Standing in pouring rain with my top-tier road bike, I realized the importance of having the perfect crank size. During those tough climbs and sprints, I need reliable power transfer and comfort. After hands-on testing, I found that choosing the right size makes a huge difference—too long or too short, and performance drops. I’ve looked at options like forged alloy cranks and sturdy steel arms, all tailored to different riding styles.
From my experience, the best crank size balances leverage and cadence, especially for road riding. The Shimano Claris FC-R2000 8-Speed Road Crankset 170mm 50/34T stood out because of its lightweight aluminum build, smooth Hyperglide shifting, and a 170mm length that fits most riders perfectly. It offers a sleek, durable design ideal for daily commuting or long-distance riding, making it a top pick for both performance and value.
Top Recommendation: Shimano Claris FC-R2000 8-Speed Road Crankset 170mm 50/34T
Why We Recommend It: This crankset combines a durable aluminum alloy construction with a precise 170mm length, offering optimal power transfer and comfort. Its Hyperglide technology ensures smooth shifting, crucial during long rides. The versatility with a 50/34T double chainring setup and compatibility with common standards makes it ideal for most road cyclists, outperforming others with better durability and ergonomic design.
Best crank size for road bike: Our Top 4 Picks
- BLLREMIPSUR 2PCS Mountain & Road Bike Crank Arm Left Side – Best for Mountain Biking
- Alps2Ocean Universal Bike Crank – Best Compatibility for Various Bike Types
- CYSKY Single Speed Crankset 48T 170mm Crankarms 130 BCD – Best Crank Arm Length for Sprinting
- Shimano Claris FC-R2000 8-Speed Road Crankset 170mm 50/34T – Best Crankset for Climbing
BLLREMIPSUR 2PCS Mountain & Road Bike Crank Arm Left Side
- ✓ Durable solid steel
- ✓ Easy to install
- ✓ Fits multiple bike types
- ✕ Not suitable for square hole shafts
- ✕ Slightly heavy for racing
| Material | Solid steel |
| Crank Arm Length | 170mm (center to center) |
| Mounting Hole Type | Diamond hole (compatible with diamond hole cranksets) |
| Quantity | 2 pieces (left crank) |
| Compatibility | Suitable for bikes with diamond hole center shaft, including mountain bikes, road bikes, folding bikes, fixed-gear bikes, cross-country bikes |
| Installation Features | Precision holes for easy mounting, lightweight and compact design |
As soon as I unboxed the BLLREMIPSUR 2PCS mountain and road bike crank arm, I noticed its solid steel build—feels hefty but surprisingly lightweight in hand. The matte finish gives it a rugged look, and the precise machining of the holes shows good craftsmanship.
I immediately appreciated the 170mm length, which is a popular size that suits most riders looking for a comfortable pedal stance.
Installing the crank was straightforward thanks to the well-made, accurately drilled holes. The crank arm’s design, with a 2cm front round hole and a 1.6cm rear diamond hole, fits perfectly on the diamond-shaped center shaft.
Just double-check your original crank’s hole type—square or diamond—so you’re not caught off guard.
Once mounted, the crank felt sturdy and well-balanced. I tested it on both a mountain bike and a road bike, and it responded smoothly under pedal pressure.
The material’s robustness meant I didn’t worry about warping or bending, even during tougher rides. Plus, the simple design makes it easy to install without any special tools.
If you’re replacing a worn-out crank or upgrading your bike’s look, this offers a reliable and durable option. It’s versatile enough to work across different bike types, which is a huge plus.
For the price, it punches well above its weight—no fuss, just solid performance.
Overall, I’d say it’s a smart choice for anyone needing a dependable left crank arm that’s easy to install and built to last. Just make sure your center shaft matches the diamond hole style, and you’re good to go.
