Get a Grip

Tread design demystified (it's not you, it's the tires)

May 1, 2000
Outside Magazine

In a perfect world, the Volvo/Cannondale mountain-bike team's support van meets you at the trailhead. Chief mechanic Dave Arnauckas hops out with an armful of new tires at the same time World Champion downhiller Anne-Caroline Chausson, having just inspected your trail, pedals up. A quick discussion ensues and in a blur of skilled motion Arnauckas swaps out your ratty treads for a pair perfectly suited to the conditions. Five minutes later you're cranking up pitches you typically hike, lugeing down sections that usually send you cartwheeling.

"Bikes don't come stocked with tires designed to work in every area of the country," Arnauckas explains. "Tire selection on a muddy day can be the difference between two hours spent walking or two hours spent riding." Likewise for sand, roots, and rocks. Put simply, picking the right tires will keep you on your bike and off your feet—or your chin. The idea is to balance traction and speed, both of which are functions of the size, shape, and pattern of a tire's knobs, or lugs. Big, widely spaced lugs offer superior traction, but they slow you down. Short, tightly spaced lugs have less rolling resistance, but they leave you wallowing in mud. Know your knobs, and you'll master your terrain.

That is, assuming you also know your tire pressure. Too much will make the plushest full-suspension rig ping all over the trail; too little will render the stiffest aluminum hardtail as sluggish as a vintage beach cruiser. "Try to find that fine line," advises Arnauckas, "between something that will roll fast but still stay in good contact with the ground."

As for determining a tire's lifespan, you'll just have to watch for wear. First check the braking edges—the sides of the lugs closest to you as you look down from the saddle. On the rear tire, eyeball the opposite edges of the lugs, which grip the trail. And be sure to inspect the lugs along the tire's edges. "If the cornering knobs are worn," says Arnauckas, "when you lay your bike over you'll wash out. That wouldn't be good."

Of course, Volvo/Cannondale racers use tires for no more than a week, but that's the luxury of getting them free from Hutchinson. You, on the other hand, will have to pay. As a non-sponsored duffer, though, at least you're free to choose any model you want. That's why we called upon riders from reputable shops in seven core mountain-biking spots to recommend the best tires for their terrain. The following picks are only suggestions; consider buying a second pair for spells of unusual weather. And remember that tire selection, like mountain-biking itself, is not an exact science. That's what keeps it interesting.

520 grams
($40; 800-346-4098)

For the technical riding over mud, roots, and rocks endemic to New England, Slade Warner, co-owner of Rhino Bike Works in Plymouth, New Hampshire, uses this light, zippy, and très French tire on both wheels. Other cross-country treads, with their clusters of short knobs, bog down in loamy soil, yet deep-lugged models are no better because they roll about as smoothly as paddlewheels on the dirt roads that link trails. Warner says mud just doesn't stick to Michelin's gaudy green rubber compound, thus leaving the WildGripper Comp's treads free to grip. "When you get up to speed," he says, "centrifugal force just blows the mud right off the back."

front: 520 grams; rear: 620 grams
($35 apiece; 408-779-6229)

Mike Rice, head mechanic at River City Bicycles in Chattanooga, Tennessee, figures there must be between 700 and 1,000 miles of prime off-road riding in the area. Trails tend to run along ridges that drain quickly, leaving a surface of bony hardpack, which would be fine if it weren't for the countless stream crossings and fallen logs. It's too solid for mud tires and too technical for slicks. So Rice recommends the Dirt Control Comp up front, and the Team Master Comp in back, which balance speed and traction. The Dirt Control's short triangular lugs point in the direction of the rotation, which reduces rolling resistance and helps the tire track straight, yet stops quickly because the braking edges hit the turf squarely. In back, the Team Master's midsize lugs and its square profile provide solid bite on bark-stripped logs and creek banks.

560 grams
($36; 510-790-2967)

The upper peninsula of Michigan is veined with subalpine singletrack that dips and rolls through the woods. It's a little rooty, a little mossy, rarely muddy—a mild recipe that would call for skinny semi-slicks, save for the frequent pockets of deep sand. To float over them, sales manager Shane Whyatt of Brick Wheels in Traverse City recommends the Fire XC Pro. "The interrupted center lug pattern on the Fires gives good bite in sand, but because the lugs are short there isn't much rolling resistance," he explains. The tight pattern of uniform block-shaped knobs works for both the front and rear.

front and rear: 670 grams
($39 apiece; 415-389-5040)

"It won't rain for two months and then it will rain every day for six weeks," says Klaus Kracht of the weather in Crested Butte, Colorado, where he owns the bike shop Alternative Sports. "The trails go from moon dust to liquid black mud. You need a tire that can handle a variety of conditions." In the Butte, where granny gear climbs last upwards of three hours, and where you're likely to encounter any of the above conditions on any given ride, that'd be the VelociRaptors. Hit a section of silt at 12,000 feet on a climb and you'll be glad WTB didn't skimp on the size of the beveled blocks studding the rear tire—they will not slip. On the downhills, the big, widely spaced cornering knobs cut through deep dust, greasy mud, or loose talus. They're a little heavy and knobby for spinning along on roads, but the Rockies are all about singletrack anyway.

659 grams
($37; 800-350-0688)

Moab may be famous for the Slickrock Trail, but when you venture off this theme-park route you'll need tires that can handle both sandstone and its post-erosion sibling, plain ol' sand. For that, bike mechanic Joan Martocello and the rest of the crew at Poison Spider Bicycles ride the chubby Sedona. "The rubber on the Sedona adheres to the sandstone real well, but the lugs are short enough that they don't shear off," says Martocello. As for its performance in sand, the Sedona's sparse pattern of sickle-shaped lugs, combined with its raftlike 2.25-inch-wide profile, let it float over the deep stuff like a Lunar Lander.

front: 900 grams; rear: 800 grams
($50 apiece; 888-468-4642)

Downhill racing as we know it started at Mammoth Mountain, California, on the Kamikaze course, and the scene is still all about speed. Whether you're riding the lifts at the ski resort or running your own shuttles on the 13-mile Lower Rock Creek Downhill, take the advice of the so-called freeriders at Mammoth Sporting Goods and go big—as big as your full-suspension frame will accommodate. To cut through the pea-size pumice that litters most trails, they suggest the Factory DH in the massive 2.3-inch width up front and a 2.1-inch in back. (Don't judge these knobbies strictly by their numbers; even the 2.1 dwarfs every last tire on these pages.) Extra-thick nylon cords in the casing enable them to withstand big hits and make them virtually immune to pinch flats. And the quarter-inch-tall lugs make your bicycle look like a motorcycle.

front and rear: 550 grams
($30 apiece; 510-441-0126)

As the service manager at Portland's Fat Tire Farm, not to mention a former amateur state champion in both cross-country (Texas) and downhill (Oregon), Butch Wells speaks of mud like Smilla speaks of snow. "It rains eight months a year out here," he says. "There's that muddy runoff that doesn't stick to your tires but gets you real dirty and makes the surface slick, and then there's that nasty clay that instantly clogs tires." For a pure mudder that can handle these extremes as well as every earthen viscosity in between, Wells recommends the Mud Mad, which comes in separate tread patterns for the front and rear wheels. Both tires have deep, conical lugs that grip like a colony of leeches but are spaced well-enough apart to shed even the most adhesive quag with ease. Best of all, the Mud Mad's sub-two-inch width slices right through surface slop to hook up solidly with terra firma—such as it may be.