Cyclists have two choices, they either give absolutely no [insert rude word here] and ride outdoors whether it’s blazing sunshine, torrential rain, or even freezing snow, or they have some sanity and stay indoors when the weather is just too rough outside.
Road bikes and the indoors don’t normally mix, but hey this is what turbo trainers are for…
WHAT IS A TURBO TRAINER?
Otherwise known as indoor bike or cycle trainers, turbo trainers are devices that hold the back end of your bike off the floor and thus when you pedal you do not go flying into the wall. Essentially they turn your road bike into an indoor exercise bike. They do this in two main ways, one is that your back tyre spins on a roller that is connected to a resistance unit or you remove your back wheel completely and fix your bike directly to the trainer and your chain powers the resistance unit. The first method is by far the most common, but direct-drive trainers (i.e. your chain directly drives the trainer) as they are known are becoming more popular.
As a rule turbo trainers have a few standard features, although how these features work do vary. Turbo trainers offer resistance as you pedal so that you do not simply spin your pedals as fast as you can with minimal torque/power. So the main part of the trainer is the resistance unit (AKA resistance brake), which transfers your pedalling energy into measurable power output. Also, when you are not pedalling (or even when you have started to spin your back wheel) you need to replicate the momentum that you feel when you are on the open road. To replicate this most trainers incorporate a flywheel (usually a heavy spinning disc of metal). In essence this is what a turbo trainer is.
How do you transfer pedalling energy into the resistance unit?
1. YOUR BACK TYRE SPINS A ROLLER
The standard way to generate resistance/power as you pedal is to push your back tyre against a roller. The skewer of your wheel is clamped to support arms (normally a spare skewer is supplied so you don’t damage your bikes skewer), and your tyre pushes against a roller. Some designs have a mobile frame (support arms) and this means the weight of you and your bike push down on to the roller, just like it would on to the road if you were outside. Other designs have rigid frames and the roller itself is pushed up and fixed against your tyre. There are pros and cons to each system.
Allowing your body weight (combined with your bike weight) to push down onto the roller in theory replicates normal cycling, so if you force down hard you get more friction and thus generate more power. Also, in higher-end units the resistance within the trainer can be calculated based on your weight so that you get a more accurate feel. One issue however is that if you get out of the saddle and transfer your body weight forward over your handlebars there could be the potential for slip between your tyre and the roller since the force between the two would be reduced. This could also occur if you generate a bouncing movement as you ride. Trainers are designed to minimise this slip but it is something that may still occur.
In the video below gives an example of a mobile frame from Elite. While each company will have their own exact designs the mechanism is pretty much the same across the board.
Trainers that physically lock your back wheel and push the roller up to it and fix it in place eliminate this potential slip and provide a consistent force between your tyre and the roller This may reduce the realism of riding outdoors where your body weight and centre-of-mass does not influence the feel of your ride, although this may not be a significant factor when physically cycling on the trainer. More sophisticated trainers that automatically control your resistance use body weight to calculate resistance values, which is something the fixed wheel frames cannot do as accurately.
The video below shows how fixed frame trainers push the roller up against your bike tyre. This video is by CycleOps, and while the ‘Clutch Knob’ mechanism may be unique to CycleOps the principle of all trainers like this is the same.
PROBLEMS WITH THE ROLLER SYSTEM
There are two primary issues with using rollers in turbo trainers. These are tyre wear and noise. Turbo trainers do wear your back tyre – THIS IS A FACT. Some designs wear less but they still wear. This is why it is recommended that you use a proper trainer tyre that are specially designed to wear less, or you should use a spare (cheaper) tyre while training for prolonged periods. For quick low power training sessions you will probably be fine with your standard tyre, but for longer and/or more powerful sessions you should replace your nice road tyre with a cheaper spare or special training tyre.
The mechanism of your spinning back tyre on the roller can create quite a bit of noise, particularly if you have some kind of tread on your tyre. Using a special trainer tyre that is harder and very smooth reduces this noise, so this is another reason why you should consider removing your nice bike tyre and using a special trainer tyre instead.
2. YOUR CHAIN POWERS THE RESISTANCE UNIT
Direct-drive turbo trainers use your chain and not your back wheel to drive the trainer resistance unit. You physically need to remove your back wheel and fix your folks to the trainer, and then wrap your chain over the cassette that comes with the trainer. Some designs do not have a cassette and therefore you use your actual bike cassette, although the former way is a lot easier to set up.
