Home > Calvin's Corner

Calvin's Corner

Cyclo-cross

The Fall brings us a change in the weather, with crisp air, leaves upon the ground, and cyclo-cross racing. What is cyclo-cross? What better source to turn to, than the Italian manual, CYCLING, which explains that cyclo-cross is "...a cycling specialty considered apart as regards its technical characteristics and modalities of participation— requires special aptitudes of the athlete practicing it, foremost among which is the ability to bear severe temperature, since this type of race is held in winder in the coldest months of the year, from October to March."

Well, perhaps that sentence is wanting a bit in clarity. Cyclo-cross courses are mixed courses, including single track, woods, fields, and even stairs in the race. The courses are often very creative. A good cyclo-cross course is not as rugged as an MTB course, meaning it is fast, yet interesting enough to trash some equipment. This year's Minnesota Cyclo-cross State Championship course seemed to hit it just right. I attended the event to assist Tyson Meyer of  of Penn Cycle (figures 1 and 2).


Figure 1. Tyson Meyer of Penn Cycle using the AWS-1, and saving valuable seconds by having his AWS-3 at the ready


Figure 2. Oddly, there was much pedal work. Here Tyson tries out the new PRS-25.

As in most racing, in cyclo-cross there are two important things: Going and Stopping. In cyclo-cross racing you get some of each, and for the stopping the brake of choice is the cantilever. ("Choice" is perhaps not the best word here, because in elite UCI racing, disc brakes are not allowed.) The cantilever allows lots of room for leaves, mud, twigs, small animals, and the detritus of the forest and field. When setting up this brake, position the straddle wire between brake arms, no lower than the frame's brake bridge (figure 3). 


Figure 3. Good straddle wire carrier height, not too high, not too low


Figure 4. Some vector analysis shows the line from "X" to "Y" is not straight along the headtube. The upper cable stop could not be properly aligned.


Figure 5. The cable stop cannot be aligned because the stem is so low. A specialty cyclo-cross stem would have a hole and cable housing stop directly in the stem.

The Going should be addressed first where the rubber hits the road. Cyclo-cross tires are designed for off-road use, but are still relatively lightweight and narrow. The less the tread, the faster the tire, but if there is mud or deep soil in the course, you can slip and end up going down or at least slower in the corners. For mud, you want tread blocks with room for the mud. You don't want a tire with tread blocks packed too tightly, which will simply fill with dirt and create a heavy and slippery wheel (figure 6). But, if the conditions are hard-packed and dry, these same tires will be slower, and here you want more of the classic diamond tread pattern (figure 7).


Figure 6. Block pattern for better mud clearance...but today there was no mud to be seen...


Figure 7. Diamond tread pattern, with a light knob on the sides for cornering

 

There are two types of race tires used, the clincher tires, and for those that can afford them, the tubular tire. The tubulars are an excellent choice because they are by design resistant to pinch flats when run at lower pressure. They are lightweight, with thin sidewalls, which can quickly rot in the wet weather of racing. It is best to apply a latex sealant on the sidewalls to help protect your investment (figure 8).


Figure 8. Tubular tire sidewalls protected by latex sealant

During a cyclo-cross race there will be dismounts and re-mounts (figure 9). Here the riders must get off in order to get over a barrier. This is done at speed, and the barriers are a good place for spectator to view the racing. It becomes clear who has style and grace...and who does not. Or, as stated verbosely in the manual CYCLING
"Without considering that courage exalts the qualities of acrobacy possessed by the cross-country cyclist also because the fact of getting over certain obstacles safely and calmly raises the morale of the man who has got over the obstacle, at the same time providing a handicap to his opponents, negatively affecting their performance."

barrier
Figure 9. A fine display of "acrobacy" was on display

Cyclo-cross is not without its cast of characters (figures 10 and 11). A fine tradition is the cowbell, no doubt because it is a noise-making object familiar to spectators coming to and from the cow pastures of Belgium and all of Europe for Cyclo-cross Racing.


Figure 10. Some fans just can't have too many cowbells

matt
Figure 11. Announcer Matt Anderson and his cyclo-cross rig. He is known to create his own personalities to interview if no one is available

Back to the "Going". The drive train is the next critical item. The uneven course leads to a lot of bouncing and this can throw a chain off the rings, which is a puts a hurt on forward momentum (figure 12).


Figure 12. Double chainring with chain keeper to help prevent the chain from falling the ring off to the bottom bracket

Depending upon the course, it is not uncommon for athletes to use a single front chainring. Here again there is the danger of dropping the chain if it is unprotected. There are different devices used to help prevent this, some less sophisticated then others (figure 13 and 14).

Chain keeper
Figure 13. A double plate system to trap the chain. Effective but the chain can still bounce upward and off on extreme hits.


Figure 14. A chain keeper that surrounds the chain. It does well when pedaling foward but the system can fail if the bike is back pedaled.

Sometimes some blacksmithing is required for chain guides, and Tyson is not shy about fabrication (figure 15). A chain keeper system for double ring bikes uses a stainless plate that bends in a curve toward the left. Tyson will modify this for the single ring by removing it and straightening it in a vise. The piece is then re-installed but only to mark the line of bending. It is again returned to the vise and bent at the mark. This allows the guide to cover the chain at just the right angle.


Figure 15. Straightening the guide plate

 


Figure 16. Marking the guide for the proper bending point


Figure 17. The guide has been bent over the chain at the correct angle and the bike is ready to go

 

There are two roles for the mechanic at these races. First, there is pre-race preparation. The mechanic can do some quick work on pedals, brakes, wheels and gears. During the race, the mechanic can assist with wheel changes. This day I worked the wheels-in-wheels-out pit, which feels a bit like valet service. There were wheels laying everywhere, with a single path between them (figure 18). There is no time to waste when a rider comes in for service (figure 19).


Figure 18. Pit traffic can enter and exit smoothly


Figure 19. Focusing to get this contender back in the action ASAP
.


Figure 20. A tubular puncture resulting from striking a sharp concrete corner at speed

 

It is always good to learn or see something new at an event. During this race, a Cat IV put his foot through the front wheel in a bit of "acrobacy". This broke two spokes, which is not such a surprise. However, pulling off the rim strip revealed some interesting damage. The metal next to the nipple hole was pushed outward, not what you would expect at all. I can only guess he actually ended up stepping on the broken spokes, bending them and pushing them up into the rim (figure 21).


Figure 21. Damage where you might not expect it, inside the rim at the nipple hole

 


Figure 22. Race-time reminder to Cat IV's: lose the saddlebag, unless of course there are snacks you can share with everyone.