Pearl Izumi X Project 1.0 - First ride

Efficiency, comfort and traction from the TPU shoe

BikeRadar score 4.5/5

It doesn’t take more than a few steps in Pearl Izumi’s new X Project 1.0 shoes to realize they’re a far cry from the company’s former top-of-the-line Octane SL II mountain bike shoes. 

Unlike the completely rigid carbon shanks or soles found on most high-end MTB shoes, which slip and slide notoriously over any and every trail, the flexible TPU X Project sole grips much more like that of a non-cycling shoe. It even offers conforming flex that simply adds to the traction and comfort.

But flexible, grip-friendly cycling shoes are nothing new to the industry – just look at the footwear of choice at any gravity or BMX event. The big pre-ride question was whether these flexible, comfortable shoes were stiff enough to provide the same efficient power transfer that most expect from carbon soled (read: rigid and unflexible) shoes.

The short answer seems to be yes. With a hot lap (pun intended on this 97-degree day) on Bootleg Canyon’s singletrack, the climbing efficiency of the X Project soles was spot on. 

The story of the X Project is on the sole

But with that question answered another, more involved query arose. Without the same torsional rigidity of a traditional carbon sole, there was a hint of camber in our foot when wattage output increased. It didn’t seem to affect efficiency, and didn’t cause any pain on one ride, but it was noticeable. So is a slightly cambering foot through a pedal stroke good or bad for biomechanics?

Traditionally, cycling biomechanics have assumed that the most efficient and 'correct' pedal movement has been that of perfectly inline feet, ankles, knees and hips, like pistons in an engine. But it’s also argued that such a stringent setup goes against natural body alignment. 

One person making this argument is Dr Ray Browning, a professor of biomechanics at Colorado State University and former professional triathlete who used to run Serotta’s popular bike fit system. He played an integral part in the development of the X Project soles.

Is there a right biomechanical answer? At this point, it’s hard to say. Both theories have accredited spokespeople with data to back up their opinions. And right now we’re just trying to see how a new set of shoes rides. 

So, back to that note, the X Project does what it’s set out to do: provide an impressively efficient pedal platform and surprising comfort and traction friendliness in a single shoe.

The buckle has multiple anchor points to center the strap on top of the foot

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