4iiii Power meter

The US sports electronics manufacturer and wearable electronics specialist 4iiii has already caused a sensation with the 4iiii Precision Powermeter, which is to be offered in the American market for 399 USD, when it was presented at the Interbike in autumn 2014. We had the chance to talk to the 4iiii team about this highly interesting power meter at the ISPO in Munich in early February.

This is how the 4iiii Powermeter is constructed

At first glance, the 4iiii Precision Powermeter is similar in design to a Stages Powermeter. A small plastic box which is applied (glued) to the crank arm from the inside. A CR2032 button cell is used as battery and data transmission can be done via ANT+ and Bluetooth.

However, the 4iiii Powermeter offers some interesting possibilities that are not currently available with the Stages Powermeter:

  1. The 4iiii Powermeter can be mounted on the left crank arm as well as on the right crank arm.
  2. The power meter can be mounted on either crank arm and in this setup provides full, dual-sided measurement.
  3. The 4iiii Powermeter can be mounted on existing crank arms by the dealer after special training.
  4. In a further step it should be possible to mount the 4iiii Powermeter at home even on the already existing crank arm.
  5. The 4iiii powermeter should soon also work for carbon crank arms.

The manufacturer promises here that the product name 4iiii Precision Powermeter is also program and advertises with a measuring accuracy of less than +-1% – A value that otherwise only the science – Powermeter of SRM reach.

Besides the advanced data transmission technology and the up to now unique possibility to mount the power meter on your own crank, the 4iiii Precision Powermeter offers an active temperature compensation and a battery life of 200 hours (about 5000-6000km at 27,5 – 30 km/h).

Price of the 4iiii Precision Powermeter

Currently only prices for the US market are known, which are 399 USD for the single sensor (right or left) and 749 USD for the double-sided sensor set (right and left). The prices in Euro have not been fixed yet, but with regard to the current dollar exchange rate, import duties, shipping costs and a surcharge of 19% – 23% percent for the sales tax due in Europe, they should be in the range of 400 – 500 € for the single sensor, or 800 – 900 € for the double-sided set. This would make them by far the most affordable power meter on the market.

Delivery of the 4iiii Precision Powermeter

The delivery in the USA and Canada is planned for March 2015, when we will be able to offer the new 4iiii power meter in Europe is unfortunately not yet known, but we are still in close contact with 4iiii in the USA and will be happy to inform you directly about news.

In addition to our information, the well-known bike tech blogger DC Rainmaker has of course already dealt with the 4iiii Precision Powermeter and was even able to test it once.

What DC Rainmaker says about the 4iiii Precision Powermeter

– The assembly of the Powermeter at the own crank arm was very simple and in approx. 5 minutes to settle (without the drying time for the epoxy resin) and this although the tools and aids supplied with the test Powermeter were still in the prototype status.

– Crank compatibility: All aluminum cranks with a smooth surface on the inside. This was tested with several generations of Shimano 105, Ultegra and DuraAce and Deore XT cranks, with SRAM Rival and FSA Energy cranks. Rotor cranks are not compatible because they have a ribbing on the inside and not a smooth surface. Further tests are being carried out in the “Carbon” area, but things are currently looking good.

– Required clearance on chainstays and chain: The Powermeter builds up about 9mm on the crank arm, but the positioning on the crank arm is flexible, so you can take the place that fits best.

– Temperature compensation: The 4iiii power meter has an active “learning” temperature compensation. This means that the power meter sets the zero-offset calibration points at different temperatures and thus “learns” itself how the measurement technology reacts to temperature changes in the individual case. This is due to the fact that the Powermeter cannot be calibrated to a temperature curve in the manufacturing process, as this must be done after it is mounted on the crank arm.

– Water resistance: This is IP65 standard, so slightly better than IPX7. Thus the sensors are sufficiently protected against water, even if you hose down your bike with a garden hose (not a high-pressure cleaner).

Similar to 4iiii powermeters, Stages powermeters are built for quick and easy installation by simply replacing the left crank arm. A single sided alternative that measures pedal based would be the Favero Assioma Uno. Who is ready to spend a little more money, than for a 4iiii Powermeter receives nowadays also for under 1000, – € a two-sided Powermeter. The Garmin Vector 3 and the Powertap P2 fall into this category, as does the Favero Assioma Duo.

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