Instantly you remove two issues that tyre/roller trainers have, namely tyre wear and tyre noise. Don’t be fooled however, direct-drive trainers can still be pretty loud due to the resistance mechanism itself and also the noise of the chain on the cassette, but in theory they should be quieter than their counterparts. Also direct-drive trainers should be more accurate in terms of power output because you are driving the trainer directly from your chain thus eliminating any tyre slip issues and loss of energy between the tyre and the roller. The companies who make direct-drive trainers state that they are more efficient and accurate in terms of power transfer compared to the traditional spinning tyre trainers.
The following video shows you a direct-drive turbo trainer in action. This is the Turbo Muin trainer by Elite, but all direct-drive trainers operate in a similar way (albeit using different resistance technologies).
Direct-drive trainers are not without issues though. The main one is that is can be a hassle to remove your back wheel every time you want to use it. Some bikes are more difficult than others to do this, and if you are just looking to do a quick warm-up session it can be a drag. Also, direct-drive trainers are generally more high-end and therefore more expensive than some traditional tyre/roller trainers, and you will be hard pushed to find one that costs less than a few hundred pounds (or dollars).
3. RIM-DRIVE TRAINERS
There is also one other type of trainer called a rim-drive trainer, but this is very rare (in fact there may be only one major company doing this type of trainer – Elite). You keep your back wheel on so in this way it is comparable to the traditional type of trainer, but instead of pushing your back tyre against a roller there are two small wheels (casters) that push against the rim of your wheel. One of these caster wheels is linked up to a drive belt that in-turn is connected to the resistance unit. These trainers have decent but limited resistance and do not offer some of the power metrics, realism, and training versatility of the roller and direct-drive trainers, but they are very easy to set up, quiet, and cause zero tyre wear.
TURBO TRAINER RESISTANCE TYPES
Whether you choose a traditional roller or a direct-drive cycle trainer you have options when it comes to the technology that drives the resistance unit. Each technology has its merits whether that is price or features.
We’ll work through the different technologies in terms of sophistication, although this being said it does not necessarily mean in terms of realism or ride performance because some of the simplest tech does provide one of the best rides. The type of trainer refers to the mechanism by which the trainer (more specifically the resistance unit or brake) generates the resistance.
WIND (AKA AIR) TRAINERS
Wind turbo trainers use the most straight forward system to provide resistance as you pedal. Your pedalling energy is used to spin a fan or blade, and this spinning fan/blade is resisted by the air around it. While relatively simplistic in principle wind resistance provides a solid feel and generates a progressive resistance/power curve, which is somewhat similar to a power curves when cycling outdoors (on a flat road – i.e. zero incline). This means the correlation between speed and power is not linear, instead at higher speeds the resistance is proportionally higher. Without getting into the physics too much air resistance is more or less the friction you get on the blade as it moves through the air, and is influenced by speed and the cross-sectional area of the blade (also the shape and number of blades).
More accurately it is known as drag this resistance force is defined by the following equation:
F=(1/2)*p*V2*C*A where F = Drag Force (resistance); p = the density of air; v = velocity of the blade; A = Cross-sectional area of the blade; C = drag coefficient.
If you’re into your physics head over to Wikipedia here to get more on drag forces.
Who are wind trainers aimed at?
Wind trainers are generally seen as an entry-level option, being lower priced when compared to other types of trainer. However, one brand in particular (LeMond) have pioneered high-end wind trainers with the aim of creating the most realistic riding experience you can get indoors. Have they achieved this? If the opinions of renowned blogger DC Rainmaker are to be believed (which they should) then YES they have.
– DC Rainmaker.
The LeMond trainer is however and exception, with other wind trainers being low cost and while their performance is good they may not be the choice for everyone. There is no way to vary the resistance other than cranking up through your bikes gears, which is not necessarily a major issue. It will be like riding your bike on a flat road. Wind trainers are loud, the turbulence of the air caused by the spinning fan/blade generates a lot of noise, and when combined with the tyre noise it can be too loud for some. They are however lower cost and because the fan can double as a flywheel some wind trainers are relatively light and portable, which are definite positives.
