I was looking at 265's for my 2004.5 Dmax and asked the Dealer if he could reprogram my truck for the bigger tires. He said that GM will not allow them to do it. Anyone else hear of this and why if you know.

Thanks for the help

Actually,I think alot of guys have said that 265's make the speedo dead on as they are off with the 245's.Tell your dealer to go look at a single rear 3500.They COME with 265's.Then call him a bad word.

My dealer, who is also a friend, says the difference is so slight that they can't reprogram for it. I checked my speedo before and after putting on the 265's and it reads about 2 mph slower, if that (it is about a needles width difference).

Not to mention that the 245's will make your warranty run out faster...more revs means the odometer turns faster.:Nonono: Tsk Tsk. If you put the 265's on, the speedo will be a bit more accurate as the revs will be lower, and as mentioned above 265's come on the the SRW 3500. Sounds fishy to me.
JP

They can't reprogram the speedo anyways, even if they wanted to.
The only thing the Tech-II can reprogram is the ABS system.

I bought 265's Yoko's from the tire rack, took them to the my freindly chevy dealer to mount. When i pick up the truck he said the bill came to $48.00 for the tire change and balance then he said they reprogrammed the comp. for free? :rolleyes: It's the place we buy from

They can't reprogram the speedo anyways, even if they wanted to.
The only thing the Tech-II can reprogram is the ABS system.

That is exactly right. GM dealers do not have the capability to reprogram the speedometer. Unless they have EFI Live ;)

Subject:Compensating for Different Axles Ratio and Tire Sizes with a VCI Number - keywords calibration ECM PCM pinion recalibrate reflash reprogram ring wheel TCSC techline #PIP3096B - (06/23/2005)


Models:All GM Passenger Cars
All GM Light Duty Trucks
with a Programmable ECM or PCM



The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1676357&psdid=437&evc=sm#ss1-1676357">Condition/Concern:

If the rear axle ratio or tire size is changed, abnormal vehicle operation, such as harsh shifts or incorrect speedometer operation, may be experienced.
<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1676357&psdid=437&evc=sm#ss2-1676357">Recommendation/Instructions:

TCSC (Techline Customer Support Center) may be able to supply a VCI number on the models below to compensate for supported axle ratio or tire size changes if they were an available combination from the factory. The new vehicle sales department may be able to determine if an axle ratio and tire size combination was available as a factory option. If the axle ratio and tire size combination was not available as a factory option, TCSC can not supply a VCI number.

Axle Ratio Changes are Supported on the Following Models:


• 2002 Chevrolet Camaro

• 2002 Pontiac Firebird

• 2003-2005 Chevrolet Corvette

• 1996-2005 Trucks, Vans and Utility Vehicles


Tire Size Changes are Supported on the Following Models:
1996-2005 Trucks, Vans and Utility
If a VCI number is needed to compensate for a supported axle ratio or tire size change, contact TCSC at 1-800-828-6860. Once connected, select Prompt 1 and then Prompt 2 for VCI numbers.
Important: TCSC can not supply a VCI number to increase the fuel cut off speed if tires with a faster speed rating are installed.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Actually,I think alot of guys have said that 265's make the speedo dead on as they are off with the 245's.Tell your dealer to go look at a single rear 3500.They COME with 265's.Then call him a bad word.

265 is a 4% difference. Here's a calculator I posted a while back. Pretty handy.
http://www.miata.net/garage/tirecalc.html

For calculating mileage it's Mileage from DIC x 1.04 divided by gallons for 265s

Thanks Guys for the help a lot of good info here. What would I be able to do with a EFILive and what do they cost?

Anything that you ever wanted and could think to do.

Cost is 749.00...Plus laptop.

McRat sells his with a 500hp tune
Trippin I think sells his with a tow program.

well worth the $$ it is the best thing that ever came to town:D :D

program ecm and tcm totally export old program and inport new 1 less than 5 min after u learn it( not including making the actual program)

So you need to have a lap top?

You currently need to connect your vehicle to FlashScan V2 and FlashScan V2 to your laptop/PC to change the tune in your ECM/TCM or both. But in less than 3 months it will be standalone like a handheld tuner. You will still need a laptop/PC to view your logs and make your changes to your tune.

