$1895 (Frame and shock)

25.1 pounds

4-inch rear wheel travel

Full test: May 2008 (Click here to order this issue)

Highlights: Starting at the head tube, the Mach 4 frame uses a zero-stack headset system that allows the front of the frame to sit about a half-inch lower without compromising strength. Zero-stack differs from an integrated headset in that the bearings still ride inside a machined cup that is pressed into the frame. Integrated bearings press directly into the frame and often have fit-up issues. The zero-stack head tube is larger diameter, which makes room for the Mach 4's oversized, triple-butted aluminum tubes. The thickness of the pipes vary between frame sizes so that any sized rider will feel the same magic ride qualities. The curved downtube facilitates taller fork crowns and remote lockout devices, and a tube-gusset at the seat tube/top tube junction helps reduce the bike's standover clearance to a useful, 29.5 inches (medium-sized frame).

Best quote: "In the saddle, the Mach 4 accelerates more smoothly. The fact that the chassis can suck up the terrain while delivering efficient pedal action surprised first-time riders who, without knowing it, frequently climbed in the middle chainring where formerly they used the granny."

Bottom line: The long-travel trend calls for a five-inch suspension design that climbs and accelerates like a short-travel machine. Pivot's Mach 4 solves that equation in reverse: it gives its rider all the benefits of a shorter-stroke cross-country racer, like sharp acceleration, a dizzying rate of climb, hits the scales below ??-pounds, and delivers the downhill handling of a longer-stroke trailbike. The Mach 4 is an exemplary four-inch-travel trailbike that perfectly suits racers who don't have the desire (or perhaps the cash) to own one bike dedicated for racing and another for trail riding and training. The Mach 4 can burn laps with any cross-country racer and still rip it up on a technical trail ride. We like it.