Power Meter vs. Speed/ Cadence Sensor: How They Differ & How to Choose

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kathlene pierson spinning instructor and writer
By Katie Pierson

Spinning® Instructor & Personal Trainer

 Katie holds ten different fitness certifications, including Group Fitness, Spinning Elite, Rockstar Spinning, and Personal Training.

I tend to encounter two types of cyclists in my class or out on the road. The first type of cyclist is the one that wants to get a great workout, rides for pure enjoyment, and desires to break a sweat. The second type of cyclist is focused on performance and their metrics of how they can become faster and stronger while riding. So whether you ride to break a sweat or are driven by the data, we have a power meter or cadence sensor to improve your next workout. 

Is a cadence sensor the same as a power meter?

While both a cadence sensor and a power meter supply data while riding the bike, what they measure is quite different. A cadence sensor will calculate how many rotations per minute your wheel turns. However, a power meter, hence the name, measures your power output by analyzing your torque, distance, and duration.

Do I need a cadence sensor if I have a power meter?

If you have a power meter, then you really do not need a cadence sensor as well since a power meter will also provide a cadence reading.

Power Meter: What is it, Pros & Cons

power meter

A power meter helps to measure a rider’s power output through watts. A watt measures your energy output (power) during a given time while riding. The meter uses the metrics of torque (aka force), distance, and time to create the power calculation. A strain gauge measures force and is usually located on the crank arm, crank spider, or pedal axle. Power meters can offer single-leg or dual-leg options. Only the left leg can provide actual power data for a single-leg power meter, and the right leg will be an estimation. However, dual-leg power meters will provide information for both legs but come at a higher price point than single-leg models. The power meter uses Bluetooth and ANT+ technology to transfer the data to other apps and devices.

myx ii antena
ANT+ Of MYX II Bike

For those hardcore riders that want to see where their strengths or weaknesses are as a rider, then a power meter is a fantastic investment. The data they provide can help transform how riders train to maximize their results.

ProsCons
Provides an abundance of metricsExpensive
Ideal for elite cyclistsNot meant for beginners
Power Meter Pros & Cons

Speed/ Cadence Sensor: What is it, Pros & Cons

speed sensor moofit

Sensors are incredibly helpful in tracking the key metrics to maximize your ride. Speed and cadence sensors can be purchased individually, or there is the option of buying both sensors as one package. While combination sensors are wireless, they will require an ANT+ to be able to transfer this information to the bike computer or other device. Let’s look a little more at the metrics that this type of sensor tracks.

  • Cadence: Cadence measures how many pedal strokes per minute are completed. The cadence sensor is placed on one of the crank arms and usually connects to a monitor via Bluetooth and ANT+ technology.
  • Speed: A speed sensor tracks the distance at which you ride during a specific timeframe. Speed sensors are designed to be used on road bikes and are not usually compatible with most indoor cycling bikes since they are typically mounted on the hub of a bicycle wheel. 

This type of sensor can help you become a stronger rider by providing feedback on how fast and far you travel during your ride. For example, riders can learn what their average cadence or speed is during a specific ride in which the rider can continually try to increase the metrics.

These sensors, on average, range in price from $25-$100, although they can be much more expensive if you are wanting a version that will link directly to a smartwatch. 

ProsCons
AffordableANT+ also required
WirelessNot the best option for Elite Cyclists
Long Battery Life
Great for Newer Riders
Speed/ Cadence Sensor Pros & Cons

Differences & Comparison Table

The main similarity that these various types of sensors and meters have in common is their ability to provide real-time feedback instantly to the rider or the option to store that information to be analyzed at a different time. Check out the table below to see how these sensors and meters differ. 

Cadence/ Speed Combo SensorPower Meter
Price$25-$100$500-$1000+
Intended UserBeginner, Intermediate, AdvancedAdvanced, Elite
Metrics TrackedCadence, SpeedCadence, Force, Duration, Distance
Cadence/ Speed vs Power Meter

What Do The Popular Apps Use to Measure Power

If you do not have a power meter or smart trainer, don’t worry; many currently available apps use estimation to calculate your power and other metrics. For example, Rouvy and Zwift use your speed in addition to a power curve model they have each created for estimated power. Likewise, TrainerRoad uses a speed-to-power ratio to calculate a rider’s power output. Different sensors also can link with various apps. Later on, I will share my top recommendations. 

