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New tires. 2" shorter. Need your help.

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Old 12-13-2012, 04:31 AM
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Default New tires. 2" shorter. Need your help.
I installed my 20" wheels with a slightly shorter tire last night. The truck loves to sit on the limiter before shifting now. Is tire diameter the only thing I need to change in the tune?

Thanks in advance!
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Old 12-13-2012, 08:23 AM
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change the tire size so it adjust all the trans shifting tables.
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Old 12-13-2012, 08:55 AM
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perfect. THanks. Will do.
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Old 12-13-2012, 09:24 AM
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The rpm/mph will probably be off as well...

Where before if you were wanting to shift at say 6000rpm/55mph now 6000rpm would be at 50mph...
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Old 12-13-2012, 09:35 AM
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i was hoping when he adjust the tire size it would correct the part and wot MPH shift tables.
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Old 12-13-2012, 11:02 AM
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Does it do that?? I've honestly never noticed...
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Old 12-13-2012, 11:24 AM
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EFI live will if you click apply haha..

never fooled with HPT that much.
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Old 12-13-2012, 12:00 PM
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I have efi live so the tire size will fix the shift tables and everything correct?

Seems to be what I am getting from this but just want to make sure.
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Old 12-13-2012, 12:46 PM
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It's an option for HPT also. When you change the tire size there is a check box to also scale the trans tables. Does a decent job from what I have seen so far
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Old 12-13-2012, 01:00 PM
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Both HPT and EFI will auto scale I believe, as mentioned above HPT just has a box you check to do so.
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