The Pivot Mach 4 Mountain Bike Frame is perhaps Pivot's most versatile machine. If you consider that you can use it as a full blown cross-country race bike this weekend and roll through hidden backcountry trails with a backpack and an attitude for adventure the next, you'll know what we mean. The key to its utility is the 100mm (4) DW-Link rear suspension.The Mach 4 is a super-efficient race machine because it pedals well without inducing strange or wasted motion in the rear suspension. At the same time, it has deceptively plush travel that just makes it a fun bike to ride. Though these characteristics might seem to be mutually exclusive, the DW-Link suspension makes it all possible because of its anti-squat characteristics. By virtue of Newton's Third Law of Motion, when something accelerates, its mass is transferred rearward. The DW-Link counteracts this transfer to minimize your impact on the rear suspension. This is why Pivot is able to get such a lightly damped tune on the 7. 25 x 1. 75 Kashima Coated RP23 rear shock from FOX. With the DW-Link controlling unwanted suspension squat, the lightly damped shock can respond with ultra-sensitivity to the demands of the trail. As a result, the Mach 4 delivers a comfortable ride and awesome climbing traction. It floats over rocks, roots and ruts, yet it still remains firm while hammering out of the saddle. In short, the Mach 4 adapts to virtually any situation you throw it in.The great rear suspension would be nothing without being hung on a flex-free structure. Pivot builds the Mach 4 frame from hydroformed 6000 series aluminum tubing and 3D hollow aluminum forgings. The production processes for these raw materials both help to align and strengthen the grain structure of the alloy. The result for the Mach 4 is that it's light enough to build a complete bike at 22 pounds or so, yet the front and rear triangles are unyielding to the stresses from the trail. This gives you stability and precision enough to inspire...