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4iiii PRECISION 3+ Shimano Ultegra R8000 Power Meter

Josh Matthew November 15, 2024
4.94 out of 5 based on 32 customer ratings
(32 customer reviews)

$389.99

4iiii’s PRECISION power meter combined with Shimano’s Ultegra R8000 groupset

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4iiii PRECISION 3+ Shimano Ultegra R8000 Power Meter

Introducing the all new 4iiii PRECISION 3+ Shimano Ultegra R8000 Power Meter. 4iiii has combined their patent pending 3-D tri-axial strain gauge technology, measured at +/- 1.0% accuracy, with Shimano’s best of breed Ultegra R8000 groupset. The result is one of the lightest, most affordable and most accurate direct force power meters available.

The PRECISION determines your total power based on the force that is generated by your left leg. This left-only design allows for a power meter that is lightweight and easy to install. Specifically, the power meter adds only 9 grams to your crank arm and is installed in about 10 minutes. In addition, the PRECISION is compatible with both ANT+ and Bluetooth SMART devices. This means you can use it with your favorite bicycle computer, watch or smart phone.

 

Key Product Details

Compatibility:

This power meter is compatible with Shimano R8000 cranksets. It can also be installed on other Shimano road cranksets, as long as they use Shimano’s Hollowtech II interface. See Compatibility tab for more information.

Power Measurement:

This 4iiii power meter measures left leg power and doubles the value to account for both legs (assumes both legs are generating the same force).

New 4iiii R8000 PRECISION 3+!

The all new 4iiii R7000 PRECISION 3+ power meter features the following improvements over the version 2:

  • Apple Find My which allows you to always know where your bike is!
  • 800 hours of battery life – the longest coin cell battery life in a power meter on the market!
  • Sleeker, slimmer profile making most incompatibility issues a thing of the past.
  • Stronger antenna for even better connectivity.
  • Indicator light for battery life, successful zero-offset and when the unit has been turned on.

Key Features:

Affordable, accurate to within +/- 1.0%, lightweight at only 9 grams of added weight, 800 hours of battery life, CR2032 user-replaceable battery, ANT+ and Bluetooth compatible, easy to install, 3-year warranty. See Specs tab for more information.

Advice From Our Staff:

4iiii left side crank arms are some of our best-selling units. They work with most Shimano cranksets, are affordable and easy to install. The one consideration is they only measure left leg power compared to some other power meters that measure power from both legs (those versions usually cost more however).

 

Options For This Power Meter

Crank arm lengths: 165 mm | 170 mm

 

Other Versions to Consider

Dual-Sided R8000 Crankset: We also sell the 4iiii PRECISION PRO Shimano Ultegra R8000 Dual-Sided Crankset which is a complete crankset. It is more expensive, however it measures power from both legs.

Compatibility

Crankset: This 4iiii power meter is compatible with Shimano R8000 cranksets.

Please note, the power meter can also be installed on other Shimano road cranksets, as long as they use Shimano's Hollowtech II interface. These cranksets can easily be identified by the two opposing pinch bolts that are used to secure the left side crank arm. Please see the image below and contact us if you have any questions on compatibility.Shimano Hollowtech II Left Crank Arm

Check Frame Clearance: Crank-arm based power meters attach a sensor on 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 8 mm of clearance for the PRECISION 3+. Also, make sure that you don't have a bottom bracket mounted rear brake (used on some aero and TT bikes). The important area to measure is right in the middle of the crank arm. Please refer to the image below.

If you find that your clearance is close but not quite sufficient, what many people will do is simply install a 1 or 2 mm bottom bracket spacer (between the left crank arm and the frame). This should provide you with the clearance you need.

The clearance between the frame and left side power meter crank arm

4iiii PRECISION 3+ Shimano Ultegra R8000 Specs

Name4iiii PRECISION 3+ Ultegra R8000
Bike TypeRoad
Location of Power MeasurementCrank Arm
Left or Both Legs MeasuredLeft only
Independent Left/Right MeasurementNo
InstallationEasier
Crank Arm MaterialAluminum
Communication ProtocolANT+ and Bluetooth SMART
Claimed Accuracy+/- 1.0%
Automatic Temp. CompensationYes
Weight9 grams (sensor) | 208 grams (170 mm)
Battery TypeCR2032 coin cell
Battery LifeVersion 2: 100 hours / Version 3+: 800 hours
Method of Cadence MeasurementAccelerometer
Warranty3 years

In the Box

  • 4iiii PRECISION Shimano Ultegra R8000 Power Meter
  • CR2032 coin cell battery

Tools Needed for Installation

You will need the following tools for installation of this product. You can purchase many of these commonly used tools in our store.

