As I write there are many, many power meter options available for cyclists, and probably almost as many again in the pipeline for 2016. The internet is full of reviews and opinions, but it is undoubtedly confusing for the majority of people to make a selection and be confident it is the right product for them. In order to cast some light on the topic and perhaps help as you put together your Christmas list, this article will describe the different categories of product available, highlight the various advantages and disadvantages, and finally try to bring together the price, ease-of-use and reliability equation into something useful.
In the beginning there were two. Well, probably more, but let’s keep it simple at the risk of insulting someone. SRM and Powertap have been around ages, but with very different offerings. SRM was the choice of pro-cyclists (someone else was paying) and Powertap was more for the home-brew geek. Back in the day, SRM’s chainring-based strain-gauge system had the reputation of being hard to fit and calibrate (unless you had a team-mechanic to do it) while Powertap’s rear-hub-based strain-gauge design meant that if you could replace a wheel, you could get started (assuming you bought the hub in a pre-built wheel version of course). Now while SRM has carried on with basically the same concept (accurate, expensive etc.), Powertap has branched out into additional areas such as pedal and chainring systems (more of which in a moment).
Other more recent offerings (from Garmin and Polar / Look among others) have focused on the pedal as the primary location for the measuring and gathering of power data. These products promised simple set-up and portability between bikes. After what felt an age ‘in development’, they have been with us for 3-4 years now, and are revealing themselves in comparison to both the ‘old guard’ (SRM and Powertap) and of course, to a new category, the crank-based power-meter. Perhaps the best known of the newcomers is the Stages system used by Team Sky. Additionally, there are newcomers in the chainring category where SRM’s high prices have left plenty of space for cheaper solutions such as that offered by Quarq.
Finally, falling into the ‘other’ category, there are cleat and bottom-bracket based systems. The former may be worth a mention, the latter almost exclusively are not.
So let’s try to navigate through the offerings by type first of all. The Powertap hub is almost unique so we’ll start there. As noted, it’s very easy-to-use, reportedly reliable, and costs £584 (today on Wiggle) before it is built up into a wheel. Of course you can move it from bike-to-bike, but you can’t change the rim once it is built, so it probably has to be either a training or a racing wheel. The Powertap hub ‘broadcasts’ data in the ANT+ format which allows for a choice of head unit. It runs on a watch battery which you can replace yourself. You can pay extra for the chance to broadcast using Bluetooth.
The SRM crank spider / chainring based format has been adopted / adapted by several others including Quarq, Power2max and Powertap themselves. As the big-daddy of this type of product, SRM has offerings compatible with all of the major groupsets and uses the ANT+ format. Once again, this means you can ‘import’ data into your choice of head unit, and you don’t have to shell out for the SRM-specific kit. For most people, the major drawback with this system (apart from the approx £2k price) is that it is not really practical to move your chainset back and forward between bikes. Oh, and you have to send it back for a new battery – not often, but there it is. There are undoubtedly cheaper offerings available now, and I have it on good authority that some specialists really rate the Quarq Riken product. Keep in mind that although difficult to move from bike to bike, these solutions offer genuine left / right power measurement, and are proving robust in both set-up and use. And you can change the Quarq’s battery yourself!
So what about the pedal-based options? Well, here’s the thing – it would appear there was a reason why these devices took so long to develop. Both of the major offerings (Garmin and Polar/Look) have suffered from teething problems. Inevitable you may say, but for the price it seems hard to accept. The Garmin Vector is now into its second edition, but remains pricey (around £1200 or £800 for the single pedal version) and somewhat tricky to set up. Like Garmin, Polar/Look now offer a single pedal version which offers a substantial saving (£600 vs £1000 for left/right), but there are concerns that Look will ‘go it alone’ next year with a new offering. In both cases, you will need to use Look Keo cleats which may not of course suit everyone. While not solving the Look-only cleat problem, Powertap has impressed many people with its P1 pedal offering. Cheaper and easier-to-install suggest this is a system worth investigating. At about £1000, the system is also genuinely left/right measuring – the cheaper options from Garmin and Polar/Look simply measure one side and then double it. You do have to use specific Powertap cleats however.
Let’s move on to crank-arm measuring devices. The best known of these is Stages which will be well-known to many in the UK thanks to its relationship with Team Sky. It’s a pretty fool-proof concept wherein the device is set onto and into the left crank-arm. You basically buy and fit a replacement crank-arm for your existing bike. To the extent that you have the same crank-arms on all your bikes, the system is quite portable. The price will obviously vary according to the crank you choose, but a Shimano 105 with Stages is available for less than £400 (today on Evans). As noted with the single pedal versions from Garmin and Polar/Look, the Stages system evidently only measures your left leg, and then simply doubles the power output. This output however is in both ANT+ and Bluetooth compatible formats, once again allowing you to import the data into a significant range of head units and smart-phone apps. A second edition product, which aims to address some durability issues, is launching at this time.
Oh yes, I mentioned that there is one cleat-based system. This may be of interest if you use Speedplay pedals and cleats – the bad news is that system is ‘in production’ i.e. not available just yet. What is promised is a system that attaches to the soles of Speedplay compatible shoes. Watch out for more news on the Brim Brothers ‘Zone’.
I don’t think it is useful to research a topic, share the information and then NOT come up with a conclusion. However before any grand ‘reveal’ can take place, there are certain caveats which need emphasizing. Hard-working people put a lot of thought and effort into all of the products mentioned – the latest versions of all of these products will likely do a fine job for you. If things have been described as fiddly that might suit those of you who enjoy tinkering. Nonetheless I have to assume that most people are more interested in the ability to ‘fit and forget’ for a given level of accuracy. In addition, very few people are insensitive to price so while we might all like a dedicated SRM set up on each bike we own, that just isn’t going to happen for most of us.
So considering all noted criteria, my personal choice for measuring power would be as follows: a Powertap hub built into a solid winter training wheel, and a Stages crank arm to slip between road and TT bike in the summer. For me this represents a good price vs ease of use vs reliability solution – I would value the accurate power data obtained through winter training from the Powertap hub; I could then swap the wheel into my road bike for the spring. Finally by the time I wanted to use a more aero bike or wheel set-up, I’d be happy to use a one-leg-only version of my power output in order to keep (you guessed it) one eye on my performance. Both devices would output to my existing Garmin thus keeping the cost down. Honourable mentions also to the Powertap P1 pedal system as well as the Quarq Riken crank spider system.
Please let me know your experiences with these or other power-measuring devices.
The writer wants to confirm that he is not sponsored or supported by the manufacturers or distributors of any of the products reviewed. This is not an issue of moral hazard, but rather that he has never been a good enough rider to be approached by anyone.