Choosing your Power Meter
Getting the right power meter for your needs and budget can be a little daunting. That’s where I hope to help. There are just a few questions you need to answer to help narrow down the options. If you want some personal advice and assistance then please feel free to use my – Power Meter HELP form.
Different styles / fittings
Ease of Fit > This is a very subjective issue. I have friends who will say it’s easy to fit a new bottom bracket and build a wheel on a new hub. Not me. There are several styles of power meter. I have listed these styles below in order of skill level required to fit them (and in some cases special tools)
- Pedals (eg. Garmin Vector, Powertap P1) – more info
- Crank Arm (eg. 4iiii, Stages & Pioneer) – more info
- Chainring / Spider (eg. Quarq & Powertap C1) – more info
- BB Axle (eg. Rotor InPower) – more info
- Rear Wheel Hub (eg. Powertap G3) – more info
I have awarded each product a score for ease of fitting. The scale is a little subjective and has been based on my personal skill level. I am competent to adjust gears, fix a puncture, adjust brakes, change a pedal or a crank arm … anything else, I’d take it to my LBS.
One spanner = EASY, Two spanner = I’d struggle, but might try, Three spanner = Local Bike Shop
With regard to accuracy they are all excellent. Most leading brands quote accuracy figures of +/- 1 to 1.5%. More important than accuracy is CONSISTENCY. I have omitted any dubious power metering systems. All the power meters reviewed on this site are of the very best quality.
Single or Both sides
Single or Dual sided? > this makes a big difference to the price. You can expect to pay almost double for a power meter that measures power output from BOTH legs. Single sided measure the true power in ONE leg only. They still provide an estimate of TOTAL power by doubling the single leg figure. Dual sided systems measure the power from BOTH legs. Some systems provide TRUE left and right power balance by independently measuring power from each side. The obvious option for dual sided true power metering is pedals eg. Powertap P1 or Garmin Vector 2 and crank arms such as 4iiii Precision Pro.
There are other systems that provide an ESTIMATED left and right power balance. Such devices include some of the chainring meters. They have one sensor in the chainring that continually monitors power. It then attributes all the power on the downstroke to the RIGHT leg (chainring side) and all the power during the upstroke to the LEFT leg.
ANT+? or Bluetooth? > If you have already got your bike computer then you need to check if it supports ANT+ or Bluetooth devices. Many brands of power meter fortunately produce units that transmit in BOTH ANT+ and Bluetooth eg 4iiii. If you have a Garmin unit, it’s ANT+. Polar use Bluetooth. If you haven’t already bought your bike computer it makes sense to consider this option when narrowing down the choices.
If you are lucky enough not to have to worry about budget grab a pair of power monitoring pedals, either Garmin Vector or Powertap P1. If you need to be aware of budget here’s the main systems listed in order of PRICE, cheapest FIRST.
- Crank Arm (eg. 4iiii, Stages & Pioneer)
- Rear Hub (eg. Powertap G3)
- Pedals – single sided versions (eg. Garmin Vector 2S, Powertap P1S)
- Chainring / Spider (eg. Quarq & Powertap C1)
- Bottom Bracket chassis system (eg. Rotor InPower)
- Pedals – dual sided (eg. Garmin Vector 2, Powertap P1)
I have awarded each power meter a score for price / value for money.
One £ = entry level price, Two £ = mid-range, Three £ = top budget
Feature & Functionality Icons
The icons below relate to the feature and functionality icons listed against each product in the category view pages
ANT+ & Bluetooth – This is the best of both worlds. These power meters will communicate with Garmin (ANT+) and Polar, Lezyne, Suunto, Wahoo and any other computers running the Bluetooth 4.0 protocol (BTLE). If you are the type of cyclist who regularly changes head unit / watch, then I’d recommend a DUAL transmission power meter. If however, you are a life long Garmin fan then you may consider an ANT+ only power meter … and likewise, Polar fans can opt for the Bluetooth power meters.
