What’s different between indoor trainers?
Turbo trainers (traditional and smart), rollers and static bikes are the varieties of indoor trainer currently available. Briefly:
Traditional: Attach your bike to the turbo via the quick release of the rear wheel, which sits against a roller connected to a resistance unit (air, fluid or magnetic). The mechanism by which you change the resistance whilst you train will vary depending on the cost of the trainer.
Smart trainers: Similar to the traditional turbo in set up, but the indoor resistance units on these interact with software (e.g. Zwift and TrainerRoad) and control the resistance you feel when pedalling. These types of trainer also ‘measure’ your power.
Rollers: Exactly as they sound – a metal frame containing three rollers. These take some skill to ride on, as the bike isn’t attached to anything, so you have to have good balance and bike handling skills.
Static bikes: Those things you mainly see in the gym or spin studio. We’ll just leave it there.
What does ‘low inertia’ mean?
Right. SCIENCE. We love Science at Jam. Science means prizes…or something. Anyway, the definition of ‘inertia’ is this: (Ahem) A property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force. (Ignore the bit about rest, because honestly if you’re just chilling on your bike on the RevBox, then we can recommend a variety of significantly more comfortable places to sit). So…'remains in uniform motion' is the bit that interests us.
Something will remain in uniform motion because it is carrying momentum; so, high inertia means more momentum and low inertia means less momentum.
Training on a RevBox is a lot like riding into a headwind. You won’t receive any assistance from the turbo itself, so you do all the work. This means pedal technique and power transfer are optimised because you rotate the cranks with a natural and unhindered action, and momentum won’t build up in the system and throw your legs around the pedal stroke.
Still none-the-wiser? OK. Imagine a group of you are on a weekend ride and a pretty severe head wind has picked up. You sit on the front (because you’re a top human) and pedal your socks off into the wind that is directly opposing your effort, so there’s no momentum carrying you forward, only the force from your muscles (a low inertia situation). If you stopped pedalling, you’d come to a halt pretty sharpish.
The lucky lads and lasses behind you, however, were benefiting from your slipstream and, without a face full of headwind, were building up some sweet momentum meaning that, for a fraction of the effort, they’re moving forward at the same speed as you.
What are the benefits of using a direct mount turbo trainer?
The turbo trainer is directly connected to the drive chain of the bike, which results in a low friction mechanical connection between the bike and the fan. The fan displaces a large volume of air and provides the exponential resistance for you to train against. The whole set up makes for a smooth ride and encourages efficient pedalling technique.
Additionally, you don’t have to deal with any of the other issues associated with training on a turbo with your rear wheel on, such as distorting said wheel, wheel slippage and punctures!