Ultra-wide tires: Unfair advantage in ‘cross?

Last weekend was the first cyclocross race in Seattle. Almost every year, the first race catches me by surprise. Summer is over? It’s ‘cross season already?

Usually, I oil the chain on my trusty Alan ‘cross bike and head to the races. This year, the Alan’s tubular tires needed regluing. The glue must cure for 24 hours, and the race was too close for that.

What to do? I looked at my Firefly, still dusty from the Volcano High Pass Challenge and the Bicycle Quarterly Un-Meeting. What if I raced it instead?

The morning of the race, I took off the low-rider rack and two bottle cages, then rode the 25 miles (40 km) to the start. I arrived with just enough time to remove the last bottle cage, unclip the underseat bag, and do a practice lap. I let some air out of the tires, and then it was time to race.

At the start, I was a bit nervous, because I had forgotten to swap my touring pedals for dual-sided mtb pedals. On the bumpy course, clipping in after a remount wasn’t easy. I knew I’d lose some time. And I worried about the grip of my “road” tires at race speeds on the loose stuff, especially the grass. Hopefully, the competition wouldn’t be overwhelming. I had entered the Category 4 race – the lowest of the three categories offered.

Then we were off! I’ve never been an explosive sprinter, and so I found myself somewhere around 15th position as we went into the first corner. A long straight followed, and I was surprised by how fast my bike went. I know what bumpy grass feels like on 34 mm tires, and it was a totally different experience on 54s. Instead of bouncing, I was able to put down power and ride smoothly.

I had moved up to 3rd position when we reached the first sandpit. And since I hadn’t been working as hard as the others on their narrower tires, I could outrun them. (In the deep sand, even my 54 mm tires didn’t provide enough floatation to make riding more efficient than running.) I took the lead at the exit of the sand pit and never looked back (top photo).

I ran through the next sand pit, too, but the third one was relatively short, and I found that momentum carried me across. Just accelerate hard on the approach and keep going! Where the course doubled back on itself, I could see my pursuers. I was surprised how quickly my gap had grown. I would like to claim superior fitness, but I think the bike’s speed deserves more credit. I’ve raced Cat. 4 in the past, and I’ve never experienced such a speed difference.

With so much grip, I rarely touched my brakes. I did realize why ‘cross bikes have higher bottom brackets: After leaning deep into a corner, I righted the bike until I thought that I was straight again. When I started pedaling, I was still leaning much further than I thought. I clipped a pedal, and next thing I knew, I was on the ground. My lap times show that I lost 10 or 15 seconds, and my pursuers came back into sight. But adrenalin enhances performance, and I managed to hold onto my lead to take the win after 42 minutes of all-out racing.

What did I learn? First, on bumpy terrain, wider tires are much faster. We already knew this, but the magnitude of the effect surprised even me. Being able to pass other racers at will really represents an unfair advantage. Cornering grip on the loose, but dry, surfaces also was far superior to what I am used to.

What about the lack of knobs on my tires? We know that on gravel, knobs don’t make any difference, and I found that the same holds true on dirt and even dry grass. Perhaps I shouldn’t have been surprised: Traditional dry-weather ‘cross tires (above) have almost no tread – in fact, they are so smooth that we used to ride them on the road, since they were a little bit wider than the 21 mm racing tubulars we had back then.

Of course, riding the Firefly with its 54 mm tires in a ‘cross race is unfair. The best rider should win, not the rider on the widest tires. Road racing and its muddy cousin, cyclocross, are traditional sports, and the bikes are clearly defined by the rules. It may be possible to make faster bikes, but finding the fastest bike isn’t the point of racing – it’s finding the fastest rider. As BQ contributor Hahn Rossman (below) put it: “Cross is about riding a road bike off-road. You really shouldn’t ride across bumpy terrain on narrow tires, but it’s great fun.”

Cyclocross has an element of underbiking, and that is why the UCI has limited tire widths for professional racers. For amateurs in the U.S., the UCI rules usually don’t apply, but I feel it isn’t in the spirit of the sport to ride a bike that is so blatantly outside the accepted norm.

I am also not sure my advantage would persist as the weather turns rainy. On a muddy course, my ultra-wide tires may not work so well. A narrower tire – say 35 to 40 mm wide – digs into the mud and probably creates more lateral resistance when cornering. A super-wide tire may just skate across the muddy surface without finding any grip. Once the weather turns muddy, I could put a set of mountain bike knobbies on the Firefly to find out.

Or I’ll just ride my Alan (above) again, because it’s already set up for muddy riding. In the end, my experiment hasn’t shown anything we didn’t know already: On bumpy surfaces in the dry, wider tires are much faster. We also know that in mud, you need knobs to dig into the surface and generate grip.

If you have been intrigued by cyclocross, give it a try. It’s great fun, and what you learn about bike handling will improve your skills on all surfaces, year-round. Don’t worry if you don’t have a cyclocross bike. Just ride the most suitable bike you have. Cyclocrossers are very relaxed about the competition – nobody complained that I rode ultra-wide tires. Last weekend, old road bikes, a randonneur bike (with the fenders removed), and mountain bikes mixed it up with the purpose-built ‘cross bikes.