Alps2Ocean Universal Bike Crank
- ✓ Sturdy forged alloy build
- ✓ Easy to install and adjust
- ✓ Fits multiple bike types
- ✕ Limited size options
- ✕ Check compatibility carefully
| Material | Forged Alloy 6061 |
| Crank Arm Length Options | [‘152mm’, ‘160mm’, ‘165mm’, ‘170mm’, ‘175mm’] |
| Spindle Interface Type | Diamond Hole |
| Compatible Pedal Size | 9/16 inch |
| Intended Use Compatibility | City Bike, Folding Bike, MTB, E-bike, Road Bike, Junior Bike, Exercise Bike |
| Package Contents | Left Crank Arm, Crank Bolts |
The moment I grabbed the Alps2Ocean Universal Bike Crank and lined it up for installation, I could tell it was built tough. The forged alloy 6061 feels solid in your hand, giving you confidence that this crank can handle some serious miles.
I was particularly impressed by how lightweight yet durable it felt, making the whole biking experience smoother.
Attaching it to my road bike was straightforward, thanks to the clear markings for left and right installation. The 170mm size fit perfectly, matching my existing crank length, and the diamond hole interface lined up perfectly with my spindle.
Once installed, I immediately noticed how sturdy the crank felt under pressure, even during intense sprints.
Switching between different bikes—like my city bike and mountain bike—was hassle-free because of its versatile design. The fact that it fits 9/16 inch pedals is a huge plus, saving me from extra adapters.
The crank bolts came included, which made the setup even easier. Overall, this crank delivers a reliable upgrade that feels like it’s built to last, even if you’re pounding out long rides or tackling tough terrains.
One thing to watch out for is making sure you select the correct size—especially if you need a shorter or longer crank arm. But once installed, it stayed tight and didn’t creak or loosen, which is a relief.
For the price, it’s a solid choice for anyone looking to improve their bike’s performance without breaking the bank.
CYSKY Single Speed Crankset 48T 170mm Crankarms 130 BCD
- ✓ Durable aluminum alloy build
- ✓ Perfect crank arm length
- ✓ Fits standard single speed chains
- ✕ Not compatible with geared bikes
- ✕ No bottom bracket included
| Crank Arm Length | 170mm |
| Chainring Teeth | 48T |
| Bolt Circle Diameter (BCD) | 130mm |
| Chain Compatibility | 1/2″ x 1/8″ single speed chains |
| Material | Aluminum alloy 7075-T6 |
| Intended Use | Single Speed, Track, Fixed-Gear Bikes |
Many folks assume that a crankset like this one, with its 48T chainring and 170mm crank arms, is overkill for most road bikes. I’ve found that’s not necessarily true, especially if you’re into single speed setups or track riding.
The solid aluminum alloy construction gives it a serious feel, but it’s surprisingly lightweight.
When you handle it, you notice the sleek, forged design that screams durability. The 130mm BCD means it fits a variety of chainrings, but keep in mind it doesn’t include a bottom bracket, so you’ll want to plan for that.
The 9/16” pedal size is pretty standard, so finding compatible pedals isn’t a hassle.
During installation, the 170mm crank arms felt just right—long enough for good leverage, but without that awkward overlap that can hit your knees or chainring bolts. Riding on flat terrain, I appreciated how responsive and stiff this crankset felt, especially considering the price.
It’s ideal for single speed bikes, fixed gear, or even track bikes that need a reliable, no-fuss component.
One thing to note: it’s designed specifically for single speed chains, so if you’re thinking of a multi-gear setup, this isn’t for you. Also, since it’s not a lightweight racing crank, it might be a bit more robust than necessary if you prefer ultra-lightweight builds.
Still, for pure strength and simplicity, it’s a solid pick.
Shimano Claris FC-R2000 8-Speed Road Crankset 170mm 50/34T
- ✓ Smooth shifting with Hyperglide
- ✓ Lightweight yet durable
- ✓ Stylish black finish
- ✕ Limited to 8-speed setups
- ✕ May require professional installation
| Crank Length | 170mm |
| Chainring Sizes | 50/34T |
| Number of Gears | 8-speed |
| Chainline | 43.5mm |
| Compatibility | 130mm hub spacing, 110mm BCD crank arm spacing |
| Material | Aluminum alloy |
As soon as I took the Shimano Claris FC-R2000 8-Speed Crankset out of the box, I was struck by its sleek matte black finish. The 170mm crank arms feel solid yet lightweight, giving off a confident vibe right away.
Handling the hollowtech II spindle, I appreciated how smooth and sturdy it felt in my hand—perfect for long rides.
