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How to Choose A Bike Trainer for Your Home

Loads of head-to-head testing led the Kickr Snap to come out at the top among the tire drive smart trainers.
By Curtis Smith ⋅ Senior Review Editor
Friday May 19, 2017
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Do I need a bike trainer? Should I buy a standard or smart model? All the pros are using direct drive. Are they better? The bike trainer market is bigger and more confusing than ever before with the widespread infiltration of smart trainers, and the associated applications that make them tick. Let's take a moment to answer all of your questions and set you down the path to making an educated decision on your potential purchase.

Why You Need a Bike Trainer

Stationary bike trainers allow you to use the bicycle that you already have as an indoor exercise bike. Most riders who race or take their fitness level seriously use a stationary trainer as a training tool. Of course, we would all rather be out on the road or trail, but most of us have to contend with the change of seasons and the reality that cycling outdoors is not a year-around sport. Even if you are lucky enough to live somewhere that has tolerable weather and road conditions, the after-work ride can be a real challenge when it gets dark at 5 pm. So you have worked hard all summer to build your fitness and riding outside is not an option for the next few months. Cross training is a great tool, but if you want to be fit for those early season races or grand fondos, you are going to need to put in some time on the bike.

A stationary bike trainer allows you to use the bike that you already own as an indoor fitness machine.
A stationary bike trainer allows you to use the bike that you already own as an indoor fitness machine.

Advantages of Using an Indoor Trainer

Despite the perils of the indoor trainer session, there are some advantages to using one when it comes to training. Using a smart trainer to do targeted interval work in specific power zones can rapidly improve fitness. If you think about the average outdoor ride you partake in, or better yet look at the power file of said ride, you will likely find that a good deal of your overall ride time is spent coasting or in power zones that do not elicit a great deal of physiologic improvement. Simply put, the average rider is limited by the amount of time they have to train. If your goal is to maximize that time to achieve the highest level of fitness possible, then you are better served spending that time working somewhere in the tempo to the threshold range. A targeted threshold workout done on a trainer has very little filler, meaning that you maximize your time in the power zones that generate the greatest amount of training stress. You cannot coast on a trainer…well, you can, but it feels fairly silly to be sitting on a bike that is not moving.

Smart trainers can also force you to ride at a specified wattage; you literally won't be able to cheat. If you slow down your cadence the resistance per pedal stroke increases, speed up and the resistance per pedal stroke decreases, but the power output holds steady forcing you to maintain a specific power target.

Smart trainers when used with applications like Zwift also allow you to compete against other riders in a virtual setting. Competition can be a good motivational tool to get a bit more out of your body than you would if you were riding alone.

Using the ERG mode with a smart trainer forces you to maintain a specific wattage target.
Using the ERG mode with a smart trainer forces you to maintain a specific wattage target.

Types of Trainers

Indoor trainers, also called Turbo trainers, have been around for a long time. Until recently, the type of resistance the trainer employed was the primary method of classification. The vast majority of trainers on the market used either a fluid, wind or electromagnetic resistance source. Fluid trainers were thought to have the best or most realistic resistance curve, with the level of resistance being dependent on wheel speed. Within the last five years, the indoor trainer market has drastically changed. Nearly all of the big players in the market now have smart trainers available.

Smart Trainers

The Wahoo Kickr is an awesome direct drive smart trainer.
The Wahoo Kickr is an awesome direct drive smart trainer.
What is a smart trainer? The definition has evolved with the market, but at this point, a smart trainer must do the following:

-Measure user output in watts using a power meter.
-Provide user controlled resistance, in the form of watts and grade simulation.
-Have a smart phone application for control and calibration.
-Be compatible with third-party applications such as Zwift and Trainer Road.

-Use one or both of the industry standard communication protocols, ANT+ FE-C or Bluetooth Smart.

