DC Rainmaker

First look at Wahoo Fitness KICKR ANT+/Bluetooth Smart Trainer with power meter

Today Wahoo Fitness unveiled their latest product – a Bluetooth 4.0 and ANT+ enabled trainer with an integrated power meter.  The trainer will transmit power (watts) and speed information across both protocols, allowing it to bridge the gap between dedicated devices like your existing GPS units – as well as connect to cell phones like the iPhone 4s.

The trainer connects directly to your bike via swapping out the rear wheel and in place resting it into the provided cassette.  This is similar to how the LeMond Revolution and a few other units work.  This also means it can attach to just about any bike on the marketplace – from mountain to tri to road to kids.  It’s unclear how or if I could connect that wonky Hydrobike I saw last week though.

A bit of trainer background:

Before we dive into why this is such a big deal, let’s take a step back and talk about trainers in general.  Trainers are typically categorized into three basic categories:

1) Basic trainers which capture no metrics (usually ranging from $89 to $500US)
2) Trainers which capture power metrics, but cannot control specific power resistant levels (usually $500-$1,000, i.e. – LeMond Revolution)
3) Trainers which capture power metrics, and allow you to specify resistance (i.e. 250w) (usually $1,000-$1,600 and higher – i.e. CompuTrainer)

All of the above trainers that fit in categories #2 and #3 have their own software platforms built around them – which means that there’s very little above-board integration going on with different software platforms.  Meaning that when it comes to CompuTrainer integration – you’re really only able to choose CompuTrainer software, or the one other company blessed by them.  Same goes for Tacx – which only allows you to run Tacx software.  As such, we’ve seen trainer software largely stagnant for years now – not really truly keeping up with where it should be technologically.

Due to the either hard blockers (i.e. blocked coding access) or soft blockers (i.e. legal) – many 3rd party companies have struggled to really take advantage of trainers in an integrated way.  It’s always been a hodgepodge at best, and downright sketchy at worst.  If Strava wanted to develop an app that tied into your CompuTrainer or Tacx or LeMond or anything – they were completely out of luck.

Open Platform:

Unlike the rest of the trainers, Wahoo Fitness is opening up the trainer to any developer that wants to develop against it.  This means if TrainingPeaks wants to write an app for it – they can (regardless of whether it’s a Windows/Mac/iPhone/Android application).  Same goes for the popular open source Golden Cheetah platform.  They simply download the development kit and go to town.

They could write apps to allow you to do legit trainer competitions across the country – all at once (most of the platforms today rely on an aspect of honesty on the part of the end-user).  Or they could write an app that allows you to create your own RealCourse-style videos and then re-ride your friends GoPro ride in South Africa.

Applications supporting it today:

As of today, they’ve already got three apps onboard, including their own.  The first up is their in-house application.

Wahoo Fitness default app & Strava integration:

Today at Eurobike, the app that Wahoo Fitness was showing was primarily targeted at developers and to show the configuration options of the trainer.  You can see below some of the settings that developers (and thus by extension – end users) would have access to.

Additionally, the unit will support firmware updates wirelessly (over the air):

In addition, Wahoo Fitness has put together a pretty sweet proof of concept app that does Strava ride integration.  The app allows you to pick out any Strava segment, and then any particular riders recorded activity of that segment – and race against it.

To test this out, we dug down into a Strava segment I posted back in June down in Florida.  You do this by simply clicking/zooming on the map or searching by location – similar to how it works on the Strava app itself:

You can see me up towards the top of the list there.

After selecting your victim who your racing against, the timer will start and it’ll start to emulate the route itself.  It’ll show you their recorded information (power/cadence/etc) and yours at the same time.

Here you can see the two side by side:

Here’s a quick two minute video giving a rundown on how it all works:

Strava integration with KICKR

Now at this time the app does not allow you to store the data back up on Strava – rather only compete against it.  There are tons of pros and cons to allowing a trainer app publish data to Strava, all of which will undoubtedly be discussed for a while by the general internets as well as Strava and Wahoo.

TrainerRoad App:

TrainerRoad had exploded in popularity in the year it’s been on the scene.  Their training platform is completely based around power, allowing you to use either a power meter – or ‘VirtualPower’ with one of the various lower end trainers that support a known power curve.

Today the only trainer that supports wattage control with TrainerRoad is the CompuTrainer. But with KICKR, they now have control of the trainer itself – and can change the resistance on the fly there as well.  This means that their workout library is now fully automated.

