I have a 2015 Suburban LTZ with 22" wheels. The wheels are gorgeous, but not practical. I looked everywhere for one with 20" wheels, did not want the 22" wheels. I wanted adaptive cruise and could not find any vehicle with adaptive cruise w/o 22" wheels. I have the max towing package as well. The ride is terrible, I saw the post about a TSB for improving the ride on 2015 LTZ's and will be speaking to my service dealer about that.

We ski race, so we needed snow tires. Not a good selection for 22" wheels, so I bought 18x8 wheels and P265/65R18 snow tires. The ride is much better on the 18's. I bought them from tire rack, and didn't pay attention to wheel width. Found an article that said that for 2015 GM increased the wheel width for better stability - the stock LS and LT is 18x8.5. So I am thinking my 18x8's are not as safe as the 18x8.5's. They were also cheap, so I'm not worried about replacing them.

I will be towing a 5,000# trailer.

Manual says 20" and 22" wheels are for pavement only (how many owners know that???). We live in Colorado and will often be towing on dirt roads.

p.10-48: "If the vehicle has P275/55R20 or P285/45R22 size tires, they are classified as touring tires and are designed for on road use. The low-profile, wide tread design is not recommended for off-road driving. See Off-Road Driving on page 9-5, for additional information."

So either the LTZ can not ever be driven off pavement (crazy), or it must be okay to put 18" wheels on the car.

I would like to find some Chevy 18x8.5 takeoffs, and get rid of the 18x8's and the 22's.

2015 Burb stock tire sizes:
18x8.5 P265/65R18 Std LS,LT
20x9 P275/55R20 std on LTZ
22x9.5 P285/45R22 opt on LTZ - what I have

I want all the safety systems that I paid for to work at their maximum effectiveness.

p.10-64: "If wheels or tires are installed that are a different size than the original equipment wheels and tires, vehicle performance, including its braking, ride and handling characteristics, stability, and resistance to rollover may be affected. If the vehicle has electronic systems such as antilock brakes, rollover airbags, traction control, electronic stability control, or All-Wheel Drive, the performance of these systems can also be affected."

?'s:
Is there a way to get an official answer from Chevrolet?
Do you see any problems with putting 18x8.5 wheels on the LTZ suburban?
Is the 18" okay for magnetic suspension, given that it is only offered with the LTZ and the smallest LTZ wheel is 20?
Will safety systems be affected by changing wheel size?
Do I need to have something reprogrammed?
Any recommendations for tires - I will use dedicated snows in winter, these are for mileage, comfort, towing?

 

you should be able to update the ebcm programming to match the updated tires. requires a full function scan tool.

 

I have an ltz as well. I have the 20" wheels and run Michelin ltx at2's. While I would no go rock climbing withe the truck, I'm pretty confident about medium off roading. From what I understand the tire heights are pretty much the same on the 265/18's and 275/20's. It's the rim size that's different resulting in less sidewall. A reprogram of one of the modules as stated above will give you the proper speedometer settings..