Fluid turbo trainers can be seen as an upgrade to wind trainers. Instead of spinning a fan/blade through air they spin it through a fluid. This immediately makes them a lot quieter than wind trainers because spinning blade in fluid causes less noise than spinning it through air. Also, this all happens in a fully enclosed water tight chamber (for obvious reasons) which further dampens the noise. Generally, fluid trainers are recognised as the quietest on the market so if this is a major selling factor for you then you should consider this kind of trainer. See a selection of fluid trainers here.
– Figure taken from the Official Kurt Kinetic website.
The progressive power curves generated by fluid trainers can be very realistic and comparable to power curves generated when cycling outdoors (see the graph above). The reason for this, particularly in higher-end fluid trainers, is because the viscosity of the fluid is specifically engineered to create these accurate power curves. Like wind trainers fluid trainers do not allow you to increase resistance via the trainer itself and you need to ramp up through the gears to get more resistance, which like wind trainers may not be a major issue for you. You can get hybrid trainers that do allow varying resistance levels, and we’ll chat about them in a minute.
Along with not being able to set various resistance levels via the trainer, another issue with fluid trainers is that the spinning fan/blade causes the fluid to heat up. As the liquid gets hotter its viscoelastic properties change, which means the power curve that was once very realistic may lose some of its realism. Whether this is noticeable or not is up for debate, but if you have spent a lot of money on a trainer because you want a quiet and realistic ride you want it to perform consistently. To combat this issue some trainers add a fan to blow cold air into the resistance brake to keep the fluid at an optimal temperature, such as the CycleOps Jet Fluid Pro (which also looks pretty cool too, pun intended). Obviously this cooling fan impacts on the quietness of the trainer.
Who are fluid trainers good for?
A fluid trainer is ideal for anyone wanting a road-like feel to their workout and anyone who wants a quiet (relative to other trainers) training session. The progressive resistance is a major selling point to serious cyclists, and if don’t want to annoy your other half, neighbours, or you just want to watch TV while you ride then a fluid trainer could be for you.
Magnetic turbo trainers, or simply just mag trainers as they are known are seen as entry- to mid-level trainers. Unlike wind and fluid trainers you DO have the option to set different resistance levels meaning you can have a tougher/stiffer workout that in some ways is like pedalling up an incline. Mag trainers, and in particular the lower priced ones have linear power curves, which are not as realistic as the progressive power curves that wind and fluid trainers generate. However, if you are just looking for a way to get a good solid workout on your bike indoors then this may not (and probably won’t) bother you.
– Graph from Kurt Kinetic magnetic resistance page.
Magnetic turbo trainers work by spinning a metal (usually steel) disc relative to a magnetic disc(s) or vice versa. The spinning disc causes what are known as “Eddy Currents” – see Wikipedia description here – that generate a drag on the metal disc (end result – your pedals feel stiffer). So, you pedal, your back wheel spins on a roller, this spins a metal disc (or your chain spins it if you have a direct-drive cycle trainer), and you generate a resistance.
Spinning a metal disc within a magnetic field causes it to heat up, which can become hazardous. To combat this a lot of mag trainers incorporate a fan, which can be noisy. Mag trainers aren’t quiet, so be prepared for a relatively noisy workout when using one.
Mag trainers are very popular because you can set different resistance levels, meaning you can have an easy warm-up session or a tough hill like workout. This is achieved by moving the spinning metal disc closer or further away from the magnetic disc(s). On cheaper (lower cost) trainers this resistance can be set on the braking unit itself before you start pedalling, or you can get a model with a handlebar mounted lever or knob that allows you to change the resistance as you cycle. Most trainers come with around 5 to 10 different levels of resistance.
Like the standard mag trainers, electromagnetic trainers use a magnetic field to generate drag on a spinning metal disc. They achieve this in a more sophisticated way however, using electromagnetic fields that can be incrementally varied by increasing the electrical current to the resistance unit. Because electromagnetic trainers use electricity they can be controlled digitally and in most cases wirelessly, making them a lot more practical to use. Instead of having 5 to 10 set resistance levels (like in standard mag trainers) you can control the resistance much more freely in almost infinitely small increments and using metrics such as % or Watts.