And if you need cyclocross tires – whether for dry or muddy conditions – our Steilacoom 700C x 38 mm and Pumpkin Ridge 650B x 42 mm knobbies are hard to beat. I just wish they fit my old Alan, which dates from a time when 28 mm tires were “huge”. It would save me from having to re-glue my tires!

Photo credits: Westside Bicycle (Photos 1, 3, 4, 5), Natsuko Hirose (Photo 8).

About Jan Heine, Editor, Bicycle Quarterly

Spirited rides that zig-zag across mountain ranges. Bicycle Quarterly magazine and its sister company, Compass Cycles, that turns our research into high-performance components for real-world riders.
This entry was posted in Rides, Testing and Tech, Tires. Bookmark the permalink.

22 Responses to Ultra-wide tires: Unfair advantage in ‘cross?

  1. Christian DiCenso says:

    That’s true what you said about the spirit of cross, about riding a road bike off-road. Now it makes me feel a bit guilty about my race that I won last year on a 26″ mtb with 2.2″ tires. I felt a lot faster on the bumpy sections than my competitors. This year, I’m going traditional! But I’m gonna really miss that cush. I think I could get away with the 38c Steliacooms without too much guilt.

    • Don’t feel too guilty – your fitness must have been good, too, to win that race!

      When we designed the 38 mm Steilacooms, we wanted to offer the performance of a 34 mm tubular in a clincher tire. Instead of providing an unfair advantage, that just levels the playing field.

  2. jeffoyb says:

    Nice report! Tires and CX are an awesome topic combination.

    Amateur CX races often see mtbikes in the fields but they don’t seem to do better than usual. Maybe it’s because their tire-tread is often knobbier than it needs to be? Yet quite a few modern mtb tires do have quite fine tread. I have yet to see a bike and tires like you used, though! (I did see a fatbike win the Masters once on hardpack.) …It might also be just that you’re FLYIN’! …Do a comparison once your Alan tires have dried.

    Your report reminds me that I need to re-glue on my filetreads to get ready for the season! I tried them a little last year on dry hardpack and noticed that they slipped more in corners but were perhaps nicer elsewhere. The fast-dudes sure like them. I haven’t used them enough yet to know for sure for my own abilities. I’ll keep trying them, tho! Maybe my skills can catch up enough to take advantage of their zip.

    In a recent US pro race a ‘crosser used a mtbike when he noticed a gap in the rules. He won and rivals complained so wider tires (and maybe also suspension) do seem to be accepted to be faster in some cases. (I think in his case that he was able to easily ride up some stairs.)

    I read a review of Dugast 30mm CX tubies that said they were awesome in mud — better than 33mm. So maybe, like you were pondering, once things get sloppy narrowness comes on as a virtue.

    It’s all part of the magic of ‘cross! Comparing tires on various conditions to sort out what’s best for you.

    • A mountain bike has many disadvantages over a ‘cross bike – riding position, tread (Q factor), frame stiffness, etc. The Firefly is a road bike with mountain bike tires, so it really combines the best of both worlds. Add the super-fast Compass tires, and it may be unbeatable on dry courses.

      • fnardone says:

        Is the comment about the Q-factor an objective one ? I thik I “feel” better on my MTB cranks than the rod ones.

        You mention also riding position, I always wondered why cross bikes use drop bars (apart from tradition): I would think that a wider flat bar (maybe not as wide as current mtb ones) would afford more control over dodgy terrain and that aereo is not much of a factor. But then I know next to nothing about cyclocross.

      • You don’t muscle a cyclocross bike like you do with a mountain bike – there are no ruts to climb out of and the like. So it’s more about flow and picking a good line. And aerodynamics actually are quite important, because the speeds are high.

  3. luld says:

    Im guessing you’re a very strong rider compared to others in Cat 4. How did your lap times compare to other categories?

  4. Han-Lin says:

    Do the ultra wide tires also need to be supple at the same time? I read that silica makes tires have good grip and low rolling resistance because it has low hysteresis at low frequency and high hysteresis at high frequency. How would it perform off road? The Continental GP4000 S II tires have activated silica. Their largest is 28c with an actual width of possibly 31c.

  5. Conrad says:

    I love it! I suspect wide tires would be an advantage last Sunday. I wouldn’t feel bad about using a different tire than most people. Given that most people are riding expensive carbon wonderbikes, tires are a much more egalitarian way to gain a performance advantage. My daughter raced on her old heavy mountain bike, but shod with compass tires i dont think she had much of an equipment disadvantage!

  6. nellegreen says:

    Jan,

    You had two unfair advantages in this event. First, the UCI tire width rule encourages a “level playing field” and limits the undue expense of many multiples of tire/wheel combinations. For ensuing events I encourage you to compete with similar equipment as your fellow amateur competitors. My opinion is the 38mm Steilacoom also constitute an unfair advantage as they exceed the 35mm width restriction.

