Wheel Offset & Tires On 09 Gmc 4x4

dgreene396 · November 20, 2009

Well folks, I am a newby to the website, and from the various information I have read, there is a lot of good information to be shared by a lot of knowledgable people here. And who better to ask than the people who have suspension mods to their GM trucks who know what they are doing. Experience goes a long way with this topic!!

And I would like to express my appreciation to all in advance for the shared information.

There are a lot of pics of trucks with suspension mods and new tires/wheels with sizes, but very little mention of the wheel offset or backspace.

Here's what my dilemma is:

2009 GMC Sierra 1500 4x4, Ex-Cab, Std box. Factory P265/70R17 aluminum wheels/tires.

Vertical dim to wheelwell from ground: 36.38" Front, 39.00" Back (BEFORE LEVELING KIT)

I am planning to install a CCM 2-1/2" Leveling kit in the next few days.

If it would be greatly beneficial and keep the tires from rubbing, I could install the ZoneOffroad 1-1/2" or 3" Body Lift, but not this next week.

I am planning to buy a set of MotoMetal 951 18"x9" chrome wheels later... (offset to be determined)

My question for the experts:

Moto Metal 951 comes with either -12mm offset (4.53 Backspace), +18mm offset (5.71 Backspace) or +30mm offset (6.18 Backspace).

I know what the offset and backspaceing does to the location of the wheel, but I do not know what will rub and what will not with the different setups.

Where do the tires rub when there is an issue? On the inner wheel wheel? On the lower outer painted area of the vehicle fender, or on something else? I would prefer not to trim any metal!!

I am contemplating a few different sets of tires to be used on the MotoMetal 951's, depending on rubbing/trimming.

Cooper Discoverer STT

LT275/70R18 33.35 x 11.00 (on 8.0)

LT275/65R18 32.32 x 10.98 (on 8.0)

LT305/60R18 32.64 x 12.09 (on 9.0)

LT325/60R18 33.22 x 13.30 (on 9.5)

Nitto Trail Grappler

LT285/65R18 32.83 x 11.93 (on 8.5)

Goodyear Wrangler Duratrac

LT275/70R18 33.20 x 11.00 (on 8.0)

LT295/65R18 33.10 x 11.80 (on 8.5)

Basically, I would like to have a tire with as wide of a stance as I can without having to trim any metal from my truck.

I do not want my tires to stick out beyond the fender like the trucks with 6+" of lift do, and I believe that is what the -12mm offset will do for me. But would an 18"x9" wheel with a +30mm offset be stuck too far in toward the center of the truck?

If anyone has any pics of your truck with a similar setup, I would greatly appreciate your assistance. My email addy is [email protected] if needed.

andylear · November 20, 2009

I can tell you from my experience that the 4.5 backspace rubs with 32.8x12.3 and 2" of front lift. I think the 5.7 backspacing will allow you to run the 305/60/18 or the 285/65/18 tires without issue if you want a wide tire, but I'm sure there's someone here who can verify that from their own personal experience.

blackout07 · November 20, 2009

I would go with 275/65's and choose the wheels with +18 offset. This will minimize any rubbing issues and prevent the need to trim metal.

Matt_ · November 20, 2009

I would go with 275/65's and choose the wheels with +18 offset. This will minimize any rubbing issues and prevent the need to trim metal.

x2

The +18mm offset 9" wide wheels will put the tires in near perfect alignment with your fenders (thats what i have). The +30mm will tuck them under some more (lol about 12mm to be exact)

Also, with the 9" wide wheels with +18 offset... the 275/65/18s are probably the biggest you can go with that leveling kit. I have 3" (body lift) and had to trim quite a bit for my 305/55/20s.

stlavsa · November 21, 2009

I would go with 275/65's and choose the wheels with +18 offset. This will minimize any rubbing issues and prevent the need to trim metal.

x2

The +18mm offset 9" wide wheels will put the tires in near perfect alignment with your fenders (thats what i have). The +30mm will tuck them under some more (lol about 12mm to be exact)

Also, with the 9" wide wheels with +18 offset... the 275/65/18s are probably the biggest you can go with that leveling kit. I have 3" (body lift) and had to trim quite a bit for my 305/50/20s.

thought u were doin 305/55s not 50s

Matt_ · November 21, 2009

typo... i do have 305/55/20s

nice catch

dgreene396 · November 22, 2009

Andy, Matt, Matt & Steve, I appreciate the information. I have read a lot of posts from Matt (Blackout07) and Matt (sk1er18) on here. Seems like you guys have experimented with a lot of different things.

