Upgrading crank arms can improve pedal feel, geometry, and efficiency on road bikes. This guide highlights reliable options from trusted brands, covering different hole types, sizes, and materials to help you choose a compatible, high-quality crank arm set. Below is a quick reference of five well-suited picks, followed by in-depth product details and a buying guide to assist with a confident purchase.
| Product | Hole Type | Sizes | Material |
|---|---|---|---|
| Alps2Ocean Bike Crank Arms | Diamond Hole | 89mm–175mm | Forged Alloy 6061 |
| Alps2Ocean Universal Left Crank Arm | Diamond Hole / Square Hole (Left) | 152mm–175mm | Forged Alloy 6061 |
| Alps2Ocean Square Hole Crank Arm Set | Square Hole | 140mm–175mm | Aluminium Alloy |
| THALOUS Universal Left Crank Arm | Diamond Hole | 170mm | Forged Aluminum Alloy 6061-T6 |
| BUCKLOS Square/Diamond/Hollow Crank Arm Set | Square / Diamond Hole | 152mm–170mm–175mm | Aluminum Alloy |
Alps2Ocean Bike Crank Arms, Diamond Hole (89–175mm)
Product overview: This crank arm set is forged from Alloy 6061, delivering high strength and durability with good resistance to deformation. It is available in multiple lengths (89mm to 175mm) to accommodate riders seeking a shorter or longer crank. The spindle interface is Diamond Hole, and compatibility requires matching hole orientation on both sides. Ensure your crank’s hole and orientation align before purchase.
- Material: Forged Alloy 6061
- Sizes: 89mm, 102mm, 114mm, 127mm, 140mm, 152mm, 160mm, 165mm, 170mm, 175mm
- Spindle: Diamond Hole, 12 cm diameter
- Note: Pair left/right arms with the same hole type
Alps2Ocean Universal Left Crank Arm (152–175mm)
Product overview: This left crank arm is forged from 6061 alloy, offering solid strength and durability. Available in 152mm, 160mm, 165mm, 170mm, and 175mm, it is designed to fit 9/16 inch pedals. Choose the Diamond Hole orientation for compatibility with your drivetrain, ensuring both arms share the same hole type.
- Material: Forged Alloy 6061
- Sizes: 152mm, 160mm, 165mm, 170mm, 175mm
- Spindle: Diamond Hole
- Left-arm only
Alps2Ocean Square Hole Crank Arm Set
Product overview: This square-hole crank arm set is crafted from premium aluminium alloy, focusing on durability and resistance to deformation. Available sizes include 140mm, 152mm, 160mm, 165mm, 170mm, and 175mm. It uses a 130mm BCD and requires a 9/16 inch pedal interface. Match hole orientation on both sides for optimal performance.
- Material: Aluminium alloy
- Sizes: 140mm, 152mm, 160mm, 165mm, 170mm, 175mm
- Spindle: Square hole, 130mm BCD
- Color: Black
Alps2Ocean Left Crank Arm (Diamond Hole) 152–175mm
Product overview: This left crank arm is available in 152mm, 160mm, 165mm, 170mm, and 175mm lengths and is compatible with 9/16 inch pedals. It features a Diamond Hole interface with 12 cm diameter, and aligns with same-hole orientation across both crank arms for proper fit on city, folding, MTB, E-bike, road, or exercise bikes.
- Material: Forged Alloy 6061
- Sizes: 152mm, 160mm, 165mm, 170mm, 175mm
- Spindle: Diamond Hole
- Left-arm only
BUCKLOS Ebike Crank Arm Set (Square/Diamond/Hollow)
Product overview: This set offers square and diamond hole options across sizes including 152mm, 170mm, and 175mm, suitable for electric bikes, road bikes, and other configurations. Forged aluminum alloy construction emphasizes durability and long service life. It’s designed for straightforward installation with standard hole-cut tolerances, enabling easy upgrades or replacements with compatible cranksets.
- Materials: Forged aluminum alloy
- Sizes: 152mm, 170mm, 175mm
- Interfaces: Square and Diamond Hole
- Single-arm or paired options available
Buying Guide: Crank Arms For Road Bikes
Orientation, compatibility, and endurance are the key factors when selecting crank arms for a road bike. This guide reviews common considerations to help you compare options from the list above and choose the best fit for your setup.
- Hole type: Diamond Hole vs Square Hole. Diamond Hole is common on many Shimano-style/spindle systems; Square Hole is often found on older or specific brands. Confirm your crankset’s hole orientation and ensure both arms match.
- Arm length: Typical road-bike crank arms range from 140mm to 175mm. Shorter arms can improve clearance and cadence for some riders; longer arms can increase leverage but may affect pedal stroke. Pick a length that matches leg mechanics and pedal clearance.
- Material and durability: Forged aluminium 6061 alloys offer a balance of strength and weight. Aluminium alloys provide good stiffness with manageable weight, while steel options offer great durability for heavy use but add weight.
- Compatibility: Check pedal thread (9/16 inch is common for modern bikes) and ensure the spindle interface matches your crankset. Verify whether you need a left-arm, right-arm, or a complete pair.
- Installation: Look for precise hole cutting tolerance and straightforward installation. Some arms require tools beyond a standard crank-puller set, while others are simpler to mount and align.
- Riding context: For competitive road riding, accuracy and stiffness are important; for commuting or casual riding, durability and ease of installation may take precedence.
- Brand and warranty: Reputable brands often provide better quality control and longer warranty periods, reducing the risk of premature wear or fit issues.
- Pairing: If buying a single left arm, ensure the right arm is available in a matching hole type. In many setups, a complete matched pair is recommended for balanced performance.
Across these options, the Alps2Ocean and BUCKLOS lines cover a broad range of hole types and sizes, making them versatile choices for road-bike crank upgrades. When selecting, prioritize exact length, hole orientation, and compatibility with your drivetrain to ensure smooth power transfer and reliable performance on the road.