“What power meter should I get?”
This is a question I get asked a LOT as a sports scientist, rider and coach. It’s a good question, really–there are so many options!
Power Meter AND BrakeAce Brake Power Meter
Power meters are super important for anyone looking to improve their race performance, which is a venture that can manifest itself in many different ways. A lot of people think they are only useful for determining training zones and that once they do then they just have to stare at the numbers endlessly… but there’s a lot more to it. I talked extensively about making the most of your MTB power meter data, so it’s worth checking out to learn more.
I got my first power meter back in around ’08. It was a clapped-out second-hand PowerTap
Fast forward to 2011-- I was getting pretty serious about this whole science thing, and the guys at PowerTap helped me get involved in some new reserach on mountain bikers:
I tested over 20 riders twice, and collected data at several races. After that I had a pretty good idea what it all meant, and I bought one of the first MTB Quarq power meter
Testing a bike just after that race for Mountain Bike
The technology has changed dramatically since then, and ever year there is some radical new way to measure what we are doing on the bike. When the Stages Power Meter came out, we were all skeptical. I talked with my PhD supervisor, and we decided to buy one to run a study comparing three different power meters, which we published as, Agreement between Powertap, Quarq and Stages power meters for cross-country mountain biking.
My personal take-home point was that power meters are pretty close to each other–especially during steady riding–and if you want accuracy you should use the same unit every time. It doesn’t seem to matter whether it is a wheel system, a left-side-only-system or a chainring spider version–they are all pretty much the same! Also, this affirmed that reed switches are probably slower than accelerometers in terms of reading cadence, and that technology needed to catch up in every brand. Tech has caught up since, and most brands are using accelerometers, which is a plus for all of us looking for good units.
Since then, lots of power meter articles have been published, which is in thanks to skeptical, enthusiastic biker-scientists. They all seem to come to the same thing: different brand power meters are pretty close to each other. What’s more, is even the most highly touted brands have error between units. So they’re all pretty good, but none are perfect. In my opinion science doesn’t need any more of these articles; power meter manufacturers spend years developing their algorithms, and their business models depend on good products. In this case, my general consensus is that yes, you should have a power meter, and no, you don’t need the best one. Just get one!
Lots of my athletes have used this Stages MTB Power Meter, from the world championships to club events
Testing the prototype Team ZWatt power meter in Canada last year. I run this on my bike and only charged it 4x in a year!!
For me, all my athletes have power meters. It’s job security for me, and tangible proof for them. It safe-guards us form making mistakes and lets us know when things are working or not. Most of the time, this is the athletes’ first power meter and having just invested in coaching they are leery about investing in a new gadget. It’s for this reason that I always recommend the least expensive option, which has generally been Stages
Mountain bikers are always asking this main question: “do I get one for my MTB or road bike?”
My answer is always to get it for your race bike!
Sure, serious mountain bikers might do most of their training on the road, but it’s the races that matter! Hear me out…
The main benefits of the power meter are:
Determining weaknesses and strengths of the athlete in racing situations
Regular testing to guide training interventions
Guide understanding of pacing based on individual ability
Monitoring training sessions based on zones
I really think the above is in the order of importance, especially as one gets the feel for what each zone actually should feel like and especially HOW TO RIDE STEADY in that zone. In this case, monitoring each training session is the least important of all, and is something that can be gleaned from using a power meter to pace and watching the heart rate’s response. In focusing on just monitoring training, an XC rider with only a road power meter won’t have much of a clue what’s going on in the races, which really doesn’t benefit in determining what to target in training. I’d rather have the rider understand points 1-3 and use an old-school heart rate monitor in training than to not be able to understand race performances. You might disagree because you think that monitoring each training session to carve out exercise stress numbers from your training software is super important, but I disagree; zones are guidelines, and it’s important to understand that muscular contraction and thus cellular metabolism don’t adhere to percentage zones based on normative data. I do however think it is very important to start to understand what these zones feel like, and how it feels to stay within them, so practicing regularly with your power meter on these points is super important. In terms of testing, you can test on your race bike no matter what kind of bike it is (mostly; probably hard to do hills on the DH bike). Testing happens once/month so it’s not much of an issue to use a MTB on the road.
If you can only have one power meter and it can only be on your MTB race bike, there’s no reason why you can’t use that bike for a few key workouts. For example, if you have trouble staying steady on endurance road rides, do some endurance road rides on your MTB race bike. This is really the only way you’ll finally get better at steady riding.
Given what’s available now, I’d still recommend the Stages Power Meter
One the other hand, I've had the same Quarq XX1 mtb power meter for the last 6 years, and this thing has found its place on a number of my bikes. It just won't die! These are a little more pricey, but you can measure left and right power since the strain gauges are on teh chainring spider.
You could spring for an SRM power meter. These are great from what I hear, and have been come to be known as the 'gold standard'. However, as we discuss in the power meter article, the claimed error in all power meters is really pretty similar, so I don't see much reason to get the most expensive option when they are all pretty good.
I've been pretty fortunate to test the Team Zwatt power meter. I can’t seem to find any for sale on the internet, but your LBS should have them soon. These are left side only, but are rechargeable, which is super awesome. The batteries last a long time, and I have only charged it about 6 times in 18 months with regular use. That’s much cooler than a coin cell, and certainly the way of the future.
So overall, when choosing a power meter, choose one from a brand that stands behind their products and one that won’t break the bank. Spend time understanding what the numbers feel like. Test with it. And most importantly, race with it.
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