Cannondale Lefty: Structure of the 2013 model

Hans-Peter Ettenberger

· 29.09.2012

Photo: Georg Grieshaber

Cannondale Lefty: Structure of the 2013 model

The single-arm Cannondale Lefty doesn't just look unusual - its design makes it technically unique. BIKE lab manager Hans Ettenberger explains the inner workings of the 2013 suspension fork.

The Cannondale Lefty has been technically revised for 2013. It is now called Lefty Hybrid, the addition to the name is due to the combination of needle bearing and plain bearing. Stiffness is the trump card. The figures speak for themselves: two triple clamps clamp a 40 millimetre thick tube (carbon or aluminium, depending on the version). A 32-millimetre tube runs up and down this tube, guided by needle bearings. The damper cartridge sits protected inside. One tube is lighter than two. This results in a weight advantage of around 300 grams compared to a comparable telescopic fork. The important change for 2013 is the water-tightness achieved through new bearings - resulting in longer maintenance intervals. Why doesn't everyone ride a Lefty? Firstly, you need a special frame or adapter, and secondly, 130 millimetres of travel is the limit. Less objective reasons: Not everyone likes the look, it takes longer to remove the wheels, and most riders find the steering behaviour peculiar when riding freehand.

Photo: Hersteller Cannondale Lefty: the inner workings of the 2012 suspension fork

1. the needle bearingsFour of them ensure the sensitive function of the fork. They now reset automatically when they have travelled. Previously, this required a small intervention.
2. the plain bearing (green) supports the needle bearings, especially when the fork is deeply compressed. It also increases stiffness.
3. the scraper ring or the new lip seal (pink) keeps the dirt out and the oil in. The needle bearings run in an open oil bath in 2013.
4. mudguard instead of bellows. One thing is certain: the 2013 fork looks better thanks to the motocross style. You can finally see the suspension travel used on the rubber ring.

THE FUNCTIONAL PRINCIPLE OF THE LEFTY

On the Lefty, the dip tube and standpipe have four needle bearings (green graphic). The damper cartridge is on the inside. Torsion of the tubes against each other is impossible compared to a conventional suspension fork (red graphic). The response behaviour also benefits from the needle bearings.

Photo: Hersteller On the Lefty, the dip tube and standpipe have four needle bearings (green graphic). The damper cartridge is on the inside. Torsion of the tubes against each other is impossible compared to a conventional suspension fork (red graphic). The response behaviour also benefits from the needle bearings.

OLD and NEW

Only in the lower, visible area is the 2013 fork round instead of square (right). The inner workings, in the area of the needle bearings, retain the square cross-section. The new seal, made possible for the first time by the round cross-section, makes the bellows superfluous.

Photo: Hersteller Only in the lower, visible area is the 2013 fork round instead of square (right). The inner workings, in the area of the needle bearings, retain the square cross-section. The new seal, made possible for the first time by the round cross-section, makes the bellows superfluous.

THE CONSTRUCTION MAKES THE DIFFERENCE

Photo: Hersteller The Lefty beats conventional telescopic forks in terms of torsional rigidity.

While the distance between the plain bearings on the telescopic fork remains the same during compression, it increases on the Lefty and also ensures the lowest possible flex here. This shortens the distance to the wheel (leverage is reduced). As a result, the sensitive response behaviour is maintained even deep in the suspension travel.

Photo: Hersteller While the distance between the plain bearings on the telescopic fork remains the same during compression, it increases on the Lefty and also ensures the lowest possible flex here. This shortens the distance to the wheel (leverage is reduced). As a result, the sensitive response behaviour is maintained even deep in the suspension travel.