Wheel/Tire thoughts for stock height 3500 SRW

pdscfx · May 3, 2019

Hello all, came up with a combo to replace stock wheels and trying to see if it'll work out and if I am thinking about the fitment correctly.

Truck in question is a 2019 GMC 3500 SRW Denali - completely stock and I'd like to see if I can run 305/55-20s without having to add a lift or level

Stock wheels: 18in x 8in +44 (I think)

Stock tires: 265/70-18

I was looking at maybe going with XD822 Monster II 20x9 +18 with 305/55-20 tire mounted

So the new rim is 1 inch wider but given offset is less +18 vs +44 by almost exactly 1 inch the inner aspect of the rim and tire will be the same as stock. Just the tire will stick out 1 inch further to the outside.

The stock tire should be 32.6" tall given its sizing. The 305/55-20 would run 0.6" taller at 33.2" height. Sidewall will be 0.7in shorter on new tires and rim would clearly be 2 in taller.

In the stock setup there appears to have plenty to clearance and I'm speculating it could accommodate the 0.6 inch increase in size without difficulty and the width would only be increased outward so shouldn't impact the fit. Think this would work?

Has anyone tired anything like this? Poking around on here it looks like most people add at least a level kit prior to tires.

gforce_15 · May 3, 2019

it should be pretty close, might have to zip tie/suck in the inner fender liner to the frame. I got 20x9 +18 offset wheels and put 275/60 Nittos on my truck and they fit with zero rub after pulling in the fender liner a little bit. The extra width is the challenge for most of these trucks. Going over 12" wide on the tires on stock height seems to sometimes cause rub issues. Here is a link to someone with the same set up you're going for and it looks like he had no issues:

https://www.customwheeloffset.com/wheel-offset-gallery/383587/2015-gmc-sierra-2500-hd-gear-alloy-726c-stock-stock

Hope that helps

pdscfx · May 4, 2019

Awesome thanks, going to give it a try and see how it turns out. Guess can always add a leveling kit if some minor tweaks doesn't cut it.

CRApex · May 5, 2019

If you have splash guards, they may need to be trimmed. I have 305/55.20’s on +10’s with about an inch of lift, no rubbing. My 2015 SRW 3500 was stock height and I had 305/55/20 with +25 wheels..No rubbing or trimming on that one.