Mountain Gear

Michelin, WTB Reworking Their Rubber

Tires are the least expensive component upgrades available for your bike, but one that can make a huge plus in performance.

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One of the least expensive component upgrades available for your bike also happens to be the one that can take it to the absolute pinnacle of its potential performance. What’s this supremely important component choice? Your bike’s tires.

Here’s a look at Michelin’s all-new line and the development undertaken at WTB for 2010, along with new model highlights from Geax and Kenda.

Michelin Revamps Mountain Line

Michelin unveiled a completely renewed mountain bike tire line for the 2010 season at last month’s tradeshows. The new line brings a new naming system, as well as one new cross-country/trail tire called the WildRock’r. Name changes are as follows: WildGrip’r uses the tread pattern previously designated as A/T and the WildRace’r uses the same pattern as the Dry2.

The new tire is designed for muddy and extremely rocky terrain. It’s said to grip more aggressively than the Grip’r, which is meant for intermediate terrain. The tread pattern of the Race’r remains relatively untouched, rightly so, as it is proven as one of the best dry condition tires in the industry as it rolls almost as fast as a semi-slick but with much more grip.

The predecessor of the Race’r, the Dry2, has been the go-to tire of Adam Craig and his Giant Factory Team since the its inception. The Grip’r differs from the old A/T by hollowed center knobs, which will presumably act like sipes, enhancing grip.

For 2010, Michelin will continue with only one 29-inch model, although the tread pattern will change from the Grip’r (A/T) pattern to the Race’r tread pattern. The Race’r 29-inch will be available in a 2.1-inch width only.

Michelin’s cross-country and trail tires are available with a standard bead and 60tpi casing or an Advanced version with a unique dual tread compound — a harder base compound with a softer outer compound — and 127tpi tubeless casing. Michelin offers a reinforced casing option, which adds four protective plies under the tread to prevent puncture in select larger tire sizes.

Other options available in select tires include a new technology called Gumwall, which is a secondary rubber layer that is placed on the sidewall of the tire. Michelin’s cross-country and trail tires range between $50 and $65 depending on features.

Michelin’s light duty tires, aside from the new model, build upon proven concepts, a trend the manufacturer employs to assemble its renewed downhill line.

The trio of downhill tires includes the new WildRock’r tread, the WildGrip’r, which is the resurrected DH 16 A/T and the WildDig’r is a revised version of its previous DH Mud3. Michelin’s WildGrip’r downhill tires are available in 2.5- and 2.6-inch sizes, while the WildRock’r comes in 2.25- and 2.5-inch sizes. All of these variations feature “Descent Technology,” which is a wire bead that’s designed to keep the tire on the rim under heavy cornering pressure.

The WildDig’r downhill mud tire is only available in a 2.2-inch size. Michelin’s downhill tires range between $51 and $76 depending on size and technologies.

WTB 2010: Race Developed

The man who put all-mountain racing on the map, Mark Weir, is a salaried employee of WTB. He has been for almost a decade. Weir has bounced from working in WTB’s office, to one of its athletes and is now heavily involved in the brand’s development of new tires.

Weir and Jason Moeschler, who heads up product development at WTB and has won the famed Downieville all-mountain title three times, stepped up the brand’s development effort in the last year. With the “mission of ensuring that not one of the brand’s competitors have a tire that we’d rather ride,” Moeschler and Weir took a hard look at the tires WTB produced and what changes were needed.

The first step of their plan took them to Weir’s ranch in Novato, California, where the duo built a test track specifically to test tires and compounds. The 2.5-minute test run consists of conditions that a rider might encounter on an average ride. It includes an artificial mud pit, rock face, deep loose dirt and the dreaded loose-over-hard surface. By using timing sticks and GPS, the duo benchmarked the brand’s current line up of tires.

Once they had a “bunch of ideas,” they had a meeting with WTB tire designer Mark Slate, co-founder of WTB, and man who has designed more tires than anyone in the industry. according to Moeschler.

Slate takes a comment like, “doesn’t brake hard enough,” and knows to increase the knob height and the distance between the next, Moeschler said. Once he worked all of their comments into the new designs, a mold would be cut and the tires prototyped. The process depends heavily on good feedback and an experienced designer. Even still, sometimes a mold doesn’t work out, said Moeschler.

Once the molds were cut, seven sets of prototypes were molded for each tread pattern and then sent to Weir’s ranch for testing. Each prototype set highlighted a different rubber compound or combination of rubber compounds. Compounds for each of the new tires were then narrowed down. Instead of going through each tire here, the best illustration might be to use Weir’s namesake as an example, the Weirwolf, a tire that already had a buzz surrounding it at last months tradeshows.

The original Weirwolf is a proven race tire, but it had two problems, according to Moeschler. First, it didn’t roll fast enough and it had a large “drift zone.” Weir likes to drift, said Moeschler, but for the majority of riders it provided too much time in this zone and required too steep of an angle before it hooked up.

To fix these issues, Slate reduced the number of side knobs to three in each grouping for more of a rail-like ride and cut them with a new three-tiered stepped shape that’s also siped. Then he decreased the dead space between the center and side knobs, as to reduce the drift zone. And finally he pulled the center knobs closer together so the package would roll faster.

After much test riding, Weir settled on a 53d shore rubber compound for the center and a 45d shore for the side knobs.

The new tire is available in 2.1- and 2.3-inch sizes; the 2.1-inch tire has four different levels, including UST tubeless, TCS (a sealant based tubeless technology that conforms with UST rims) as well as Race and Comp series (the Race designates a foldable bead and Comp a steel bead.) The Weirwolf costs $25 in the Comp, $50 in the Race model and $60 for the TCS or UST tubeless models.

Besides the new Weirwolf, WTB brings tread refinements to its Vulpine, Mutano, Wolverine and Dissent tires.

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