First post rookie, here. Howdy all. I threw out a catchy title to get some bites...but I do have a very remedial tire question that I could not find in my searches. School me if necessary.

About that title. I am in the process of transitioning from a 2019 Stelvio Quadrifoglio to a 2020 GLC63. I test drove a GLC prior to purchasing the Quad in 2019 and found it to be really great all the way around except for a bit of an oddly jerky transmission during stops and creeps. Just could not get the price right and a Quadrifoglio popped up and I took it instead. If anybody is curious, I will tell you the factory Quad rides a bit harder than the GLC63. It is sharp and super precise...like cutting the road with a surgeon's scalpel. I understand the tranny to be the same as the M5 Comp; it does work very well. There is no launch control, though. The 2.9L V6 is a great motor and makes a great sound...but only at higher RPMs and when really stepping into it. Its note is pure exhaust; there is nothing piped through the speakers. Otherwise on the grocery runs, I swear it sounds like a flat 4. It is not bad, just different. The Stelvio is all business and no frills...and there are very few on the road.

Enough of that comparison. Here is my question. I kept the factory Stelvio rims and upped the tire width by 10mm to 265/45/20 and 295/40/20. I did not change the aspect ratio. This was great. It looks to me like I could, If I chose, do the same on the GLC63....go 275/45/20 and 305/40/20....keeping everything else stock. I could not find anybody that went that route...either by choice...or maybe there is a fitment issue. Anybody know?
Thanks.

 

I don't know about your tire question, but thanks for posting your review on the quad.

 

Interesting as I just went from a Stelvio to a GLC 43 and have very similar impressions. The cost difference between the Stelvio and the GLC 43 was significant (they have some killer Alfa deals to move product), but I still chose the GLC 43:

1) Significantly better interior (can't stress that enough). The best Stelvio seats have seat back adjustments but the bottom cushion only goes forward and back as a good example.
2) The MB technology isn't even in the same universe. I had an '18 Stelvio with a terrible infotainment system. The '21 I looked at was vastly improved but still nothing like the MB.
3) Improved reliability. While my '18 Stelvio had only one mechanical problem in 3 years, I had countless electronic issues, some they couldn't fix (I can't begin to tell you how annoying it is to not be able to put up the passenger window if it's raining).
4) The MB dealer won't be going out of business (we've had 2 dealers stop selling Alfa's in this general area).

The pro's I had for the Stelvio:
1) It's Italian and looks it. Great looking vehicle.
2) The handling is incredibly precise and while fast, not too fast.
3) The car begs to be driven like you stole it... and I did.

Around here (Philly), there are quite a few Alfa's so the attraction of something rare doesn't hit quite so hard. I see an Alfa pretty much daily.

As for you tire question, when I asked about tire and wheel options they did caution me against upsizing, although the conversation was brief and I didn't inquire any further.

 

A. - I like your style
B. - You absolutely CAN bump your section width on both front and rear with no issues. You will have a slight deviance in your MPH readings, the upgraded section width adds ever so slight overall height/outter diameter to your set up so your speedo will read 60km/h when you are really turning at 60.7km/h. Rock on and when you do it, post up pics! Should add some meaty shoulders the OEM set up.

 

Great post. Thanks for the rundown and sharing your thoughts.

I'm in the same boat re tires. My '21 GLC63 just showed up. Not picking it up for a few more weeks because there's still skiing to be had and I'd rather hold onto my big truck a bit longer before I swap it for the smaller GLC.

Anyway, the GLC came with Conti SportContact6's. Not really interested in keeping those on the car for a single moment. Reviews are iffy. In my time on track with sports cars etc I was never a Conti guy, nor were any of the guys whose opinions I trusted. Here's the thing though. They look phenomenal. Like, great. I got the smallest wheels I could on the car because I wanted a larger aspect ratio. For the looks (I like a meaty sidewall) and for road noise and a bit of a more compliant ride.

So, now I'm trying to replace these tires cause reviews suck, they're super high performance summers (I live in NY), the road noise is supposed to be bad (huge factor when youre DD'ing the car) and I hear they're harsh. At the end fo the day, yes this vehicle is an awesome weapon, but its not a track car. I'm not worried in the least about giving up a bit of performance in an SUV (remember, its an SUV) versus a higher quality overall ride in regards to noise and comfort. But like I said, the sidewalls looked wonderful. The car looked so aggressive when I ran by the dealer to see it.

