Indoor Trainers and Rollers 101

Bikewagon - BWCC

Few people who ride bikes like to do it inside, but sometimes it's a necessary evil if you want to keep up your fitness. While there are several ways to ride indoors, this article will be about using trainers and rollers.

Trainers are devices that basically turn your current bicycle into a stationary exercise bike. Some people get exercise or spin bikes to train inside, but many people like to use their current bike since they're already familiar with it and they're usually cheaper if you already have the bike.

Rollers are another option. They require a little more skill than trainers. The biggest difference between rollers and bicycle trainers is that with trainers, pretty much the only thing that moves is the rear wheel. Everything else is fixed in place (yes you can turn the front wheel but it doesn't do anything). On rollers, the whole bike is allowed to move and only the rollers stay in place. You don't move forward, but you can move side to side.

Trainers work by clamping your bike's rear axle into into the trainer's frame. Then the rear wheel spins a drum that in turn actuates the resistance unit. A roller is a set of three drums that spin in a metal frame; the bike sits on the metal drums. There is a belt that runs from the drum the front wheel sits on to the front drum at the rear. The bicycle's rear wheel sits between the rear drums, and the front wheel sits on the front drum, the wheel axle just behind the axle of the drum.


There are three primary types of rear-wheel trainers based on the resistance type used. Wind trainers are the entry level trainer, followed by mag trainers and then fluid trainers. There are also computer based trainers, but we'll give them their own section because they have very different capabilities than the other three.

Wind trainers are the most basic level of trainer. They use a fan to create resistance -- air resistance being the opposing force. They don't allow much adjustability of resistance and don't allow much resistance at all in general. They are much cheaper than the other options. They also tend to be a little noisier.

The resistance is created by the spinning fan pushing air. The faster the fan spins, the more air gets moved, and thus the more resistance. This means that by shifting gears, you can create more resistance as the rear wheel travels faster. This same principle applies to all of the trainers, including the rollers as well.

Mag trainer

Mag trainers are the next step up, giving you many more options than wind trainers. Mag trainers use magnetic forces to create the resistance to the rear wheel. They often have different levels of resistance selected via a switch. Some have a remote switch that you can mount on you handle bars so you can select between resistance settings without having to get off the bike. Mag trainers are a little quieter than wind trainers but can still be quite loud if you're hammering it.

Most mag resistance units are similar, but some are a little more finely tuned, and the price is usually a bit higher for the extra features. What is meant by "finely tuned" is that the resistance curve is tuned in such a way that it feels more like riding in real-world conditions. Mag trainers have a tendency to have a flat resistance curve, meaning as the speed of the rear wheel increases, the resistance doesn't ramp up as fast as it would if you were outside riding. The more finely tuned mag trainers try to better replicate the resistance curve one might feel while riding outdoors.

Fluid trainers are considered the best mechanical trainers available. The resistance is created by a flywheel spinning inside of a case filled with fluid. This creates a very realistic feel to the trainer as the resistance ramps up fairly quickly as the speed of the rear wheel increases, giving a more true-to-life resistance curve than the other trainers. They also tend to be the quietest trainers.

Some of the higher-end fluid trainers also allow power measurement to be taken. This is very important for cyclists that train for sport -- or anyone who wants to know their power output -- since direct power measurement is the most accurate form of measuring your workload.

For all of the trainers, resistance can be adjusted some by tire pressure and the force applied from the drum pushing on the tire. Tire widths can also vary the resistance.

Computer-based trainers

Computer-based trainer

Computer-based trainers are on a completely different level. They are typically much more expensive but have a litany of extra features. The resistance unit is typically a motor that is essentially a brake. It can also accelerate the rear wheel. This is a very important feature because the computer based trainers allow virtual rides so they almost exactly replicate a real-world course. Some allow turning of the front wheel to steer, but the biggest advantage of the computer-based trainers is the ability to get a real world feel or to “pre-ride” a course without leaving your home.

Some of the computer based trainers use online sources (like Google Earth) for obtaining maps, while some require previously created maps to work. The benefit of the ones that use online sources is that you can ride pretty much any course that can be mapped out on Google.

The biggest catch to the computer based trainers is that you also need a good computer that can run them. This means that on top of getting the already expensive trainer, you also need to have a computer that is powerful enough to run the virtual reality software. Sometimes you will also need to buy the software for the trainer, though it is often included with the trainer or can be bought in a bundle option.


The drums are either made of aluminum or a plastic-like material, the metal drums being better in general. Some drums are also slightly ramped towards the center of the drum or just at the ends of the drum, referred to as parabolic rollers, making it easier to stay in the center of the drum, which is sometimes attractive to riders new to rollers. This makes it harder to ride off the edge of the rollers, which generally isn't a good thing.


A bike is free-standing while on rollers, so nothing holds the bike up. To start using rollers, many riders will use something to hold themselves while they get the wheels spinning. If you haven't taken a physics course, this may seem very strange, but I'll lightly run through the mechanics.

When the wheels spin, a force is generated that is perpendicular to the wheels. This perpendicular force keeps the bike upright. The faster the wheel spins, the more force is created. this means that faster the wheels are turning while on rollers, the easier it is to stay on the rollers.

To start using rollers, many riders will use something to hold themselves up to get the wheels spinning. More advanced riders will get the wheels spinning and then hop on while keeping the wheels moving. For beginners, it is recommended to start between something like a doorway so that you can lean against the door frame or walls (if in a hallway) while you get used to the feel of the bike on rollers. Steering inputs tend to get over exaggerated by the rollers, which takes some getting used to.

Resistance for rollers is mostly created by tire pressure and wheel speed. Rollers in general don't tend to have a lot of resistance when compared to trainers, but adequate to get a good workout. They do offer other benefits as they allow a more road like feel in that you're not locked into place. This trains pedalling smoothness and the stabilizer muscles that may see limited use during a trainer session.

There are resistance units that can be added to create additional resistance. These either use a magnetic bar on the back of the roller's frame, close to the rear drum, or a fan unit that is connected via a belt that is like adding a wind trainer onto the rollers.

A new development for rollers is a special rear drum that creates resistance from inside the drum using magnetism. It's currently only made by Sportcrafters and creates a fairly real resistance curve and greatly increases the resistance of the rollers as a unit.

There are some rollers that are much more complicated, where the roller frame moves inside of another frame so that the bike can move front to back as well. They tend to be easier to ride but are much more expensive. They create a very realistic ride feel, since regular rollers take a little more finesse to ride than riding outdoors.

Trainer accessories

You may want to consider a few trainer accessories if you're using a trainer a lot. One is a bike thong (think sweat catcher) or a towel to help keep sweat off of the bike. The salt in the sweat can be quite damaging to the metal parts on the bike, especially in the headset area where a lot of sweat would tend to fall.

A floor mat makes riding on carpeted areas or spots where the trainer may slide a nicer area to train on. Along with giving more grip for the trainer to sit and pushing the carpet down a little for clearance (for rollers), the mat also keeps the large amount of sweat you're likely to expel off the floor.

A fan is probably the best accessory you can get because you will heat up quickly if you start putting in much effort at all. You don't need anything fancy with a lot of settings, just something that moves a lot of air to keep you cool.

There are also training videos that will help improve the experience of being locked into place while using a trainer, as it can be mind-numbing at times if you are spending a lot of time indoors training during the winter months.

Trainers are a great way to get your training during times of bad weather or when you don't feel like going outdoors. They're also good for getting a very specific workout if you don't mind training indoors. There are benefits to getting the higher priced models... if you're going to use them often enough to justify the expense. Happy riding.