Indoor exercise bikes: how to choose one you will use
An indoor bike is the piece of exercise equipment most often bought and least often used. That is not a failure of willpower: it is usually a failure of the machine, bought on price without knowing which specifications decide whether it is pleasant to sit on for 45 minutes.
This guide covers the three things that actually matter — resistance, adjustability and noise — and the traps that turn a cheap bike into a clothes horse.
Resistance: the first decision
Indoor bikes use one of three resistance systems, and the difference between them is bigger than any other specification.
Magnetic resistance
A magnet moves closer to or further from a flywheel to change resistance. It is quiet, smooth, and consistent, and the resistance does not wear out because nothing touches.
Two variants: manual (a knob you turn) and electromagnetic (a motor or console controls it, sometimes following a programme). Manual magnetic is the sensible default for home use; electromagnetic is what you need if you want the bike to change resistance automatically during a workout.
Magnetic is the right choice for a flat, a shared house, or anyone who trains early or late.
Air resistance
A fan attached to the pedals pushes air. The harder you pedal, the more resistance — which feels natural, and provides a cooling breeze. It is also loud, and the resistance curve cannot be changed: there is no easy gear.
Air bikes suit rowers, sprinters and people doing interval work in a garage. They do not suit a flat with neighbours.
Friction (felt pad) resistance
A pad presses against the flywheel. It is the cheapest system, and it is the one to avoid if you plan to use the bike regularly: the pad wears, the resistance becomes inconsistent, and it gets noisy as it ages. It is what you find on the £30-80 bikes, and it is why those bikes feel different after three months.
Adjustability: the reason people stop using it
An indoor bike that does not fit you is a bike you will ride twice. Four adjustments matter:
- Saddle height. The same rule as an outdoor bike: with the pedal at the bottom, the leg should be almost straight with a slight bend.
- Saddle fore and aft. To get your knee over the pedal axle.
- Handlebar height. This is where indoor bikes often fail: many cheap ones have a fixed bar height, which forces a hunched position for taller riders.
- Reach. Some bikes allow the bars to move fore and aft; most do not.
Check the rider height range in the listing, not just "adjustable". A bike that claims to fit 150-190 cm with 10 cm of saddle adjustment is not telling you the truth.
If you are between 175 and 190 cm, bar height is the specification to check first, because it is the one that cannot be fixed afterwards.
Noise, which matters more than you think
In a flat, noise decides whether you use the bike at 7am. Magnetic is quiet (a soft hum); air is loud (a fan); friction is quiet when new and noisy when worn.
If you live above someone, also consider a mat under the bike. It absorbs vibration, which travels through floors more than sound does.
Stability and weight
Every other category on this site rewards light bikes. Indoor bikes are the opposite: heavier is better. A 20 kg bike with a heavy flywheel feels smooth and stable under hard efforts; a 12 kg bike rocks and skips.
Flywheel weight is the number to look at. 6-8 kg is entry level and feels choppy; 10-15 kg feels smooth; above 15 kg is studio-grade.
What the console is worth
Many listings lead with the console: heart rate, programmes, apps. Be realistic:
- Basic display (time, speed, distance, calories): useful, and all most people need.
- Heart rate straps and pulse grips: the grips are unreliable; a chest strap is accurate. If heart rate training matters, budget for a strap separately.
- App connectivity (Bluetooth/Zwift): genuinely useful if you train with apps, and worth paying for if you do. If you do not, it is a feature you will never use.
- Built-in programmes: rarely used after the first month.
Do not pay a premium for a console. Pay it for the frame, the flywheel and the resistance.
What to check before buying
- Resistance type — magnetic, ideally.
- Flywheel weight — 10 kg or more for a smooth feel.
- Bar height adjustment — especially if you are tall.
- Rider height range — and whether it is credible.
- Maximum user weight — check it against your weight with margin.
- Noise — magnetic unless you have a garage.
- Footprint and folded size — measure the space before you buy.
The honest summary
Buy magnetic resistance, a flywheel of 10 kg or more, and a bike that adjusts to your height. Skip the console features, skip friction resistance, and skip anything that does not state its maximum user weight.
A £250 magnetic bike used three times a week is better value than a £90 friction bike used twice. The cheap one is not a cheaper version of the same thing; it is a different, worse machine that will put you off.
If you are buying to train seriously rather than to keep fit, budget £400 and up, and consider a bike that takes a standard saddle and pedals so you can swap them for ones that fit you.