Resistance is the most crucial component of a turbo trainer and is where trainers vary a large amount.
The type of resistance affects the feel of the ride, and the higher the specification (and price) the more natural it feels when pedalling.
Most turbo trainers offer something in the way of adjustable resistance, whether on the unit itself, via a handlebar-mounted control, or in the action of the flywheel.
Remember, though, you can adjust how hard you are working on a cheaper turbo just by using the gears on your bike. Listed below, however, are the technological options on offer.
The original turbo trainer technology, using a plastic fan to generate wind resistance.
While affordable, it's a noisy solution - like Concorde taking off, in the worst cases - and offers limited adjustability, so air resistance turbos are increasingly uncommon.
You're now more likely to see magnetic resistance turbo trainers at the low-to-mid end of the market.
These units use a metal plate which spins inside a magnetic field, creating a ride sensation which is smoother than an air resistance turbo, but not as silky as a fluid resistance trainer.
Most magnetic turbos offer adjustable resistance, on the unit itself on cheaper models (which is a pain if you want to change the unit resistance mid-session), but normally by way of a simple handlebar-mounted, cable-operated lever which moves the magnet to create more (or less) resistance.
A lot of magnetic turbos will have a built-in fan which cools the flywheel (the Tacx Booster, for example
), but those that don't, like the Minoura V130
, can get extremely hot so give it time to cool down after use.
Another step up in price, a fluid turbo uses an impeller (fan) revolving in oil to create resistance. It's a quiet and smooth solution, but usually expensive, too.
Many offer resistance adjustment by a handlebar-mounted lever which adjusts the flow of oil, though the CycleOps Fluid 2
, intorduced in 2012, is a progressive unit which increases and decreases resistance in response to changes in wheel speed.
If you need a little more to enliven your indoor training experience, top-of-the-range turbos use electromagnetic resistance to offer a virtual reality riding experience where the world is your oyster.
It's an expensive option, and one for only the most committed of turbo riders, but many allow you to hook the turbo up to a television or PC to ride, for example, a Belgian cobbled climb or Tour de France stage, while the BKool trainer, which impressed us back in 2012
provides Strava-like feedback to motivate your winter riding.
Most electromagnetic resistance trainers offer an array of training data, sometimes including power output.