Bluetooth only – this power meter transmits data in Bluetooth 4.0 (BTLE) protocol only. This transmission medium is used by Polar, Lezyne, Wahoo and Suunto to name just a few.
ANT+ only – this power meter transmits data in ANT+ protocol only. This is the most widely used transmission medium as it’s employed by Garmin in their hugely popular Edge, Fenix and Forerunner models
DUAL SIDED – All the power meters featured in this category measure the power from both both sides. If supported by the monitoring device these power meters can provide feedback on LEFT and RIGHT power balance. If metering the power generated by each leg is a little OTT then I’d recommend a SINGLE sided power metering system, often almost half the price of these dual metering systems.
SINGLE SIDED – All the power meters featured in this category acquire their power measurement from one side only. These power meters DOUBLE the wattage from one leg to give an average total power output. What can’t be measured with these power meters is LEFT and RIGHT power balance. The best way to do this is with power pedals or a double crank arm system. However, for a vast majority of cyclists this averaged total power figure is more than adequate. These single sided power meters are some of the most popular on the market due to their ease of fitting, accuracy and low price (compared to pedals/chainring power metering systems)
More information on the different systems
PEDAL – these are arguably the easiest to fit power meters. Simply remove your existing pedals and fit these new ones. Pedal based power meters are available as both single sided option with just ONE pedal fitted with the sensors, cheaper option. This type gives averaged total power by multiplying the power measured in one leg by 2. They are also available as two pedal variants. Both pedals are fitted with the sensors giving TRUE left & right power measurement. Expect to pay almost double the price of the single version. (e.g Garmin Vector and PowerTap P1)
CRANK – these are reasonably easy to self fit. Simply remove your existing crank arm(s) and pedal(s) and fit the new ones. Crank arm based power meters are available as a single sided option with just ONE crank fitted with the sensors. This style provides averaged total power by multiplying the power measured in one leg by 2. They are also available as two crank variants with both cranks fitted with power sensors giving a TRUE left & right balance. Expect to pay almost double the price of the single version (e.g 4iiii Precision Dual).
Axle / Spindle (Bottom Bracket) – to self fit these power meters you must be confident at removing a bottom bracket system (or pay your LBS to do it for you). These units are very robust as the power sensors are contained within the BB assembly, brilliant for MTB and XC riders. The power is usually measured only from one side. They provide averaged total power by multiplying the power measured in one leg. The Rotor InPower devices are very popular as they use regular AA batteries giving 300 hours+. They have been designed for VERY EASY battery change. (e.g. Rotor INPower 3D+ and 3D30)
NOTE > there are a few units like the Rotor 2InPower that have TWO sensors, one in the BB/axle (left leg) and the other in the crankarm (right leg). These devices provide TRUE left & right power balance feedback. The total power output is also a TRUE value as it’s measured from both legs, not estimated. (e.g. 2INPower by Rotor)
CHAINRING – a competent self taught bike mechanic should be able to fit these. If you’ve every changed your chainring before, you should be fine. These units measure the power from the right leg. Like many power meters they provide average total power by doubling the power measured from the drive-train side leg. Some units, like the Powertap C1, provide estimated left & right power balance. They do this by attributing the power on the down stroke to the right leg and the upstroke to the left leg. It’s not absolute but it’s consistent. (e.g. Powertap C1 Power Meter)
SPIDER – similar technical skills required to fit this system as the chainring system above. These units measure the power from the right leg. Like many similarly priced power meters they provide average total power by multiplying the power measured in this one leg.
REAR HUB type – these are arguably the easiest to fit power meters. Simply remove your existing pedals and fit these new ones. Pedal based power meters are available as both single sided option with just ONE pedal fitted with the sensors, cheaper option. This type gives averaged total power by multiplying the power measured in one leg. They are also available as two pedal variants. Both pedals are fitted with the sensors giving TRUE left & right power measurement. (e.g. Powertap 3G Power Hub)