Marin Rift Zone
Price: $2,799
Weight: 27lbs
Components: Shimano XT/LX/Deore, SRAM 7.0 cassette, TruVativ crankset
Frame & Fork: QUAD System frame, 6061 aluminum twin-monocoque front triangle, monocoque swing-arm, and Fox Float R rear shock (4”/100mm travel). Manitou Skareb Elite with adjustable rebound and compression damping (3.15”/80mm travel)
Geometry: 71º head tube, 74º seat tube, 23” top tube
Sizes: 15”, 17”, 18.5” (tested)
Comments: “Marin: Putting Formula One engineers to better use.”
www.marinbikes.com

Rift zone. It sounds like something lifted from surfer lingo, but the truth is that a rift zone is a crack in the earth, an extensive system of fractures and faults. As bike names go, it’s a bit ominous, but only for geography geeks. In fact, not only is the name unlikely to draw any skepticism, but there is also enough about the Rift Zone’s appearance and background to create some positive tremors in those looking for a new cross-country-oriented suspension bike.

Marin’s new QUAD series of full-suspension mountain bikes is perhaps the most aptly-named suspension design ever: with four inches of travel, this four-bar linkage is available in four models, with a unique suspension design based on a Quadratic axle path.

I first learned of the design from the designer himself, John Whyte, at Interbike last October. Whyte is a former Formula One engineer and a cyclist, giving him all of the credentials necessary to create some pretty fast bicycles. The rear wheel, he explained, moves in a quadratic path as the wheel absorbs an impact: first backwards, lengthening the wheelbase in the first third of the travel, then forwards to better absorb bigger hits. The chain, fighting the design’s tendency to extend the wheelbase, literally pulls the rear wheel into the ground for improved climbing and sprinting traction. The unique rear-axle path is accomplished via two short CNC links, each running on triple-sealed cartridge bearings that connect the rear swing-arm to the main triangle. These “Quick Links” not only provide remarkable lateral stiffness, but also reduce side-load stresses on the rear shock, and all without adding a significant amount of weight compared with a traditional single-pivot design! Even my 18.5-inch Rift Zone (the biggest size Marin makes) felt respectably light, which made me look forward to climbs even more.

I must applaud the collection of components on the Rift Zone: even as the third model in its line, it still ends up looking pretty sexy, with the ever-popular Hayes disc brakes that worked flawlessly, a smart selection of Shimano components that included an XT rear derailleur, a very nice-looking CNC-machined FSA four-bolt stem, TruVativ cranks that shifted admirably, sealed-bearing disc hubs, and a selection of WTB bits, including its extra-trick Stealth composite clipless pedals. Pretty sweet, indeed. My only gripe was my personal preference for wider bars (the Rift Zone riser bar is 25 inches) and the 27.0mm seatpost, which is fine, but is less common than 27.2mm and limits options with replacement parts.

On the trail, it’s quickly apparent that this is a lightweight cross-country-inspired design that was not intended for hucking off of anything, but rather for speed-enhanced trail riding and possibly even racing. Even though it has just 80mm of travel, the Manitou Skareb Elite was well-matched to the longer rear travel, thanks to the progressive feel of the rear shock (I’d have liked the option of 100mm, in case it’s not race day).

The rear suspension felt very similar to a single-pivot design, but it did show a remarkable and impressive propensity to stay connected with the ground on climbs, making traction a non-issue, even in loose conditions. Bigger impacts were comfortably absorbed, with a requisite amount of feedback that you’d expect from a bike designed for cross-country riding. Where it differed most from single-pivot designs was in the lateral rigidity: this is one seriously stiff design that sprints incredibly well, thanks to the wide-stance support of the QUAD links.

The geometry felt familiar, and there was little remarkable about the Rift Zone’s trail manners—they were predictable and fairly neutral in all conditions. Still, I wished the top tube were longer, a trend that continues in its small and medium sizes. Considering the speed-focused nature of these designs, I found myself wishing for a bit more breathing space in the cockpit on long climbs. The QUAD design would shine even more brightly with a slightly more stretched out geometry.

But more subtle features about the Rift Zone impressed me: the clean design doesn’t appear to be as complex as it actually is, and aesthetically, it’s exceptionally well-executed, all the way down to the rear-shock mounting point, which is seamless. The only minor issue I have involves the top-tube bottle mount. There isn’t much standover clearance, so the last thing I’m looking for is a way to reduce my clearance even further.

The Quad system performs as well or better than a single-pivot design, and is also remarkably stiffer. For those seeking a fast cross-country dualie, the Rift Zone or any of its kin are a fabulous execution of a good design.