Tire Size Change 2008 2500hd

mjhr · February 5, 2010

I have a 2008 2500HD with a 6.0L 373 gear. I want to change tire size from 245 to 285. I am wondering what is all involved with reprograming computer. I also do not like the tire pressure settings from factory, @80 rear and @55 front. Can i change these with a hand held programmer? When i talked with dealer at point of purchase, they stated they could not change the settings, i also could only go to 265 tire size. I am also worried about loss of power if i do go to taller tire. Can anyone point me in the right direction? I DO NOT UNDERSTAND WHY GM PUTS THESE SMALL TIRES ON THE TRUCKS IN THE FIRST PLACE.

yukon25008.1 · February 5, 2010

I have a 2008 2500HD with a 6.0L 373 gear. I want to change tire size from 245 to 285. I am wondering what is all involved with reprograming computer. I also do not like the tire pressure settings from factory, @80 rear and @55 front. Can i change these with a hand held programmer? When i talked with dealer at point of purchase, they stated they could not change the settings, i also could only go to 265 tire size. I am also worried about loss of power if i do go to taller tire. Can anyone point me in the right direction? I DO NOT UNDERSTAND WHY GM PUTS THESE SMALL TIRES ON THE TRUCKS IN THE FIRST PLACE.

Ive had 285,s on almost everypickup ive had old and new gas and diesel.your not gonnanotice any power loss,

as far as speedometer goes a handheld prograammer will fix/adjust so will a blackbear tune, set the pressure were you want, if your loaded or haulin leave 80, most 285,s are load d and have a 65 psi max, run 60

Lousdepot · February 5, 2010

i am in the same boat, i have a 2009 with the same!! driving me crazy. what about moving to a 18" rim? anyone know max tire on an 18" rim that will fit with at most a leveling kit? i know its my first post but i have read everything and i am flat out confused!! pics would be great too.....thanks

brentm · February 5, 2010

I was wondering the same thing. I bought my truck used and it has 285s and I have always had them on my z71s but I was wondering the difference between the 285s and the 265s. Will it effect the gas mileage any because if its not a big difference then I am sticking with the 285s cause smaller tires look ridiculous on these big trucks.

thearborbarber · February 5, 2010

Contact this member;

Mike@Diablosport

He can set you up with a handheld programmer to change your speedo for different tire sizes.

or

You can send your PCM to

http://www.blackbearperformance.com/

They both are site sponsors and can meet your needs

travistabbert · February 6, 2010

I have a 2008 2500HD with a 6.0L 373 gear. I want to change tire size from 245 to 285. I am wondering what is all involved with reprograming computer. I also do not like the tire pressure settings from factory, @80 rear and @55 front. Can i change these with a hand held programmer? When i talked with dealer at point of purchase, they stated they could not change the settings, i also could only go to 265 tire size. I am also worried about loss of power if i do go to taller tire. Can anyone point me in the right direction? I DO NOT UNDERSTAND WHY GM PUTS THESE SMALL TIRES ON THE TRUCKS IN THE FIRST PLACE.

I just had new 10 plys put on my half ton crew and was told to get the best wear out of them to not go below 50psi, which is quite a bit more than the 35psi the p metric goodyears it came with. I took it to my local dealer and they had no problem adjusting the tpms settings to run at the appropriate range for the new tires. I was told there was something like an 8 or 10 psi range for the system so they set it accordingly. As far as a larger tire size affecting power or mileage, ive heard it sometimes will and sometimes doesnt. I stayed with the 265s, though mine is a half ton. good luck

alaska511 · February 6, 2010

i am in the same boat, i have a 2009 with the same!! driving me crazy. what about moving to a 18" rim? anyone know max tire on an 18" rim that will fit with at most a leveling kit? i know its my first post but i have read everything and i am flat out confused!! pics would be great too.....thanks

Yep. 275/70/18

Lousdepot · February 6, 2010

i am in the same boat, i have a 2009 with the same!! driving me crazy. what about moving to a 18" rim? anyone know max tire on an 18" rim that will fit with at most a leveling kit? i know its my first post but i have read everything and i am flat out confused!! pics would be great too.....thanks

Yep. 275/70/18

THATS PERFECT!!! any leveling kit needed? and if you dont mind what are specs on wheels width?, backspace? thanks

alaska511 · February 6, 2010

Leveled, 18x8.5, 5.25 BS, +18 OS

mjhr · February 8, 2010

Thanks everyone for input. I installed 285/75 R16 Kelly TSR yesturday, they look great. Not sure how much the speedometer is off, but dont seem like much. I had to make some minor adjustments do to rubbing on tight turns. With a heat gun on inner fender, a cable tie for emergency cable, and a little persuasion they no longer rub with 1 inch for clearance. I will try to get some pics on soon. New at this so may take a while. Truck looks soooooooooo much better.

Polensky Racing · February 11, 2010

Thanks everyone for input. I installed 285/75 R16 Kelly TSR yesturday, they look great. Not sure how much the speedometer is off, but dont seem like much. I had to make some minor adjustments do to rubbing on tight turns. With a heat gun on inner fender, a cable tie for emergency cable, and a little persuasion they no longer rub with 1 inch for clearance. I will try to get some pics on soon. New at this so may take a while. Truck looks soooooooooo much better.

How the new tires working out for you? I put 285/70/17 on my 08 2500HD and lost 2 MPG city and 3 highway. I love the looks but not sure what to do.

Silverado4x4 · February 11, 2010

You speedometer is only off by about 2 mph so if your speed-o is showing 60 mph your truck is really going 62 not enough to worry about. I had 285s on my Duramax when I had it.

Silverado4x4 · February 11, 2010

Thanks everyone for input. I installed 285/75 R16 Kelly TSR yesturday, they look great. Not sure how much the speedometer is off, but dont seem like much. I had to make some minor adjustments do to rubbing on tight turns. With a heat gun on inner fender, a cable tie for emergency cable, and a little persuasion they no longer rub with 1 inch for clearance. I will try to get some pics on soon. New at this so may take a while. Truck looks soooooooooo much better.

How the new tires working out for you? I put 285/70/17 on my 08 2500HD and lost 2 MPG city and 3 highway. I love the looks but not sure what to do.

Did you figure it out by hand or are you going by the trucks mpg reading? Mpg will vary that much on any truck between fill- ups.