For those of us living in regions with harsh seasons, a good way to beat the winter blahs is to stud a set of tires, rejet and get your dirt bike out on the trails or even on the lake (make sure the ice will support you and your bike's weight first). The most-popular way to do this is to buy a couple hundred ice studs and screw them into a set of old tires. The disadvantage to this is the tire is constantly losing studs, and you have to fill in the missing spots every couple of rides (depending on conditions). Additionally, we found the studs rounded off quickly, especially on frozen trails.
Or you could try studded ice tires. Unfortunately, the ones made by Trelleborg are no longer available in their original form. The Czech Rubber Company has picked up the line and builds the tires in the Czech Republic. But thanks to Conny Alfsson, a Swedish Michelin employee, the ice tire is back in a high-quality form. You see, Alfsson competes in Swedish winter rallies that are routed over frozen rivers and deep snow. Frustrated that he couldn't find a quality ice tire to mount for racing, he convinced Michelin to produce a limited number of winter tires each year.
The result is the Michelin Studded Winter Tire, which uses 1-inch carbide-tipped studs to give good grip in bare ice and deep snow. The studs are hand-drilled with a special machine and then glued into place, leaving 7 to 8mm protruding from the tire. The technology is not new; it was developed for the Swedish military back in the 1950s.
The tires are extremely effective. We mounted them on a project DR-Z and took it for a winter ride on a mix of open lakes and single-track trails, even through deep snow.
Our first ride was across a windswept lake that mixed foot-deep drifts with completely bare patches of ice. On all of this, the studs hooked up very solidly. We could wheelie on the ice, and the bike felt solid and planted in the corners. The only disconcerting feeling came when the tire rode up into the foot-deep hard drifts. When the studs floated out of the ice and into the hard snow, the wheel would break loose until the studs dug down and bit back into the ice. The result was the front would give a bit of a wiggle and wash a little as we crossed the snow patches. Not dangerous but unnerving.
The network of trails had anywhere from a few inches of packed snow to about 2 feet of deep powder. The tires were awesome in both conditions. On the packed stuff, they hooked up much like a regular knobby on dirt. We could spin the tire at will, but traction was plentiful enough to wheelie.
Note that Michelin warns that frozen ground will tear out the studs more quickly than snow or ice. We did not lose a single stud on our ride, but bear in mind that these tires are not made to stand up to digging dirt.
In deep snow, the tires performed as well as conditions would permit. They had to dig down to either the ground or the ice beneath to get solid traction. Powdery snow simply does not supply much in the way of traction. Still, the bike plowed through the light stuff just fine. In packed snow, care had to be taken as the bike would quickly dig a trench and hang up on the skid plate.
These tires are not cheap, at $250 for the 90/90-21 front and $295 for the 110/100-18 or 110/90-19 rear. If ultimate winter traction is your interest, they are well worth it. And although writing that check may hurt, it beats spending a weekend screwing studs into a tire.