For all riders who want to feel that all their effort is being translated into speed, a carbon fibre sole is almost a prerequisite feature of a shoe. Normally to get a shoe that incorporates a full carbon sole would involve shelling out three figures but the B’Twin 700 Carbon costs less than ninety quid. So the question to ask is, how can B’Twin do it?

Good looking

The 700 Carbon is definitely good looking. The upper has a slim and expensive looking profile, dominated by the BOA-esque twin dials and massive B’Twin logo emblazoned across the rear half. Matt black is the right option for a shoe designed to be used in muddy race conditions, and with minimal mesh venting they wipe clean relatively easily. The tiniest of rubber toe bumpers is present to help protect the toes and shoe material from rocks and debris. Although somewhat vague in their action the Atop dials held up to typical abuse.

Matt black uppers with twin Atop dials for retention.

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Super stiff carbon

At the heart of the 700 is the aforementioned super stiff carbon sole. There is practically zero flex across the entire unit, not even at the tips of the toe box. Carbon fibre is used as it can produce stiffer soles that are much lighter and thinner than a nylon/plastic unit. There are different qualities of carbon, however. The type used in the 700’s sole is relatively thick and heavy in comparison to that found on higher priced shoes. It is also of a very flat, uniform shape where it meets the foot. This reduces the cost of manufacturing but does nothing to support the foot through the pedal stroke.

The super stiff carbon sole in all its glory.

Falling short of the mark

Maybe I have been spoilt by the quality of most MTB shoes I have worn recently but the 700 Carbon failed to live up to my expectations. Normally B’Twin kit stands out as offering decent performance for great prices.But in the case of the 700 Carbon, it feels like it’s being made to a budget. That’s not to say that it fails completely, but that it falls short of the mark.

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On the plus side the 700 Carbon feels really comfortable when the dials are tightened; the seamless inner construction, thicker materials and padded rear end minimise any tight spots and cradles most of the foot snugly. However, a really stiff sole needs an upper that can hold the foot firmly in place. And this is one of the areas that the 700 Carbon fails to deliver. The heel cup just doesn’t hold the foot securely enough, reliant as it is on only padding and a bit of silicon to cradle the heel. This heel lift is noticeable with every pedal stroke and effectively negates any advantages that a carbon sole brings.

Deep lugs are bonded to the carbon for off-bike grip.

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Pedalling dynamics

The other critical issue brings us back to the shape of the sole. Our knowledge of cycling biomechanics has improved to now understand that the foot needs to be supported during pedalling. This is to prevent unwanted movement and potential injury. Whilst this might be more relevant for road racing rather than enduro racing, it is still important that your shoe delivers at least some arch support. In the case of the 700 this is minimal, so it really does feel like your foot is pushing against a flat plate rather than being cradled.

The good news is that this can be improved by adding some better insoles such as the Specialized BG versions, but this additional purchase would obviously bump up the overall investment.