The hardest part when learning to ride a bike is balancing it on two wheels, and what makes a bike easier to balance? Speed. It’s true. The gyroscopic nature of a wheel means that when it picks up speed, it’s easier to stay in a straight line.
This must be the train of thought with the new Mondraker Grommy, a two-wheeled balance bike, like a Strider, but with a motor. Either that, or the bike industry is trying to get people on e-bikes as early as possible.
“The new Mondraker Grommy elevates the balance bike category to a whole new level, with its innovative and expertly delivered electric motor power and advanced frame and components, creating the first true e-balance bike.” The Grommy is available as a 12- or 16-inch wheeled bike for youngsters, with a 250W “power unit,” which Mondraker says is easy to control.
The Grommy is made from 6061 alloy in Alicante, Spain. The 12-inch model is intended for kids aged 3-5 and 16-inch is intended for kids aged 5-8. Like other Mondraker bikes, even the Grommy sees some of the brand’s Forward Geometry.
There is internal routing for the rear Tektro disc brake and the motor is connected to a twist grip on the right-hand side. Mondraker says that it is a “throttle-style power mode selector.”
The battery unit is capable of 60-minutes of run time on a full charge. The charge also takes about an hour, but Mondraker says batteries can be easily swapped.
“Mastering the three-speed controls is child’s play. The learning starts on the first setting, ‘Balance’ (max speed 8.1km/h, 5MPH) and the grins get broader on 2 and 3: ‘Fun’ (12.1km/h) and ‘Advanced’ (max 17.7km/h, 10.5MPH). Or turn off Grommy’s motor and kids can use it like a traditional balance bike.”
The motor and battery are IPX4-rated and water-resistant and the Grommy has standard componentry like saddles, seatpost, handlebars, stem, and disc brakes.
The Grommy will sell for 749€ and comes with a 2-year warranty. It does not look like it will be available for sale in the US. See the Mondraker website for more info.
Quick specifications
Grommy-12” – 190mm frame, 12-inch wheels, weighs just 7.5kg, with saddle height range 37-47cm, for riders aged 3-5 years
Grommy-16” – 250mm frame, 16-inch wheels, weighs just 8.5kg, with saddle height range 43-58cm, for riders aged 5-8 years
Both models feature:
- Superlight Mondraker Alloy Frame & Fork
- Three power modes: ‘Balance’ (max speed 8.1km/h), ‘Fun’ (17.7km/h) and ‘Advanced’ (17.7km/h)
- Quick-change 4Ah battery: 60 minutes run time, 60 minutes full charge time
- Integrated base footrest
- ‘Big bike feel’ MTB standard componentry and compatibility
- Internal cable routing
- Mechanical disc brake
It isn’t gyroscopic effect that stabilizes a bicycle, especially with wheels this size. You really ought to know this as a bike reviewer.
You left us hanging! If it’s not the gyroscopic effect, then what is it?
Also, while a physics degree might be helpful, it’s not required to review bikes. Haha!
From several sources after googling “why is a bike more stable when it’s moving”: There are two theories as to how the bike keeps itself upright. One is the gyroscopic theory, where the spinning wheel provides enough stability to stop the bike from falling.
Please elaborate Chris, or try it at home. Stand a wheel up and let go while it’s not moving. It falls down. Roll it down the street and when it picks up enough speed it will continue to roll.
When a bike starts to tilt to one side it has to steer into the direction it is leaning. That is the only requirement for self-stabilization. All normal bikes do this by having a sloping head angle which, when combined with positive trail, lowers the center of gravity by steering in that direction, effectively falling into the turn faster than it actually falls over, thus staying upright. This also explains why at low speed bikes are less stable.
Experimental bikes have been made with things like zero gyroscopic effect and rear wheel steer that are also able to self stabilize using that primary principle.
While it might be the only requirement, it still doesn’t really invalidate what’s said… I didn’t say that the gyroscopic effect was solely responsible for a bike staying upright, just that it helps.