Mounting it onto my bike was straightforward thanks to the versatile 130mm hub spacing and 110mm BCD compatibility. The 50/34T chainring setup is a sweet spot for both climbing and cruising, making it ideal for daily commuting or leisurely tours.
I immediately noticed how quiet and precise the shifting was, thanks to Shimano’s Hyperglide tech.
During my test rides, I found the power transfer to be efficient, with no noticeable flex or slipping. The chainline at 43.5mm kept everything running smoothly, even on rougher roads.
The included fixing bolt is sturdy, giving me confidence that it won’t loosen over time. Overall, it feels like a real upgrade for anyone wanting a reliable, stylish crankset without breaking the bank.
At just over $69, this crankset offers excellent value. It’s durable enough for daily use yet light enough to not weigh down your ride.
Whether you’re cruising through town or tackling longer distances, it delivers consistent performance that makes pedaling feel easier and more enjoyable.
What is Crank Size and How Does it Affect Performance on a Road Bike?
Solutions for optimizing crank size may involve testing different lengths through adjustable crank systems or borrowing equipment to find the best fit before committing to a purchase. Additionally, cyclists should consider how crank size interacts with other components such as saddle height and handlebar position to ensure a holistic approach to bike fit and performance enhancement.
What Factors Should You Consider When Determining the Best Crank Size for a Road Bike?
When determining the best crank size for a road bike, several factors must be taken into account:
- Rider’s Leg Length: The length of a rider’s legs is crucial in selecting crank length, as a proper fit can enhance pedaling efficiency and comfort. Riders with shorter legs may benefit from shorter cranks, which can help avoid knee strain and improve overall pedal stroke.
- Riding Style: The rider’s preferred style, whether it be endurance, racing, or climbing, plays a significant role in crank size choice. For instance, racers often prefer longer cranks for better torque, while endurance riders might opt for shorter cranks to maintain comfort over long distances.
- Bike Geometry: The overall geometry of the bike, including frame size and design, affects how crank length interacts with the rider’s position. A bike with aggressive geometry may require a different crank size compared to a more relaxed setup to ensure optimal performance and comfort.
- Cadence Preference: A rider’s preferred cadence or pedal speed can influence crank length decisions. Shorter cranks typically allow for a higher cadence due to reduced leg extension, which can be beneficial for cyclists who favor quick, high-revving pedaling.
- Cleat and Shoe Compatibility: The type of cycling shoes and cleats used can also impact crank size selection. Certain shoe setups may require specific crank lengths to maintain proper leg alignment and avoid discomfort or injury.
- Power Output and Efficiency: The ability to generate power efficiently can be affected by crank length, as it changes the leverage applied during pedaling. Riders aiming for maximum power output might find that longer cranks suit their needs better, while those focused on endurance may prefer shorter cranks to maintain energy over time.
How Does Your Height and Leg Length Impact the Ideal Crank Size?
Different cycling disciplines may necessitate varying crank lengths, impacting comfort and speed based on rider’s preferences. For instance, competitive racers may choose shorter cranks to allow for higher cadences, while touring cyclists might prefer longer cranks to maintain a steady power output over long distances.
What Role Does Riding Style Play in Choosing Crank Size?
- Riding Terrain: Different terrains require different power outputs, which can influence crank size selection.
- Cyclist’s Fitness Level: A cyclist’s strength and endurance can dictate the ideal crank size to optimize performance without causing strain.
- Pedaling Technique: Individual pedaling styles, such as cadence and torque preferences, can affect how effectively a crank size translates to speed and efficiency.
- Riding Goals: Whether the cyclist is focused on racing, endurance, or recreational riding can lead to varied crank size preferences.
Riding Terrain: Riders who frequently encounter hilly or varied terrains may benefit from shorter crank sizes, which can enhance cadence and allow for quicker gear changes. Conversely, those riding primarily on flat surfaces may prefer longer cranks, enabling a more powerful pedal stroke that maximizes speed on straightaways.
Cyclist’s Fitness Level: A more experienced and fitter cyclist might opt for a larger crank size to take advantage of their strength, allowing them to generate more power. In contrast, a beginner may find shorter cranks more manageable, as they can facilitate smoother pedal strokes and reduce fatigue, leading to a more enjoyable riding experience.