Given you've got an LLY, if you did have access to a laptop or were able to connect your PC to FlashScan and your vehicle, you could purchase FlashScan V1 for $549. This model will never have standalone features.

Cheers

Cindy

This model will never have standalone features.

And it will never be able to tune LBZ's or newer trucks. So if you plan to get a new truck in a few years go with the LBZ.

till they update it you need a laptop, but once they update then you will be able to load the tune into the EFIlive V2 unit from your desktop and take it out to the truck and load it.

How tuff is it to use, I mean to create tunes ect.. and will this program read and delete codes?

Not bad to use. With a LLY there is a pretty large selction of programs for you to try already on the board.

Or if you want to go the simple route you can get a Predator 2.02 for around $300 used (IIRC) and it can read codes, remove speed limiter, adjust for tire size, and disable the EGR alerts. It's not even close to being as feature laden as EFI but if you want simple it's the way to go.

TCSC (Techline Customer Support Center) may be able to supply a VCI number on the models below to compensate for supported axle ratio or tire size changes if they were an available combination from the factory.
Meaning no updates for 265/75-16, 286/75-16, or any 17".... NOR for any axle ratio other than 3.88.

The tire/axle ratio combinations for gassers are more varied than they are on the Duramax.

Given you've got an LLY, if you did have access to a laptop or were able to connect your PC to FlashScan and your vehicle, you could purchase FlashScan V1 for $549. This model will never have standalone features.
How long before you will support the early '06 OS... or for that matter, how do I know what OS I have?
I did get the recall reflashes last April.

My speedo with the stock crappy 245's is right on the money unless my gps is wrong :)

My speedo with the stock crappy 245's is right on the money unless my gps is wrong :)

Borrow someone else's GPS and re-check it if you're not sure. My truck was indicating 1 1/2 mph fast with the stock 245's.

1-1/2?????
That's close enough, depending on the speed, but at 50mph that's within 3%.
Really... you're talking indicated 100 when you're doing 97.
That's having the warranty on the engine run out a half an oil change early.

Fed standards allow 10% error from the factory (which is incidentally where most imported motorcycles are, which explains why you see them doing 5-10 under the limit).

3%? Ya... a set of 265/75-16s will fix it and run the speedo about 1/2mph slow at 50.

1-1/2?????
That's close enough, depending on the speed, but at 50mph that's within 3%.
Really... you're talking indicated 100 when you're doing 97.
That's having the warranty on the engine run out a half an oil change early.

Fed standards allow 10% error from the factory (which is incidentally where most imported motorcycles are, which explains why you see them doing 5-10 under the limit).

3%? Ya... a set of 265/75-16s will fix it and run the speedo about 1/2mph slow at 50.

1 1/2 mph was at 70mph. It's dead on now, though. Well, as close as I can get with that fat speedo needle GM puts on these trucks.

1 1/2 mph was at 70mph. It's dead on now, though. Well, as close as I can get with that fat speedo needle GM puts on these trucks.
LOL!
So you were worried about 2%? 265's will have you running 2% slow :)

If you're within 5mph cops aren't going to mess with you.

LOL!
So you were worried about 2%? 265's will have you running 2% slow :)

If you're within 5mph cops aren't going to mess with you.

No, I wasn't worried over it. I have a Predator and have the capability to get the speedo right on the money. Why not? I just like things to be accurate. BTW, I'm running 285's (and the speedo is accurate with those on also). :cool:

I have a friend that has an 04 with an 8" lift and 37" tires. His speedo is off over 10mph. That would drive me nuts!

You currently need to connect your vehicle to FlashScan V2 and FlashScan V2 to your laptop/PC to change the tune in your ECM/TCM or both. But in less than 3 months it will be standalone like a handheld tuner. You will still need a laptop/PC to view your logs and make your changes to your tune.

Given you've got an LLY, if you did have access to a laptop or were able to connect your PC to FlashScan and your vehicle, you could purchase FlashScan V1 for $549. This model will never have standalone features.

Cheers

Cindy

Are there plans for the new V2 tuner and earlier LB7's ???

