Tri Tech - Power Meters Explained

Choosing the Right Power Meter for Your Bike

In this post, we’re going to discuss your options when looking at purchasing a new Power Meter for your bike!

Today, I’ll cover the 4 basic types of Power Meters you’re most likely to encounter in the new or used market, these include:

1. Pedal Based

2. Crank Based (spindle vs spider vs crank arm)

3. Hub based (artefact)

4. Inferential (Power Pod/ other wind based electronics)

With those 4 categories in mind, let's take a closer look at some of the strengths and weaknesses of each of these styles of power meter to help you make a more informed choice!

Pedal Based Power Meter

1. Pedal Based Power Meter

These are power meters that measure your output directly from the pedals. They are typically heavier and bulkier than a traditional bike pedal as they house the electronics required to both measure and transmit the torque applied to them. These are easy to transfer between different bikes as they only require a bike to have cranks to mount to, however they will require you to commit to a specific type of pedal cleat, as each model/brand will cater to a specific type of cleat (see: LOOK, Shimano SPD SL, Shimano SL, Speedplay, etc.)

Typically these will have the most versatility as you can mount them on your road, triathlon, indoor spin bike, or even your commuter without requiring specialized tools or a shop to make the adjustment. These pedals can typically be purchased with single-sided or dual-sided measuring capability and can be upgraded in the future if you start with Single-sided only. 

Crank Based Power Meter

1. Crank Based Power Meter

This style of power meter replaces your existing Crank Arm, Spindle, or Spider to measure the power directly from the cranks themselves. This means you will be measuring power very close to its source again, as with the pedals, with very little interference (more direct = more accurate). Crank based power meters have the least amount of added ‘bulkiness’ to them, and often look the same as their conventional counterparts, with the caveat of a small blinking light somewhere or a battery port.

Although these are difficult to change between bikes on the fly, when you upgrade or change bikes, they can be moved over to your new bike with minimal hassle. If you have the tools, you can do this yourself, however a bike shop is your best option when dealing with changing the cranks & spindle over. Again, these can be purchased with single or dual-sided capabilities and can generally be upgraded in the future for more precise measuring.

1. Hub Based Power Meter

Having your power meter on your wheel is a more cost effective option, and you’re more likely to come across it used rather than new. These are somewhat of a relic of the early power meter adoption days. Having the power meter in the hub meant you could easily use that wheel for training rides, then swap your race tires on and have a race ready rig to track your power.

The major limitation here is that you’re training and racing on the same wheel. If you want to have nice race wheels, then you’re spending time training on your nice wheels, if you have a cheap trainer wheel, then you probably don’t want to use your Power meter wheel on race day. This option to have the hub on your training or racing wheels only, restricts how you use your power data as if you train with power you likely want to race with it, and vice versa.

Single sided power isn’t really possible, through AI analytical data you can infer which pedal is being applied force to and where in the cycle it is, however it’s not a direct measurement. The best use is as a gross tool, measuring the total power applied at any given moment. That said, these are generally inexpensive compared to hub and pedal based systems, and provide you with direct force measurement.

1. Inferential Power Meter

Through the use of data analytics, instantaneous GPS tracking, and weather data, devices can create a fairly precise inference of your power at any given moment in your ride. These devices typically mount on your handlebars and based on the wind speed reading they take in, compared to the GPS speed measurement, will spit out a calculation of your instantaneous power.

These devices are easy to move between bikes, and as long as you have the requisite peripherals (phone or GPS device) you can use this anywhere on any bike without issue. The major caveat comes into play if you spend any amount of time training indoors and want to track your power, while PowerPod has this capacity, it is not a direct measurement. Using the “Power Curve” of an indoor trainer, paired with a speed sensor, devices like PowerPod can calculate your resistance. If precision isn’t your priority, then this isn’t really an issue. Alternatively, if your indoor trainer is a Smart Trainer, you also don’t care because you have power measurement directly from your trainer.

This type of measurement device is a budget friendly option, and as such also comes with the most limitations to the data. If you’re looking for a simple tool to measure outdoor power data then this is more than sufficient, however if you want a deep dive into specific data, this is likely too far along the spectrum away from that to justify.

That sums up the most common power meters you will find on the market, to conclude we’ve created a decision tree to help you narrow down your needs & priorities for choosing a power meter! Let us know how it helped you, and if there’s any other additional information or perspectives you’d like to read! And be sure to check out our team supporter Oak Bay Bikes for all your Power Meter needs!