The physics of flywheels tells us that if you take a heavy flywheel and double its weight it will store twice as much energy if you keep the speed the same. This is the key point that you need to remember when thinking about the Keiser flywheel. Interestingly, the laws of physics tell us that large diameter and heavy flywheels store more energy than smaller diameter and lighter flywheels. However, flywheels that spin faster store much more energy than ones that spin slower. Kinetic energy is a function of mass and speed, flywheels can therefore come in all different shapes and sizes. Flywheel Designs – The Different Options Available and What is the Best Designįor the flywheel to perform its function correctly it needs to store a certain amount of kinetic (moving) energy to accurately simulate the smooth pedal motion of a road bike.Ī “good” flywheel will typically take some force to set it spinning (think of the force required to get an outdoor bike going) and will typically take some force to make it stop (think of how your outdoor bike will keep going for a while once you stop pedalling, unless you apply the breaks of course). If there was no flywheel, or an ineffective flywheel on your spin bike, it would be very uncomfortable to ride, and could eventually lead to the rider developing an injury. In addition, if you think of the initial feeling of resistance you experience when you start to ride a bike outside – that is the feeling the flywheel on an indoor bike is trying to replicate. By having some momentum built up in the flywheel, you have less slowing of the pedal stroke and a more consistent pedalling action. At the point when your pedals are horizontal you are exerting maximum force, but when the pedals are vertical (straight up and down) you are applying a lot less force and the wheels can start to slow. Specifically, on a fixed gear indoor spin bike, the amount of force you can exert changes during the pedalling motion.

The flywheels job is to help to simulate the feel of an outdoor bike – it does this by storing energy which is then used to smooth out the cycling motion to promote a consistent cadence (the speed at which your legs spin as they pedal). It can be found at the back or the front, and is the most prominent feature on most spin bikes. The Flywheel is the big round disc that spins around underneath the bike. What Is the Flywheel on a Spin Bike and What Does It Do?įirst off, let’s get this out there in case you are a complete beginner, looking to get into spinning. In this article Groom+Style will explain why this light flywheel myth is incorrect, at least when it is applied to a high end, well engineered spin bike like the Keiser.

The story goes that light flywheels do not create enough inertia which can cause some riders to develop an “up-down” or choppy pedal stroke – which in turn can lead to stress on joints and ultimately injury. This has caused a few readers to question how Groom+Style can rate this bike so highly when there is quite a bit of older information “out there” mentioning that heavier flywheels are better.

Flywheel spinning bike