Planning to add a power meter to your Shimano crankset?
There are four options for you to consider;
- Left-sided
- Spider-based
- Crankset-based
- Pedal-based
In this article, we’ll explore the four options in detail.
Left-sided power meters
4iiii and Stages manufacture left-sided power meters that fit onto a Shimano crankarm;
- Stages Power Left
- 4iiii Precision 3
- 4iiii Precision
You can purchase the left crankarm with the built-in power meter. The unit weighs 9g for 4iiii and 15g for Stages.
With 4iiii, you can also send the existing left crankarm to them to fit the power meter unit.
They’re available in 165, 170, 172.5, or 175mm and for the Shimano 105, Ultegra, and Dura-Ace range, as depicted by the table below.
| Crankset model | 4iiii | Stages |
|---|---|---|
| Shimano 105 R7000 | Yes | Yes |
| Shimano Ultegra R8000 | Yes | Yes |
| Shimano Ultegra R8100 | No | Yes |
| Shimano Dura-Ace R9000 | No | Yes |
| Shimano Dura-Ace R9100 | Yes | Yes |
| Shimano Dura-Ace R9200 | No | Yes |
More reading : 4iiii Precision 3 vs Precision Power Meter Comparison
Crankset-based power meters
Besides left-sided power meters, 4iiii and Stages also have crankset-based (dual-sided) power meters.
- Stages Power LR
- 4iiii Precision Pro
There will be two power meter units, one each on the left and right crankarms. They’re available for these cranksets;
- Shimano 105 R7000
- Shimano Ultegra R8000
- Shimano Dura-Ace R9100
Spider-based power meters
For spider-based power meters, there are two options from Power2max.
- Power2max NG Road, the top-of-the-line model with ±1% accuracy, rechargeable battery, and advanced power metrics.
- Power2max NGeco Road, a mid-range model with ±2% accuracy and uses a CR2450 coin battery.
The Power2max will work the existing 4-bolt Shimano chainrings (110-4S), but will require a new crankarm from Rotor with 24mm spindle (ALDHU 24). The crankarms are bundled with the power meter.
More reading : Power2max NG Road vs NGeco Road Power Meters
Pedal-based power meters
For pedal-based power meters, you can choose between;
- Garmin Rally RS (Shimano) or RK (Look)
- SRM Exakt
- Favero Assioma
Pedal-based power meters are the easiest to install by just swapping out the existing pedals.
| Comparison | Garmin Rally | SRM Exakt | Favero Assioma Duo | Favero Assioma Duo-Shi |
|---|---|---|---|---|
| Accuracy | ±1% | ±2% | ±1% | ±1% |
| Weight (pair) | 320g to 326g | 310g | 303g | varies** |
| Connectivity | ANT+, BLE | ANT+, BLE | ANT+, BLE | ANT+, BLE |
| Battery | LR44/SR44 | Rechargeable | Rechargeable | Rechargeable |
| Battery Life | 120 hours | 30 hours | 50 hours | 50 hours |
| Cleat type | Shimano SPD-SL | Look Keo | Look Keo | Shimano SPD-SL |
| Pedal stack | 13.5mm | 10.5mm | 10.5mm | varies*** |
| Q-factor | 53mm | 54mm | 54mm | 64/65mm**** |
| Warranty | 1 year | 2 years | 2 years | 2 years |
| Price | $1100 (dual) $650 (left) | $1300 (dual) $750 (left) | $759 (dual) $495 (left) | $659 (dual) |
Notes :
- * Weight – Garmin Rally RS200 (320g), Rally RK200 (326g), Rally RS100 (160g), Rally RK100 (163g)
- ** Weight depends on the Shimano pedal body used. The spindles weigh 198g/pair and 314g/pair when used with a Shimano R8000 pedal body.
- *** Pedal stack depends on the Shimano pedal body used.
- **** Q-factor – 65mm (Shimano R8000/R6800), 64mm (R550/R540)
Garmin Rally
The Garmin Rally is the latest power meter by Garmin, with four models.
- RS200, dual-sided, Shimano SPD-SL cleats
- RS100, left-sided, Shimano SPD-SL cleats
- RK200, dual-sided, Look Keo cleats
- RK100, left-sided, Look Keo cleats
More reading : Garmin Rally RS200 Review
SRM Exakt
The SRM Exakt is an SRM power meter built into a Look Keo pedal. It’s available in single-sided (left) or dual-sided options.
Favero Assioma
The Favero Assioma is available in three variants;
- Assioma Duo, dual-sided, Look Keo cleats
- Assioma Uno, left-sided, Look Keo cleats
- Assioma Duo-Shi, dual-sided, Shimano SPD-SL cleats
The Favero Asisoma Duo-Shi is sold with pedal spindles only and without a pedal body. You’ll need to use an existing Shimano pedal and install it on the Favero Assioma Duo-Shi.
The compatible pedal bodies are the Shimano PD-R8000, PD-R7000, PD-6800, PD-R550, and PD-R540.
Alex Lee is the founder and editor-at-large of Mr. Mamil. Coming from a professional engineering background, he breaks down technical cycling nuances into an easy-to-understand and digestible format here.
He has been riding road bikes actively for the past 12 years and started racing competitively in the senior category during the summer recently.