Friday, January 9, 2015
Studded Tire Performance in Icy Weather
Photo from several years ago, but bike and tires look same now
I have a 15+ year old heavy ChroMoly Giant mountain bike with studded mountain bike tires - they were sold under the NashBar brand, but were made by Kenda (I think). 1.95 (or really 2) inches wide. There are two rows of studs, kind of alternating in position relative to one another looking across the tire. They are far enough out from the center of the tire that one can significantly influence how many studs may be in contact with the ground by changes in the tire pressure.
Three days ago it was snow, not ice, and I had the tires at 55 pounds per square inch. I made pretty good time but the studs were not really necessary. Two days ago the conditions were much more icy for about half the ride, in other words, the part that is NOT MAINTAINED BY THE NATIONAL PARK SERVICE (unlike Arlington County, which pretreats its bike trails, God help us). I rode to and from work with the tires inflated only to 40 pounds per square inch and clearly that improved the studly-stickiness of the tires - very little sliding around. On the other hand, on bare pavement, the road resistance is pretty noticeable (and unpleasant). A compromise.
Typical Mount Vernon Trail conditions - thanks for nothing, NPS
This morning I increased the pressure to 50 pounds per square inch since I was hopeful that the trails would be more clear today, but there were still significant areas that were covered from one side of the trail to the other. 50 pounds per square inch was too much to have the same kind of good traction that 40 provides, but I chose to ride along the edges of the trails where there was less bare ice or in a few cases off on the frozen ground along the trail. The improvement in rolling resistance by having more air in the tires made up for a small amount of slow riding in the few really bad spots.
I have now had these studded tires for something like eight years - maybe more. Of course there was at least one year where I didn't use them at all, but I don't ride them much. Originally I thought that if I rode what must be cheap metal studs on lots of bare pavement that I would pound them flat (ruin them) in no time, but in fact they seem to show little wear at all.
Last year I realized that I had lost several on each tire - they are kind of like short thick nails, with a head at the opposite end from what sticks out of the tire. Nashbar sells replacement studs with a tool for installing them and that works fine. I am now riding with a full complement of studs.
I see that there are road tires with studs - the rows of studs are of course much closer to each other. I assume that overall in most urban conditions these would be faster but for now I will stick with the mountain bike approach.