For decades, cyclists and fitters alike have treated crank length as sacred—often dictated by outdated rules or assumptions that “taller riders need longer cranks.” But recent research paints a very different picture—one that challenges conventional wisdom and brings the focus back to function over tradition.

Myth: Longer Cranks = More Power

At face value, the idea that longer cranks generate more leverage and therefore more power seems logical. But Martin and Spirduso (2001) debunked this in a landmark study where cyclists rode with crank lengths ranging from 120 mm to 220 mm. They found that maximum power output remained unchanged across crank lengths between 145 and 195 mm—a surprisingly wide “neutral zone” with no performance loss.

More recently, Burrus et al. (2021) tested novice cyclists using 145 mm and 175 mm cranks. Riders using the shorter cranks produced 3–5.5% more power at the same oxygen cost—indicating improved efficiency, not just mechanical leverage.

No Major Differences in Joint Power, but Big Differences in Fit

Barrett et al. (2011) and Barratt et al. (2016) explored crank lengths from 150 mm to 190 mm and found no significant difference in hip, knee, or ankle power contribution. However, longer cranks did increase joint range of motion, particularly at the hips and knees. This matters, especially in aero positions where hip closure can restrict breathing, reduce glute recruitment, and cause discomfort or injury.

A 2023 study using statistical parametric mapping (SPM) confirmed that shorter cranks reduce excessive knee and pelvic motion, promoting a more stable and efficient pedal stroke.

Crank Length and Efficiency

From an aerobic perspective, research continues to show crank length has little to no effect on oxygen consumption or heart rate at submaximal efforts. Whether you’re using 165 mm or 175 mm cranks, your engine runs just as efficiently, assuming cadence remains consistent.

For time trialists, triathletes, and riders seeking a more aggressive position, shorter cranks help open the hip angle, improve comfort, and reduce the risk of overuse injuries—without sacrificing performance.

Real-World Trends

Many pro cyclists are shifting toward shorter cranks—not to gain watts, but to reduce joint strain and allow for more aerodynamic positioning. At the 2025 Tour de France, 160–165 mm cranks were increasingly common in the peloton, even among taller riders (Cycling Weekly, 2025).

Practical Takeaways

So, should you change your crank length? Here’s what the science suggests:

• Stick with what works if you’re comfortable and performing well in the 170–175 mm range.
• Go shorter if you’re experiencing hip, knee, or low back discomfort—especially in aero setups.
• Don’t chase leverage—you won’t gain power with longer cranks, but you may sacrifice joint health and positioning.
• Fit always comes first. Crank length should complement—not compromise—your position, flexibility, and performance demands.

Final Word

Crank length isn’t a magic bullet. But when dialed in properly, it can significantly improve your comfort, biomechanics, and long-term durability on the bike. If you’re unsure whether your setup is optimized, a professional bike fit may be the smartest investment you can make in your training and performance.

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References

• Martin JC, Spirduso WW. (2001). Determinants of maximal cycling power: crank length, pedaling rate, and pedal speed.
• Burrus B, Armendariz M, Moscicki T. (2021). Shorter crank lengths improve cycling performance in novice cyclists. J Strength Cond Res.
• Barrett RS et al. (2011). Crank length does not influence joint-specific power during submaximal cycling.
• Barratt PR et al. (2016). Influence of crank length on cycling biomechanics.
• Cycling Weekly. (2025). Five tech trends from the 2025 Tour de France.
• SPM Study: PubMed ID 40464620

“Don’t believe everything you read on the Internet.” – Abraham Lincoln

If you didn’t just chuckle out loud, read that first line again. It’s so easy to trust the quotes, articles, and images that are served up to us online, including those about sport! As we scroll through our social media apps and click through our emails, you might see something and think, “Is that for real?” 

You’re not alone! Coach Brady spotted this social media ad last week and it made him say, “Huh?” 

He sat down to fact check this social media ad. Here’s his feedback:

“In the image and the description, the company states that pressure is put on the ‘pubis bone’ due to the necessary rotation of the pelvis for an aero/triathlon position. 

It is true that we do have to rotate our pelvis forward in the aero position. It is also true that certain saddles and a bike fit that includes that saddle can help you avoid discomfort.

What’s misleading here is the idea that your rotation would be extreme enough that your weight and pressure is supported by the pubic symphysis (pubic bone.) That would result in a contact point in front of your genitals. This would not only be uncomfortable but very awkward from a positional standpoint. Ouch! 

The change that actually occurs when we move to this position is from our ischial tuberosity on to the inferior rami of the ischium.”

 

Drawing By Henry Vandyke Carter – Henry Gray (1918) Anatomy of the Human Body (See “Book” section below)Bartleby.com: Gray’s Anatomy, Plate 235, Public Domain, https://commons.wikimedia.org/…

If you ever have a question about training advice, technical specs, or the athlete’s body you see online, your Science of Speed coaches are here to confirm or debunk! Science is the first word in our brand name and we take that very seriously. It’s why our team is comprised of people with the highest level of education, experience, and expertise. We looking forward to hearing from you soon!