tires

Siping has been done for a long time in the heavy trucking industry, along with recapping. I recall a company called Bandag that used to do that, not sure if they're still in business. Siping has maximum benefit on wet roads and especially on ice and snow: the siped treads can flex more to contact the surface, and the siping channels away water better too. Check out any modern snow tire, especially a Bridgestone Blizzak WS-50, and you'll see what I mean. Some folks claim the handling is more "squirmy" with a heavily siped winter tire and I've noticed this too, though the much-increased winter traction is MORE than worth it. I run good all-season tires for the three seasons, and a studded snow tire in winter