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On test: Biomac bio-mxc2 shoes, June 3, 2009

Going against the grain

Biomac's unique shoes are stupendously lightweight
Photo ©: James Huang
(Click for larger image)

It is commonly accepted that pedal axles should be positioned near the balls of our feet, but is it really the best place? German shoe designer Götz Heine doesn't think so and Cyclingnews technical editor James Huang says his mid-foot cleat position is at least worth a closer look.

The concept

Heine's 'bio-mxc2' cleat position eschews conventional cleat position methodology by placing the pedal axle roughly beneath the arch of your foot - several centimeters behind what most people would consider normal.

Though unusual, the idea behind Heine's mid-foot or 'arch' cleat positions is rather logical: he and other mid-foot proponents such as renowned coach Joe Friel and Cyclingnews fitness panelist Steve Hogg surmise that the vast majority of a rider's power is produced by the quadriceps, glutes and hamstrings while the lower leg only serves to stabilize the efforts of what happens above. As such, the lower leg is merely a conduit and doesn't produce enough effective power to justify the metabolic cost.

Moving the cleats back to the arch - a location Heine defines as optimal - thus substantially reduces the workload on the calves and leaves more oxygen and energy remaining for those larger muscle groups to produce more total power before fatigue and exhaustion can set in. In other words, you can go faster for longer with no additional training required aside from adjusting to the new position.

"Compare it to doing push-ups," says Heine. "One time on your fingertips, second time on the palms of your hands. Total [lactic acid production and oxygen consumption] will be equal but the fingertip exercise will exhaust you sooner."

Interesting enough. But does it work?

The riding

Biomac's real claim to fame, though, is the midfoot 'bio-mxc2' cleat position,
Photo ©: James Huang
(Click for larger image)

The mid-foot cleat position feels awfully weird at first but it only took a couple of rides to adapt and dare we admit it, we actually like it - at least most of the time - and it's interesting to note that most gravity MTB riders on platform pedals naturally adopt this position already.

With the relatively flexible lower leg system taken out of the equation, power transmission is noticeably more direct and the power stroke is effectively lengthened. As promised, almost all stress on the calves is relieved - thus virtually eliminating cramps there - and we really did find ourselves motoring along on flats and extended climbs better than usual.

On the downside, the mid-foot position seems to sacrifice some of the 'spring' in your pedal stroke and high-cadence pedaling definitely takes longer to relearn. Sprinters and criterium riders will likely be put off as such but long distance riders might appreciate the efficient diesel-like feel. Not surprisingly, the mid-foot cleat concept has also been making headway in the multisport realm - reduced stress on the calves on the bike leaves the legs fresher for the run.

Moving your foot that far forward has substantial ramifications on bike fit however. We had to lower our saddle over 2cm to compensate for the loss of ankling - where the heels drop at 12 o'clock and the toes point slightly at 6 o'clock - which makes for a lower and more stable center of gravity but also requires the front end to come down a similar amount to maintain the overall feel. In some cases this will just require a rejigging of headset spacers but some bikes simply won't accommodate this depending on the setup.

In addition, having the cleat that far rearwards produces gobs of toe overlap.

The shoe

The sole plate is so thin that the two-bolt cleat inserts
Photo ©: James Huang
(Click for larger image)

Such extreme cleat positioning obviously doesn't work with conventional cycling footwear so Heine supplied us with his own equally radical -and insanely expensive - Biomac shoes, which tip the scales at a remarkable 348g per pair - about 50g lighter than Pearl Izumi's feathery Octane SL, 150g better than a pair of Specialized S-Works shoes, a substantial 250g under Sidi's Genius 6.6 and roughly equal to one Shimano R300.

Even so, overall sole stiffness is superb thanks to the carbon fiber outsole's unique bathtub-style construction whereby the edges curl up around the entire periphery of the foot and the rear forms an integrated heel counter complete with a notch to prevent tendon irritation. The resultant U-shaped cross-section is inherently stiffer than a flat plate and thus can be made with less material for comparable rigidity. As a side benefit, stack height is a paper-thin 4mm and standard cleat hardware actually has to be shaved down to avoid pressing into the footbed.

As a side detriment though point stiffness at the small two-bolt cleat could be a little better, there is almost no room for cleat position adjustment, there are no ventilation ports in the carbon structure, and walking on hard surfaces is clumsy to say the least. The minimal footbed also offers almost no padding so it's a good idea to drop in your own insoles to avert hot spots. Heine says his Biomac shoes can also be made to work with three-bolt pedal systems though and this may ultimately be the best way to distribute pedaling pressure for those willing to take the plunge.

The synthetic materials absorb very little water
Photo ©: James Huang
(Click for larger image)

Heine uses a similarly minimal upper built with a non-absorbent synthetic punctuated with metallic mesh inserts, just two Velcro straps, and an outer cover but unfortunately we weren't nearly as impressed here as we were with the outsole. The unpadded straps tended to cut into the tops of our feet after a while, heel hold was just average, and the stiff feel lacked the glove-like fit of say Sidi or Specialized.

On a more general level, finish quality just isn't that good and the shoe just looks and feels cheap. There were some slight asymmetries left to right, uneven cut lines, visible glue seams, and the slick fabric liner in the heel cup - which admittedly was effective at staving off blisters - is trimmed shockingly rough. We can appreciate that Heine still builds each Biomac shoe himself but anyone dropping this kind of money is bound to expect something far more polished.

To be fair, Heine can add padding to the straps if requested, a custom-molded shoe would obviously fit better, and the shoes are still insanely light and stiff. But performance or not we expect more - much, much more - for €499.

As an alternative, some conventional shoes can be modified to accept a mid-foot cleat position but that route requires careful measuring, a drill, and a hearty conviction.

A new way of thinking

The two straps are reasonably well placed
Photo ©: James Huang
(Click for larger image)

Riders who regularly do longer distances at a steady pace owe it to themselves to investigate the concept further - even if only by moving their current cleats as far back as they'll go or experimenting with some older shoes - before making a commitment nearly as expensive as Heine's full-blown Biomac shoes. The benefits are tangible given the right application and while your riding mates may ridicule you, they may not laugh as hard as you ride away from them at the end of your route.

As to why top-level athletes haven't yet adopted the concept if it's so promising, we say, 'not so fast'. Some actually already have, such as Swedish pro and two-time UCI road race world champion Susanne Ljungskog, 2008 Tour of Austria winner Thomas Rohregger (Milram), 2007 RAAM two-man team winners Urs Samtleben and Hape Narr, and countless multisport athletes.

So is mid-foot for everyone? Not by a long shot. But don't write it off just yet.

Price: €499
Weight: 348g/pair (sz42)
Pros: Fantastically light yet superbly rigid overall, ultra-low stack height, mid-foot cleat position seems to work as advertised
Cons: Disappointing finish quality, non-adjustable cleat position, some point flex in sole, unpadded straps, space-age aesthetics, mid-foot position yields lots of toe overlap, hideously expensive
Cyclingnews rating: Click for key to ratings (the shoes); Click for key to ratings (the concept)
More information: www.biomac.biz



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Images by James Huang/Cyclingnews.com