Pedaling Technique: Cyclists with a high cadence may find that shorter cranks allow for a more fluid and rapid pedal motion, enhancing their efficiency. On the other hand, riders who favor more torque in their pedaling style might benefit from longer cranks, which can help in delivering greater power during climbs or sprints.
Riding Goals: Competitive cyclists may gravitate towards specific crank sizes that optimize their performance for racing, focusing on speed and power transfer. In contrast, those who ride for leisure or fitness might prioritize comfort and ease of use, leading them to select crank sizes that enhance endurance and reduce strain over long distances.
What Are the Most Common Crank Sizes for Road Bikes and What Are Their Differences?
| Crank Size | Typical Usage | Gear Ratios |
|---|---|---|
| 160 mm | Suitable for very short riders below 5’4″ – helps improve cadence and comfort. | Lower gear ratios, advantageous for steep climbs and maintaining a high cadence. |
| 165 mm | Ideal for shorter riders 5’4″ to 5’6″ – improves cadence and reduces knee strain. | Lower gear ratios, beneficial for climbing steep hills and enhancing efficiency. |
| 170 mm | Common for riders 5’6″ to 5’10” – balanced for performance. | Standard gear ratios for climbing and flat terrains. |
| 172.5 mm | Popular among average riders – provides a good blend of power and comfort. | Versatile gear ratios suitable for varied terrains. |
| 175 mm | Recommended for taller riders 5’11” and above – enhances power output. | Higher gear ratios, may be less efficient on steep climbs. |
| 180 mm | Best for very tall riders above 6’2″ – maximizes power output but may reduce cadence. | Higher gear ratios, suitable for flat terrains, less efficient on steep climbs. |
What Are the Advantages and Disadvantages of Various Crank Sizes for Road Biking?
| Crank Size | Advantages | Disadvantages |
|---|---|---|
| 165 mm | Lower cadence, better for short riders (under 5’5″). | May lack power on climbs; less efficient for long rides. |
| 170 mm | Balanced option for average height riders (5’5″ to 5’10”). | Can be less efficient for tall riders; may cause fatigue on long rides. |
| 175 mm | More power, suitable for taller riders (5’10” to 6’2″). | Can cause knee strain if improperly fitted; potential for leg fatigue on long distances. |
| 180 mm | Maximizes leverage for strong cyclists (over 6’2″). | Less efficient for average riders; can be cumbersome and lead to quicker fatigue. |
How Can You Accurately Measure and Calculate the Right Crank Size for Your Needs?
Manufacturer Recommendations: Consult your bike’s manufacturer specifications, as they often provide ideal crank sizes based on your frame size and height to ensure compatibility and performance, helping you make an informed choice.
What Recommendations Do Professional Cyclists Have About Crank Sizes?
Professional cyclists offer several insights regarding the best crank sizes for road bikes to optimize performance and comfort.
- Crank Length (170mm to 175mm): Most professionals recommend crank lengths between 170mm and 175mm for road cycling. This range strikes a balance between power output and comfort, allowing for efficient pedaling while accommodating a variety of leg lengths.
- Personalization Based on Leg Length: Cyclists are encouraged to choose crank lengths based on their inseam measurements. A general guideline is that for every 10cm of inseam, a crank length of 5mm can be adjusted, ensuring proper leg extension and reducing the risk of injury.
- Power Transfer and Torque: Shorter cranks may allow for quicker cadence and better torque application, making them favorable for climbing and sprinting. However, longer cranks can provide more leverage, which is beneficial for generating power at lower cadences.
- Consideration of Riding Style: Cyclists who focus on endurance may prefer longer cranks for sustained power output, while those who engage in track racing or criteriums might opt for shorter cranks to enhance their ability to accelerate quickly. This choice should reflect individual riding preferences and competitive needs.
- Bike Fit and Comfort: Proper bike fit is essential, and crank length plays a significant role in achieving that fit. Cyclists should consider how different crank sizes affect their knee angles and hip alignment to ensure comfort during long rides.
- Experimentation with Different Sizes: Many professionals suggest trying various crank sizes to find the best fit. This trial and error can help cyclists discover which size allows for optimal performance and minimizes discomfort.