Tire change/reflash pcm

[BigRedHD]

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]

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]

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.

 

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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]

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]

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

 

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Nah,

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

[BigRedHD]

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!