Bridgestone
Monday marks the official start of winter here in the United States. Not that the weather needs permission from the calendar; many parts of the country began to see snow a few weeks ago. And, of course, you don’t have to wait until December 21 to switch to winter tires. First, the sticky compounds used in high-performance summer tires are not designed to work when the mercury drops below 45 degrees Fahrenheit (7.2 ° C) and this can happen long before the soil disappears under a layer of the snow.
“This has to do with the glass transition temperature of the compounds. The compounds become heavier as the ambient temperatures cool, and the winter tires are designed for a much lower range and temperature,” said Dale Harrigle, chief engineer. the Bridgestone.
This is partly due to the mixture that forms a winter tire. “We use silicon compounds on the tread in our dedicated winter products. We can adjust the dedicated winter products to have a good grip at lower temperatures, without significantly affecting the rolling resistance that we had 20 years ago. So I think a lot of composite and materials technology is what allowed some of these performance jumps, ”Harrigle told me.
For example, Bridgestone winter tires use what Harrigle calls a multi-cell compound, which has a lot of small holes or holes in it. “At certain temperatures, the ice has a layer of water and it’s the layer of water that makes the ice slip. So the gap with several cells in the tire is designed to absorb that layer of water, like a sponge, so that the rubber “And this is the biggest performance improvement in our Blizzak line – the great performance on ice it offers,” he said.
The gaps are microscopic, so you won’t see them just by looking closely at a winter tire. What you might see are more complicated models of tread cuts and grooves – also called “digs” – than in the tires of the past.
“For a very long time, the tastes were basically, you know, a piece of metal in the mold that didn’t have the necessary geometry. It was sliced into the tread … It’s like a butter knife, it’s a flat blade.” , said Harrigle.
Now, Bridgestone is taking advantage of additive manufacturing to create tire molds, which result in sips with significant three-dimensional profiles that change as you travel along them (both down and along the length of the ditch).
“What this 3D profile allows us is to change the rigidity of the tread under braking, under acceleration, so what happens is that we can put a lot of edges in the tire to allow winter traction. But these edges do not affect the tire. in terms of wear duration or driving or braking traction. It allows us to get the best of both worlds in tire design, ”he explained.