Of course, that in and of itself isn’t terribly different from what trainer companies have been doing for a decade or more.  What is different is the fact that it isn’t the trainer company themselves controlling that – it’s now a completely third party company, and one doing it above board (most of the CompuTrainer wattage controlling that 3rd party apps do isn’t really kosher with RacerMate Inc., the CompuTrainer maker).

Within TrainerRoad, you can see the pairing to the KICKR – as well as other Bluetooth Low Energy sensors, like the BlueSC and BlueHR.

Here’s a quick video I shot this morning showing how this all works within the TrainerRoad application:

TrainerRoad Video Integration with KICKR

Kinomap App:

Next up is Kinomap.  Kinomap allows you to ride course videos both in a single-player and multiplayer mode.  Additionally (and most importantly), you can go ahead and shoot your own videos with cameras like the GoPro and Contour.  From there you can upload the videos and let you or others ride them.

In relation to KICKR, you can see the new menu’s allowing you to select the trainer as a training device.  Kinomap (like TrainerRoad) supports mixing and matching of ANT+ and Bluetooth Smart devices.  Meaning that you can have a Bluetooth cadence meter with an ANT+ heart rate strap.

Kinomap controls the power on the trainer according to the elevation profile within the video.  In order to deal with inaccuracies within the elevation recorded – they do a bit smoothing.  Otherwise the fast sub-second update frequency of the KICKR might result in power control spikes due to incorrect data recorded on the file attached to the video itself.

Speaking of videos – here’s a quick video showing how this all works:

Kinomap integration with KICKR

KICKR Technical Details:

Here’s the rundown of the trainer, divided up into a bunch of technical areas.

Bike Connection to Trainer:

The bike connects to a trainer with a 12-27 SRAM/Shimano cassette, which is included in the package.  You can see it below:

You can swap out the cassette if you’d like, as there’s no issues or internal dependencies in doing so (up to 11 speeds, Shimano). In order to connect the trainer, you’ll need to remove your entire back wheel first, and then attach the trainer just as if you were attaching a wheel.  This can be a bit more cumbersome than a normal trainer which attaches to the wheel at the rubber, depending on your specific bike (for example – on my P3C triathlon bike, this ends up being a bit of a pain with the rear-exit system).

Here’s a quick video showing it being removed from the trainer and mounting again:

Adding and removing bike from KICKR

Now traditionally trainers like this (such as the LeMond) have been a wee bit loud.  More like jet-engine loud.  But the Wahoo KICKR was far quieter than the LeMond Revolution – almost completely quiet on the showfloor – the sound of the drive train was louder on all three bikes than the trainer itself.  Interestingly enough, they’re actually sending out a unit to a lab to get tested from a decibel standpoint.

Of course, on a busy Eurobike show floor, it’s difficult to compare actual measurements.  So in order to solve this problem I ordered a deciblemeter the other day, which will allow me to make direct measurements between the LeMond and the KICKR from the comfort of my apartment.  A significant secondary aspect will be how-long until the folks a floor below start screaming about either…

Power Resistance:

The unit has a maximum advertised resistance of 2,000 watts.  The unit was engineered such that a 175 pound rider (at max resistance) would feel as though they were riding up a 15% grade.  Due to the flywheel aspect, the unit really does feel like you’re riding on a road – very similar to how the LeMond Revolution feels like you’re actually ‘coasting’ when you stop pedaling.

Now technically they note that there’s no real limitation on resistance levels or measurement.  Rather, it’s a function of speed.  For example, if you’re going a pedestrian 4MPH the limitation if 600w, but at 8MPH the limitation is 1,200 watts, and at 16MPH, the limitation of 2,400 watts, and so on.  Of course, if you can output that much power.  The curve is linear.

The electronically controlled change in resistance upon command is instant.  Meaning that if the software removes resistance – it can go from that 15% incline to coasting down a hill instantly.  This is different from most trainers tend to take a few seconds or more to release the resistance – so this is ideal for those doing intervals.

The KICKR updates the power resistance on the trainer electrically every .25 seconds – meaning that if you waver in power – it’ll respond in less than a quarter second and adjust accordingly.

Due to the ability to provide resistance – the unit will require being plugged in.  But the charge is minimal enough that a 12V cigarette lighter will work (so you can do workouts near your car ahead of a race).  They area also considering adding a battery pack if there’s demand for it.

