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Our superlight, innovative and high-quality children's bikes offer your child no end of safe riding fun.

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What makes the components on our woom mountain bikes so special – Part 4: The Drivetrain

For part four of this series, we're shifting our focus to the child-specific drivetrain on our woom mountain bikes. Keep reading to discover what makes up the drivetrain and how we've engineered these components to meet the needs of young riders.

Hanna Stadler

The drivetrain on a woom mountain bike is made up of the two cranks, the pedals, the chainring, chain, derailleur and cassette, with either nine or eleven sprockets depending on the bike.

Putting our data-crunching into practice with premium materials

Right since the get-go, we've put years of research into determining the best-possible dimensions for all components, including the cranks, into order to develop the ultimate pedaling setup for kids. 

To suit child-sized hips and shorter legs, these are engineered with proportionally shorter crank arms compared to conventional adult lengths as well as a narrower distance between the pedals, known as the Q-factor. The result? Natural movement patterns that are kinder on the knees. Our move towards shorter cranks also takes away the risk of toe-overlap as well as unwanted pedal contact with the ground while taking the corners on a flowy descent. What's more, these flat pedals have all the qualities kids need while off-road: a wide footprint that features pointy metal pins to provide excellent grip even in the wet.

Mountain bikes don't get an easy life. Subjected to steep climbs, descents and almost-constant rough stuff under their tires in all conditions, each component has to have some built-in resilience to survive. Alongside demonstrating durability, they also need to provide comfort, safety and fun for long-term enjoyment. 

That why we smartly put together high-quality components and frame materials that form a cohesive, reliable and child-friendly unit. 

Note the forged aluminum crank arms and slip-resistant plastic pedals – not only do these contribute to reducing the overall weight, but also add longevity and tough-wearingness to woom mountain bikes.

The benefits of a narrow-wide chainring

The chainring is a key player in the drivetrain setup and sits directly on the driveside crank. It efficiently transfers the force that the child puts into the pedals to the back wheel. On our woom mountain bikes, this chainring is specifically developed for optimal power transfer.

Not only is it lightweight, but there's another benefit to the design of our narrow-wide chainring: with 28 alternatively sized teeth – hence the name narrow-wide – the chain sits better on the chainring to improve chain retention, even on rough terrain. For the rider, this means less frustration and more fun.

What's more, the narrow-wide tooth profile results in less wear from shifting as there is a more equal distribution of power, which adds up to a long lifespan for this component.

Child-specific design = more intuitive shifting on woom MTBs

As with all the components on our mountain bikes, we knew that easy-to-operate, kid-centric gearing was a must. That's why we settled on a SRAM groupset, which provides quick and accurate shifting thanks to its EXACT-ACTUATION technology and a reliable, smooth performance in all conditions – even those when it's so muddy and wet that the sofa may feel like a better option. When it comes to shifting intuitively between the gears, the rider has a thumb-actuated trigger shifter that's really easy to operate.

But why is there no visible gear counter?

Kids don't benefit from seeing which gear they're currently using. What's more important is that they tune into the sensation of when to change gear and develop an instinct for shifting higher or lower as needed. That's why we decided against adding unnecessary distractions , like a gear counter feature, and instead let them focus on the ride. As they grow up, they'll turn into skilled riders with a native understanding of how their bike responds and how their gears work on various gradients and surfaces.

The woom UP & its natural, intuitive motor

The woom UP features a child-specific electric motor from the German brand Fazua. It provides extremely natural-feeling and almost silent support that's a big asset for kids wanting extra power on longer rides or steep climbs. 

The 250 watt motor, which is subtly integrated into the downtube, gives out 55 newton meters of torque and tops out its moderate pedal-assist at 20 km/h. 

The intuitive handlebar-mounted display unit allows kids to switch between the four color-coded support modes: white for 0% support, green for 30%, blue for 60%, and pink for 100% power.

The free Fazua Rider App puts the option to customize the motor's output and the support modes at your fingertips. You and your child can use the app to personally modify the modes and check out the stats – how much power is given out in which modes, and how much remaining range until you need to charge it again. It also records and tracks your rides. The drive unit, consisting of the motor and battery, can also be removed, which allows you to ride the woom UP like a regular analog mountain bike.

What's the MTB component series all about?