These wild, Italian-made alloy MagneticDays Forza Pura cranks spin everything you know about pedaling a bike on its head. Developed to force cyclists to pedal perfect smooth circles with both legs, the Forza Pura crankarms disengage from each other, making each leg deliver power to the chain separately.
MagneticDays Forza Pura cranks spin separately to refine pedal stroke
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While looking into MagneticDays’ premium Jarvis indoor smart trainers (more on those soon), we came upon these even wilder Forza Pura alloy cranks. Born from the idea to improve pedaling efficiency by refining the pedal stroke of each leg, these crankarms can be completely disengaged from each other.
With each leg able to separately put power into the drivetrain, a rider is forced to develop a smooth, circular pedal stroke without relying on one leg to make up for the shortcomings of the other.
The crazy cranks were a project developed with ultra-endurance athlete Nico Valsesia, who used them to refine his pedal stroke in the lead up to several of his From 0 to… attempts, cycling from sea level up until he transitioned to running on foot to ascend high peaks with massive vertical altitude gains in Europe and around the world.
The bulky (and expensive) crankset is CNC-machined in Italy from 7075-T6 alloy aluminum, and anodized in nice bright read for everyone to see. Because you aren’t going to hide these monsters anyway. And don’t ask how much they weigh. At least that weight is as low as possible on your training bike.
Simple “Fast & Easy” locking levers on each arm allows you to disengage, then re-engage each arm from the drivetrain independently. With separate bearings & ratchets in the oversized center of each arm allowing either crankarm to freewheel while the other is pedaling power into the chainring spider and subsequently into the chain.
The entire system is said to work with almost any bike. The cranks attach with a seemingly conventional square taper bottom bracket interface, and MagneticDays selling compatible BBs to fit most bikes. The cranks also feature a classic road compact 5-bolt 110mm BCD to work with many available chainrings. Crank length appears to be adjustable with an eccentric pedal thread insert, offering 170, 172.5 & 175mm lengths.
MagneticDays also has a number of Forza Pura-specific training plans. Or you can simply work on your pedal stroke & separate muscle groups independently, training one or both legs at a time, indoors or outdoors. Then, flip the levers back to engage both legs together and continue riding normally.
MagneticDays Forza Pura – Pricing, rental & payment plan options
First off, the MagneticDays Forza Pura cranks aren’t cheap. At 1200€ to get their training benefit, it’s a pretty big leap to make. But, MagneticDays understands that too, so they offer a couple of ways to make it more palatable. Rent the cranks for one month to see if they really benefit you for 100€. Then if you feel like they are a boost to your training, you can buy them outright for another 1150€, or pay them off in an installment plan over 22 months that will add just 50€ extra in total.