If I were to guess it's due to a much softer sidewall. The tire is able to 'flex' more than a performance tire. Also, the compound is quite different which also helps. If I were to guess...

 

Then it makes me wonder, I am also a member on the Stelvio discussion board and if I remember correctly, the 20” wheels come with Continental CrossContact, is this more capable of driving in snow than the ContiSportContact available on the 21” or the Pirelli Scorpion on the 20” of this car? Because I really don’t see those owners to have buy smaller wheels/tires to drive in snow.

I think the other models, like the X3, Velar or F-Pace have similar tire models (mostly come with the Pirelli Scorpion), not sure if they have to do the same.

 

There are winter tires available in 20" and 21" sizes to fit Macan rims, and that will certainly improve winter traction, but there are good reasons to have a winter set on 19" or 18" rims instead:

• The increased sidewall height will be more forgiving over winter potholes and other irregularities.
• The narrower tread on the 18's and 19's allows a more concentrated weight on the road surface to improve winter traction.

All those above factors are why I have a set of summers on 21's and a set of winters on 19's.

 

I doubt the "only" part - I've been actively reading 4-5 different car-brand-model forums over the years and it's always been the case, you'll have people going from staggered setup to square, to smaller rims and to narrow tires. Some do it to save, others to rotate, etc.
Everyone has their own reasons - you'll find fans and foes for every options.
Me - I am driving 21" in summer and 20" staggered in winter.

 

I doubt the "only" part - I've been actively reading 4-5 different car-brand-model forums over the years and it's always been the case, you'll have people going from staggered setup to square, to smaller rims and to narrow tires. Some do it to save, others to rotate, etc.
Everyone has their own reasons - you'll find fans and foes for every options.
Me - I am driving 21" in summer and 20" staggered in winter.

How are you liking your R182 rims? Will be shopping for a winter setup shortly and saw your posts from last year.

 

@Canuck, let's not take over @bolden's thread and take this offline to Winter tires/rims in Canada

 

$$$

What is the price difference between 18 and 20” set of wheels?

 

There's a bigger difference in the price of tires.

But cost aside, more sidewall is better for absorbing potholes and rougher winter roads

 

From Tire Rack:
"Winter tires are designed with special materials that stay soft to provide maximum traction in temperatures below 45 degrees."
"Winter tires have tread block patterns designed to grip snow-, ice-, and slush-covered roads better than any all-season tire."

 

To expand on what @JRB said, here's the Tire Rack tech article:

https://www.anrdoezrs.net/click-100...=autolinker&url=https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=126

(If you're not familiar with them, I'm guessing that Tire Rack is the largest mail-order tire and wheel outfit in the country, they've been around a long time, they do their own research, etc.)

I first dealt with Tire Rack back in 2014. At that time, I went to their site, to order a winter wheel and tire package for my 2010 Camry (six-cylinder SE, 268 HP, a monster!). That car came stock with 17" rims and A/S tires, but TR's ordering process recommended -- didn't insist, but recommended -- that I drop down to 16" rims, and listed a bunch of 16" snow tires. So that's what I did, picked out a set of 16" wheels (that were actually nicer looking than the stockers) and four snow tires.

Fast forward to late fall 2017, a month or so after my wife and I took delivery of our 2018 Macan S. That car came stock with 19" rims and A/S tires. We went to our local P-car dealership to inquire about a winter wheel and tire package. The service manager recommended the same sort of thing, i.e., drop down, in this case, from 19" to 18", and get some 18" snows. And that's what we did. These were official "Tequipment" Porsche rims, by the way, with NO-spec snow tires (and still a "staggered" setup).

 

Good TireRack article.

Unless you are in a high snow area I don’t think it’s necessary to drop down to 19’s. I’m running 21” Turbo wheels with summer tires. Went with 20” wheels and winter tires (not all seasons) for the winter. It would be rare if I had to plow through deep snow so I didn’t want to give up much performance in dry winter conditions by dropping down any smaller than 20”. Did want a little higher profile than 21’s for winter and spring pothole protection.

 

My CPO Macan came with winter rims/tires, 20"RS Spyders shod Dunlop Wintersport 4D's, staggered, same size as the summer rim/tire set. Had my first winter in it last year and they work just fine.

Our '13 Cayenne diesel, (I custom ordered in 2012), I spec'd 20" RS Spyder for the all seasons and bought from the dealer 18" Cayenne S III rims with N spec Dunlop SP Winter Sport 3D's.

The rationale has been outlined above. Narrower tires I guess sink and grip better, and taller sidewall is much better to keep rims from getting damaged. When the snow gets plowed and piles up along the shoulders or sidewalks, covering curb, or if lots of fresh snow obscures potholes, etc. you'll have more than a relatively thin bumper of rubber helping your rim stay clear.

 

I got my Macan with 21" wheels in December, and I ended up buying a set of 18" rims / snow tires for the winter. I'm in Colorado and make several trips to the ski areas each year, and they are fantastic on the Macan. I looked into 21" snow tires, but they were 3X the price per tire and, as been noted here, would not perform as well. My new set of 18" wheels / tires were much less expensive than 21" snow tires alone.

 

Going from 21" to 18" is quite a drop! From summer to winter, you are getting the best of both worlds, assuming no major snowstorms and/or ice conditions that occur out of season. I guess the good news for you is that in Colorado the slippery stuff melts pretty quickly, especially on the main roads at reasonable altitudes, so your 21" summers would rarely be a problem.

If I might ask, what Macan trim and model year do you have, and what 18" winter wheels and tires are you running?

 

I run 21" in the summer, and 20" in the winter.

The Macan is the best performing snow vehicle I've ever owned. Full stop.