HOW TO CHOOSE A POWER METER – BUYING GUIDE

Shaun George BOTS Guides, E-commerce, Triathlon

If you’ve been cycling for a while, you probably know that training is a big part of a cyclist’s routine. As the sport of cycling has evolved, so have methods and equipment for training. Today, we’re going to get to know the controversial “power meter” a little better and whether its right for you. Controversial? Yes, because most of us can’t seem to agree on whether they’re actually worth it or not.

WHAT ARE POWER METERS?

Love them or hate them, when it comes to cycling tech controversy, power meters are right up there with tubeless VS tube and disc brakes on road bikes.

A power meter is essentially a device fitted to a bike that measures the power output of the rider. Most commonly, power meters use strain gauges that deflect slightly when a force is applied. By measuring this torque and combining it with angular velocity – power (measured in watts) can be calculated. There are other ways that power meters measure too, but we’ll get into that later.

There’s no denying the befits of riding with power data, knowing your stats enables you to track and measure your performance, and ultimately improve it. One of the main reasons cyclists use power meters is to help you work towards specific target power goals, and most importantly, when to rest and recover. This ultimately helps you get the most out of your ride.

POWER METER PLACEMENT OPTIONS

As ever, there’s no single power meter type or model that is the best. Being able to decide on one particular type depends on multiple factors. Let’s first look at the array of places you can mount a power meter on your bike.

  1. Rear-wheel
  2. Crank spider
  3. Crankarms
  4. Pedals
  5. Bottom Bracket

The locations listed above are the most common for the installation of “Direct Force Power Meters” (DFPM). A majority of the power meters these days are DFPM’s. Mainly because they are believed to be the most accurate. There are a few really accurate Non-DFPM power meters out there too – for whatever reason they aren’t as popular.

FUNCTIONALITY

Let’s get into the functionality that most power meters feature these days – these are features you must look out for when buying a power meter.

  1. ANT+/Bluetooth Support – Most power meters on the market today transmit via ANT+ to compatible head units and devices.  This allows you to use one of many different head units out there.  For power meters specifically, ANT+ tends to be the most stable and the protocol with the least compatibility issues – when compared to Bluetooth. Ideally, you’d want to look at a power meter with Dual Band connectivity (ANT+/Bluetooth). Bluetooth Smart is most popular when used with applications and on platforms like iOS that don’t support ANT+.
  2. Total Power (Watts) – One of the most important things to look at. Every power meter has this today. This is simply measuring and transmitting your total power output to a head unit of some type. Look at the specifications and see what the maximum power ratings are.
  3. LeftOnly power meters – These were common some time back and are still often used as they are cheaper than Dual-sided power meters. So basically how these power meters work is that they measure power generated by your leg only on the left side. All of these units then simply double the left power and produce a total power figure. As you can see this is not the most accurate readings.
  4. Torque efficiency & Stroke smoothness – These two parameters are usually found on the really high-end/premium power meters. If you’re really serious about your training then this is something to consider.

WHICH KIND SHOULD I GET?

There’s no such thing as the “right power meter”. If you’re looking for some flexibility and want to swap your power meter between bikes, a pedal-based system will be the most convenient. Simply attach it to the bike and forget about it. Crank based power meters are a reliable choice, but you won’t want to swap and change them around too much between bikes unless you’re mechanically minded and have the time and tools on your hands.

For the most reliable system, go for a hub-based power meter – they’re incredibly accurate. Having said that’ they’re the least convenient – they’re fixed to one wheel only, so if you have separate training and racing wheels then you’ll have to prioritize one over the other.

1. CRANK-BASED:

Crank-based power meters are located on the cranks of your bike (as the name suggests). They measure torque using a strain gauge usually located on the crank spider or inside the crank arm itself. These units require specific cranks or cranksets, but can be interchanged between bikes, depending on compatibility.

A typical crank power meter adds approximately 50-300 grams to the crankset. Crank-based power meters were the first type of power meter ever made and they remain the most heavily adopted system by professional athletes due to their accuracy and reliability.

2. PEDAL-BASED

Pedal-based road power meters incorporate strain gauges inside the pedal itself. Manufacturers such as Favero, PowerTap, and SRM all make a pedal-based power meter. These power meters usually come with proprietary or LOOK Keo style cleats that must be used with the pedal. Out of all the power meter types, pedal-based systems are perhaps the most convenient in terms of compatibility and installation. These advantages make them one of the most popular power meter types owned by cyclists.

3. HUB-BASED

On hub-based power meter, the strain gauges are located in the rear hub and measure power through the drive chain. PowerTap (currently owned by SRAM) remains the only major manufacturer of a hub-based power meter. It must be noted that there are drivetrain losses within the chain and other components. Therefore, power measured at the hub might be slightly less than the power measured at the crank – this doesn’t make hub-based power meters less accurate, they just measure power differently. Hub-based power meters have been a go-to power meter for years, for many cyclists.

Currently, one of the best rear-hub power meters in the market is the – PowerTap G3 (pictured above).


There are several types of power meters and they all have their own set of advantages, price points, and considerations. Yes, most power meters are pricy and are usually only used by the pro or riders really looking to get the most of their rides. Remember, there are no good or bad power meters – it all depends on your requirements, budget, and usage.

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