    Second, I encourage you to compete with similar caliber athletes as you, since your demonstrated capabilities are far beyond a CAT 4 level rider.

    Best,
    Tom

    • It’s nice that you have such a high opinion of my fitness, but I must disappoint you: I am not “far beyond” Cat 4 riders. I’ve competed in Cat. 4 in the past without winning every race. This year, I have less training… That leaves the bike, and we can treat it as an experiment. Often, equipment rules really don’t make much sense. In this case, they may.

      As to the Steilacoom, our goal is to level the playing field. If you ride 34 mm tires, tubulars give you a big advantage. Most amateurs have clincher wheels, so we wanted to offer the same ride. Ideally, the UCI would set different standards for clincher and tubular tires…

      • nellegreen says:

        Fitness comes and goes. Your proven skills are the relevant issue when categorizing your entry. I recommend racing against your peers will provide a better “test” of the equipment.

    • Conrad says:

      Except that it is a UCI rule as you stated, with the intent that a fully supported Euro pro has the means to travel to races with 50 different sets of wheels and tires. Makes sense for a UCI race but not an unsanctioned cat 4 race. Amateurs should race with whatever they have and whatever they feel like.
      As for the second part… if you win a race you should probably race up a category. Even if that means feeling a little bit humiliated at your next race (but you won’t be…) Otherwise you are going to be mercilessly heckled at the next race 🙂

  7. Mark B. says:

    I run a weekly cyclocross series here in Alaska. We have a large number of participants on mountain bikes and a few on fat bikes, because that’s what they own. I always try to design the courses so those who show up on cross bikes have a little edge, but the fat bikes tend to fly through tricky corners and sandy patches to the point of negating the disadvantage of the tires.

    That said its about getting people to show up and have fun. It’s important not to take yourselves too seriously and race what you got. I and several others here like the challenge of racing on cross bikes, and more and more come around to the idea every year. But I’d rather have folks come race, than enforce a certain set of rules. There is a place for restrictive rules and finding the best rider, but I’d guess for where most folks are at it just doesn’t matter if it’s an advantage. Plus having nearly equal riders on two types of bikes creates a really fun yo-yo effect as you go around the course that I find very fun and challenging.

  8. Sam Krueger says:

    I have to agree on it seems you sandbagged this race, even if everything you say about your tires and bike are true – Cat 4 for you Jan really seems unfair. You’re a world class athlete who’s set records on courses all over the world – Cat 4 is for normal joe’s who ride a lot and want to race around where they live (for fun), but aren’t really ready for prime time. Why not Cat 1 or 2 and challenge yourself a bit? These categories mean a lot: when I was in college racing, it was obvious when folks dropped down a level to get a high result.
    (Btw, I’m so far from being any kind of racer now it’s ridiculous, so I’m just having some fun here. Love the blog, tires, and all you are doing!)

    • As mentioned above, I am not a world-class cyclocross racer by any means. I’ve only raced three times in the last 2 years due to my schedule. So it seemed logical to enter Cat. 4… I may upgrade to Cat. 3 soon. I can tell you that I have no hope of staying near the front in Cat. 1 or 2 any longer. Those days are long past…

  9. Tim Nielsen says:

    Shout out to those who organize/help put on cyclocross events. Thanks! Cyclocross courses vary, some are fast, some are sloppy and slow, and in dry conditions they should just cancel the event altogether (jk). The old : “Event runs rain or shine, even if it’s really nice out.” I’ve had some courses suit me, while others made me feel extra lousy. Jan, In the interest of Science, you should ride your puffy tires for an entire season (assuming different courses and conditions).

    I used to just race an old downtube shifter steel road bike with Campy Nuovo throughout, and some Tufo tubulars with stylish tread design. In the end I found that some people are just really strong and fast, and they will kick your rear no matter what they (or you) are riding.

    I urge everyone out there to try cyclocross out, on any bike. It is a great experience. Just need a helmet to race, I think.

  10. Jeff says:

    Depending on the course, an MTB can offer a massive advantage. I’ve seen a guy on a fat bike in the top 3 in A grade, on a firm course. The next week on a very wet course he was a blithering mess. On a wet course with steep transitions a typical MTB will offer a massive advantage because of the speed you can carry through the bottom of the dips, with no fear of pinch flatting. Bets are off with slicks though. I have a bike like yours and while its great fun, its not a legal bike so I don’t ride it in the CX races. I have a CX bike for that. How about you hunt down a wet race for the RTP’s Jan and report back !

    • How about you hunt down a wet race for the RTP’s Jan and report back !

      Not necessary. We all know that knobs are needed to get traction in mud. That is why Compass offers two different knobbies.

      What fewer people know is that knobbies don’t offer any advantages on gravel or dry ‘cross courses. I wasn’t the only racer on “road” Compass tires, by the way. The others reported that their tires worked fine, too.

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