Speedo Calibration - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevyboy55 · 09-24-2009, 07:33 PM

A guy I work with has either an 06 or 07 (he's not sure,the door says 06,title says 07) 1/2 ton 4wd. He is wondering what he needs to do to get the speedo calibrated after putting oversize tires & wheels on it.

**bwood** · 09-24-2009, 11:13 PM

His door may say 06 meaning it was manufactured in 06 for the 07 model year. Usually anything on or after Aug will be for the next model year. My 98 was manuf in 12/97. As for his tires, this should be something the dealer could handle or anyone who has the ability to adjust the tire size in the computer. You can also purchase something like the hand held power programmers or send the computer out to be redone. The dealer may be the cheapest option, especially if you can talk them into maybe just charging for just a half hour. I can't remember what criteria they will need to make the change, but just to be safe, get the tire size, revolutions per mile (should be available from tire manuf web site) and tire outside diameter (also should be available from tire manuf web site).

GCncsuHD · 09-25-2009, 12:04 PM

Dealer can do it, although they are always reluctant, and alot of techs don't know that they can do it with the Tech2. But if the truck is out of warranty by now, he may be better off getting a custom tune for the truck (I recommend Black Bear Performance). And by this I don't mean one of those crappy handhelds like hypertech or superchips, I mean EFI live etc actually custom tuning the PCM. This is actually cheaper, although a little less convenient than a handheld, but they can correct speedometer, change shift points for the change in tire size, as well as add a good bit of hidden power potential and fuel mileage gains.

Shon · 09-30-2009, 04:20 PM

There are options for changing the tire size.
He can either have the PCM programmed by someone to make that change (and more if he wants) or buy a programmer to make those changes and others.

chevyboy55 · 09-30-2009, 09:30 PM

Thanks, I'll pass the info along to him. He will have to take it somewhere, he does not even know what a wrench looks like.
He just knows he a bought a truck that looks cool with a lift kit & big tires.

09-24-2009, 07:33 PM	#1
chevyboy55 Senior Member Join Date: Aug 2004 Location: Kelso,Wa Posts: 3,637	Speedo Calibration A guy I work with has either an 06 or 07 (he's not sure,the door says 06,title says 07) 1/2 ton 4wd. He is wondering what he needs to do to get the speedo calibrated after putting oversize tires & wheels on it. __________________ Great minds think alike,So do ours

09-24-2009, 11:13 PM	#2
bwood Registered User Join Date: Jan 2003 Location: Denison, Texas Posts: 1,919	Re: Speedo Calibration His door may say 06 meaning it was manufactured in 06 for the 07 model year. Usually anything on or after Aug will be for the next model year. My 98 was manuf in 12/97. As for his tires, this should be something the dealer could handle or anyone who has the ability to adjust the tire size in the computer. You can also purchase something like the hand held power programmers or send the computer out to be redone. The dealer may be the cheapest option, especially if you can talk them into maybe just charging for just a half hour. I can't remember what criteria they will need to make the change, but just to be safe, get the tire size, revolutions per mile (should be available from tire manuf web site) and tire outside diameter (also should be available from tire manuf web site). __________________ 1998 GMC Sierra SLE 1/2 ton 2WD 305 Vortec -Gibson Stainless Cat Back Swept Side -SS Wheels 2005 Honda CRF250R 2006 Honda CRF150F

09-25-2009, 12:04 PM	#3
GCncsuHD Charlie Daniels w/ a Tq Wrench Join Date: May 2009 Location: Statesville, NC Posts: 1,570	Re: Speedo Calibration Dealer can do it, although they are always reluctant, and alot of techs don't know that they can do it with the Tech2. But if the truck is out of warranty by now, he may be better off getting a custom tune for the truck (I recommend Black Bear Performance). And by this I don't mean one of those crappy handhelds like hypertech or superchips, I mean EFI live etc actually custom tuning the PCM. This is actually cheaper, although a little less convenient than a handheld, but they can correct speedometer, change shift points for the change in tire size, as well as add a good bit of hidden power potential and fuel mileage gains.

09-30-2009, 04:20 PM	#4
Shon Registered User Join Date: Sep 2005 Location: sc Posts: 1,203	Re: Speedo Calibration There are options for changing the tire size. He can either have the PCM programmed by someone to make that change (and more if he wants) or buy a programmer to make those changes and others. __________________ 71 Cheyenne C10 LWB cam'd 6.0/T56 Swap

09-30-2009, 09:30 PM	#5
chevyboy55 Senior Member Join Date: Aug 2004 Location: Kelso,Wa Posts: 3,637	Re: Speedo Calibration Thanks, I'll pass the info along to him. He will have to take it somewhere, he does not even know what a wrench looks like. He just knows he a bought a truck that looks cool with a lift kit & big tires. __________________ Great minds think alike,So do ours



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