If you like using a particular app and are looking at which sensor or meter to purchase, check the specifications to see if they will work together before purchase.

What to Choose & How

The decision to purchase a cadence and speed sensor or a power meter really depends on what type of rider you are and the type of investment you want to make. Power meters are a great piece of technology that provides a ton of feedback, but unless you are a seasoned cyclist looking to take your training to the next level, they might not be the best choice for you. Since power meters can cost thousands of dollars for a top-of-the-line model, it is vital that you understand the metrics this device will provide and how to use that information. Otherwise, it might not be the right investment at this time.

For beginning and intermediate riders, a cadence/speed sensor is the best purchase you can make. Not only are these types of sensors affordable, but they provide enough real-time feedback to improve your training and make the most out of every ride. Of course, you can always transition to a power meter farther down the line.

FAQ

Does a power meter also measure cadence?

Yes, a power meter also displays the cadence or RPM output.

What is the difference between cadence and speed?

Cadence calculates your RMP (rotations per minute), while speed calculates the rate you ride a certain distance you travel during a specific timeframe. 

Can you calculate watts from speed and cadence?

Since watts are measured through force, getting an accurate watt calculation of watts from speed and cadence is difficult. Many variables tie into measuring force, such as incline, wind, body weight, etc.

My Best Pick as a Spinning Instructor

  • Sensors: As far as cadence and speed sensors are concerned, a Wahoo sensor is a great pick. We love that the Wahoo RPM Cycling Speed and Cadence Sensor pack is affordable at only $69.99 and offers a 4.5 out of 5 rating with almost 20,000 reviews. Another fantastic feature of the Wahoo sensor is that it links to many cycling apps. If you do not feel like visiting the Wahoo website to check out the complete app list, here are just a few compatible apps: Strava, FulGaz, TrainerRoad, Zwift, and Rouvy. 
  • Power Meter: We have discussed that power meters are more expensive, but the technology can be awe-inspiring. Garmin’s Rally RK Dual-Sided Power Meter Pedals allow riders to get accurate metrics no matter what bike they ride, as the pedals can be switched from bike to bike. However, if you change bikes often, then this power meter option might become more of a hassle. These pedals calculate your power and track the time spent in each position. They are ideal for longer training sessions and rides as they offer a full 120 hours of battery life. They use Bluetooth and ANT+ connectivity and also pair with other devices such as computers and phones. However, these enhanced metrics have a higher price tag at just over $1,000. If this price tag is more than you are looking to spend, a single-sided pedal option is also available from Garmin. 
  • Indoor Cycling Bike with Power Meter: Not everyone is interested in using a smart trainer, so purchasing an indoor cycling bike might be an option to explore. If you want to buy an indoor cycling bike with the best power meter on the market, I highly recommend looking at the Schwinn Z Bike. It offers the greatest accuracy I have seen for indoor cycling power meters. Not only does this power meter show what your output is during your ride, but it also can break your ride into different stages to accurately evaluate your ride.

Want to learn more about the Schwinn Z Bike? Check out our detailed review.

Verdict

If you are newer to cycling or like to ride as a form of fitness, then a combination sensor will probably be sufficient. However, a power meter might be the wiser investment if you are becoming serious about cycling and want to improve your riding significantly. If you are unsure where you fall as far as your cycling goals, we recommend starting with cadence and speed sensors and then progressing to a power meter later.

Katie Pierson

Katie is the creator of MT Girl Fitness and has been a certified fitness professional for almost twenty years. She currently holds ten different fitness certifications, including Group Fitness, Spinning Elite, Rockstar Spinning, and Personal Training. Fitness is her passion, and she loves seeing her clients reach goals they never imagined.

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