(an option for those of us that only have desktop PC's and don't want the added cost of purchasing a laptop PC)

Thanks.....Quick 6 Racing

i think you can

No, I wasn't worried over it. I have a Predator and have the capability to get the speedo right on the money. Why not? I just like things to be accurate. BTW, I'm running 285's (and the speedo is accurate with those on also). :cool:

I have a friend that has an 04 with an 8" lift and 37" tires. His speedo is off over 10mph. That would drive me nuts!

What tire size did u program into the Predator to make it right for the 285's?

What tire size did u program into the Predator to make it right for the 285's?


The Predator walks you through the process. You'll need to know tire width and aspect in mm - in my case the width is 285 and the aspect was 75. Then they will ask you for rim size. You have to modify tire size for each program. In my case I have the 65hp tune downloaded. You could theoretically have different tire sizes set up for each tune IIRC.

I actually had to go to 34 or 34.5 for the 285's on my Bullydog to make it accurate.

My dealer has quoted me 765.07 for LT26575R16's BFG A/T KO's with a 300 allowance for the OEM OOR 245's..... so final cost to me would be 465.07 and he made sure to mention that included the reprograming of the ECM .....

My brother, user name lilrazz, just bought an 04 Duramax. Has brand new 245 pyo's on it. When we were bringing it home on the interstate it sure seemed like the speedo was off. We do a test and sure enough, 1 actual mile traveled show 1.2 miles on the dic. My guess is the previous owner had 285's on it. So I call the dealer and tell him about the situation and he says he can reprogram the speedo to correct tire size. Not sure if he know's what he's talking about, but I guess we'll find out.

What tire size did u program into the Predator to make it right for the 285's?

To get my speedo dead-on, I used 277-75-16. I know it sounds weird, but with the larger 285 tires and the built in errors in the original factory setup, that's what it took.

My dealer has quoted me 765.07 for LT26575R16's BFG A/T KO's with a 300 allowance for the OEM OOR 245's..... so final cost to me would be 465.07 and he made sure to mention that included the reprograming of the ECM .....

Very intersting that he can reprogram the speedo when everyone else here says the dealers can't do it. They must have EFI Live or a handheld programmer. Be sure they don't lock you out of your ECM if using a handheld programmer.

To get my speedo dead-on, I used 277-75-16. I know it sounds weird, but with the larger 285 tires and the built in errors in the original factory setup, that's what it took.

Interesting. I did not know that. Good info.

To get my speedo dead-on, I used 277-75-16. I know it sounds weird, but with the larger 285 tires and the built in errors in the original factory setup, that's what it took.

I had to use 234/78/16 for my 265's.

Question for those who put odd-ball sizes into the Predator for tire size correction: Did you use a GPS unit to determine the actual distances traveled, and then use trial-and-error to zero in on the GPS results?

Thanks,

Joseph

Very intersting that he can reprogram the speedo when everyone else here says the dealers can't do it. They must have EFI Live or a handheld programmer. Be sure they don't lock you out of your ECM if using a handheld programmer.
Ditto.
If they use a handheld and you end up stuck somewhere and need to go to a different dealer and they decide to reflash (either due to a failure or due to a recall) then you're screwed.

The Tech-II cannot reprogram the speedometer, only the ABS system.

Question for those who put odd-ball sizes into the Predator for tire size correction: Did you use a GPS unit to determine the actual distances traveled, and then use trial-and-error to zero in on the GPS results?

Thanks,

Joseph

We use the GPS to show our actual speed, then make changes with the handheld programmer until the speedo on the truck matches the GPS.

I usually use 70 mph as my check speed because that it what I usually cruise at on the highways.

SixPak

What tuner are you using to set tire size

SixPak

What tuner are you using to set tire size

Predator V2.02

Just an update on this issue. Took my brother's pickup in to the dealer to get tire size recalibrated. Just talked to service tech and he told me the computer was programed for 265's. They reprogrammed it for 245's and everything is in spec now.

Question for those who put odd-ball sizes into the Predator for tire size correction: Did you use a GPS unit to determine the actual distances traveled, and then use trial-and-error to zero in on the GPS results?

Thanks,

Joseph

Yes!, the odometer was correct as verified by GPS, but the speedo was still off by about 2 mph.