Wheel Tire help on '18 silverado, 285/70/17

brian2382 · July 14, 2019

What I have: 2018 Silverado LTZ Z71, Midnight edition, 5.3L

I am looking to go down to 17" wheels and 33" tires. I heard I need a 2" lift to do this so will be getting Fox 2.0 coilovers and rears.

1) Everytime I select the 17x8.5" wheel from the brand I want, 6x139.7, 0mm offset, the websites typically say "this wheel is not compatible with your truck, can not guarantee fitment", Is this just because its a size lower then OEM? or will these not work?

2) I want 285/70/17 tires, but does the 285 fit on 8.5" wheels? or does it have to go on 9" Wheels for these tires to fit? Maybe I am misunderstanding that first number.

Any help would be so greatly appreciated, I've been researching for days now and I keep going in a loop of the same information which makes me confident, then the next source unsure.

brian2382 · July 15, 2019

Damn, No one can help me out?

Gagliano7 · July 15, 2019

The work trucks had 17 in wheels so you should be fine.

Praedator · July 15, 2019

My 2018 4x4 Sierra 1500 has 17" rims from the factory and I have 265/70R17 tires. My truck is a base Crew Cab W/T model. Hense the smaller size rims which I actually like! I can fit up to 285/70R17 tires with a 2" front level kit just fine on my stock rims.

Donstar · July 15, 2019

17 hours ago, brian2382 said:

2) I want 285/70/17 tires, but does the 285 fit on 8.5" wheels? or does it have to go on 9" Wheels for these tires to fit? Maybe I am misunderstanding that first number.

I checked the Michelin website and they recommend a rim width of 7.5"-9" for their 285/70/17 Defender. (My choice) The specifications they provide on their website are based on an example of 8.5" wide rim. You are right to do your research before you buy and be aware that larger, heavier tires do more than change the look of your vehicle.

tanner709 · July 15, 2019

17's will most definitely work. The website recognizes your stock size and it says this doesn't match - error error.

I've had 17" wheels and 285/70/17 on my '16 w/ bilsteins at the top setting. I believe they were 17x9 +6

An 8.5" wide wheel will actually look better (beefier) than a 9". I had a 9" wheel and it left the tire looks square as opposed to round on the sidewall.

You'll get this look;

more so than this;

Where the tire looks stretched or square.

an 8" wheel even better again IMO. the 285 will not measure anywhere near the 11" in a relaxed, off-the-wheel state.

Yondu · July 15, 2019

I agree in that 17x8.5 and a 285/70r17 is the ideal pairing. I think 17x9 would look better with a 295/70r17

I haven't tried your fitment but from my research you will need a small level most likely and pull back the front wheel liner.

Donstar · July 15, 2019

I was told a couple of years ago by a reputable tire shop person that a 285/70/17 would fit on my truck without any level or lift. (This thread has rekindled my interest in this tire size upgrade!) I may be an impulse buy away! Has anyone reading this thread tried this size without any suspension modifications?

tanner709 · July 15, 2019

1 hour ago, Donstar said:

I was told a couple of years ago by a reputable tire shop person that a 285/70/17 would fit on my truck without any level or lift. (This thread has rekindled my interest in this tire size upgrade!) I may be an impulse buy away! Has anyone reading this thread tried this size without any suspension modifications?

Unlikely. There may be a one-off case, or maybe with the norcal mod.

285/70/17 still rubbed my liners with a 2" level.

tanner709 · July 15, 2019

1 hour ago, Yondu said:

I agree in that 17x8.5 and a 285/70r17 is the ideal pairing. I think 17x9 would look better with a 295/70r17

I haven't tried your fitment but from my research you will need a small level most likely and pull back the front wheel liner.

Definitely. 2" level and maybe a few zip-ties. That was my setup.

brian2382 · July 15, 2019

3 hours ago, Donstar said:

I checked the Michelin website and they recommend a rim width of 7.5"-9" for their 285/70/17 Defender. (My choice) The specifications they provide on their website are based on an example of 8.5" wide rim. You are right to do your research before you buy and be aware that larger, heavier tires do more than change the look of your vehicle.

I am aware, but what specifically are you referencing? Maybe I have overlooked soemthing

Donstar · July 15, 2019

1 hour ago, brian2382 said:

I am aware, but what specifically are you referencing? Maybe I have overlooked soemthing

On my last truck I went from P245/70/17's to LT265/70/17's. The look was an improvement, imo, but the extra unsprung weight noticeably impacted mpg's . I also felt the truck was less responsive when starting from a full stop, but will accept this as a feeling more than a fact! The size and rating of stock tires meet or exceed the vehicle's load limits . Larger, heavier tires do not enhance the capabilities of your truck but arguably will improve the appearance!

brian2382 · July 15, 2019

23 minutes ago, Donstar said:

On my last truck I went from P245/70/17's to LT265/70/17's. The look was an improvement, imo, but the extra unsprung weight noticeably impacted mpg's . I also felt the truck was less responsive when starting from a full stop, but will accept this as a feeling more than a fact! The size and rating of stock tires meet or exceed the vehicle's load limits . Larger, heavier tires do not enhance the capabilities of your truck but arguably will improve the appearance!

What do you think your MPG's went from and to? I care about my MPG's! I know it will be affected, but I am hoping its more of like 1-2mpg than like 5-6.

Edited July 15, 2019 by brian2382

brian2382 · July 15, 2019

6 hours ago, tanner709 said:

17's will most definitely work. The website recognizes your stock size and it says this doesn't match - error error.

I've had 17" wheels and 285/70/17 on my '16 w/ bilsteins at the top setting. I believe they were 17x9 +6

An 8.5" wide wheel will actually look better (beefier) than a 9". I had a 9" wheel and it left the tire looks square as opposed to round on the sidewall.

You'll get this look;

more so than this;

Where the tire looks stretched or square.

an 8" wheel even better again IMO. the 285 will not measure anywhere near the 11" in a relaxed, off-the-wheel state.

do you have another picture to that? The second picture is broken and I am very curious to see what it looks like

Donstar · July 16, 2019

7 hours ago, brian2382 said:

What do you think your MPG's went from and to? I care about my MPG's! I know it will be affected, but I am hoping its more of like 1-2mpg than like 5-6.

Sorry, I didn't calculate mpg's before or after the heavier tires. I was commuting a long distance at the time and my time between fill-ups was reduced. At just 2 mpg that translates to a reduction of 50 miles in range per tank of gas.( It wasn't better than this and probably worse)