Well the good news is…you have a lot of options. I guess this is also the bad news as it can make deciding more difficult! 🙂 Ok, here goes:
Left Crank Arm Power Meter
4iiii and Stages Cycling both make crank arm power meters for Shimano R8000. You just swap out your current left crank arm for the new power-equipped one and you are good to go. These power meters measure power from your left leg and double to value to approximate your total power.
Please note, these power meters attach a sensor to the inside of the left crank arm. On some bikes, there is not enough room between the left crank arm and the chainstay for the sensor to clear the frame. Therefore, you should make sure you have at least 10 mm of clearance for Stages and 4iiii PRECISION 2 power meters and 8 mm of clearance for 4iiii PRECISION 3 power meters. Also, please make sure that you don’t have a bottom bracket mounted rear brake (used on some aero and TT bikes). Please refer to the image below.
Pros: Affordable, easy to install, don’t have to change crankset
Cons: Measures left leg power only
Crankset Power Meter (Spider Based)
power2max ROTOR ALDHU Road Power Meter Crankset (staff favorite)
This is a new crankset (power meter spider, crank arms and spindle), excluding chainrings. power2max makes wonderful power meters. They measure both left and right leg power, are reasonably priced and are as good as it gets in terms of reliability. If you select the 24MM spindle option, it will fit your current bottom bracket exactly like your Shimano crankset (no need to change bottom brackets). In addition, if you select the Shimano 4-Bolt spider, you can even use your Shimano R8000 rings on it.
This too is a new crankset (power meter spider, crank arms and spindle) and can be purchased with or without chainrings. The INspider measures both left and right leg power, comes in a variety of crank arm lengths and can be set up in a 1X or 2X chainring configuration. This power meter can also be purchased with a 24MM spindle so it will fit your current bottom bracket without any changes. You can use your current Shimano chainrings on it or buy new ROTOR rings.
Like the power2max above, this is spider-based crankset and it’s a wonderful option as well. You would purchase the DFour Power Meter spider as well as Quarq DZero DUB crank arms. At $640, this is quite a bargain for a high-end power meter and carbon crankset. However, there are two considerations with this option:
1) The power meter is designed for use with Shimano DURA-ACE 9100 chainrings. Shimano Ultegra R8000 chainrings and 105 R7000 rings will work, however they will not match the shape or color of the power meter as nicely.
2) Unlike the power2max and ROTOR options above that will fit your current bottom bracket, the DFour requires a SRAM DUB Bottom Bracket. They are relatively inexpensive, but it does make installation a bit more involved.
Pros: Moderately priced, VERY reliable, measures both legs
Cons: Have to change your crankset
Crankset Power Meter (Crank Arm Based)
In addition to making left side crank arms for Shimano, 4iiii and Stages also make complete dual-sided R8000 cranksets. With these power meters, you get a new Shimano crankset with a power sensor attached to the inside of the left and right crank arm. Therefore, they are able to measure power from both legs as well as tell you how much power each leg is producing individually.
Please note, as with the left side power meters above, you need to confirm you have 10mm of clearance between the left crank arm and the chainstay in order for the sensor to clear.
Pros: Measures both legs, provides independent left/right power
Cons: More expensive
Power Meter Pedals
Power meter pedals can be installed on any crankset. We have several models to choose from.
Pros: Easy to install, works on any bike, can move from bike to bike, don’t have to change crankset