The upper level of resistance is however limited because as you increase the electrical current to the electromagnet within the resistance unit the thin wires that carry the electricity heat up – get a simple explanation about electromagnets here. Too much heat can compromised the wires or cause them to heat up significantly (i.e. dangerously hot), and because it is the electricity causing the heat cooling fans will not eliminate the issue. High-end trainers can however simulate high resistance equivalent to an incline (gradient) of 20% in some cases, so don’t worry if you think you won’t get a tough workout because you will.
The video below is by Tacx for their i-Vortex turbo trainer that uses an electromagnetic resistance brake. It is a good example of how the trainer hooks up with a computer, but it is not just Tacx that do this, other companies such as Elite, CycleOps, Bkool, Kurt Kinetic, Minoura and more also have apps and software for smart devices and computers.
One massive plus point with these trainers is the ability to control them digitally, which means you can not only use a handlebar control unit but you can quite often use a smart phone, tablet, or computer. It doesn’t stop their either, now you have the power to control things using fancy software you can run training programs that automatically vary your resistance, or even better you can enter GPS data of real rides so you can recreate the same experience indoors. We’ll cover this more in the interactive trainers section, but there is now the ability to ride films and 3D virtual reality environments against other real-life riders in online races. This turns indoor training into something fun and addictive.
Motor turbo trainers are not very common, in fact only the manufacturer Tacx current use this technology on their high-end trainers, the i-Genius, Ironman, and Bushido. As you can probably guess it uses a motor as a resistance mechanism, which without getting too technical (see here for a simple explanation) involves spinning a current carrying coil within a magnetic field. A torque is generated on the coil, which is accurately controlled via the amount of current applied to the rotating coil. Increasing the torque necessary to spin the coil means you increase the pedalling power needed in your legs.
Ultimately the performance and experience will not differ much compared to an electromagnetic turbo trainer, however motor trainers have one feature that no other trainer can match. This is their ability to apply torque in both directions, thus they can physically spin your bike wheel. This means if you are riding on a GPS course via your tablet or laptop you will get a realistic feel when cycling downhill (a maximum of a 5% decline is the current limit).
The main disadvantage of a motor trainer is the price, with only high-end trainers currently having this technology. Also choice is an issue, with only one brand (Tacx) supplying these trainers. While the mechanism of spinning your back wheel is unique, other modern and high-end electromagnetic trainers can simulate the feel of downhill cycling by adjusting the resistance of the trainer and using a well-balanced flywheel.
Hybrid trainers aim to combine benefits of different technologies, such as smooth progressive power curves of a fluid trainer with the variable resistance of a magnetic trainer. This is seen for example with new Elite Turbo Muin direct-drive trainer that combines fluid and magnetic technologies and aims to be one of the quietest and smoothest trainers available. In this example the trainer uses a direct-drive mechanism (eliminating back tyre noise) and an oversized flywheel that spins in silicone oil (for smooth and quiet progressive resistance). They use electromagnetic resistance to provide the wide and controllable resistance range which is something standard fluid trainers cannot. You can read more on the official Elite website.
DANCING FEET AND SWINGING TRAINERS
When you ride outdoors things are not always stable. I don’t mean you are falling of your bike but there are times when you get out of the saddle and throw your bike around, swaying and rotating side-to-side. The vast majority of trainers hold your bike relatively upright and have very limited mobility, but there are two trainers that address this issue.
Elite have special Ritmo feet on some of their trainers (although they can be added to some of their other models) that allow the frame to bounce and move up and down and create a nice feel as you ride. This adds a realistic movement as your cycle. The RealPower, RealAxiom, and RealTour all come with dancing feet.
Skip to 1:10mins to see the dancing feet.
Kurt Kinetic, who are a major brand in cycling, have a trainer called the Rock & Roll turbo trainer. Essentially the trainer uses standard fluid resistance (albeit a high-end fluid trainer) but it houses this resistance unit on a mobile frame. This frame tilts and rolls as the rider shifts their body weight and recreates the sprint mechanics of cycling very realistically.
MAKING INDOOR CYCLE TRAINING MORE FUN
While dancing and swinging trainers add to the enjoyment of home training, things can move to another level when you can hook up cadence sensors, power meters and heart rate monitors and display all of your data on your laptop or tablet as you work out. This technology is here now and makes indoor training more rewarding and beneficial. But there is a way to motivate you even more, and this can even take you to the point where it is darn right fun (if sweating your butt of can be fun?).