  • Shimano Crank Arm Cap Tool
  • 5 mm Allen key

Common Questions and Answers

Question: What is the difference between the 4iiii PRECISION 2 and PRECISION 3+?

Question: How do I determine what length my current cranks are so I can make sure I get the same size?

  • Your crank arm length should be printed or stamped on the inside of the left crank arm, usually near the pedal end.

End of crank arm showing crank arm length

32 reviews for 4iiii PRECISION 3+ Shimano Ultegra R8000 Power Meter
  1. David Morimoto (verified owner)

    I had a very positive experience with Power Meter City. Before making my order, Josh from Power Meter City answered my questions about bike compatibility and tools required for the installation of the 4iiiii power meter. After I submitted my order, PMC shipped the product on the same day. While there was a slight delay in the actual delivery, this was strictly on the UPS side, which I was informed of via the UPS notifications. My power meter arrived in a reasonable timeframe and I was able to install it without too much trouble. I was able to use the power meter data, along with a heart rate monitor, to help me properly pace a climb recently. I’m very happy with my 4iiii Shimano Ultegra R8000 power meter thus far.

    • Power Meter City

      Glad we could help! Thank you for this kind review, David. It was a pleasure doing business with you! We hope you will continue to enjoy your new power meter and if there is anything else we can do, please let us know!

  2. Mike Marsh (verified owner)

    I am very happy with the 4iii Precision 3 from PMC. Josh was very knowledgeable, friendly, and helpful. He even responded to my e-mails after regular business hours. PMC is one of those businesses (and there aren’t many) that I am glad to be a customer of. The 4iii was easy to install, wakes up and calibrates every time. It’s just right for me. Thank you Josh and PMC.

    4iiii PRECISION Shimano Ultegra R8000 Power Meter on a Trek bicycle

    • Power Meter City

      Hi Mike! It was a pleasure doing business with you too! Your crankset looks awesome! Thank you for this kind review. If there is anything else we can do to help, please let us know!

  3. Luke (verified owner)

    Great price… The Precision is pretty good. My gravel bike uses a Stages Gen 3. Between the two, I feel that the 4iiii is quicker to wake up when I start my Garmin computer… Usually within a few seconds. The Stages will often take a minute or 2. I often will need to search it out to calibrate. They bother calibrate the same way and I don’t think the performance is any different. I think the 4iiii is a little taller and may cause clearance issues near your frame. I haven’t had it long enough to know about battery life, but the new version is supposedly vastly longer. I do prefer the Stages app to the 4iiii one – the 4iiii is pretty bad. I admit that I got the 4iiii because the Stages was out of stock everywhere in my 170mm crank size. However, I am very satisfied with the 4iiii and Powermetercity’s service and awesome price.

    • Power Meter City

      Thank you Luke, Glad you are happy with your purchase! We hope you will continue to enjoy them and we are here if there is anything else we can do! Ride safe!

  4. Rodrigo Muñiz (verified owner)

    Excellent, I installed it on my CH2 Tere without any problem. It synchronises very well with my garmin edge 530.
    I have doubts about the battery door, I am a little nervous that it can open mid-ride, hopefully not.

    • Power Meter City

      Hi Rodrigo, Thank you for this kind review on your new 4iiii PRECISION Shimano Ultegra R8000 Power Meter – we hope you will continue to enjoy them. Good luck on your rides and please let us know if there is anything else we can do!

  5. Jim Brewer (verified owner)

    Thanks PMC for the prompt handling and shipping of my 4iii power meter. I was using a heart rate monitor, but with the power meter I find myself not only enjoying looking at all of the data during and post ride, but pushing harder because I can now see what is actually occurring. The zero offset is simple as is setup. Thanks again, Jim

    • Power Meter City

      Glad we helped you find a solution Jim and thank you for taking your time to leave us an awesome review! We are here if there is anything else we can do! Ride safe!

  6. Carlos Silva (verified owner)

    Very happy with my 4iiii, so far so good, the customer service from PMC has no rival they were able to accommodate all of my requests. Thank you guys once again!

    • Power Meter City

      Thank you for this Carlos – we also want to thank you for being a great customer! We hope you will enjoy your new power meter! Let us know if there is anything else we can do! Ride safe!

  7. Stacker (verified owner)

    PMC is as great outfit to work with. Packing, shipping and support all exceed expectations. I now have two 4iiii left side crank arms. Both have significant miles in all conditions. Both perform excellent and I have no concerns/complaints with my purchase.

