2005 Silverado 2500HD MAX tire size?? Has any owner or MR. Goodwrench, of/to, a 2005 Chevy Silverado,  upgraded to 285/75/16 or larger tires without cranking up the torsion bars, body lifts, or lift kits?? The project vehicle has a Duramax/Allison 4X4 combo, reg cab, 2" body spacers(factory), 245/75/16 on 6.5" rims. Planning on 8" American Eagle 101 wheel, 3-5/8 backset, -20mm offset with Nito Terra Grappler AT or BF Goodrich AT KO"S. Thanks in advance for the valued info replys, Bocalarry.  

You do know that GM will void warranty on your Allison you use tires larger than 265 and take it in for service without regearing truck. Could be a very expensive mod. When you effectivel gear the truck taller you increase strain on tranny and even worse when you boost engine to make up for it.  

i worked in a chevy dealership in maine for some time last summer and i have seen 285´s on the 2500HD´s without modification and there were no clearance issues....

one guy even ran 305´s and sayd they don´t rub, but that must be a very tight fit if it is true!

Going from 245 to 285 or 265 to 305 is like going from a 3.73 to a 3.42 axle ratio or from a 4.10 to a 3.73, there will be a loss of power too.  

thaat is true, but all i said is that the tires sizes i wrote down won´t rub without a lif, so they fit....
sure if you put bigger tires on you should also reear the truck
with the 285´s or 305´s you should probably run 4.10 gears!  

With 285's 305's 4.10's would be very wise indeed. You could try to make it up with boost like some do but it does not change that fact that the entire drive line is loaded a extra 10 to 15% or more unless you regear it.  

correct me if i'm wrong but I believe the 2500HD comes with 4.10 gearing stock.  

No, the 1500HD does but the 2500HD comes with 3.73 standard and 4.10 optional. (go figure) Usually though they are ship with the 4.10 option with 6.0, but it is not standard.  

I recently purchaced a new truck, and breifly looked at a chevy before I decided on a ford. From what I understand the 6.0 gas comes with 4.10 ratio, no way to even option for the 3.73 ratio. The Dmax comes with 3.73 ratio, no option for a 4.10 ratio. The only time you can pick what ratio you have is with the 8.1 gas.    

In 05 the 2500 6.0 can have a 3.73 (though it would be silly to get it because you will lose performance and not gain any MPG from it) and with Dmax you can get a 3.73 or a 4.10, same with 8.1. Dealers never seem to order in Dmaxs with 4.10's for stock though.  

Thank all of you for the helpfull advice. In my particular situation, I'm interested in ground clearance, as the truck will see hard dirt/rock to sandy crowned roads with varying depth tire ruts as well as mud holes. No real load will be carried at these times. I still have not decided on a tire as the only load range (E) tire I can find in the 285/75R/16 size is the Interco TRXUS MT. I have been reading a few user reviews for this tire and consenses leans to poor milage of tire tread. B.F. Goodrich, says they will have the All terrain T/K KO available in (E) range by the end of this month. I am confused as to the correct interpertation of the law as to the load range requirements, but I would rather error to the plus side and only buy one set of tires. When I have a need to tow or carry heavy loads, the 245's will go on. As to the axle ratio issue, Allison is the one pulling all the strings. They have engineered the system to work only with a 3:73 rear and  245/75R/16 tire combo(as per the user info posted on their web site for Chevy users). Chevy in turn does not offer a tire other than the 245's and lists trailer max towing weights with the 3:73 not the 4:10. Allison does not want you to use any aftermarket upgrades on their transmission, period.(should have bought another Dodge/stick shift) So as we speak, my new wheels(Pro Comp 1079's 16X8 w/4.5"bs) are decorating my living room, waiting for a tire to be manufactured(go figure).  

I just picked up my LMM Duramax 2500HD Crew Cab short bed. It came stock with LT265/70/R17 Bridgestone tires. I would like to get some 18" rims and maybe 285/70/R18 tires for it. Would this work? Front has been levelled a little. Not sure if there is enough room for these. Also heard this might affect the transmission warranty as slowing the vehicle would become harder on it.


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2008 Silverado 2500HD 6.6L Duramax LMM.
Levelling kit, everything else stock so far.  

Yea they will fit. For warranty info contact your dealer, each one is different. For a part to void a warranty it has to be proven that the 'non stock' part directly caused the failure, so this leaves a lot up to the dealer.