30 December 2009

bikefix Exclusive Review: Geax Barro Mountain 26x2.3 TNT tires

As a rider who lives in a pretty rocky part of the world, I really appreciate high-volume tires. When compared to smaller tires, they provide an extra measure of sure-footedness over loose terrain, can afford a bit more comfort, and go a long way toward protecting lightweight wheels from dents and dings. There are quite a few 2.25in and larger tires on the market, but few seem designed for cross-country riding in mind. Tire companies seem to assume that riders looking for high-volume tires are also looking for (or are willing to put up with) slow-rolling tread patterns and heavy weights. Me? I want it all: fat(ish) tires that provide good traction, predictable cornering, low rolling resistance, a reasonable weight, a reasonable price, and (because it's my wish list) good puncture & cut resistance. For all of these reasons I was excited when Geax sent out a pair of their 2.3in tubeless ready Barro Mountain tires last spring.

Geax, as Vittoria's mountain and cyclocross brand, has a good deal of tire design and manufacturing experience behind it. The company's TNT, for Tube/No Tube, casing is one of the latest generation of 'tubeless ready' casings. Rather than just putting out a tubed tire with a snug bead, Geax have realized that tires run without tubes can be especially vulnerable to tread and sidewall cuts and rely more on the sidewall to keep their shape. While supple casings can be very comfortable and provide great traction, they tend to roll a bit when pushed hard- which can make aggressive cornering, well, inconsistent. A bit more tire pressure can help a tire hold its shape better, at the cost of that comfort and traction (and without improving the tire's resistance to cuts and punctures). On the spectrum between lightweight tube casings and heavier UST tire casings, Geax's TNT are much closer to the tubeless end of things. Based on the lack of weepy wet sealant spots that I've seen on the outside of these and other TNT tires over the past eight months, I'd even go so far as to say that they're more puncture-resistant than other companies' dedicated tubeless casings.

The $45 Barro Mountain's tread, a slightly taller version of their Barro Race's, features widely-spaced knobs in a reversible pattern (one way for speed, the other for traction). The overall profile is very round overall and the rubber compound on the soft side of things. Overall, the bent knobs remind me a bit of a reworked Continental Cross Country tire from the mid-90s. The TNT sidewall is a handsome dark gray and the tires weigh in at 680g apiece- not light, but not bad for their size (and lighter than the claimed 700g).

When riding, the Barro Mountains roll much faster than their large volume and widely-spaced knobs would suggest. Being wider than they are tall, the knobs aren't anywhere near as squirmy as others I've used over the past year, making them feel especially planted on blue groove and rocks. In loamy conditions the tires really come into their own, with each knob given the ability to bite individually. Loamy conditions also don't ask as much of the relatively low shoulder knobs, which allows for good cornering in those conditions.

Here in the desert Southwest, where short, closely spaced knobs (like those on WTB's ExiWolf) do a good job of keeping traction in sandy or loose conditions, the Barro Mountain's knobs often felt just too widely-spaced, requiring careful application of power and brake use (front and rear) to prevent the tires from breaking loose. While not squirmy, the shoulder knobs just don't seem to bite well enough to be cornered hard, which tends to override their speed advantage when things get twisty (after all, speed is only good if it can be carried through corners). Reversing the rear tire (to it's traction orientation) improved climbing a bit, but made the tire even more skid-prone than before, which can be embarrassing as well as frustrating. The tread's Sticky Soft rubber also wore very quickly on our local rocks. I have the feeling that the same tire in the 2.1in width's harder Aramid 3D Compound might not work as well as the current compound when brand new, but given the speed at which the Sticky Soft knobs' sharp edges rounded, the harder rubber might feel much better in the long run. The harder-wearing rubber would likely make a 2.3in front/2.1in rear combination a good option.

While the Barro Mountain clearly isn't particularly well suited to desert or Southern Rocky Mountain conditions, it really shines in loam. For riders in the Northeast or higher Rockies, the tire's ability to roll fast and grip well without packing up with mud has a lot to recommend it. In fact, that's what our readers' feedback suggests. The extra volume doesn't come with much of a weight penalty, so riders don't need to fear rock gardens, running low pressures, or for the safety of their lightweight wheels. Geax's TNT casing has to be one of the best I've tried- it seems altogether bombproof (which is nice for a change). I wore the Barro Mountains down to the nub and, despite the large expanses of tread-free tire and a number of sidewall scrapes, didn't see one puncture. The low price is an added bonus. Since wearing out my Barro Mountains, I've bought a set of 2.2in Saguaro TNT tires and am finding those to be much better suited to my rides and riding style. Keep an eye out for a review in a few months.



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