    • Power Meter City

      Thanks for this Stacker – we really appreciate it! We are glad you liked your new 4iiii PRECISION Shimano Ultegra R8000 Power Meter. If there is anything else we can do, please let us know! Ride safe!

  8. Sean (verified owner)

    This is a game changer. Having the power information while riding helps immensely with managing training load and conserving energy on longer rides. Installation was easy and just took about five minutes. (Be sure you have a torque wrench.) Power Meter City provided a great level of service, which I found about perfect for an internet merchant.

    • Power Meter City

      Thanks for this awesome review Sean – We hope you will enjoy your new power meter! Please let us know if there is anything else we can do to help. Ride safe!

  9. Tony (verified owner)

    I was concerned I would not receive the latest 4iiii power meter. I sent an email and Josh responded promptly. He assured me that I would receive only the latest device, which really put my mind at ease and an end to my search. My 4iiii power meter arrived quickly and with a follow up from Power Meter City about any concerns of which they were none. THANK YOU SO MUCH PMC!

    • Power Meter City

      Thanks for this kind review Tony. We are glad you finally have your new power meter – we hope you will enjoy them. Please let us know if there is anything else we can do!

  10. Tom S (verified owner)

    The 4iiii template indicated the PM might be a close fit to the chain stay but all went well with several mm to spare. Installation was a snap and the PM paired immediately to both the 4iiii android app and the Garmin head unit. Now I have power on both my smart trainer bike and my outside ride. Sweet.

    • Power Meter City

      Great! Thanks for letting us know Tom. We hope you will continue to enjoy new power meter! Let us know if there is anything else we can do! Ride safe!

  11. Jeramie Thompson (verified owner)

    After researching several different options, I decided to go with the 4iii and couldn’t be more happier and impressed with this power meter. The package shipped quickly and arrived unharmed. The crank was an easy install and paired with my Garmin 520 perfectly. Been on several rides with it and I’m impressed with how easy it is to use and works with my computer. Thanks Power Meter City!

    • Power Meter City

      Looks like you are enjoying them – good luck on your rides Jeramie. Please let us know if there is anything else we can do! Ride safe!

  12. Mal (verified owner)

    Foremost the 4iiii PM arrived on the other side of our planet in a timely fashion and it was nice to see it was appropriately packaged.
    As a previous post has commented, my Canyon Endurace chainstay didn’t allow this crank to fit (only by a cats whisker) but this was quickly remedied with a spacer with no issues. From there setup was achieved in no time. Josh from PMC responded to my emails in a friendly and professional manner.
    I’m very pleased with both product and service.

    • Power Meter City

      Hi Mal. Thank you for this kind review! We hope you will enjoy your new power meter. Good luck on your rides and we are here if there is anything else we can do!

  13. Ron (verified owner)

    Impressive delivery speed, expected to be delay due to COVID-19 pandemic, but end up received earlier than expected. Good product, good price, finally with a power meter without burning a big hole on my pocket..thx powermetercity:)

    • Power Meter City

      Hi Ron. We really appreciate this! Thank you for being a great customer too. We are here if there is anything else we can do!

  14. gaston2010 (verified owner)

    Amazing power meter.
    Great results riding your bike, it’s perfect for jumping into the power meter metric to control your performance.
    You will be able to get faster and doses your power.

    • Power Meter City

      Thanks for this Gaston. We hope you will continue to enjoy your 4iiii PRECISION Shimano Ultegra R8000 Power Meter. We are here if there is anything else we can do!

  15. Cullen M (verified owner)

    Quick and easy delivery from PM, works well! Make sure to order the Shimano crank tool.

    • Power Meter City

      Hi Cullen. Thanks for this kind review! We hope you will continue to enjoy your new 4iiii PRECISION Shimano Ultegra R8000 Power Meter. We are here if there is anything else we can do!

  16. STEPHEN ESMACHER

    Power Meter City (PMC) is great to do business with. Before ordering the Ride Ready – Left Side version I reached out to 4iiii and there was a little confusion about whether there would be sufficient chain stay clearance on my Canyon Endurace. They said it would so I ordered one from PMC but it didn’t have sufficient clearance. PMC took it back and gave me a full refund. I hope I have a need to do business with them again.

    • Power Meter City

      Hi Stephen. Thanks for this. Let us know if there is anything else we can help you with!

  17. Marcos Pereira (verified owner)

    Easy to install, light and good price!

    • Power Meter City

      Hi Marcos. Thanks for this kind review! Let us know if there is anything else we can help you with!

