Self-Tapping Carbide Tire Studs

Self-Tapping Tire Studs

"I just thought I would give you an update on the studs! I have about 1000 miles on them right now and they are not showing any wear. The ones on the hack still look brand new. The ones on the bike's rear wheel which is taking a hit with all the different conditions are looking almost new after 600 miles of mixed asphalt, ice, snow and all sorts of crap.

"I installed these on the bike in Castlegar, B.C., after I went across the Pass without them. The conditions were not nice, but it only took me an hour to install them. I then proceeded to cross the Salmo Creston Pass which is a doozy, believe me! The studs made it possible for me to climb it. I can tell you that without them I was hooped (screwed)!

"The studs are easy to install and they sure save your tire from wearing down. As I go along I will take pictures of the studs to show you. But at this rate they will take me to Montreal easily I think!

"Here is a picture of the bike’s rear tire. The wearing down of the tire has almost stopped as compared to when I did not have the studs. The traction on ice and snow is unreal, and I cannot feel any vibration at all. The little "nipple" has worn down a bit, but considering that almost 2000 kilometers was ridden on frozen asphalt and ice, it is pretty impressive. As far as I can see, even if the protruding nipple wears down, the traction does not seem to be affected. I am sold! Anyone considering riding on ice or in any winter conditions would be a fool not to use these."

— Paul Mondor (January, 2008)

Tires provide traction/friction because at a microscopic level their surface deforms slightly to interlock with irregularities in a road’s surface. Over-simplistically, in cold weather tire rubber gets harder so there's less interlocking going on, which means less traction/friction. "All-season" auto tires typically are made from slightly softer rubber for this reason.

When a stud is added to a tire for winter street riding it needs to be short enough to allow the weight of the vehicle to press as much of the tire's rubber surface surrounding each stud against the road. If the stud is too long this will not happen and one ends up riding on the tips of the studs only -- and this is very bad. There is almost no traction between the carbide tips of the studs and the road surface.

As a tire studded with a short studs rolls, the weight of the vehicle against the road forces the stud upward and into the tire, so most of the tire's tread rubber remains in contact with the road. But because ice is much softer than the road surface, whenever this is encountered the stud is pressed with enough force into the ice surface to chip out a little divot, providing some traction.

Obviously there is an optimum trade-off between how tall a stud should be above the tire’s tread, and how soft the tire’s rubber should be to maximize traction on both surfaces. Most winter tire studs intended for use on paved surfaces seem to protrude about 1/8" (or a little less) above the tire surface. The scooter studs (#4719 and #4720) are about this high, and are what we recommend…but I've actually never built a tire with these studs.

I have made, purchased and ridden on several sets of studded tires, but they've all been for off-road ice and snow riding so the studs have been longer. I've used these studded tires on pavement for a few miles but only riding at slow speeds and very, very cautiously. It's a very uncomfortable feeling, even riding a light weight bike.

The studs that are most suitable for street use are the very short #4719 and #4720, and in some situations the slightly taller #4706, #4707 and #4708's also can work well. Be positive all of the tire's rubber around each stud remains fully in contact with pavement. On both pavement and ice experiment and test a studded tire's frictional limits carefully. These modified tires provide less total grip compared to regular unstudded tires on dry pavement at warm temperatures. If I were building a set of tires for winter street riding, I might experiment with mixing these types. Maybe one row of the slightly longer #4706's down the center of the tire, spaced about an inch or two apart surrounded by the shorter studs on either side and in between? The studding arrangement would depend on the tire's tread pattern. And regardless of pattern and stud types I’d ride with caution until learning the gripping characteristics of my newly studded tires.

-- Mr. Subjective 12-13