A True Dual-Purpose KnobbyJan Heine
“Don’t do this on knobby tires!” would be most cyclists’ advice when looking at the photo above. Everybody knows that cornering hard on pavement and knobby tires don’t go together.
And yet, the photo shows me on Compass Steilacoom knobby tires. And I didn’t take any undue risks. It was a cold winter day, and the pavement was still moist from a recent snowfall, so I didn’t push the limits, and the tires always had plenty of grip in reserve. (I apologize for the blurry photo – there wasn’t enough light for high-speed photography on this dark winter day.)
We took this photo during an all-paved ride around Mercer Island – a fast-paced route with many corners and subtle (and not-so-subtle) ups and downs. It’s a challenging course to ride fast. And it’s even more challenging when riding with my friend Ryan, who trains here several times a week and knows every inch of the road.
I rode a bike with Compass 700C x 38 mm Steilacoom knobbies (above), because I wanted to find out how well they perform as dual-purpose tires.
After a full season of cyclocross, we already know the Steilacooms work great on mud and loose surfaces… What about rides that are mostly on pavement, but include enough muddy trails that you’d want some knobs on your tires?
I had always been bothered by how terrible my cross bike felt on the few paved sections of the race course. Those sections rarely measured more than a few meters, but if there was a corner, I had to take it carefully. Annoying when I really wanted to go all-out. I figured that there had to be a better way. And when designing the Steilacooms, we thought hard about how to make a knobby perform well on pavement, too.
How do you make knobbies that perform well on pavement? We designed the tread pattern together with the engineers at Panaracer. They were excited to bring all their knowledge to the project, with no concern about “what people expect a knobby tire to look like.” Together, we spent a lot of time thinking about knob shapes and spacing, and how the tire transitions from one knob to the next.
The key difference to previous knobbies is that we didn’t look at each knob individually. We treated them as a system that interacts, not just as the tire is rolling forward, but also as it leans into a turn. We made sure that there always is the same amount of rubber on the road, not sudden changes as you transition from one row of knobs to… sometimes almost almost no rubber at all.
We also discussed knob sizes with Panaracer’s engineers. They have to be small enough to dig into the mud, but large enough that they don’t fold over during hard cornering. It’s not rocket science, but it requires visualizing what the tire will do as it rolls and corners.
On the Steilacoom, you don’t fall off one knob and then climb onto the next, so the tires roll more smoothly than most knobbies. And the knobs are big enough that they don’t squirm, which also helps with your speed and cornering.
I had high expectations for the Steilacooms, but even I was surprised how well they perform on pavement. On that ride around Mercer Island, I had no trouble keeping up with Ryan, even though he was riding his new titanium bike with smooth Compass Babyshoe Pass Extralight tires. The Steilacoom knobbies did not just perform well on the straights, I also didn’t lose any ground in the corners. Of course, this doesn’t prove that the Steilacooms roll quite as well as the Babyshoes, but if there is a difference, it is much smaller than I anticipated.
During our next “BQ Team” ride, I switched bikes with Mark. At first, he was reluctant. “Why would I ride knobbies on the road?” he asked. But then he, too, was surprised. He said: “When you hear the knobs sing on the pavement, you think the bike will be slow. But on the downhills, the wind drowns out the tire noise, and then you realize that they perform pretty much like a good 38 mm road tire would.” And this from the guy who had sworn off knobbies for good when he designed his 650B randonneur bike.
Now, we understand that many readers will be skeptical when a maker claims that their new tire revolutionized how well a knobby tire rolls. So we took a few photos… with a little tree to show that we didn’t just tilt the photo to make it look more dramatic. The Steilacoom really raises the bar beyond what even we thought possible.
The optimized arrangement of knobs is only part of the story. Just as important for the Steilacoom’s speed is the supple Compass casing. The result is a knobby tire that is faster than most slick road tires.
Are there drawbacks of the Steilacoom tread pattern? Of course, otherwise, we’d all ride knobbies from now on. First, once we test them on the track with a power meter, I fully expect that they will roll a little bit slower than our other tires. That is unavoidable, but the difference is too small to notice on the road. That is pretty remarkable.
The knobs also add weight to the tire. And the bigger you make the knobs, the heavier the tire gets. Thanks to our lightweight casings, the Steilacoom still isn’t a heavy tire, but it weighs about 30 g more than our Barlow Pass with smooth tread. This won’t slow you down much even when climbing mountain passes, but if you don’t need knobs, why carry the extra weight?
Like all knobbies, the Steilacooms tend to wander a bit while going straight. You are rolling from one knob to another, rather than on a continuous tread. Again, it’s not a huge deal, but if your ride doesn’t require knobbies, I would pick one of the other Compass tires with their road-optimized tread. And finally, there is more noise from the tires as they roll. But compared to other knobbies I have ridden, all these disadvantages are very subdued.
The Steilacoom’s excellent pavement performance opens up completely new rides. Imagine you are heading into the mountains and expect muddy sections along your course, but most of the ride will be paved. No problem with the Steilacooms. They will make short work of the mud, without holding you back on the paved portions of your ride. That makes the Steilacoom the ultimate multi-purpose tire.
Click here to find out more about the Steilacoom 700C x 38 mm tires.
Photo credits: Ryan Hamilton (Photo 1, 4), Heidi Franz (Photo 2), Duncan Smith (Photo 5), Hahn Rossman (Photo 6).