NorthRoad Talks. Should you spec a power meter on your new bike?
Indoor training has created an insufferable wave of FTP comparisons between pals, but should you ride with a power meter out on the open road?
We’re finally starting to see a drop off in the price of good quality, reliable power meters. It wasn’t that long ago that the options really were too spendy for the hobbyist rider – and frankly the reliability was questionable at best. Spaffing a grand on something that might go kaput if it rains is just bad business when you live in the UK.
Fast forward to today and we have a range of options, a range of different approaches, and importantly, a range of prices.
First things first. Why would you bother with a power meter?
You don’t have to be a pro to benefit from the data a power meter can give you. Even if you’re not out seeking personal bests or KOMs, knowing some baseline statistics can allow you to enjoy your ride a little more, and here’s how.
Have you ever been on a ride and found yourself just not really feeling it? it’s happened to most of us at one time or another. We might not have eaten well enough, or the wind might be a bit stronger than we anticipated. As the ride progresses it gets harder and harder and we end up trudging home feeling beaten up.
Having a power meter and understanding your own benchmarks will help you determine whether it’s you that’s the problem. If it’s windy and you’re pushing twice as much power as usual you’re going to get tired quicker – but it is almost impossible to gauge how much more effort you’re exerting without a power meter. If you know your numbers, you’ll sooner accept that the ride might be a little slower than usual and settle in to a rhythm. Likewise with false flats and long dragging climbs, a power meter can calm you down and let you relax into your own ride rather than turning yourself inside out before you get to the end.
By contrast, if you can’t get to the numbers you normally would, you can have more confidence in blaming poor fuelling or underlying sickness. Knowing you’re not right can help you make better decisions for the rest of the ride.
So before we talk about specific power meters, it’s worth quickly understanding the different types of power meter that are available.
1. “Crank” based systems.
These are power meters that are built into the crank arms of a bicycle. They can be double sided (ie, they read power from the left and right sides individually) or single sided, where usually the left crank arm has a power reading and then it’s doubled to give your overall figure. Crank based systems are usually powered by a small coin cell battery that will give between 100-200 hours of battery life and most options today will be within a few % of accuracy which is more than accurate enough for the average rider.
2. Pedal based systems
As the name suggests! These options replace your pedals completely with pedals that have power meters built into them. Like the crank option, they can be single or double sided. There are options to suit a wide range of different clipless solutions including Shimano SPD, Shimano SPD-SL, and Wahoo Speedplay among others.
3. Hub based systems
These systems use a gauge in the rear wheel hub to measure the power being transferred into the wheel.
4. Wind/resistance based systems
Not as widely adopted as the other options, these units don’t use a strain gauge, instead they measure wind resistance against known values like rider weight and road gradient to calculate power required for a given speed over a given distance.
Which power meters do we recommend?
Quarq Rival AXS dub power meter
This new offering from SRAM and Quarq has seemingly slipped in under the radar. SRAM’s Rival AXS groupset has re-set the barrier for price when it comes to electronic groupsets, but they’ve also reset the bar for power meter pricing, too.
Why it’s excellent
The Quarq range of power meters have been around for a long, long time. They’re tried, tested, and among the most reliable in the industry. By building them into the SRAM Rival crankset options they’re bringing power meters to a whole new level of affordability. The accuracy is well within a useful range for 99% of riders. At a relatively meagre RRP of £322 for the full chain set, if you’re building a new bike the value cannot be overlooked.
Why it might not be for you
As It’s only a left hand measuring system, you might not get the full picture when analysing your data. There’s very few people who have a reliable 50/50 split of power between both legs. It’s all well and good being our best value for money pick in this list, but there is the mighty big assumption that you’re happy with the rest of the 12 speed SRAM AXS system. We’ll struggle to find reasons not to recommend SRAMS wireless electronic systems but some people are just downright Shimano folks, and that’s okay. Which takes us on to our next crank based recommendation.
Stages Left Sided Power Meter, GEN 3
Another stalwart in the power meter industry. Stages have been around for a long time and now they’re in their third generation of power meters, they’ve had chance to make incremental improvements all round.
Why it’s excellent
Stages provide replacement left hand cranks for most road, gravel, and mountain bike groupsets. Yes, if you’ve got a mid to high end groupset on your bike, Stages will likely be able to provide a power meter for you. In most cases, you simply take off your left pedal and left crank arm, put the replacement crank from Stages on, screw your pedal back in, and off you go. Their third generation features improved signal across both Bluetooth and Ant+ and increased resistance to water ingress. The actual power meter aspect of the unit adds next to no additional weight over the standard crank (~20g) and they’re super easy to retrofit to your existing system.
Why it might not be for you
Like the Quarq Rival system, this is a one sided system that might not show the full picture if you don’t have a perfect 50/50 balance between your legs. It also relies on you having an existing crankset to replace one arm of. Though Stages do offer full crankset options if you are building from scratch.
Favero Assioma Duo
Favero have done an incredible job at bringing dual sided power data down to a slightly less eye watering price compared to the competition. You might not have heard of Favero before, but they’ve fast become the industry standard for dual sided power measurement among the hobbyist. Think of them as the Shimano 105 of dual sided power meters, functionally they’re the same as options costing twice as much, just a fraction heavier and less refined – for most of us that won’t matter.
Why they’re excellent
They just work, flawlessly! Their accuracy and reliability has been proven among some of the most demanding reviewers in the industry and they are even used as the benchmark when comparing new equipment for the inimitable GPLlama in testing. They are easily serviced and because they use the Shimano SPD-SL cleat system they will work with any three bolt shoe and shimano cleats. You can also easily swap these between bikes, it really is as easy as unscrewing from one bike and popping them on another.
Why they might not be for you
There’s no getting away from it. They’re a road pedal and gravellers are out of luck. This is not a system we’d recommend using off road. We are aware of some hacks to use the axle with a Shimano SPD pedal bodies but it’s not supported by the company at this moment in time. They also increase the “Q factor” of you pedals, which is to say it pushes the pedals a few mm outboard of your bike on each side. There’s mixed reviews on how much of an impact this has on your fit and performance but it’s worth considering.
Garmin Rally XC100 SPD Pedals
If you read the review of the Favero Assiomas and got to the point where we said they’re no good for off road and huffed, then here’s the option for you. The Garmin Rally XC100 are the long awaiting SPD style pedal power meter. They come in single and double sided and are advertised as being strong, light, and accurate.
Why they’re excellent
Though gravel riding has firmly taken hold, a gravel friendly pedal power meter has been a long time coming. Not everyone wants a power meter that can’t be moved between bikes, power meters are expensive and having to have one per bike can be prohibitive so pedals make sense to be able to switch between machines. The weight difference over “normal” pedals is negligible, so if you want to ride to power and you want to ride off road, this is the option for you!
Why they might not be for you
With an RRP of £620 for single sided or £1059 for double sided there’s no denying these aren’t a cheap option.
Why no hub drive or wind resistance units?
You’ll notice we’ve not recommended any hub or resistance units to our list. The fact is, we just don’t come across enough of them to recommend them heartily. We will only recommend things we have had some experience with either ourselves or from our customers, and cross reference this against as much information as we can find elsewhere.
If this has been useful, fantastic! But if you’re still in a whirl about your options, get in touch and we’ll talk specifically about your requirements and the options that will best suit you.