On a basic level you can get special downloadable films of races that you can ride along to, some of the best (and toughest) are made by The Sufferfest. These videos can be used with or without a smart high-end trainer, but you do need a way to alter your trainer’s resistance to get the full benefits.
Electromagnetic and motor turbo trainers allow a computer (laptop, smart phone or tablet) to control your workout. They sync up with your trainer, communicate with your sensors, and automatically vary your resistance accurately to GPS data of real cycling routes. This is where things start to get really cool.
Companies such as CycleOps, Tacx, Elite, and Bkool all provide films and online experiences that you can interact with. Select a film of a real cycling route and your speed is automatically calibrated with the film speed, meaning pedal faster and more powerfully and you will travel faster on the road. Also, go up an incline and the resistance of the trainer will automatically increase, adding to the realism. Also, online communities and races exist where you can ride against real-life cyclists, which is a fantastic motivator and something that will get you on your bike more when you can’t get outside (and maybe even when you can).
Some trainers only work with their own software and apps, which is understandable but can also be a bit limiting. However, others such as the Wahoo Kickr does not come with their own software but does hook up with other company’s software. For example, the Wahoo Kickr can be used with the Bkool software as well as The Sufferfest videos and the popular TrainerRoad software.
VIRTUAL REALITY CYCLING
The above screenshots are from Bkool and Tacx respectivey. Technology has reached a point where you can cycle in 3D computer environments against other people how are furiously pedalling in their own homes. Over take Bob, hunt down Sarah, push up 20% gradients, and cross the finish line in Paris.
The following video shows off what is possible. This is the Tacx Advanced software that you can use with the high-end Tacx trainers. You can learn more about this software on the Tacx website.
It is not just Tacx that brings this virtual world, Bkool are a newer company that have high-end trainers at a lower price, and their software is also pretty impressive as shown in the short video below.
Beautiful 3D rendered environments are ready for those with the technology. You’ll want a cool high-end turbo trainer such as a the Tacx i-Genius, a Wahoo Kickr, or for considerably less money the Bkool Pro trainer. Basically you need an electromagnetic or a motor resistance trainer to get the most out of the virtual reality and the interactive software. However, you can take advantage of the software using other trainers but the experience will not be the same because the resistance of your trainer will not be controlled via the software, thus when you ride up a hill you will not experience the true resistance. For example, in this CycleOps overview all the CycleOps trainers can be used with the VirtualTraining software, although only their top-end electromagnetic trainers control the resistance you feel.
Tacx and Bkool have the software to generate 3D worlds to ride in, and the Wahoo Kickr can access the Bkool software. This is where things are heading and is why new companies such as Zwift are entering the market and stirring up quite a storm. Zwift are aiming at bring 3D cycling to the masses and claim that just about any indoor bike trainer can be used in online races or at least in the online worlds. Things are in there infancy and Zwift are still in their testing stages. It should be noted that only virtual speeds will be estimated if using a lower-end trainer because you will need at least a power meter to get power data and an electromagnetic trainer if you want to feel realistic resistance as you ride on different terrains.
HANG ON, WHICH TRAINER SHOULD I GET?
It’s impossible for us to say which trainer is best for you. If you want the most realistic realistic (road-like) feel and are not concerned with how much noise a trainer makes then you can’t ignore the LeMond Revolution, which will set you back around £400. Be warned, it’s a loud beast but a fantastic trainer. For a quieter option but still possessing a nice progressive resistance then some kind of fluid trainer will probably suit you best, such as the CycleOps Jet Fluid Pro or the new Elite Turbo Muin direct-drive trainer.
If you are in the market for an entry-level trainer then the Tacx Blue Motion gets great reviews and costs around £130, or the Minoura B60-R which is a steal at £110. If it comes down to being able to ride on films and compete in online races then you need to look at the CycleOps Powerbeam Pro, the Wahoo Kickr, the Tacx i-Genius, the Elite RealAxiom (or RealPower) , or the Bkool Pro (about ½ the price of the others here).
Hopefully you now understand more about turbo trainers and the different options available to you. See a full list of turbo trainers on our website here and filter them down to find the right one for you (at the best possible price – we compare 18 different turbo trainer retailers across the UK).
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