Many newer BMW, Mini, and Mercedes vehicles often come with performance summer tires that happen to be run-flat tires. This has led to the belief that run-flat tires are bad in the winter. But that’s not always the case.
We’ve written extensively on summer and winter tires, but here’s a quick refresher: Rubber, like many substances, gets harder in the cold. Yet to maintain a proper grip on the road, a tire must remain soft. Tire manufacturers have developed different compounds that remain soft and pliable in the cold weather. These are winter tires. They shouldn’t be used in the summer, however, because temperatures get so hot that the softer rubber degrades too quickly.
Summer tires offer a different formula. In the summer they are soft and pliable while remaining durable, but get too hard in cold weather. Additionally, they often come with wider tread blocks that work fine in the rain, but are unsuited for snow. Season-specific tires are ideal for performance driving situations and locations with large swings in temperature between the summer and winter.
All-season tires offer a middle ground, providing grip and durability year-round, but not the same level of performance as season-specific tires.
So it’s not that run-flat tires are bad in the winter. It’s that summer tires are bad in the winter, and these run-flats just happen to be summer tires. Not only will they provide less grip, hardening in the colder temperatures, they’ll also become more brittle, resulting in faster degradation.
Run-flat tires have the incredible ability to drive normally after a puncture due to their internal structure. A tire’s season is all about the external qualities of the tire— the compound of the tread. The two aren’t related.
Why do manufacturers install run-flat tires from the factory? It’s often so they don’t have to include space for a spare tire. In cars like the Mini, or the rear-wheel-drive BMW or Mercedes offerings, interior space is at a premium. So tires that preempt the need for a spare are often the first choice.
Yet many manufacturers who use conventional tires have also stopped including a spare to cut costs. Instead they’ll give you a can of aerosol tire repair (which doesn’t always work). The puncture-resistance of modern tires coupled with the growing popularity of and access to roadside assistance services has begun to make the spare tire obsolete.
So why summer run-flats? Many German cars like the aforementioned brands are sold on performance, and most new cars are sold in the spring and summer. Manufacturers, and sometimes dealerships, merely choose the best tires for the season.
While all-season tires tend to work just fine in KC and Dallas 95% of the time, winters still get cold enough in both areas that running summer tires all year long is not a good idea. We recommend replacing them with a set of all-season tires, which can be run-flat or conventional, or investing in a second set of wheels equipped with winter tires that you can swap into place when the cold weather hits.
Zohr can help you with either option. Start shopping for your summer run-flat replacement tires today, and we’ll deliver and install them at the location of your choice
16 Essentials to Keep in Your Vehicle During Winter | Zohr
