Just purchased a used 2012 Subaru all wheel drive Forester. It came with a new set of Wild Peak AIT Trail tires 215/65 R16 on generic rims. Owner also provided Cooper 225/553 R17 Discoverer True North tires on original Subaru rims. Not sure why two sets of tires. Are the Coopers all weather or do I need to swap them out for the winter months. Also, confused about different sized rims. Obviously, I know nothing about tires and need advice. Thanks
From The Tire Rack:
The Discoverer True North is Cooper’s Studless Ice & Snow winter / snow tire developed for the drivers of coupes, sedans, crossovers and SUVs. Designed to provide exceptional traction in snowy, slushy and icy conditions along with responsive steering and confident handling, the Discoverer True North meets the tire industry’s severe snow service rating and earns the three-peak mountain snowflake (3PMSF) symbol.
The specialized, winter-focused compound of the Discoverer True North boasts the highest silica content of any Cooper winter tire. Wide tread blocks in the outboard shoulder improve lateral grip for dry handling traction, while the higher void ratio of the middle of the tread and inboard shoulder aids wet performance. The circumferential center groove and wide lateral notches evacuate water and slush to improve hydroplaning resistance, and the specialized winter compound combined with the high sipe density provides traction on wet surfaces, in light or deep snow and on ice.
The internal construction of the Discoverer True North consists of a two-ply polyester casing that helps balance the relationship between durability and ride comfort. Two wide, steel belts support the tread area, and a single-ply, nylon reinforcement aids handling response and provides high-speed capability.
Due to the traction capabilities of the Discoverer True North, Cooper Tire recommends using Discoverer True North tires only in sets of four to provide the best handling characteristics and tire performance.
Sounds like just recommended for winter weather.
Good winter tires are not great for summer, and vice versa. Some people go for a compromise ‘all-season’ tire, which is not best in either summer or winter, but you don’t have to change them twice per year. Other people change back and forth to get better traction in winter and summer. If you’re going to change back and forth, having an extra set of rims means you can change them in your driveway if you want to. If you don’t have an extra set of rims, you have to take the extra set of tires to a tire shop and have the shop mount and balance the other tires. If I were going to use different winter tires, I’d buy an extra set of rims.
Since you already have winter tires, I’d just switch to those about the time you expect the first snow in your area. Then swap back in the spring. Once the winter tires are worn out, you can decide whether it’s worth continuing to do the semiannual tire swap. Unless you live in a place with particularly awful winters, I’d probably just use decent all-season tires on that car and make sure they have plenty of tread before winter.
The different rim size isn’t a problem. You can use different rim sizes on the vehicle (it might even have had different rim sizes as factory options).
Winter tires have rubber compounds that stay softer in cold weather so the tread has a better grip on the road. If you run them in warm weather the rubber gets too soft and will wear excessively.
The reverse is true for tires designed for summer driving, the rubber compounds for those typically hold up well in hot conditions but get hard in frigid conditions and that makes for a slippery ride. The wide sipes and aggressive tread patterns will help on snow, but on ice all bets are off unless you have studded tires. Some manufacturers used walnut shells in the tread rubber for a while but the results were only so-so. I don’t know if those are still available.
When I lived in south-central Alaska most people switched to studded winter tires from October to March.
Thanks to everyone who responded. This was extremely helpful.
Hawaii is not on that map? Or did I just not see it?
There are only 2 places in Hawaii where we have snow and ice, generally above 20,000 feet. We can get inclement weather there at almost any time of the year. Still it is an oddity. I was at the top of Mauna Kea (White Mountain is so named because of the possibility of snow). So I’m up there in shorts and t-shirt and flip-flops. I am holding a bag of coffee with snow behind me, as a joke for an ad on how to make iced coffee. Outside the frame is a guy in total snow gear with skis. He was looking at me as a crazy guy in shorts in the snow and I was looking at him as a crazy guy in heavy snow parka in Hawaii.
We have had freak blizzards with snow down to 4,000 feet elevation. I have seen 6 foot drifts of snow on the webcams. We also have had people die in a blizzard in Hawaii. We have snow plows in Hawaii.
Here is a recent blizzard warning: A BLIZZARD is coming to Hawaii this weekend - YouTube
By the way, any time we hear thunder we most likely have snow arriving at the summits of the Big Island and Maui.
If you work at an observatory at the summit, you are to position your vwhicle downhill and are not to lock your vehicle doors. This is due to the possibility of ice in the lock keeping you from making a hasty exit.
Currently is is about 42 degrees up there at 7:30am. Webcam views - no snow at present. Also we have neat views of stars. http://mkwc.ifa.hawaii.edu/current/cams/index.cgi?mode=multi
I thought to myself, “I didn’t know Hawaii had a peak over 20,000 feet.” But it looks like you may have meant 2,000 feet.
I live in Minnesota. No one with an all wheel drive vehicle swaps tires. If you have all season tires on you are good.
https://www.usgs.gov/volcanoes/mauna-kea
Mauna Kea is the tallest mountain (volcano) when measured from base to peak. It is 13,803 feet above sea level and another 20,000 feet under water to the base.
Mauna Kea is a dormant volcano on the island of Hawaiʻi. Its peak is 4,207.3 m above sea level, making it the highest point in the state of Hawaiʻi and second-highest peak of an island on Earth. The peak is about 38 m higher than Mauna Loa, its more massive neighbor. Wikipedia.
The highest mountains above sea level are generally not the highest above the surrounding terrain. There is no precise definition of surrounding base, but Denali, Mount Kilimanjaro and Nanga Parbat are possible candidates for the tallest mountain on land by this measure. The bases of mountain islands are below sea level, and given this consideration Mauna Kea (4,207 m (13,802 ft) above sea level) is the world’s tallest mountain and volcano, rising about 10,203 m (33,474 ft) from the Pacific Ocean floor.