When searching for new tires for your vehicle, it would be ideal if you could just buy 1 pair of tires that would make your car perform its best and be equally as safe in all types of weather conditions. In 1977, the Goodyear Tire Company released the first all season tire to try and fulfill that need, however, all-season tires still do not have the same performance year round that you can achieve with tires that are designed specifically for summer/winter seasons.
Do You Really Need Two Sets of tires?
Most new cars will come with all-season tires mounted on them, and you wouldn’t be considered “unreasonable” for using an all-season tire in all of the seasons. Even if you rent a car from the Denver, CO airport in the middle of the winter, your car will still likely have all-season tires.
So are all-season tires “safe” for winter driving? Yes, you can call them safe. Rental companies (who have insurance liabilities) wouldn’t be putting them onto cars if they weren’t “reasonably safe”. However, it should also be noted that out-of-town drivers who are driving rental cars without snow tires are also fairly easy to spot in Colorado. Those are the cars sliding around the most and resting peacefully in ditches and highway medians. Being “safe” doesn’t mean that you are going to be able to keep your car on the road.
When do I need to mount winter tires?
The magic number is approximately 45 degrees Fahrenheit (R. Hosier). When the environment reaches down to this temperature, the rubber molecules start to undergo a change which results in the compound being harder, with less ability to grip the road.
When do I need to put my summer tires back on?
The soft rubber of a winter tire is affected noticeably at approx. 50 deg. Fahrenheit. At this point, the treads are no longer functioning the same way that they are designed to function, and your tires will begin to have less grip on the road. Stopping distances can increase by 5% at this temperature (R. Hosier). If you want to read more about the engineering and scientific aspects of how temperature affects the performance of various rubber compounds, we recommend reading the following article by Ralph Hosier which has been referenced in this blog – Winter Tires – the truth.
Of course, there is an upfront cost increase because you have to buy a second pair of tires (and usually a second set of wheels). However, you are not using all 8 at once. If you did not have to pay to get the tires changed twice per year and you didn’t buy an extra set of rims, you would actually save money by using two sets of tires.
How can this be? The softer rubber that is used for winter tires gets worn down quicker in the summer months than the rubber on summer tires. This means that by switching back to your summer tires after the winter, you will be reducing the amount of wear that your tires are subjected to in warmer months.
What if you pay to have your tires changed and you also buy a new set of wheels?
Now you have increased the cost of running two sets of tires fairly significantly. Calculating your savings or cost increase now becomes an exercise in measuring the added tire life that an owner will see as a result of switching tires. For most drivers in this last scenario, you will see a slight direct cost increase as a result of your decision to run two sets of tires.
There are other factors at play if you really want to try and calculate the true cost increase of adding a second set of tires to your arsenal. Since proper tires can prevent accidents, lack of proper tires can have an indirect cost increase associated with them due to the increased possibility of being in an accident. You also have to consider the % of time that the temperature will be above or below the 45 to 50 degree Fahrenheit range in your area to determine how much unnecessary wear the tires will see in the winter season. It becomes a fairly complex calculation that is dependent upon estimations and generalizations. Our best advice… Just get a set of winter tires and move along.