Smart trainers have many advantages over a standard fluid trainer, with the primary benefit being the ability to use the vast range of third-party applications available. The applications allow the user to ride in a virtual world against or with other riders who are also logged in using a smart trainer and to do targeted workouts that use the resistance unit on the trainer for interval work. Also, applications can allow a rider to experience a climb or race course through realistic video and grade simulation. From a training perspective, the ability to see your power and adjust resistance in real time is a significant benefit overriding by feel on a standard trainer. Beyond the benefits of power measurement, the entertainment factor associated with these applications can be a life savor for the cyclist locked indoors.

Communication Protocols Editor's Note

Smart trainers are dependent upon applications to control resistance and create simulated riding experiences. All of the trainers we tested, except for the trainers from Kinetic, broadcast on both ANT+FE-C and Bluetooth Smart. Below we break down the difference in communication protocols, and most importantly why it matters to you.

A bit of history: When smart trainers began popping up on the market in mass, every brand utilized their own wireless communication protocol. Also, the smart trainers available were in general only compatible with the manufacturer's proprietary app. For example, if you purchased a Tacx smart trainer, it would only work with the Tacx application. If a third party wanted to create an application for smart trainers, they would have to do all of the software engineering on a case-by-case basis for each brand that they wanted their application to support. Clearly, this business model was a huge detriment to the consumer.


Fast forward a few years and Dynastream, the maker of the popular ANT+ wireless communication protocol, releases ANT+ FE-C. The FE-C portion stands for Fitness Equipment Control. Most of the big players in the trainer world jump on board, and there is suddenly a common two-way communication protocol that allows applications to receive data from smart trainers as well as control resistance. The ANT+ FE-C protocol revolutionized smart trainer applications by making it possible for an application to use the same communication protocol for almost every trainer on the market.

Bluetooth Smart

So now you are likely wondering where Bluetooth Smart figures into all of this? Bluetooth Smart is a low energy wireless transmission similar in function to ANT+, but it is open source and lacks a common communication standard. Many trainer companies use Bluetooth Smart for their smartphone applications, as most modern smartphones both IOS and Android are Bluetooth Smart enabled. These applications allow you to control your trainer with your phone without the need for any dongles or accessories. Some PC applications also use Bluetooth Smart for Mac and newer Windows computers.

So why does this matter to you? If you are in the market for a Smart Trainer, you want both ANT+ FE-C and Bluetooth Smart communication capabilities. This will ensure that you have access to the largest range of apps. Also, it will allow the highest possible level of interconnectivity between the devices you will use to display applications during training. These devices include; PC, Smartphone, Tablets, and Garmin cycling computers.

Types of Smart Trainers

There are two types of smart trainers available, tire drive and direct drive. How the bike attaches to the trainer is the main differentiating feature.

Tire Drive Smart Trainers

Tire drive trainers use the tire and wheel of your bike to turn a drum that is attached to the resistance unit. The bike is clamped to the trainer at the rear axle, and a cam or tensioning device is used to force a smooth drum against the tire. As the tire turns it rotates the drum, which is attached to the resistance unit. The two primary advantages of tire drive trainers are a lower price, and not needing to remove the rear wheel of your bike to use the trainer. The primary disadvantages are less accurate power measurement, need for more frequent calibration, excessive tire wear, and lack of versatility with mountain and cyclocross bikes.

Tire Drive Smart Trainers like the Kickr Snap use the bike's rear wheel to turn a drum connected to a resistance unit.
Tire Drive Smart Trainers like the Kickr Snap use the bike's rear wheel to turn a drum connected to a resistance unit.

Direct Drive Smart Trainers

Direct drive smart trainers replace the rear wheel of your bike, and the bike frame is mounted directly to the trainer itself with the rear wheel removed. The bicycle chain then sits on a cassette that is permanently mounted to the trainer. As the cassette and hub of the trainer turn, a belt transfers the movement to the trainer resistance unit. The main disadvantage of a direct drive trainer is the need to remove the rear wheel of your bike to use the trainer. Direct drive trainers also tend to be heavier and much more expensive than their tire drive counterparts.