Power Measurement:

The unit does not require a calibration procedure to measure power.  The trainer includes an internal thermocouple to self calibrate the strain gauge based on temperature variations.

From an accuracy standpoint, they are going with an advertised measurement of within +/- 2%.  However, they are trying to get it down to being lab quality power measurement and believe they can get it within 1 or 2 watts at most normal wattage ranges (which they defined as 200-400 watts).  The unit technically measures across 4,000 points, allowing accuracy within .5 watts.  However, today the various protocols only broadcast to the nearest full watt (1w).

Obviously as we get closer to final release, we’ll get more clarifications from them on this.  The Wahoo team has said they will look to try and work with an independent body for doing some power measurement tests.

Today, the unit will broadcast once per second.  However, the unit can stream data across at 64 times per second, should an application want to burst higher.  Given it’s not battery strained – there’s no power concerns there.

Data Broadcasting and Control:

The biggie here aside from open API’s is the fact that it’ll be broadcasting on both ANT+ and BTLE.  It can dual-broadcast on both protocols at once, since there are no battery concerns or chip issues here.  Here’s the technical details on both:

ANT+ Broadcast:

The unit will use the ANT+ Bike Power Meter device profile, as well as the Bike Speed device profile to broadcast your current power and speed.  This means it’ll be compatible with all current ANT+ power meter head units.  For example, the Garmin FR310XT/FR910XT/Edge 500/Edge 705/Edge 800, all CycleOps Joule units, Timex Global Trainer, Magellan Switch, and countless other apps).

It will not at this time broadcast cadence though, so you’ll need to add an ANT+ cadence meter into the mix in order to get that.  It’s something I’ve talked with them about adding (cadence to KICKR) – and they are looking into it, but not yet sure they’ll be able to deliver there.  The issue is that due to the larger flywheel it’s harder to guess/estimate cadence compared to trainers with a smaller flywheel.

From a trainer control over ANT+ compatibility with other devices standpoint, the unit will require that the ANT+ power meter device profile be updated to add a trainer control protocol. This is in progress.  Obviously, if such an extension of the ANT+ device profile were added, it would then have to be added to the firmware of any ANT+ device that supports it – which may take a while.

Note however that even though the protocol may not yet be in place for trainer control publically, Wahoo is able to deliver that privately to any of the 130+ apps that use the Wahoo Fitness iPhone key and/or API.  Meaning that any of the apps (like Kinomap) could use ANT+ today via the key and communications between the two.  Wahoo is committed though to getting the final public version updated/implemented as soon as ANT+ completes it.

The unit will not use the existing Fitness Equipment device profile that allows a handful of lower-end Garmin devices to receive power data (such as the FR60/FR70).  Instead, only devices that support the ANT+ power meter would work.

Bluetooth Low Energy Broadcast:

Initially, the unit will broadcast on BTLE (Bluetooth Smart) using a private protocol, as the Bluetooth 4.0 power protocol is not yet released.  In other words, since the standards are yet ratified in this area – it won’t be the final power protocol.  However, since Wahoo Fitness is one of the key members of the group that ratifies these protocols – there’s little doubt the two won’t look almost identical down the road.

Even if they are different, the KICKR does support firmware updates via the phone app.

In order to access the Bluetooth Smart data stream, you will need to have a Bluetooth Smart compatible device – which means a device that supports Bluetooth 4.0.  Today the biggest phone on the block that supports this is the iPhone 4s.  There are more and more handsets and devices (like all new Macs) that support BTLE (Bluetooth Smart) coming on the market each day – so I don’t expect this to be a big long term blocker.

If you don’t have a phone that supports Bluetooth low energy (for example, iPhone 4, not 4s), you’d need the Wahoo Fitness key.  Additionally, Mac’s that have Bluetooth Smart are also supported, and for those Macs without Bluetooth Smart (older macs), they can pickup the IOGear Bluetooth Low Energy USB adapter.  This adapter does not yet include Windows drivers, but Wahoo is working on that too.


At present I think the KICKR trainer will really shake up the trainer industry, especially in the realm of interoperability.  Their goal is to have the unit available by the holidays – at a price that is ‘competitive’ with the market place – and available internationally.  They were hesitant to talk specific pricing until they can finalize discussions with dealers, etc. – however it was clear that they were NOT talking CompuTrainer level pricing ($1,600) – but rather something significantly lower.

With that – as always, feel free to drop questions below and I’d be happy to try and get answers.