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How to get on Zwift without a smart turbo trainer

Joseph Delves
8 Dec 2021

Could you start riding online with just your existing kit?

Virtual cycling app Zwift allows you to swap the drudgery of indoor training for racing around a colourful computer game-style simulation.

However, it also works best with a smart trainer – something that can both read your power output and automatically vary the resistance offered to simulate what's happening on screen.

Of course, not everyone has one of these. However, there are probably thousands of us in a position to dust down a formerly neglected cheap turbo trainer.

Happily, even if yours is as dumb as they come, there's still likely a way to get yourself online.

Do I need a smart trainer for Zwift? No!: How to use Zwift with only a speed sensor

Assuming you've got some form of trainer on which your bike can spin, the cheapest way to use Zwift is by using a speed sensor and the app's estimated power function.

This will translate the effort you're transmitting through the pedals and generate a likely wattage with which to power your online avatar.

Normally coupled to a GPS bike computer to give a more accurate measurement of speed when riding outside, you might already have a cycling speed sensor on your bike.

If not, an option like Wahoo's RPM model is a good choice. Strapping to the hub and costing just £30, it can send information via Bluetooth and ANT+ and should be able to connect directly to whatever computer, tablet or phone you’re using to run Zwift.

Alternatively, if you've already got an array of older ANT+ sensors that won't pair with your screen, it's still possible to get a USB adapter that will help them talk to your computer.

However, given that the cost of these adapters is often similar to that of a new sensor, you might decide now is the moment to upgrade.

Zpower vs. Estimated Power

Once you're ready with your speed sensor, Zwift will present you with a choice between Zpower or Estimated Power based on the trainer you're using. Zpower is available to riders with older trainers made by many better-known brands.

Essentially, Zwift went and mapped the power-curve of each trainer, creating an estimate of the effort needed to spin it up to a particular speed.

You select your model of trainer in the game, then return to the real world and set it to the resistance level specified, capped at 1,200 watts. You're then free to pedal away, with Zwift calculating the power you're generating with a reasonable degree of accuracy.

Coming in at £230 and with a progressive level of fluid resistance, we think Saris's entry-level Fluid 2 Trainer makes an excellent budget option. Plus it's supported by Zwift's Zpower function when used with the included speed sensor. 

Estimated Power 

Less precise than Zpower, Estimated Power applies to a larger list of name-brand trainers. Working in the same way as Zpower and again capped at 1,200 watts, as long as you hold a relatively steady effort you should get a reasonably accurate result.

What you won't get is quite so quick a response when changing pace, such as when chasing or launching an attack.

Unsupported trainers 

Using an unsupported trainer and speed sensor is the last and least good option. If you got your trainer at the Salvation Army or from well down the Amazon rankings, this might be your only choice.

Selecting this generic option will limit you to 400 watts and kill off your chances of being responsive in any race. Nevertheless, you'll still be able to power your virtual avatar around an imaginary world rather than stare blankly at the wall, so it's not all bad.

When it comes to setup, a little bit of twiddling with the trainer's resistance setting will help you find a happy compromise. Just don't be tempted to rig the game by fiddling this to your advantage.

Ride with any of these options and you'll find yourself able to not only explore Watopia, but also enter many of the competitions organised on the Zwift platform.

That said, although it makes a great introduction to online racing, many race organisers bar those using both Zpower or Estimated Power from occupying podium places due to the lack of accuracy inherent to both options.

Using a power meter

In the game, you might have noticed some riders have a lightning bolt next to their watts per kilogram number. This means they're either using a Zwift-verified turbo trainer – or a power meter.

Now unless you're a bike fanatic you're unlikely to have one of these lying around. Used by professional athletes and keen amateurs to measure their efforts while racing or training, these strain gauge-eqipped devices cost several hundred pounds at a minimum.

However, when applied to Zwift they'll also let you mash away on any old trainer while broadcasting a perfectly accurate power output. Of course, you won't get the automatic resistance control offered by a smart trainer, although hills can always be simulated by shifting into a harder gear on your bike.

You'll also be able to grab podium spots in competitive races and be able to compare your virtual and real-world efforts by using the same equipment in both areas.

Again, you'll either need a device that uses Bluetooth to communicate or a computer and dongle through which to route any ANT+ units. 

Although expensive, you'll struggle to find a more universal and convenient power meter than the pedal-based Garmin Vector 3. Read our full Garmin Vector 3 review here.