Direct drive trainers have many advantages over tire drive models. The most important being more accurate power measurement. Also, they are more stable, reduce drivetrain and tire wear, and need less frequent calibration. Direct drive trainers often offer better road feel. Larger flywheels and the lack of tire to drum friction are the primary reason for the more realistic road like experience. Another advantage of the direct drive trainer is increased compatibility with a wider range of bicycle frames. Mountain bikes and other bikes with knobby tires tend to slip and create noise and vibration when used with a wheel drive trainer. Direct drive trainers do not suffer from this as the rear wheel is removed.

Direct drive smart trainers like the Kickr replace the rear wheel of your bicycle using the bike's drive train to turn a resistance unit.
Direct drive smart trainers like the Kickr replace the rear wheel of your bicycle using the bike's drive train to turn a resistance unit.

Standard Trainers

Standard trainers use wind, fluid, or magnetic resistance units and are not compatible with applications like Zwift or Trainer Road. The vast majority of standard non-smart trainers are tire-drive units. Unless they are paired with a crank or hub based power meter, you will not experience application-controlled resistance as you would with a smart trainer. Wind and fluid trainers have adjustable resistance based on the gear you are pedaling in or, more accurately, the speed of the rear wheel. Magnetic trainers often have wired resistance controllers that can be mounted to the handlebars, but also rely on shifting of gears for fine-tuning pedaling effort.

The Kinetic Road Machine is a standard trainer with a fluid resistance unit.
The Kinetic Road Machine is a standard trainer with a fluid resistance unit.

Fluid trainers offer the most realistic road feel, with a progressive resistance curve that mimics the effect of changing gears to increase speed as you would on the road. Fluid trainers are also extremely simple to operate, all you have to do is pedal, and shifting gears will increase or decrease resistance. While manufacturers don't publish maximum resistance values, we have been unable to exceed the resistance curve of the fluid trainers we have tested even during hard sprint efforts in the 800-1200 watt range. That is not to say that they won't hit a wall at some point, but for most riders, the available resistance is more than adequate.

The main downside to a fluid as a form of resistance is poor road feel as compared to a smart trainer. The feeling of inertia that mimics the feel of road riding is minimal. In general, fluid trainers will rapidly spin to a stop when you stop pedaling, so gear changes must be done quickly with a minimal reduction in cadence and power; otherwise, it feels as if you are pedaling in quicksand. Smart trainers are in general much better at mimicking road feel due to advanced algorithms that allow the flywheel to continue to rotate when pedaling stops or during gear changes.

Making a Purchase Decision

So you have made it this far, and you are ready to buy a trainer. Here are a few things to consider before you click to purchase it.

How Much Will You Use It?

If you plan to be on the trainer every day six months out of the year, then a smart trainer is your best choice, to alleviate boredom and keep your stoke high. Just going to use it every once in a while? Then a standard trainer might do the trick and save you a whole bunch of money.

What Bike Will You Use?

If you are only planning to use a road bike, then a tire drive trainer is a great option. If you plan to use a cyclocross or mountain bike, then you should consider a direct drive trainer. Knobby tires and tire drive trainers don't mix well. So if you are going to use a mountain bike with a tire drive trainer then add the expense of a slick trainer tire into your purchase plan. Also, pay close attention to our compatibility section in the individual product reviews. Some trainers will not work with certain axle and hub spacing configurations. If you're not sure what axle or hub spacing your bike has, swing by your local bike shop and ask before you commit to a purchase.

Tire Drive trainers are best suited to use with road bikes.
Tire Drive trainers are best suited to use with road bikes.


Spending $1500 on a trainer is a big commitment. Assess your needs and make a decision based on what is important to you. Top of the line direct drive smart trainers are amazing tools, and can truly alter your indoor experience while providing you with laboratory quality power analysis. Tire drive smart trainers offer the same level of entertainment but lack the accuracy and supreme road feel of a direct drive model, but they are half the price. Standard trainers are seriously lacking in the area of entertainment, but there is always YouTube. In the end, the addition of any indoor trainer to your training arsenal is bound to pay dividends in your spring fitness. Good luck and happy pedaling.

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