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Tire change/reflash pcm

BigRedHD

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BigRedHD Enthusiast

BigRedHD

Posted
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If I go from the 245/75 tires on my 2004 Silverado 2500 HD to 305/70's, do I have to buy a Hypertech just to reprogram my speedometer or can I just go to the dealer and have them do it? Will they charge me? Thanks!

Peter_C Enthusiast

Peter_C

Posted
Posted

If you take the truck to the dealer you can have them change it but instead of telling them the tire size tell them the circumference. I have heard this works. The other alternative is to get a Wester's PCM which is the way I went along with many others. Having the extra power is a major benefit.

vhato Enthusiast

vhato

Posted
Posted
If you take the truck to the dealer you can have them change it but instead of telling them the tire size tell them the circumference. I have heard this works. The other alternative is to get a Wester's PCM which is the way I went along with many others. Having the extra power is a major benefit.

 

 

 

 

 

My local Stealer will do the change for $75.00.

Peter is right. If you tell the Dealer to program for 33" tire you will be wrong. The ABS/Speedo and Tranny Shifts will still be off. A 305/70r16 cpmes out to around 30-31".

 

In the HyperPing Manual it explains how to correctly meaure tires. If you want to know I can post how.

Stocklook Enthusiast

Stocklook

Posted
Posted

I have question about this: If you only go 1/2" to 1" bigger or smaller from stock wheels w/tune does it matter or will need to send PCM for repro

vhato Enthusiast

vhato

Posted
Posted
I have question about this:  If you only go 1/2" to 1" bigger or smaller from stock wheels w/tune  does it matter or will need to send PCM for repro

 

 

 

 

 

Nah,

I "think" the only noteable change will be the transmission will shift a few RPMS later than usual.

BigRedHD Enthusiast

BigRedHD

Posted
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Posted

Thanks. I'll check with my dealer when the time comes, but if it's $75, I'll just see if I can get a used Hypertech or some other PCM tune. BTW, I thought that the 305/70/16 ended up being 33" (according to the tire manufacturer's listing). I appreciate the quick replies! Love this board!

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