I figured the wheel with the 4.5" backspace would cause the tire to stick out causing rubbing issues. So if I understand correctly, the tire will rub at the lower wheelwell area of the painted fender area.

sk1er18, on your M/T ATZ's, your size measurements for the 305/55R20 are 33.4x12.5 on 9.5" wheels, so on 9" wheels, it would reason that the tire may be a tad bit larger diameter. It is understandable that you would rub more.

Honestly, my order of preference is

1. Cooper STT 305/60R18 at 32.64 x 12.09

2. Goodyear 295/65R18 at 33.1x11.8

3. Nitto Trails 285/65R18 at 32.83x11.93

But you guys recommend the Cooper STT 275/65R18 32.32 x 10.98 ?? Seems a bit narrow???

Would you expect that installing the 1-1/2" BL would allow any of my three preference tires?

I would consider the 3" BL but am unsure how the back area between the bumper & bed would look.

Thanks guys!!

Matt_ · November 22, 2009

Hey Dave... the 1.5" body lift and 2" leveling kit would make it a bit easier to clear any of those combinations on the aftermarket wheels... but honestly my recommendation is to get the 3" body lift and the 1.5" leveling kit. The smaller the leveling kit the better the front end geometry will be which will help in terms of wear and tear and ride quality. Not to mention that even with the 1.5" BL and 2" leveling kit you may still run into some rubbing issues with the aftermarket wheels and some of those tire combinations. 4-4.5" lift is really the perfect height for these trucks to clear 33s cleanly on a 9" wide wheel

I have the 3" BL and no one can tell...(no leveling kit though)

blackout07 · November 22, 2009

I would definately recommend going with the 3" body lift. If you are leaning towards the larger tires, then going with the bigger lift is the better decision. I guarantee that you will not be dissapointed, and can almost guarantee that if you opt for the 1.5" that you would very soon regret not going larger. As far as tires go, I think Coopers are a great tire.

dgreene396 · November 22, 2009

Thanks for the additional photo sk1er18, and thanks for the info!!

BTW, nice truck!!

Thanks for the recommendations Blackout07!

Nice truck too!!

cheriff · November 26, 2009

Please be sure to post some pictures when you get your setup done. Your original post couldn't have summarized my situation absolutely any better. I need to accumulate the various parts over the winter and can't rest until I get everything figured out. I guess my only difference is that I am aiming for 20's.

sk1er18 & blackout07 your trucks have been my inspiration as I comb through the old threads on these topics.

dgreene396 · November 26, 2009

Hey cheriff. Just an update. I got my 2-1/2" CCM leveling kit installed on Sunday, and everything went well. Ended up cutting ~ 3/16" to 1/4" off the ends of the factory strut studs, not enough to even matter in the event I wanted to remove the leveling kit and go back stock.

I started out like you in that I wanted 20" wheels, until I saw a lot of photos and read about people with 20's and the ride quality (or lack thereof). Also, get some prices on 33x12.50x20" tires in the MT version. The get pricey, very quickly. I like the look of 33's on 18's. Not an excessive amount of bling-bling. Just my opinion!!!!

I am leaning toward the 1.5" Zone Offroad lift kit, and I have came to terms about trimming if needed. Sometimes you gotta do what you gotta do.

I will post before and after photos of my truck next week when I get back to work and can have some play time! LOL

BTW, the 2-1/2" CCM leveling kit raised the front end exactly 2-1/2'. No fudging here!!! I really like it!!!

Got my front end re-aligned and I am good to go.

Heading to the IRON-BOWL in Auburn Alabama in the morning at 4am. War Eagle to all !!!!!!!

stlavsa · November 27, 2009

Hey cheriff. Just an update. I got my 2-1/2" CCM leveling kit installed on Sunday, and everything went well. Ended up cutting ~ 3/16" to 1/4" off the ends of the factory strut studs, not enough to even matter in the event I wanted to remove the leveling kit and go back stock.

I started out like you in that I wanted 20" wheels, until I saw a lot of photos and read about people with 20's and the ride quality (or lack thereof). Also, get some prices on 33x12.50x20" tires in the MT version. The get pricey, very quickly. I like the look of 33's on 18's. Not an excessive amount of bling-bling. Just my opinion!!!!

I am leaning toward the 1.5" Zone Offroad lift kit, and I have came to terms about trimming if needed. Sometimes you gotta do what you gotta do.

I will post before and after photos of my truck next week when I get back to work and can have some play time! LOL

BTW, the 2-1/2" CCM leveling kit raised the front end exactly 2-1/2'. No fudging here!!! I really like it!!!

Got my front end re-aligned and I am good to go.

Heading to the IRON-BOWL in Auburn Alabama in the morning at 4am. War Eagle to all !!!!!!!