Stock 17 to “stock” 20 calibrations?

mandrewbot3k · May 17, 2022

I picked up a set of lightly used 275/65r20 wheels off a 2021 denali for my 2500 I just picked up Saturday. I have the gas/6 speed and I’m wondering if there are any calibrations that I may need from the dealer for shift points or speedo. Wasn’t sure how speed was determined on these new trucks given they have gps I figure they may be able to self calibrate. I know the sizes aren’t too different and the ones I’m putting in are a stock size but I picked up my truck in transit so I was able to get it in 8 days compared to 8 months.

haven’t even hit 100mi but it’s definitely an adjustment from my 2019 5.3L. Can’t wait to pull my trailer lol.

nards444 · May 17, 2022

just going to be a speedo. I would get the dealer to calibrate, without it your going speedo will be 3-5mph off maybe more depending on the speed.

CamGTP · May 17, 2022

Possible that you can ask the dealership to re-program the truck for the other factory size tire. No idea what that would cost. Or get a aftermarket tire size re-calibrator to fix it. \

From the looks of it you're going from a 31.6in tall tire to a 34in tall tire, so you're speedo will be off by nearly 5mph at 60 and over 6mph at 80.

nards444 · May 17, 2022

47 minutes ago, CamGTP said:

Possible that you can ask the dealership to re-program the truck for the other factory size tire. No idea what that would cost. Or get a aftermarket tire size re-calibrator to fix it. \

From the looks of it you're going from a 31.6in tall tire to a 34in tall tire, so you're speedo will be off by nearly 5mph at 60 and over 6mph at 80.

they will flash it to other OEM sizes but most likely will charge you do it. Ive had it done for free once but that as a while. might cost you 50-100

newdude · May 17, 2022

Yes. Dealer can flash to OE sizes.

mandrewbot3k · May 27, 2022

On 5/17/2022 at 9:32 AM, nards444 said:

they will flash it to other OEM sizes but most likely will charge you do it. Ive had it done for free once but that as a while. might cost you 50-100

I was quoted $300 at my dealer. They said GM charges them $150 just for the firmware file to flash and they charge another $150. I'll probably keep asking.

One thing I was wondering is if the stability control/braking/shifting are impacted by the speedometer. The dealer stated "only the speedometer changes", but that may have indirect impacts, no?

CamGTP · May 28, 2022

They wouldn't do the change if it made those systems have problems.

Very likely that the flash covers the speedo and transmission related parameters so it can shift correctly. This is how aftermarket systems do it and they have no trouble keeping the ABS systems happy.

nards444 · May 31, 2022

On 5/26/2022 at 10:02 PM, mandrewbot3k said:

I was quoted $300 at my dealer. They said GM charges them $150 just for the firmware file to flash and they charge another $150. I'll probably keep asking.

One thing I was wondering is if the stability control/braking/shifting are impacted by the speedometer. The dealer stated "only the speedometer changes", but that may have indirect impacts, no?

Cant imagine it changes anything but the speedo and the MPG calculation. But they will flash to stock sizes, and like you have said I think my dealer now charges 100 to hook it to the machine. 300 seems excessive but is what it is

pokismoki · May 31, 2022

pick up the HP tuner bluetooth module to communicate to your phone, , the parameter are easy to change

It's Tim · May 31, 2022

59 minutes ago, pokismoki said:

pick up the HP tuner bluetooth module to communicate to your phone, , the parameter are easy to change

So how much is that, like $50 or something?

mandrewbot3k · May 31, 2022

1 hour ago, pokismoki said:

pick up the HP tuner bluetooth module to communicate to your phone, , the parameter are easy to change

Wouldn't that basically cause warranty issues? And I'd have spend more money for that device than what they'd charge

mandrewbot3k · May 31, 2022

On 5/27/2022 at 10:06 PM, CamGTP said:

They wouldn't do the change if it made those systems have problems.

Very likely that the flash covers the speedo and transmission related parameters so it can shift correctly. This is how aftermarket systems do it and they have no trouble keeping the ABS systems happy.

I more meant that updating it would "correct" problems. Ie... stability control would be better calibrated due to the accelerometers and speedo being sync'd now.

nards444 · May 31, 2022

1 hour ago, mandrewbot3k said:

Wouldn't that basically cause warranty issues? And I'd have spend more money for that device than what they'd charge

Possibly. Anything that changes parameters or what the computer does is tuning and creates warranty issues. Not saying it will happen. But they are getting tight with the stuff, they got lawsuits in on this stuff trying to make the components illegal to tamper with.

Honestly I used to the play the game with tuners, aftermarket stuff and came to realization it either cost more money to go aftermarket or was just junk and created issues. And do I trust the multi billion dollar company that sinks millions into RD (dont always get it right though) or the guys in their garage that beta this stuff on one car and start selling it.

any legit tuner out there depending on what it does is going cost 200 up to 1000. Most the stuff people have are in the 2-400 range.

With that said these computers these days know every change/entry into it now and whether it was authorized or not

Edited May 31, 2022 by nards444

mandrewbot3k · May 31, 2022

23 minutes ago, nards444 said:

Possibly. Anything that changes parameters or what the computer does is tuning and creates warranty issues. Not saying it will happen. But they are getting tight with the stuff, they got lawsuits in on this stuff trying to make the components illegal to tamper with.

Honestly I used to the play the game with tuners, aftermarket stuff and came to realization it either cost more money to go aftermarket or was just junk and created issues. And do I trust the multi billion dollar company that sinks millions into RD (dont always get it right though) or the guys in their garage that beta this stuff on one car and start selling it.

any legit tuner out there depending on what it does is going cost 200 up to 1000. Most the stuff people have are in the 2-400 range.

With that said these computers these days know every change/entry into it now and whether it was authorized or not

Yeah, that's what I was thinking. Part of the reason for the move from my 2019 1500 was to re-up the warranty. Plus I paid for an extended with my (very trustworthy) dealership, so doesn't seem like something to compromise. I did see also that the Rough Country speed adjuster said 'not for sale in California', which made me wonder about potential other issues with the emissions/ and eventual need to smog.

nards444 · May 31, 2022

22 minutes ago, mandrewbot3k said:

Yeah, that's what I was thinking. Part of the reason for the move from my 2019 1500 was to re-up the warranty. Plus I paid for an extended with my (very trustworthy) dealership, so doesn't seem like something to compromise. I did see also that the Rough Country speed adjuster said 'not for sale in California', which made me wonder about potential other issues with the emissions/ and eventual need to smog.

Yeah not for everybody but I dont buy trucks to last 10 years. I keep them during original warranty and send them on. When you factor purchase price, maintenance, replacing wear items, depreciation, etc. My formula works out to just go new every few years.