Thorns - Perhaps the most persistent offender is the goatshead thorn, a thistly wildflower that grows in the Southern half of the United States. Bike shop owners in those areas report that riders new to the area quickly get frustrated at patching tires several times a week - almost always because of a troublesome goatshead. It and related offenders such as caltrop, bullheads and kallstroemia are infamous in the "thorn belt" of Oklahoma, Texas, Arizona, New Mexico and Southern California, and are even more problematic than cactus needles (although cactus needles do remain a significant hazard.)
"The goatshead, or T. Tribulus, is appropriately called a 'puncture-weed'," said Dr. David Weaver, an agronomist at Texas A&M University. "The species derives its name from its objectionable fruit, which separates into five small nuts each bearing two, strong sharp spines or thorns up to 1/4-inch long. These can easily puncture tires and poses a real threat to unsuspecting riders. " Throughout the summer, the region's constant sunshine hardens the thorns into natural tacks tough enough to pierce a tire, creating a risk for cyclists. The thorns puncture the tire, then work their way through to stab the inner tube, causing a flat. Thus, the rider faces a triple loss: the tire, the tube and a pleasant biking experience.
One Arizona cyclist was an hour into the desert when a goatshead attacked. By the time he finished changing the tire, he was nearly dehydrated.
Thorns, while perhaps the most widespread and infamous offender for bicyclists, are not the only problem. Environmental hazards include both natural and human-produced materials, and they vary from region to region.
Pines and Needles - Still, cacti remain a serious problem in the western deserts. "A friend of mine was flying down from the Sierra Nevadas toward the Mojave (Desert) when suddenly he had this major blowout," said Mike Fischbein, owner of Bike Business in Yucca Valley, CA. "He ran over a low lying cactus and flew face first into the pavement. It totaled his bike. "It took three hours before someone came by and picked him up. They had to take him to the emergency room. The incident trashed the bike-about $2,500 gone because of a few cactus needles. "
On the Eastern seaboard - especially the Carolinas and Florida - shell fragments plague bicyclists. "A cycling friend told me she had a shell flat as far inland as Durham," said Jill Nelson, a marathon cyclist from Charlotte, NC. "The best we could figure was that the state must have used shells in the pavement."
On mountain trails in Vermont, New Hampshire and upstate New York, are notorious for natural perils cloaked by mud Cyclists frequently complain of unseen dangers such as sharp stones and twigs mixed into the slop.
In major cities such as New York and Boston, cyclists must slalom through man-made Urban hazards such as broken glass and chunks of concrete or asphalt. Other parts of the northeast are plagued by potholes caused when winter freezes swell and contract the ground.
Climate causes difficulties in other parts of the country, as well. In rain-heavy areas like the Pacific Northwest, civil engineers have befriended auto traffic by designing roads that slope down from the middle. But that creates a combat zone for bicyclists, who must maneuver through the piles of debris (dried-out pine needles, branches, or shards of glass) washed to the sides by rain.
Industrial areas have their share of problems. Factory and manufacturing employees who shuttle by bike from plant to plant can get flats from fragments of metal or other textiles.
Faced with such myriad hazards, a flat tire may be inevitable, but at least there are ways of postponing the inevitable. which boils down to riding smart and making sure your equipment is equipped to do battle--goes a long way.
Puncture Prevention - The Culprits