  18. Adam Phillips (verified owner)

    This thing is awesome!! I have been riding for a little over 22 years with a few years of racing. I had a power meter years ago, back before things was this simple. I can’t believe how easy and affordable this 4iiii is. Only takes a few minutes to put on and works perfectly out of the box. Plus you get cadence as well. It will not give you individual leg watts unless you buy the dual, but for me I don’t need that. Not a lot of difference between my two legs and no matter what I do can’t seam to change that. The single arm doubles you out put at the crank and gives a very accurate reading. Also like getting the reading at the crank not the wheel so I can see what I’m doing not the loss of drive chain and wheel. Great product great place to buy from as they are on top of their game. It got shipped out right away. I have no doubts that the customer service is out standing although I have never had to use it. If you want to get better at cycling, power out put is the best information tool you can have and at this price its very affordable

    • Power Meter City

      Hi Adam. You’re right! This 4iiii PRECISION Shimano Ultegra R8000 Power Meter really works great! Thank you for this awesome review! We hope you will continue to enjoy them and please let us know if there is anything else we can help you with!

  19. Dave Fishman (verified owner)

    Love the power meter has opened up a different way to train. And train more accurately. Power Meter City delivers great service at an affordable price. Was going to purchase earlier but they were out of stock. Had them add me to email list when available. Got notified purchased the meter and was delivered on time. Thanks for the great service.

    • Power Meter City

      Hi Dave. Looks like you are enjoying your new 4iiii PRECISION Shimano Ultegra R8000 Power Meter. We want to thank you for being a great customer! Let us know if there is anything else we can help you with!

  20. Fazlee

    Excellent product! Flawless pairing to my Garmin Edge 530 and Forerunner 945. Comes packaged very nicely. I don’t use the 4iiii app for much, but for updating the firmware of the power meter, it worked effortlessly on the first try. Power meter installs easily of course, just the standard 2 bolt interface for Hollowtech II cranksets.

    The item was shipped out the same day I placed the order (maybe even within the hour!) and I received it a week later (thanks pandemic + elections shutting down the local mail office).

    Happy purchase, happy result, and I will definitely return here the next time I purchase a power meter (which will likely be soon now that my wife has seen what this does…)

    • Power Meter City

      Hi Fazlee. Looks like you are enjoy your new 4iiii power meter! Good choice BTW. Good luck on your future rides and we are here if there is anything else we can do.

  21. joel mclarry (verified owner)

    Power meter works great with wahoo bolt. No issues, power drops or spikes. Very easy install that took 5 minutes.

    • Power Meter City

      Hi Joel. Thanks for leaving a great review on your 4iiii PRECISION Shimano Ultegra R8000 Power Meter. We hope you continue to enjoy them and we are here if there is anything else we can do!

  22. Chuck P (verified owner)

    Doing a new build and since I have a 4iiii Precision power meter on my other bike (b-day present last year) that has been flawless, why fix what ain’t broke? Very fast shipping from Power Meter City. Easy peasy installation and pairing to my head unit (Wahoo ROAM with associated iPhone app). The only learning curve was figuring out you can’t pair two power meters at the same time on the 4iiii app. Minor inconvenience, but not a big deal. But it does mean having to unpair one power meter and re-pair the other whenever I switch riding bikes. Otherwise, the 4iiii Precision power meter works as advertised, i.e., it tells me how much I suck. 🙂

    • Power Meter City

      Hi Chuck. Thanks for this! Good choice BTW. We hope you continue to enjoy your new 4iiii PRECISION Shimano Ultegra R8000 Power Meter. We are here if there is anything else we can help you with!

  23. Kris J (verified owner)

    This is an excellent power meter. Took 5 minutes to install and link with head unit. That’s it. Works exactly how it should.

    • Power Meter City

      Wow! Thanks for this Kris. We hope you continue to enjoy your 4iiii power meter and we are here if there is anything else we can do!

  24. jpipkens (verified owner)

    First to the credit of Power Meter City; ordering was easy. I ordered on 8/3/20, it shipped on the 4th and was in my mailbox on the 7th! After pouring over reviews of Stages vs 4iiii I decided to go with this PM. The packaging and product itself are top notch, like opening an Apple iPhone. Installation was easy and took just minutes. No issues here with the app or connectivity. Everything synced well with my Wahoo Elemnt Roam. Calibration is easy and initiates right from my Wahoo computer. Just make sure the bike is perfectly still and the cranks are perfectly vertical. My biggest concern was accuracy so I ran multiple comparisons. One was the crank PM paired with my Wahoo Roam. The other was my Wahoo Kickr controlled by and paired with Zwift in ERG mode. I put all of the .fit files into DCR Analyzer and was pleased with the result. The power output of the crank is very spiky and of course cannot show left/right leg imbalances, but thus is the nature of left sided PMs. Across the entire plot though the averages matched up and I did not see any drift over time. Satisfied with that I began playing with the zero offset from the 4iiii app, which does work nicely in either direction, and luckily for me the zero setting on mine was the closest match to my Kickr’s output. All in all I could not be happier with the purchase and the product itself. I love using the metrics of power to pace and push my indoor training and now I’ve found a reliable way to take it on the road! Buy it and enjoy!