I'm shooting to go with identical specs on the replacement tires. All seasons, not dead set on getting winters yet cause I'll prob get a dedicated truck for winter. I want to keep the specs in line cause the Conti's looked so good on the vehicle. What I've found are the Pirelli Scorpion Zero All Season Plus'. Same specs. Phenomenal reviews. And I've enjoyed P Zero's in the past. I trust'em enough.

Keep us posted on what you're thinking and decide to go with. I'm pulling the trigger here in a few days and the dealer is glad to swap them onto the car, balance, etc at no charge.

 

Got it figured out...at least for now....I may change my mind; LOL. I will stay with the factory size of 265/45/20 and 295/40/20. But, the Sportcontact 6 will be replaced with Continental DWS06. I ran these on the Quadrifoglio with terrific success. I do not have any loyalty to tire brands, but I keep coming back to the DWS06 because they have been working for me. I also used them on a few cars prior to the Quad.

During my research, I was reminded of an old article in Car and Driver that showed test results of a car with varying tire/wheel combinations. Great article in that they did not merely explain the effect of wheel/tire weight, they published their test data. Great read; link is below.

Continental just released the DWS06 Plus. Apparently it is the same great tire but lighter than the current DWS06. In fact, it is lighter than the Sportcontact 6 by 5 lbs. Correct, 5 lbs. per tire. This has me thinking about some forged 20x9 and 20x10.5 that I found on Tire Rack that weigh in at 20.3 and 23.15 lbs respectively. I don't have my GLC63 yet, but I intend to check the weight on those factory 20" wheels.

I understand the reduction of unsprung rotational mass could have a significant effect. If I saved 10 lbs in wheel/tire weight per corner for a total of 40 lbs....I have seen estimates as high as this being equivalent to removing 40 x 10 or 400 lbs of 'weight' from the car. I think I also read the report of a better ride.

If anybody has experience, here, would love to here the story.

https://www.caranddriver.com/feature...-wheels-tires/

 

So you're saying these Conti's may be a better choice than the Pirelli's I'm thinking about? Can you send tirerack link that shows them in that exact size? When I searched for tires that fit the car's OEM spec I don't remember these Conti's showing up.

How were they on the Alfa with comfort and road noise?

 

Link below to the available sizes for the DWS06 Plus. Look for 265/45/20 and 295/40/20.

I only had them on the Alfa for 7,000 miles. To me they were very quiet. Prior to the Alfa I ran them on a Volvo V60 Polestar. Again, tremendous experience, but if I recall correctly they gradually began to get noisy around the 17,000 mile mark. I replaced them at 25,000 miles and they were worn all the way down to the 'D'. So, do not expect them to be a high mileage tire.

The OEM tires on the Alfa were Pirelli P Zero 255/45/20 and 285/40/20; a bone jarring experience for me. I went one size wider with the DWS06 on the factory Alfa wheels. It is reported to have softer sidewalls and thus a more compliant ride. I can say it improved the ride on the Alfa, with minimal loss of 'feel' IMO. However, some say these tires are squishy. I do not share that sentiment around town. I had lots of fun on ramps and lane changes, and the Alfa felt every bit the Alfa with these high performance all seasons. Im sure the DWS06 gives it up on the track....but not to the grocery store or Home Depot.

The Alfa will soon be leaving my garage. I took it to the shop yesterday for a tire swap; we reinstalled the OEM Pirellis and I will put the DSW06's on the 63 when it arrives. Anyway, I backed out of the parking space and BANG BANG BANG....nasty crabbing on the P Zeros. I can say definitively that the DWS06 did not crab on the Alfa, and I assume they will not on the 63.

There are a lot of good tires out there. Some like the DWS06; some don't. It is difficult for me to move away because tires are expensive, and I know what I am getting with the DWS06...and it is good enough to stick with.

https://www.tirerack.com/tires/Spec....ct+DWS+06+Plus

 

I went with the 20 inch all season pirelli scorpion zeros for my 2021 Glc 63 w4 and absolutely love them. In the past I would always stick with Michelin tires but they didn't make them for the GLC 63 in the factory size .The pirellis did great in the snow this winter here in Ohio I highly recommend them.

 

I run 275 / 315 20s P4S on 9.5"-11.5" 20" rims for warm weather. GLC 63s
265-295 21" snows on stock rims for cold weather.

 

Do you have a photo from front or angled that show the shoulder girth (sidewall) of the tire compared to the stock Sportcontact 6's?

 

Thanks for sharing!