05 April 2009

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

What would the perfect mountain bike tire look like? There's no one answer to that question- the ideal tire varies by region, season, riding style and rider preference. This is a good part of the reason for the massive number of tires currently available. My personal perfect tire? It would be a wide-ish tubeless tire that rolled reasonably quickly while encouraging (and supporting) aggressive cornering. It would be light but not fragile, reasonably priced and long-lasting. Good luck, eh?

For a long time, Specialized's Roll X was my go-to tire. At under $50, it was a reasonably-priced, fast rolling tire tubeless with a good amount of volume to protect lightweight rims and tenacious cornering ability. Sadly, it was dropped from Spez' line over a year ago. Since then, I've been adrift, looking for a suitable replacement. At 24 Hours in the Old Pueblo this spring, I got to talking to Geax's Ryan about his sweet Sprinter conversion. Eventually, we got around to talking tires and the company's various technologies (including mountain tubulars and the company's tubeless-ready offerings). I have to say that I've been leery of "tubeless ready" tires. The idea makes sense- the widespread use of sealant allows for the removal some of the extra sealing rubber from heavy(ish) UST tires, saving weight without compromising functionality (and possibly improving feel, thanks to a more supple casing). Unfortunately, my (and friends') limited experience with the type has usually ended with burping beads and sidewall cuts- many "tubeless-ready" tires just weren't ready for the aggressive riding and rocky terrain that tubeless tires typically beg for. Geax's TNT (Tube/NoTube) casings are a bit different than most. Rather than just changing the beads on their tubed tires, the company uses a stronger protective layer of nylon fabric and abrasion-resistant rubber in the sidewalls to improve durability and a tubeless bead to ensure consistent and burp-free inflation- but do without the butyl layer that their true tubeless tires use to hold air without sealant (Geax recommend their own PitStop Sealant as they feel that Stan's NoTubes can be harmful to the tires over prolonged use). In the 2.3in Barro Mountain tread, the 700g TNT tire (ours weighed 680g) is only 80g heavier than the standard folding version but a full 110g lighter than the UST version.

The idea was appealing. I tend to cut sidewalls on lightweight tires but don't feel like I need to be hauling freeride tires around. The Barro Mountain tread reminds me of a more organic version of Continental's Cross Country tread from the early 1990s (at this point I can't honestly remember how those rode)- the knobs are relatively short and somewhat closely spaced, to minimize squirm and decrease rolling resistance. The profile is a bit rounder than I'm used to, placing the shoulder knobs well off to the sides but promising a predictable transition from upright to leaning. I figured that they looked like a good match for New Mexico conditions and Ryan was happy to send a set out for test.

When the Barro Mountains arrived, I mounted them to my own tubeless wheelset with the idea of swapping with the stock Michelin XCR Dry2 tires on our Giant Anthem X2 test bike, depending the trail and conditions. As it turns out, they've hardly left the Giant in six weeks.

My initial feelings about the Barro Mountains were mixed. While very light (particularly for their size, knobbiness and apparent durability) and fast rolling, they didn't have the cornering tenacity I was used to. In loose-over-hard conditions, they are more communicative at the limits than most tires I've ridden- I've never had them break loose unexpectedly- but the limits were a bit closer than I would have liked. Still, in Albuquerque's fast, hard foothills, they were a great match for the Giant's all-around cross-country ability. As our higher trails (temporarily) dried out, I returned to some of my favorite long rides in the mountains- and this was where the Barro Mountains really came into their own. The (slightly) loamier (this is New Mexico, after all) conditions work extremely well with the Barro Mountains' tread, providing plenty of traction for going, turning and stopping and the large volume provides plenty of confidence (and rim protection) when diving into rock gardens. Despite my misgivings about "tubeless ready" tires, Geax's TNT casing is holding up beautifully, and the tread is showing very little wear.

The Barro Mountains seem designed to fill the same niche as the Schwalbe Racing Ralphs that Charlie reviewed last month and are shaping up to be what I'd call and excellent enduro tire. Not as confident in the corners as as more aggressive rubber, but quite good while remaining lightweight and fast rolling. The large casing provides a much-appreciated measure of insurance against rock strikes and other rider miscalculation. While maybe not the ideal desert tires, I could see them being a top choice for Colorado's distance set (Vapor Trail 125, anyone?). So far, I'm really enjoying the light weight and feeling of speed and have only had to dial back my cornering a little bit. Look for a final review later this summer.




Matt Griswold said...

Hey Marc, the Marathon TNT's are my everyday tire of choice in our gritty rocky rooty singletrack out East. I roll tubeless at 25psi (I'm 180)with the 2.1 in back and the 2.3 in front. I find the softer 2.3's wear MUCH quicker than the 2.1's, which have just slightly less volume. At low pressures these pups grip to everything and the kitchen sink. Oh yeah, I just got a 2009 Anthem X2 too! needless to say, stock Michelins were the first to go. Best, Matt

bikefix said...


That's awesome- I'm glad that they're working out for you, and the Anthem as well (both are bikefix favorites). I imagine that the Barro's would make a great, fast East Coast tire... I'm really liking the Saguaro on the rear- though it probably is better on dry rocks & sand than on wet roots.