    • Power Meter City

      HI jpipkens. Nice job! Wow! We are glad you are enjoying your 4iiii PRECISION Shimano Ultegra R8000 Power Meter. Good luck on your future rides – we hope you continue to enjoy them and please let us know if there is anything else we can do!

  25. Dennis Gately

    Receiving the crank arm with power meter in just 3 days was astonishing considering shipping & deliveries during the coronavirus. The crank arm was easy to install and I got the power meter up & running quickly. Pairing to my Garmin 820 took very little effort and I am now enjoying having my power data on display whenever I ride. Thanks ???? 4iiii & Power Meter City!

    • Power Meter City

      Hi Dennis. We are glad it worked perfectly as expected. Good luck on your future rides! We hope you continue to enjoy them and please let us know if there is anything else we can do!

  26. Aaron Braswell

    Simple, fast, and awesome! Works great. Thanks for making it easy!

    • Power Meter City

      Hi Aaron. Thanks for this kind review. We are glad it worked great as expected! Please let us know if there is anything else we can do!

  27. Marc Saunders (verified owner)

    Power meter was simple to install and configure on Garmin and Zwift, and delivery to a small island in the Atlantic was speedy!!

    • Power Meter City

      Hi Marc, we are glad you got your 4iiii PRECISION Shimano Ultegra R8000 Power Meter on time. We hope you continue to enjoy it! Please let us know if there is anything else we can do!

  28. Luke Caldwell (verified owner)

    Power meter works great and it was cheaper than what I saw other places online. Customer service was top as well. They even called to make sure I had selected the correct one and had it shipped out same day.

    • Power Meter City

      Hi Luke. Thank you for leaving this great review on your 4iiii PRECISION Shimano R8000. We appreciate your business with us and we are here if there is anything else we can do!

  29. Dayle James (verified owner)

    Couldn’t have been easier to sync with my wahoo and get on the road! Based on my experience with other power meters, this has been very accurate, great battery life, and handles well in weather. Now it’s on me to get my FTP up! Already looking at other 4iiii for my other bikes!

    • Power Meter City

      Hi there Dayle! Good choice for your power meter! We hope you continue to enjoy them and Yes, please let us know if there is anything else we can do!

  30. John kneebee (verified owner)

    I’ve been using the 4iiii precision r8000 for about a month now and have logged 2k Mike’s with it. It has been flawless! I did several comparisons to its power numbers benchmarking against my wahoo kickr and it has been +/- about 2 or 3 watts which for a single sided unit for $350 is great to me. Also it is very easy to install and to calibrate. If I had to say one criticism it’s that it would be nice if it had an auto zero feature because sometimes I have forgotten to do the zero offset calibration pre ride. Other than that it’s great I would highly reccomend also side note shipping was very fast 2 days which was awesome!

    • Power Meter City

      Hi John. Thanks for this awesome review! Keep up the good work! We hope you continue to enjoy them and we are here if there is anything else we can do!

  31. M SeN Brannon (verified owner)

    After watching countless YouTube videos and read many reviews, I decided the 4iiii was to be my entry into the power meter world. I made a great decision. Installing was easy, and syncing it to my Garmin edge 520 was trouble free. Synced the meter to the 4iiii app, and done. First ride I was getting readings all over the place. Then a friend suggested that I only use it for a 3 second power average. That was what I needed. I was looking for similar readings to what I see on my smart trainer, while using zwift. Really happy with my purchase.

    • Power Meter City

      Hi M. Thanks for dropping us a quick note on your 4iiii. Yes, 3 or 5-second power smoothing is definitely the way to go! We hope you continue to enjoy it and we are here if there is anything else we can do.

  32. R. Gannon (verified owner)

    Works perfectly! No issues with the unit and super easy to use. I’m using with Wahoo bolt and is seamlessly easy. Had an initial fitting issue with frame clearance but Josh was super helpful and I was up and running same day. I wish more businesses were this way.

    • Power Meter City

      Hi Rob. Thanks for the review on your 4iiii PRECISION R8000. I’m glad we could get you squared away and I hope you continue to enjoy it.

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