Last year we covered the surprisingly strong scientific evidence
that, despite popular opinion, shorter crank arms don't compromise a rider's power output or pedalling efficiency, and in fact, may offer certain biomechanical advantages when compared to typical 170 or 175 mm cranks.
After making shorter cranks for e-bikes, Hope Technology have been experimenting with crank lengths over the last year with staff and athletes, going as short as 140 mm. They say that 155 mm is "the sweet spot" for mountain biking. As a result, a 155 mm version of their Evo crank is now available to buy.
Hope Say the shorter cranks offer the following advantages:
• "Body weight remains more centred on the bike increasing stability and making it easier to shift your body weight around."
• "Quicker to 'spin up' which can help when transitioning from descending to sudden steep uphill features." (This claim is supported by this study
• "More ground clearance for reduced pedal strikes."
• "Lighter and stiffer due to shorter length."
Other than the length, the specs remain the same as Hope's other Evo cranks. They use 30 mm diameter axles with axle lengths to suit most bikes from XC, DH, SuperBoost and Fat bikes.
Because shorter cranks reduce the overall leverage between the pedal and the tyre, requiring a faster cadence, Hope recommend dropping your chainring size by 2 teeth for every 10mm reduction in crank length. So, if you'd normally run a 34-tooth chainring with a 175 mm crank, you'd want a 30 -tooth ring with a 155 mm crank. Hope make chainrings as small as 28-tooth. Note this will also increase ground clearance when the cranks are level.
The Evo 155 is in stock at dealers now. Pricing (RRP)
Inc. Axle and Spider: RRP £290 / €360 / $365 (ex tax)
No Spider: RRP £255 / €320 / $320 (ex tax)
For more information, go to hopetech.com