Power meters can be located almost anywhere on the bicycle drivetrain; here are a few of the most common options, each with their pros and cons.
Crank Arm Power Meters
Stages
It is the first power meter brand to offer both ANT+ and Bluetooth transmission protocols. Currently best priced on the market and offering a crank based power meter for most manufacturer, alloy or carbon – Shimano, SRAM, FSA, Cannondale, Campagnolo. Stages power meter has an LED status indicator that shows pairing and battery status at a glance. Improved water resistance – Gen 3 Stages power meters are designed to meet or exceed the IPX7 standard for water resistance. The older Gen1/2 units had connectivity issues and firmware updates in 2017 resolved connectivity issues people were seeing.
Battery Life: 200 hours
Battery type: CR2032, replaceable
Accuracy: +/- 1.5% Warranty: 1 year
4iiii Precision
At just 9g the 4iiii Precision power meter is the lightest on the market. You can purchase complete crank arm, or alternatively if compatible you can send your crank arm to them and they will fit the 4iiii Precision pod for you and then courier it back to you. The power meter pod uses single coin type battery and status indicator is via their app. 4iiii Precision is a reliable and inexpensive power meter that measures left leg power.
Battery life: 120 hours
Battery type: CR2032, replaceable Accuracy: +/- 1%
Warranty: 3 year
Avio
Avio has been designed to fit selected Shimano Hollow cranks only. Avio offers a self-install kit and is the least expensive left-only power meter option on the market. Alternatively you can send your compatible Shimano crank arm to Avio or their appointed distributor/retailer to install the power meter pod for you or you can purchase a pre-installed crank/crank set.
Battery life: 75 to 100 hours
Battery type: CR2032, replaceable
Accuracy: +/- 2% Warranty: 2 year
Crank Arm Based Power Meter Verdict
These are among the most affordable power meters available.
Not always easy to move between bikes.
The crank-arms are slightly wider than normal so there may be some clearance issues when fitting them to the frame.
Crank Spider Power Meters
Quarq
The Quarq is a solid unit for those seeking easy, reliable, and accurate numbers from a power meter. Accuracy is on-par with other units, chain-rings can be fitted without issue and the battery is easy to replace. On the down side…..not much.
Battery life: 200 hours
Battery type: CR2032, replaceable
Accuracy: +/- 1.5%
Warranty: 2 year
SRM
This is gold standard, a legend. It’s a well-established brand and their reliability is generally very good. With ANT+ you can use any head unit you’d like, and aren’t limited to just the SRM head units. On the downside - it is pricey.
Battery life: 100 hours
Battery type: USB rechargeable
Accuracy: +/- 1.5%
Warranty: 3 year
Power2Max
Power2Max has packaged the power meter into the spider, so you’re free to choose from a range of cranks according to your budget. Units priced at the low end have +/-2% accuracy, uses a replaceable battery (CR2450 – a lifespan of 300 to 400 hours) and has a 2 year warranty. As per Power2Max website, you can upgrade the accuracy to 1% for 100EURO; add left/right leg balance for 50EURO, pedal smoothness for 50EURO and or a 5 year warranty for 150EURO.
Battery life: Depending on model, 300 to 400 hours or 150 hours for rechargeable.
Battery type: Depending on model, CR2450 or USB rechargeable
Accuracy: +/- 1% to 2%
Warranty: 2 to 5 year
PowerBox
Spider-based power meter that provide total power output measurement of both legs. Battery life has proved to be excellent. It uses a CR2450, which is bigger and has a much larger capacity than the more commonly used CR2032.
Battery life: 300 to 400 hours
Battery type: CR2450
Accuracy: +/- 2%
Warranty: 1 year
Shimano
Shimano's first power meter and there are some issues which will be rectified through updates. Shimano’s easy to use dual-sided power meter (temporally flawed) comes in at a high price; you may want to consider other options.
