Will this invalidate my manufacturer’s warranty and maintenance plan? Do you have any Costco tires to recommend for a 2018 GLC300? It came with Pirelli Scorpion Verde all season run-flat tires
If I don't have a spare tire, do I need to get run-flat tires? TIA!

 

Tires wouldn't void your warranty so you can buy any tires you like that will fit and not rub (if you get a larger size). If you don't buy run-flats, you'll need a compressor and plugs or will need someone to tow your vehicle to get repaired if you get a flat.

 

Thank you! It seems that Costco currently only carries one type of run-flat tires (Bridgestone) that can go with my car...

 

Costco is very good for tires -- I've bought tires there for years and they never scratched my wheels when mounting. You also get free nitrogen fill and lifetime rotations/rebalances and prorated hazard coverage.

They run a coupon every month - typically $150 off a set of 4 tires -- the current coupon is Michelin, but they rotate - this coupon just started this week, and the next will be around 3rd week of June.. I can't say what brand it will be, but the last Bridgestone one was the March/April, so it might be next on the rotation...

 

I replaced my OEM Pirellis with non run-flat models at the first tire change, will go back to run-flats for the end of the lease to turn it in but wanted to get a smoother ride and better economy out of the softer tires for now.

You can go anywhere for tires, it makes no difference, just put a good quality tire on the car. Bridgestone makes excellent tires, I love their products.

 

Most of those coupons are actually from the tire manufacturers, just a pass through.
Some Costco stores have people who know tires, others don't. The most universal chain with people who actually know tires, is Discount Tire. I'm changing to them. They do all the free balances / rotates/ etc., even if you haven't bought tires from them.

 

I am running Continental Cross Contacts on my 2017 GLC300 2WD. Getting about 24k miles. Smooth ride and quiet enough. Purchased them at Discount Tire. They match prices with Sam’s, BJs and Costco as well as TireRack.

 

First going to another brand RFT will not effect your warranty neither will going to standard tires non run flats.

Costco is pretty strict only following manufactures directions. I bet they will not put non run flats on a car that came with Runflats. I know they will only put the same size tire on. You need to check that. I purchased my last set of tires from Costco, they include rotation and tire repair. And they have specials for reduce price usually manufacture rebate and Costco sometimes only charges a penny or dollar, maybe free (cant remember) installation.

As far as replacing the RFT with non RFT, there are pros and cons. Pros being - smoother ride, cheaper and more tire selection. especially if you are on the road and totally destroy a tire.CONS: you will need to risk having a flat and how you will address it. Like mentioned above you will need compressor and tire repair kit or carry a space to include jack, lug wrench, or just carry Fix a Flat.

Many dealers will not repair a RFT tire that has had a puncture. It depends on the tire manufacture or Car company. In BMW case they tell you not to repair a RFT that has been puncture. Bridgestone allows RFT to be repair, but there are restriction. You need to find out what Mercedes recommends what the tire manufacture recommends. If you buy at Costco, they should know.

I know RFT are better for punctures, and will get you to a service station, but trying to find a replacement tire on a road trip that is same size, a RFT , is a crap shoot. I carry a can of Fix a Flat in all my cars, even though I have a space. I purchased a 2021 BMW X3 which normally comes with RFT but option for the normal tires and spare tire kit.

There are also some post on this site about spare tires for GLC

 

I replaced RFT with non RFT at Costco. I too initially thought they might not. I have Michelin CrossClimnte 2 and a Modern Spare and am very happy with both. I have had many times replaced my tires at Costco and been very happy. They do not do alignments. Though whenever i got new tires at Costco without an alignment I never noticed afterward that I in fact needed one as I saw no evidence of uneven wear on the tires.