4iiii Precision Powermeter Left Side | Shimano Ultegra R8000 | 172.5mm | Measures Each Pedal Stroke with 3 Strain Gauges

For quite some time, I've been weighing the different technological options for getting a power meter for my road bike: pedal, crank, or hub-based. With this power meter now on the market, it was time to take the plunge. I really liked the up-front communication from the seller (Power Meter City) to make sure that my bike configuration would have enough space, which it did. It took 3 weeks for me to actually get to the installation, because there was one important, inexpensive, but indispensable tool that I didn't have to remove the original left crank arm and install this one: SHIMANO Hollowtech-II Crank-arm/Cap Tool, TL-FC16. You definitely need it in addition to the 5 mm allen torque wrench.

Great power meter for the money. Read a ton of reviews on several different kinds and brands of power meter, narrowed down to left arm cranks then to 4iiii. Installation very straight forward, takes about 5 minutes to remove old crank arm and install this. Use their app to zero and away you go. The few rides I’ve had with it have been great.

Easy install and setup

Very easy setup. Took about 10 minutes to install and setup using my CATEYE computer. Seems to be pretty accurate.

Works great! Love it!!!

Durante el cambio de la batería , una de las solapas blancas que ayudan al cierre se daño impidiendo el correcto cierre , lo cual al mojarse se daño la biela de potencia.El ciclo computador no registra el sensor de potencia, lo cual indica su daño.Me comuniqué con la marca 4iii y al estar en los 3 años de garantía me dicen que me contacte con el dealer al quien le compré el sensor para solicitar un RMA para reparación o reemplazo.Quedo atento a sus comentarios.

I decided to try de 4iiii instead of my previous Stages power meter due to positive reviews. What no one seems to mention, is that the 4iiii module (where the batteries goes) is very thick and touches with my frame. I had to offset the crack arm by 3 mm, which is not ideal. I can't believe this flaw of design. I hope at least it has good power readings and that the offset, doesn't bother me. Just for this I would not recoment.

Its a good product but when it has problems pray because the customer service never answer the email and ee doesnt have a number to call. The only thing i have to buy a new one meanwhile i wait for the response.