Battery life: 300 hours
Battery type: USB rechargeable
Accuracy: +/- 2%
Warranty: 2 to 3 year
Rotor INspider
The first of its kind to offer multi-discipline compatibility, and can be seamlessly switched between bikes only if they all utilize a Rotor OCP-splined (Optimum Chain-ring Position) crank-set. It is dual sided, with a rechargeable battery. Again this one is a little on the costly side.
Battery life: 250 to 300 hours
Battery type: USB rechargeable
Accuracy: +/- 1%
Warranty: 2 year
Crank Spider Based Power Meter Verdict
You can change crank length without having to buy a new power meter.
Crank spider based meters can be very accurate.
Can provide left-right pedaling balance.
Not always easy to move between bikes.
BB/Spindle Power Meters
Easton
Reasonably long-term battery life, USB rechargeable and has a “travel mode” for saving battery life. It is a bit pricey for a left-only unit.
Battery life: 400 hours
Battery type: USB rechargeable
Accuracy: +/- 2%
Warranty: 1 year
BB/Spindle Based Power Meter Verdict
You can change crank length without having to buy a new power meter.
Uses a BB30 spindle; installation may be difficult and is made all the more complicated by the varying frame bottom bracket types.
Pedal Power Meters
PowerTap P1/P2
Easiest install of really any power meter out there, no pods or torque wrenches required. The battery life is a bit on the short side.
Battery life: 60 hours
Battery type: AAA
Accuracy: +/- 1.5%
Warranty: 2 year
Garmin
The pedals are Look style, and the box comes with a pair of cleats. Garmin has dropped the power meter pod which sits outside the pedal (Vector 1 and 2), which was left unprotected. The pods where tricky to install and required a torque wrench to set up it and accurate. The Garmin Vector 3 is easy to fit and uses a replaceable LR44 battery, claimed battery life span of 120 hours, user reviews claim between 20 to 60 hours. On the upside the Garmin Vector 3 comes with its own system called Cycling Dynamics for measuring pedal stroke. The system includes left/right pedal stroke, time spent seated vs standing, Power Phase (at what point during the pedal stroke power is being produced) and Platform Centre Offset (where on the pedal axle power is being produced). But it is not available with Garmin Vector 3 single power meter pedal and you will need a Garmin Edge 520, 820, 1000 or 1030 to access all the Cycling Dynamics measurements.
Battery life: 120 hours
Battery type: LR44
Accuracy: +/- 1%
Warranty: 2 year
Favero Assioma
Of the power meter pedals, Favero’s Assioma pedals have the lowest RRP. These are dual measuring power meter pedals. Accuracy is solid, and it can quickly be moved.
Battery life: 50 hours
Battery type: USB rechargeable
Accuracy: +/- 1%
Warranty: 1 year
SRM
This is a power meter pedal from an established brand. Not much to write about other than that it is dual pedal power meter and with a claimed battery life that is higher than other rechargeable units, it is expensive and installation is tricky.
Battery life: 100 hours
Battery type: USB rechargeable
Accuracy: +/- 1.5%
Warranty: 2 year
Pedal Based Power Meter Verdict
Generally speaking, power meters that measure from the pedal as opposed to the hub give slightly higher readings because a few watts are lost in transmission.
Easily swapped between bikes, except the SRM.
Single side measuring units fall within the crank arm price bracket.
Cleat limitations.
Susceptible to damage.
Rear Hub Power Meters
PowerTap
Fall into the group of most durable and accurate. You can purchase the hub on it own or a complete wheel. Manual calibration is easy and swapping out batteries is quick.
Battery life: 160 hours
Battery type: CR2032
Accuracy: +/- 1.5%
Warranty: 2 year
Hub Based Power Meter Verdict
Due to the advancements in bicycle technology the PowerTap hub it is getting left behind and losing its popularity. Depending on bike types and training wheels vs racing wheels, you may require more than one PowerTap wheel.
Which One Should You Buy
Accuracy comparisons are similar, any issues that they may have can be fixed through software updates, hardware changes, servicing and or warranties. Consider your budget, available support/backup and its proximity as well as easy of swapping if you own multiple bicycles.
-
That is it. Thank you for reading. I hope you found it to be a useful resource.