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MEP PRO patented technology

During the pedalling, our body exerts a force over the pedal at a certain distance from the crank arm. This happens for both legs indipendently of each other, whereas the combination of both movements allows to complete a full turn to the pedals. Power and nimbleness are also influenced by the length of the crank arms.

A full qualified pedalling analysis requires to know not only how much strong we push, but especially how we do that during the entire stroke of each leg. With this data, Biomechanics own objective quantities to compare different bike setups, perform accurate ergonomic analysis, and fit the athlete on its bike preventing injuries.

In years of intensive work and experience in the electronic instrumentation of bike components, Studio AIP brought out and then patented the MEP PRO technology: for each leg, the pushing (and pulling) force is directly measured along the entire pedal stroke at high sampling rates; at the same time, the position of the pushing force is precisely measured.

The MEP PRO system main innovation is tied to the separate, indipendent, and detailed measure of the full behaviour of each leg.

Representation of the parameters measured by the MEP PRO system
MEP PRO technology allows to precisely and accurately measure both the pedalling force and the position of the foot along the pedal axis

Estensimetric instrumentation of crank arms

While turning the pedals, the force exerted by the foot is transmitted to the ground through:

  • shoe/cleat
  • pedal
  • crank arm
  • spindle (only the left side)
  • spider
  • crowns
  • chain
  • pinions
  • hub/wheel

Among these components, only the first three allow to measure both the force and its position distinguishing between the two feet. In order to perform such measures in a direct and reliable way, it is necessary to measure near the phenomena. But not too much: other factors must be taken into account affecting the measures. Each mechanical coupling (e.g. hook, junction, bearing, etc.) is a source of local phenomena that gradually disappear with the distance.

More precisely, during the pedalling each component is subject to internal mechanical stresses which are not uniform. Their intensities vary according to the specific geometry of the single component and to the proximity to meachanical couplings. Electronic components known as extensimeters exploit this stresses to provide accurate measures of the parameters we target. The more concentrated and distant from the couplings is the stress, the better the measure is.

This is the main reason that addresses us to instrumenting crank arms. As shown in the picture, Studio AIP engineers expressively designed MEP PRO crank arms concentrating mechanical stresses as near as possible to the point where foot force is applied, while far from the couplings. This results in a precision of about 0.5 % for the power and sub‐millimetric for the position of the force, thus particularly suitable for Biomechanical analysis.

Stress analysis of MEP PRO crank arm
MEP PRO crank arms are designed to concentrate mechanical stresses (in red) in a specific area, where they are accurately measured

Length adjuster

With MEP PRO crank arms Biomechanics can experiment against different lengths without replacing the entire crankset. Each MEP PRO crank arm integrates a length adjuster ranging from 165 mm to 180 mm, while a clicking mechanism identifies conventional lengths in between. Playing with the length adjuster does not require to disassemble any other component.

This device is designed to preserve the precision of the measures of the MEP PRO system.

Length adjuster of the MEP PRO crank arms
MEP PRO length adjuster enables you to change the crank arm length from 165 mm to 180 mm without disassembling the pedals