maintain stock height.

So far no complaints with only a couple hundred miles, but I kept the stock rubi wheels n tires just in case.
It will be interesting to see how these hold up over time.
 
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