Tires and Wheels w/ 4" Lift

[T-bird]

Hi, all. I realize this is a long post, but I could really use some if you can bear with me....

I have an '07 Z71. I have been reading posts on the forum for awhile now while I have been trying to decide on what leveling or lift kit to go with. I liked the simplicity of the CCM leveling kit, but I wanted to go a little bit higher. I ended up buying the ReadyLift SST 4" suspension lift (4" front, 3" rear).

I am having a lot trouble understanding rim/tire fit, backspacing and offset and figuring out what rim/tire combo will work.

This is from ReadyLift's site: "The most common tire size for this application is 33x12.50 (max). In order to install a 33x12.50 (305/55/20) with aftermarket wheels, some minor trimming of the inner fenderwell may be required. 22x9.5 with 5.5" backspacing requires no fender modifications. 17x9 +0 offset on a 285/70R17 will fit with no rubbing. With a 295/70r17 minor
trimming/modification required." They say this info is for the max size that will fit without any clearance issues.

My stock rims/tires are:

18x8x+31mm (5.22" b/s)
265/65/R18

My plan was to have the kit installed and then figure out what size rims and tires to go with based on what room was available. Now it appears that won't work out unless I buy 7/8" wheel spacers to run with the stock 18" rims and tires while I decide on the new stuff. I haven't looked around, but the spacers that ReadyLift offers are $150/pr. That is a bit more than I want to spend for an interim fix and I can't leave it parked since it is my primary vehicle. So the kit sits in the box until I figure out what to do.

I want to stay in the 17-18" rim size and not have them stick out beyond the fender more than 1-2" due to state inspection regulations. I would like to go with the XD Spy rim which comes in:

17x8x+18mm
17x9x-12mm
18x8.5x+18mm (5.46" b/s)
18x9x-12mm (4.53" b/s)

I would also like to get the Toyo Open Country M/T or the Nitto Trail Grappler in a 33" minimum.

Toyo is available in:

295/70/R17 (33.5x12)
285/75/R17 (34.1x11.6)
35x12.50/R17 (34.8x13.2)

275/70/R18 (33.6x11)
285/70/R18 (34.1x11.4)
285/75/R18 (35.1x11.6)
33x12.50/R18 (33x12.7)

Nitto is available in:

285/70/R17 (33.15x11.81)
295/70/R17 (33.54x11.97)
35x12.50/R17 (34.84x13.19)

275/70/R18 (33.62x11.1)
295/70/R18 (34.57x11.73)
35x12.50/R18 (35.04x13.39)

I've figured out the following conversions:

31mm offset = 1.2"
18mm offset = .71"
Difference between +31mm and +18mm offset = 13mm or .5"


From reading through the posts as I have been typing this up, I'm getting the idea that to be safe I may need a minimum combo of 9" width and 5.5" b/s? That might rule out the XD Spy. Just guessing here...

Is it best to avoid wheel spacers for a permanent fix? State inspection regulations require them to be 1/4" or less. I would like to go with a larger tire rather than smaller tire, but not so much that it looks stuffed. Is 34" unreasonable?

I like the stance of Creeto's, Kronix's, or fco_gonzo's trucks though I realize they are higher than mine will be. Anyone know their wheel specs? Actually, I just found a post that says fco_gonzo's are 5.75 b/s. I'm willing to do some minor trimming/removing plastic. Can you all please help figure out what my best options are? I would really appreciate the help.

Thanks,
T.J.

 

[pm80]

I have a ccm leveling kit with 20x9 rims with a +16 backspacing and am running a 305/50/20 tire. It rubs in one little spot. So you can go bigger than that with the 4" lift kit. I would not go with a 17 or 18' rim you will regret it latter. They are too small for this big of a truck. hope this helps some.

---------- Post added at 10:22 AM ---------- Previous post was at 10:20 AM ----------

I would stay with a positive offset. A negative offset is going to stick out to far.

 

[felixgun]

The Toyo's and Nitto's are my two fav aggressive tires. Good choice!

 

[07Burb]

+1 what Felix said....both are good quality tires

 

[White07Tahoe]

Cant go wrong with Nittos or Toyos. I only have a CCM 2.5-1 leveling kit and I'm running stock LTZ rims with 305/55/20 which is 33.2X12 if I'm not mistaken and it rubs a little and it wont rub at all if I stop being lazy and trim it. With a 4" lift you should be able to fit 35s if you want.

 

[T-bird]

Thanks, guys. I appreciate the comments and the help. I was going to
stay in the 17-18" rim range to show more tire sidewall, but maybe I'll
move up to 20" based on pm80's comment. Something more like a 35" tire
instead of 33" recommended by the lift manufacturer would be great, but
that's where I start getting concerned.

I guess my real concern is the backspacing/offset. Maybe I am
over-thinking this whole thing? From reading the threads, I see several
people with 1-2.5" leveling kits running on 9" rims with +18mm offset
which I think is about 5.7" backspacing. The rim I want in an 18" or 20"
is 8.5" wide with a +18mm offset which is about a 5.5" backspace. I
don't mind some trimming or removal of plastic, but is there a risk of
hitting anything else that can't be removed (brakes, suspension, etc) if
the backspacing is wrong? Or is the risk just rubbing on some plastic
that can be trimmed or removed? Somebody mentioned to me that the wheel could hit the brake calipers if it is not the right backspace?