Rearward sensors for road bikes are important accessories that increase safety when cycling. The following is a summary of their advantages and disadvantages and a comparison of specifications of major products.
Table of contents
4iiiii Power Meter Features
Crank-type power meter
All 4iiiii power meters are crank-type power meters. Our patent-pending original technology “3D Power Meter Technology” realizes highly accurate power measurement.
For commercially available products, compatible cranks are Shimano cranks, which are basically the left crank without chainrings, so you can use them by replacing only the left side of your Shimano crank with a 4iiiii power meter crank. As for the double-foot sensor model, both the left and right sides are Shimano cranks with sensors attached to them.
The models available are the following Shimano Hollowtech II cranks
- 105 FC-R7000
- ULTEGRA FC-R8000 DURA-ACE FC-R9100
- GRX FC-RX810
- XTR FC-M9100 XT FC-M8100
There are choices from 165mm to 175mm.
On the other hand, there are also factory-installed models, where you send your crank to the 4iiiii factory to have a power meter installed.
In this case, cranks from SRAM, Kampa, FSA, etc., which are not available on the market, are also supported (compatible models are limited)
4iiiii lineup of power meters
The top-of-the-line model of 4iiiii’s power meters, the PRECISION PRO is a dual-foot sensor model that provides more accurate power measurement and also supports left-right power balance measurement.
The price is about 2.5 times higher than the left foot only model.
It also supports “Factory Install” which sends your crank to 4iiiii.
PRECISION 3 is the latest model in the non-PRO series of PRECISION, the popular grade of 4iiiii power meters.
Compared to the previous model, PRECISION 2.0, the battery life has been significantly increased to 800 hours, and the thickness of the sensor body has been reduced by 2 mm to a wider horizontal design. Other than that, the power/cadence measurement, weight, etc. are the same as in PRECISION 2.0.
Like PRECISION PRO, it also supports “Factory Install,” which sends your own cranks to 4iiiii.
PRECISION 2.0 is the predecessor to PRECISION 3, with a battery life of over 100 hours, which is less than the latest model, and a thickness of 7.5 mm, 2 mm thicker.
Other than that, the power/cadence measurement and weight are similar to PRECISION 3, and the price is a little lower, so if cost performance is important to you, PRECISION 2.0 may be a good choice.
How to choose a 4iiiii power meter
Double-footed or single-footed?
First of all, the choice depends on whether you want a two-foot sensor or a one-foot sensor.
If it is a two-foot sensor, you can choose PRECISION PRO, and if it is a one-foot sensor, you will have the choice between PRECISION 3 and PRECISION 2.0.
For more accurate power training, the PRECISION PRO, which can measure left and right power accuracy, is better, but if you simply want to measure power, the PRECISION 3 or PRECISION 2.0 will do the job.
Decide by the grade of cranks and components
The 4iiiii power meter is based on the model installed on Shimano cranks, so if it is a one-sided sensor, you should choose the same grade as the cranks installed on the road bike you are using.
However, the Shimano cranks used by the 4iiiii power meter are Hollowtech II cranks, so even if they are not the same grade or model number, they can be used if the crank length is the same (this is not recommended usage).