Last year, we were talking with the importer for Continental tires. Small stuff, chitchat, catching up. Out of the blue, he asks, “what do you think of 25mm tires?” We told him of our experience with the Michelin Pro3 Race 25mm tires. He didn’t mention Conti’s version, he didn’t even ask why we hadn’t tried it. He just did a happy dance. A grown man doing a happy dance over a tire 2mm wider than the norm.
25mm race tires have that kind of following. No one is bragging over their tire choice, few are advertising, but when it comes up, the membership to the secret society is mentioned in passing. Something usually to the effect of, “I figured that out a few years ago and I’m not going back,” “a lot of extra comfort for almost no penalty,” “I think they might be faster on bad roads.”
Because of this kind of devotion, we’re on our second pair of 25mm tires. This time, we’re trying out the Vittoria Corsa Open CX 700x25mm tire. As is now standard for the CX’s, these have the new 320 threads per inch (tpi) casing. Last year’s had 290tpi casing. Somehow, they found a way to create a thinner thread that allows them to cram 10% more threads in the same inch. The result is supposed to be a more supple casing that rolls better and is harder to puncture. The tire also sports the new second-generation Puncture Resistant Belt (PRB), which is probably just a strip of new casing, as it’s supposed to be thinner than the old version; that said, Vittoria is claiming it’s 40% more puncture resistant. Our tires weighed in pretty light. One came in at 215g, the other at 217g; advertised weight is 220g per tire.
We, like many people, are partial to open tubulars. It could be that we’ve been trained to believe that an open tubular is what a fast tire should look like. A casing that has a thin mixed tread glued on top. It could be that we understand the tire should be supple and that supple is fast. Hold the tire in your hands, and it feels soft. It’s not buttery smooth, but it is floppy. Take it out of the box and it doesn’t spring open and immediately take the shape of a tire. It sits there in its accordioned form. Open it up, and it flops over.
Adding to the joy of these tires is installing them. We can do it without resorting to tire levers. When it’s installed, the tire just sits flat on top of the rim, looking like a deflated tubular. Pump it up and it takes shape, looking even more like a tubular. Blown up, the tire’s width is 25.5mm, a tiny bit wider than 25mm, which is a bit surprising, as Vittoria has a reputation for making tires a bit narrower than the advertised width.
One of the questions about riding these tires is what pressure to put in. Michelin rather nicely provides a pressure chart. Vittoria does not. Interestingly, the importer suggested starting a good big higher than Michelin’s chart; his suggestion was to decrease tire pressure by 5-10% than what you’re used to with a similar 23mm tire and adjust from there. Admittedly, going with 85psi didn’t seem right, as the Vittoria feels more supple than the Michelin, and supple tires can take more pressure and still ride well, but 90-95?
We started with 95psi. On super-smooth roads, the increase in tire width doesn’t seem to do much other than making the tire feel a bit mushier when standing on the pedals. But we can have days where we hit cobblestones, dirt, patched roads, grooved roads, and virgin asphalt within an hour. Maybe the tire isn’t perfect for the virgin asphalt, but it excels everywhere else. Just yesterday we climbed a mountain, and had to negotiate grooved pavement at 45mph on the ensuing descent. We felt comfortable at that speed and didn’t even have to stay perfectly in a groove. Then, at the bottom of the mountain, we hit asphalt so new it didn’t even have lines painted. So we lost a bit there. But after four miles, we were back to patched roads. And then eight miles later, we entered a state park to do a five-mile climb on a road that hasn’t been repaved in probably 20 years. Since the road is closed all winter, time really takes a toll on this road and it felt like it was more patch than original pavement. Can’t say climbing was easy, but the ride wasn’t terribly rough. And in the long run, having the thuds and bumps of roads smoothed out could mean a faster ride as our body is taking less abuse from the road bucking our bike.
Another proving ground we have for tires is a race course at a de-commissioned airport. The pavement is large rectangular cement blocks. You’re constantly thudding over seams. One race we did there we ran the CX 25s at 90psi. It was a pretty smooth ride, a little less abuse from a course that despite zero elevation change is one of the hardest race courses we do.
Latex tubes would have made the ride even better. Problem is, you can’t use latex tubes designed for 23mm tires inside 25mm tires. They’ll explode. We’d love to get our hands on some 25mm latex tubes when they make it into the country to get an even better ride.
The lower pressures feel great when riding over rough roads. At times, when accelerating in a big gear, they do feel a bit mushy. But we’re not terribly fastidious about pumping up our tires. We put these to 95psi Monday morning and typically didn’t touch the valves again until at least a week later.
The tire isn’t perfect. We’ve flatted these Vittoria’s twice. Both times, a glass shard cut through the PRB and the casing. And, as befitting race tires, the rear tire looks pretty worn after what’s probably 1500 miles of riding, while the front, despite the label is starting to wear off, still looks like it has plenty of life left. We can probably get another 500-1000 miles on the rear so long as the tire doesn’t suffer an untimely large cut.
Still, the flats are pretty small change when compared to the tire’s benefits. For people who believe their bike is too stiff or big riders who typically pump their tires so hard as to lose a bit of traction, this tire could be the solution to your ills rather than a more upright bike, a lower saddle, and/or higher bars. 25s could also help those who think their saddle is too stiff. We certainly prefer to put the padding on the wheels rather than our saddle.
Our main concern with the tires has to do with our laziness. This time of year, we’re putting on race wheels every weekend and our wheels have 23mm tires. Switching tires means re-programming the tire size into our bike computer Friday and then re-programming again Monday. Sometimes we forget. With this caveat, we might not run 25s at all in the summer. However, our overwhelmingly positive experience gives us time to seriously consider 25mm tires for winter riding.