I have summer tires on my WRX that I switch out for winter tires around this time of year. Part of the reason is that summer tires, at below freezing temperatures, become incredibly stiff and provide little traction. Got me wondering what kind of rubber do manufacturers use for motorcycle tires. Are they more of an all-season kind of rubber, staying more flexible at colder temperatures? Or is it more of a summer rubber because manufacturers are under the assumption that motorcycles are more of a mild weather commuting device?
Just as with car tires, softer rubber compounds can be had in motorcycle tires, which should give you a little better grip on colder road surfaces, to a point. On cold pavement, it is more difficult for a tire to reach its designed operating temp. The stock IRC's on the CBR are very much a compromise tire, for both good traction and tread life. Motorcycle tires are not marketed as summer/winter tires in the way car tires are. Exercising a bit more caution with any motorcycle tire on cold roads would be a very good idea. For myself, I won't ride as aggressively this time of year as I do in the heat of summer, regardless of what tire I'm running.
I bet you can call or email the major manufacturers and simply ask them. Big companies like that usually have a surprisingly responsive PR team. I've been put in touch with company engineers for technical questions before with little hassle.
Motorcycle tires, especially those that come stock on sport bikes are almost exclusively summer compounds. Unless the tire is specifically marketed as a winter motorcycle tire, you can bet it was never intended to be used on snow or ice. It really doesn't matter if you warm up your tires on a cold day... the pavement is still cold, and your tires will be horrendous on snow/ice. I for one will not drive if there is any chance there could be snow, frost, ice, etc. on my commute to or from work. I don't mind the cold. But I don't like the taste of asphalt.
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The OP was asking about cold temperatures, not snow or ice. As he mentioned, all-season and winter tires have compounds intended for cold temperatures on top of tread patterns meant for snow and ice.
I suspect that plenty of motorcycle tires are designed with freezing temperatures in mind. Lots of people ride their bikes year 'round. I'd bet that many are made with compounds similar to all-seasons rather than summers.
I still think the OP should call the manufacturers and ask. Seems like the simplest way to get a solid answer.
Got a much more thorough response from Bridgestone today:
"Jesse,
Yours is a very good question, but very difficult to answer. Motorcycle tires, particularly in this part of the world, are not really designed for winter use. Winter conditions pose multiple problems from a tire perspective and the typical design ideas that work for passenger cars are not really applicable to motorcycles since they are so dissimilar in the way they use the tire. With passenger cars, a deep, aggressive pattern with a lot of siping is combined with a more compliant tread compound to provide grip in ice/snow and cold temperatures. Compare the typical all-season tread design on your car to that of the design on your bike and the differences are very apparent. If one were to apply a similar philosophy to a motorcycle tire, the result might be similar to running an aggressive dual-sport design with a motocross compound on a sport bike. Few riders would be happy with the result.
The only guidance I can offer from a compound standpoint is that, in general, the sportier the tire (intended use), the less forgiving the compound is likely to be in cold weather. With any motorcycle tire, particularly in cold weather and regardless of tread compound, you should ride with caution. Always avoid sudden acceleration, maximum braking, hard cornering, etc. until the tires have reached operating temperature."
Tire Compound - All Season or Summer?
