Tire size question.

[nvmtnlion]

Baby needs a new set of shoes!

I have heard rumors that going up in tire size with the diesel engine requires that the confuzer be reprogrammed. Is this true? If so, is there an easy way to accomplish this? What is the best size to go with on a stock lift? I have 3.73:1 and don't tow very heavy loads so I wouldn't mind lowering the cruise RPMs. Thanks!

Okay, search came up with the VSSB adjustment procedure. Now, what size tires??

[ 11-30-2004, 06:44 PM: Message edited by: nvmtnlion ]

[DennisG01]

Altering the computer in some way would be required for a gasser, as well. I am running 265/75 - think I heard of some guys going to 285's. I have no rubbing problems and I THINK that the the guys with the 285's are OK, too (without any type of lift). Maybe someone with 285's can chime in. I don't know if there is any difference in this area between your model year and mine, though, I doubt it.

[piersbc]

I've put 285/75/16's on mine. Turned the torsion bars 5 1/2 turns to level truck up. Then got it aligned. So far so good.

[Low_Bridge]

I've put 285/75/16's on mine. Turned the torsion bars 5 1/2 turns to level truck up Did you check to see how much it raised you rig?

I want to be able to still fit in the garage.

[Dihrdbowti]

I'm stock height with 265/75 with 3.42's (I think) I turn 1800 rpm's at 65mph. Get 21 freeway 16-17 in town. I think there is plenty of room to go to the 285/75's. It's my understanding that tire numbers break down like this. 265 is the tread width of the tire in millimeters. 75 is the aspect ratio or the sidewall measured as a percentage of the tread width. So if my math is right and someone please correct because I am probably wrong but 75% of 265 is 198.75mm or 7 7/8th's of an inch. Putting on a 285/75 has an aspect ratio of 213.75mm or 8 3/8's or an additional half inch on the aspect ratio or 1 inch overall. Whereas a 285/70 is only 199.mm and closer to the 265/75 but fatter. Make sense? or did I just confuse myself and eveyone else? lol

[DA BIG ONE]

Another consideration is rim width when you go w/larger width tires, it is best to research tire manufactures data on this.

I have Stockton Wheel making 8" wide military wheels for flotation tires because that is what the tire manufacture recommends. Yes, there are lots of wheels out there, but the issue is always wheel capacity when driving a K2500 w/6.5td, alcoa forged only goes to 7" in a 16" wheel.

[mklein]

I have 285/75/16's on my 1995 3/4 ton 4wd Suburban. I used the stock steel wheels, and they fit well, but will rub a slight amount when turning and compressing the suspension. The wheel offset becomes very important if you go up to the 285's. The DRAC can be recalibrated quite easily to keep the speedo working correctly.

[piersbc]

With the 285/75/16 tires on stock rims and the torsion bar cranked up 5 1/2 turns it only raised the truck 1 3/4 in. The torsion bar only raises the front of the truck. Levels out the truck.

[GaDixie]

Normally anything up to 285/75/16s don't cause enough problem to reset your speedometer. On some, I've seen the speedo only be 2-3 MPH at 80 with 33x12.50s (on a '97 6.5L) so I wouldn't worry about it too much.

[Turbine Doc]

Mine came stock with 285s but by GPS I'm about 3-5 mph slower than shown on speedo from 55mph & up