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4iiii PRECISION PRO Shimano Ultegra R8000 Dual-Sided Crankset

Josh Matthew July 25, 2021
4.86 out of 5 based on 7 customer ratings
(7 customer reviews)


4iiii’s 3-D tri-axial strain gauge technology, dual-sided power and +/- 1.5% accuracy

Clear selection


4iiii PRECISION PRO Shimano Ultegra R8000 Dual-Sided Crankset

The 4iiii PRECISION PRO Shimano Ultegra R8000 Dual-Sided Crankset combines 4iiii’s patent pending 3-D tri-axial strain gauge technology with Shimano’s best-selling Ultegra R8000 crank. The result is an accurate, lightweight and highly reliable power meter crankset that is capable of tacking the most grueling workouts or races.

The dual-sided 4iiii R8000 crankset also features independent left/right power measurement. With a power sensor located on the inside of both crank arms, the power meter can measure the forces generated by each leg individually.

The 4iiii is also extremely lightweight, adding approximately 20 grams to the Shimano R8000 crankset. The power meter is compatible with both ANT+ and Bluetooth SMART devices and is accurate to +/- 1.0%.


4iiii Dual-Sided Power Meter Options

  • Chainrings: 50/34 | 52/36 | 53/39
  • Crank arm lengths: 165 mm | 170 mm | 172.5 mm | 175 mm



This power meter uses a 24 mm Shimano road spindle. Therefore, it is compatible with almost any bike when used with the correct bottom bracket.

Please note, this product requires a Shimano Crankarm Cap Tool (sold by us separately) for installation.


In the Box

  • 4iiii Dual-Sided Crankset
  • 2 CR2032 batteries
  • Quick Start guide


4iiii PRECISION PRO Shimano Ultegra R8000 Crankset Specs

Name4iiii PRECISION PRO R8000 Crank
Bike TypeRoad
Location of Power MeasurementCrank arm
Left or Both Legs MeasuredBoth
Independent Left/Right MeasurementYes
InstallationMore involved (60 min. estimated)
Communication ProtocolANT+ and Bluetooth SMART
Claimed Accuracy+/- 1.0%
Weight694 grams (170 mm, 50-34T)
Battery TypeCR2032
Battery Life100 hours
Method of Cadence MeasurementAccelerometer
Warranty3 years


7 reviews for 4iiii PRECISION PRO Shimano Ultegra R8000 Dual-Sided Crankset

  1. Stephen Pair (verified owner)

    Was amazed at how easy it was to install and get connected to everything. I love that I can just hop on and get power without calibrating and zeroing out before every ride. Also shipping was surprisingly fast, I got the powermeter before I received the tools to even put it on!

    • Power Meter City

      Great job Stephen! Thanks for taking the time to leave a great review on your new power meter crankset. We are here if there is anything else we can do! Ride safe!

  2. Patrick David

    Amazing customer service. I had ordered a different power meter. It was back ordered 3 weeks. I saw the 4iii was available. The team at Powermeter City quickly adjusted my order and had the powermeter in hand in days. LBS installed the product in 3 mins direct replacement. Downloaded the app and added the device to the app. Calibration is quick. The unit is working as designed, with no issues. Looking to make some gains and PR a few segments I have been trying to break for months.

    • Power Meter City

      Hi Patrick. Thanks for this awesome review! Looks like you are enjoying your new crankset – we hope you will continue to enjoy them and please let us know if there is anything else we can do! Ride Safe!

  3. BOONPENG (verified owner)

    Fast and efficient delivery. The power meter installed and working well with no issue. Would not hesitate to order again from this site if i need another set.

    • Power Meter City

      Hi Robert. Thanks for this awesome review – agreed! These pedals rock! Good luck on your future rides and please let us know if there is anything else we can do!

  4. Florian Neuberger (verified owner)

    4iiii Ultegra Dual Side: Coming from the left side only, the upgrade was totally worth it. The unit simply works, is reliable and accurate (tested with 2 other power-meters and a smart trainer). You even can set your leg imbalance for each site and if the battery dies on one side the measurement of the remaining side will be doubled according to your imbalance and sent to your cycling computer for a smooth ride home.
    It only lags advanced metrics, but that is not an issue for me.

    • Power Meter City

      Hi Florian. We are glad you are enjoying your 4iiii PRECISION PRO Shimano Ultegra R8000 Dual-Sided Crankset. Good luck on your future rides! Let us know if there is anything else we can help you with!

  5. Broc Atkinson (verified owner)

    I am very pleased with my overall experience with not only the product, but powermetercity as a whole. I had lots of questions, which were quickly answered on the website that guided me into purchasing the right power meter for me. Shipping was quick, and product worked just as described.

    • Power Meter City

      Hi Broc. Thanks for this! We are glad you found the right and amazing power meter for you. We hope you continue to enjoy them – good luck on your future rides! Please let us know if there is anything else we can do!

  6. Thomas Airth (verified owner)

    This is a great product have had no issue with them thus far. Been out on a few rides now with them now and they have gone swimmingly. They were sent in a timely manner as well.

    • Power Meter City

      Hi Thomas. Thanks for this kind review. We are happy its working fine and we hope you continue to enjoy them. Please let us know if there is anything else we can do!

  7. Brendan Dolan (verified owner)

    Great meter but…had a known problem setting it up. The battery case on the right side battery contacts needed to be moved to ensure contact with the battery. After I did that, works perfectly. Incredible service from Josh at Power Meter City. Thank you Josh, well done and thanks.

    • Power Meter City

      Hi Brendan, good to hear that! Thank you for leaving a review and for being a great customer. Let us know if there is anything else we can do in the future.

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