Shimano 105 FC-R7100 12-Speed Crank Arm Assembly - 165mm
Build your perfect 12-speed setup — start with the right arms.
The Shimano 105 FC-R7100 Crank Arm Assembly is the hollow aluminium arm and spider from the full FC-R7100 crankset, sold without chainrings. Available in five lengths from 160mm to 175mm, it's the right starting point if you're sourcing chainrings separately, replacing bent or damaged arms, or building a custom gearing configuration your stock crankset can't offer. Hollowtech II interface, 110mm BCD, 12-speed chain compatibility — everything you need, nothing you don't.
Chainrings not included. This assembly pairs with any Shimano 12-speed 110mm BCD chainring — including the 50/34T and 52/36T sets available separately on PDL.Bike. It also accepts third-party 110mm BCD chainrings compatible with Shimano 12-speed chains.
What makes this worth it
Hollow Aluminium Arms
The same lightweight hollow construction as the full FC-R7100 crankset. Strong, stiff, and well-balanced for training and racing miles.
Choose Your Chainrings
Pairs with any Shimano 12-speed 110mm BCD chainring set. Mix 50/34T or 52/36T combinations to suit your terrain and gearing preference.
Five Arm Lengths
160, 165, 170, 172.5, and 175mm cover the full range of rider geometries. Choose the length that matches your bike fit.
Hollowtech II Interface
Drop-in compatible with any Hollowtech II bottom bracket — threaded, press-fit, and T47 shells all supported with the correct adapter.
Mechanical & Di2 Compatible
The FC-R7100 arm platform is shared across the R7100 mechanical and R7150 Di2 groupsets. One crankset. Two drivetrain options.
110mm BCD Spider
4-bolt 110mm BCD accepts standard compact and semi-compact Shimano 12-speed chainring pairs — the current generation standard for road groupsets.
Specifications
| Brand | Shimano |
| Series | 105 (FC-R7100) |
| Speed | 12-speed |
| Included | Crank arm assembly + spider (chainrings not included) |
| Arm Lengths | 160, 165, 170, 172.5, 175mm |
| Q-Factor | 145mm |
| Chainline | 43.5mm (170 / 172.5 / 175mm arms) |
| BCD | 110mm (4-bolt) |
| BB Interface | Hollowtech II |
| Compatible BBs | SM-BBR60, SM-BB92-41B, SM-BB71-41B (adapters for press-fit / T47) |
| Material | Aluminium alloy |
| Finish | Gloss Black Anodized |
| Chainrings | Sold separately |
| Groupset Compatibility | Shimano R7100 (mechanical), R7150 (Di2) |
(IFCR7100ARM)
Hollow Aluminium Arms
The same lightweight hollow construction as the full FC-R7100 crankset. Strong, stiff, and well-balanced for training and racing miles.
Choose Your Chainrings
Pairs with any Shimano 12-speed 110mm BCD chainring set. Mix 50/34T or 52/36T combinations to suit your terrain and gearing preference.
Five Arm Lengths
160, 165, 170, 172.5, and 175mm cover the full range of rider geometries. Choose the length that matches your bike fit.
Hollowtech II Interface
Drop-in compatible with any Hollowtech II bottom bracket — threaded, press-fit, and T47 shells all supported with the correct adapter.
Mechanical & Di2 Compatible
The FC-R7100 arm platform is shared across the R7100 mechanical and R7150 Di2 groupsets. One crankset. Two drivetrain options.
110mm BCD Spider
4-bolt 110mm BCD accepts standard compact and semi-compact Shimano 12-speed chainring pairs — the current generation standard for road groupsets.
| Brand | Shimano |
| Series | 105 (FC-R7100) |
| Speed | 12-speed |
| Included | Crank arm assembly + spider (chainrings not included) |
| Arm Lengths | 160, 165, 170, 172.5, 175mm |
| Q-Factor | 145mm |
| Chainline | 43.5mm (170 / 172.5 / 175mm arms) |
| BCD | 110mm (4-bolt) |
| BB Interface | Hollowtech II |
| Compatible BBs | SM-BBR60, SM-BB92-41B, SM-BB71-41B (adapters for press-fit / T47) |
| Material | Aluminium alloy |
| Finish | Gloss Black Anodized |
| Chainrings | Sold separately |
| Groupset Compatibility | Shimano R7100 (mechanical), R7150 (Di2) |
| SKU | IFCR7100ARM |
| Brand | Shimano |
| Shipping Weight | 0.9500kg |
