Best 170mm Left Crank Arm Options for Your Bike Upgrade
The following 170mm left crank arms are selected for compatibility with common square or diamond hole interfaces and 9/16″ pedals. Each product features a durable aluminum or steel construction with the standard 170mm length, making them suitable for MTB, road, folding, and hybrid bikes. This guide highlights key specs, compatibility notes, and installation considerations to help you choose the right left crank arm for your bicycle.
| Product | Brand | Arm Length | Hole Type | Interface Notes |
|---|---|---|---|---|
| Epessa Crank Arm Left 170mm | Epessa | 170mm | Diamond / Square | 9/16″ pedal compatibility |
| Epessa Crank Arm Left 170mm | Epessa | 170mm | Diamond / Square | 9/16″ pedal compatibility |
| Alps2Ocean Universal 170mm Left Arm | Alps2Ocean | 170mm | Square Hole | 5 sizes available |
| WEEROCK 170mm Left Crank Arm | WEEROCK | 170mm | Diamond Hole | Steel construction |
| Alps2Ocean 170mm Left Arm (Diamond Hole) | Alps2Ocean | 170mm | Diamond Hole | 5 sizes available |
Epessa Crank Arm Left 170mm — Diamond or Square Hole
Epessa’s 170mm left crank arm offers compatibility with both Diamond Interface and Square Interface spindle ports. The arm length is 170mm, with a total length of 210mm, and it fits 9/16″ pedals. Constructed from high-quality aluminum alloy, it aims to provide a balance of strength and light weight. Before purchase, verify that your crank port matches the two-port interfaces, as they share the same size but have different orientations.
Epessa Left 170mm Crank Arm — Diamond or Square
This Epessa model mirrors the dual-interface design, ensuring compatibility with both Diamond and Square hole crank sets. With a 170mm left arm and 210mm overall length, it accepts 9/16″ pedals and is produced from aluminum alloy for reliable performance. Confirm your original crank port type and hole spacing (170mm) before purchasing to avoid fit issues.
Alps2Ocean 170mm Left Arm — Square Hole
Alps2Ocean’s universal left crank arm is available in 170mm with a square hole interface. Made from forged alloy 6061 for strength and durability, it’s designed to fit 9/16″ pedals. The product line emphasizes careful sizing; ensure your crankset and bottom bracket are compatible with a square-hole orientation and that 170mm length aligns with your crank geometry.
WEEROCK 170mm Left Crank Arm — Diamond Hole Steel
WEEROCK offers a 170mm left crank arm in steel with a diamond hole interface. The robust steel construction provides durability for demanding riding conditions. Before purchase, verify the diamond hole compatibility and ensure the arm length and pedal compatibility align with your bike’s crankset design.
Alps2Ocean 170mm Left Arm — Diamond Hole (Diamond)
This Alps2Ocean listing provides a 170mm left crank arm with a diamond hole interface. It’s part of a family offering five available sizes, including the 170mm option. Confirm the hole orientation and ensure both crank arms match the hole type for proper compatibility and installation.
KooingTech 170mm Left Crank Arm — Diamond Hole
KooingTech’s 170mm left crank arm is made from aluminum alloy, offering a lightweight yet strong construction. It features a standard 170mm length with a square or diamond hole orientation-specific design; verify compatibility with your crank’s hole shape and confirm that the left arm orientation matches your bike’s setup before purchase.
Buying Guide
Key considerations when selecting a 170mm left crank arm include hole type compatibility (Square vs Diamond), overall arm length, and pedal thread compatibility (9/16″). Material choice impacts weight, stiffness, and durability; aluminum alloys are common for lighter builds, while steel offers added strength. Confirm the exact spindle interface with your crankset to avoid mismatches, as some models are offered in multiple hole configurations. Check the total length and chainring clearance to ensure no interference with chainrings and frame geometry. For bikes with folding or electric components, verify compatibility with the bottom bracket type and any special fit requirements. If upgrading from a mismatched arm, measure existing hole pattern and crank length to guide your choice.
When evaluating options, consider the following perspectives:
– Universal versus model-specific: Universal arms pair well with a range of bikes but require precise hole orientation checks.
– Weight versus durability: Aluminum arms save weight; steel arms provide extra rigidity for aggressive riding.
– Install ease: Some arms include clear instructions, standard spacings, and easy-to-follow torque specs; others may require professional installation.
– Availability of sizes: Some brands offer multiple lengths (152–175mm) to fine-tune rider fit and stance.
– Brand reliability: Look for parts from brands with clear quality notes and return policies to ensure compatibility and longevity.