Essax Shark saddle claims to keep riders sitting straight

40mm fin will even out pedal stroke and cut injury, claims inventor

A biomechanics specialist with links to the Movistar team has developed an eye-catching – and eye-watering looking – new saddle with a central fin to keep the rider sitting straight and true while they pedal.


Jon Iriberri of bike fitting specialist has developed the high performance Essax Shark saddle to help riders correct a contorted position.  

Iriberri says a misalignment on the saddle can have a number of unwanted consequences: a rider could be placing more weight than necessary on the soft perineum instead of the two sitbones; it could lead to riders favouring one leg over another and may lead to joint injuries.

He said that a number of developments, such as shorts with more padding, wider saddles or those with central cutouts and channels, treated the symptoms and not the underlying cause of poor posture.

Iriberri concedes the 100mm long by 40mm high fin may look aggressive but says if a rider is positioned correctly – to put it delicately, that means it fits snugly between the cheeks – they can’t feel it. The moment they deviate from the perfect position however, the saddle lets them know.

So convinced of the saddle’s benefits, Essax, the Spanish company who produce Iriberri’s design, have sent the Shark saddle to the UCI for approval. We’d love to have been a fly on the wall when the technical team opened that particular parcel.


The saddle is designed for the performance market and Essax claims it weighs less than 200g.

The essax shark saddle aims to make riders sit straight . or else.: the essax shark saddle aims to make riders sit straight . or else.