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Shimano Crank Length Lineup and How to Find the Best Crank Length
Modified at: Mar 8, 2024
Posted at: Jan 5, 2022
Crank length is a small difference, but it makes a big difference in riding style. In this article, we summarize Shimano's crank length lineup for road cranks and how to find the best crank length.
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Crank Arm Length Options
While most complete road bikes come equipped with crank arms that are either 170mm or 172.5mm in length, Shimano actually offers a broader range of crank lengths to suit different rider physiques and preferences.
Shimano’s available crank arm lengths include:
- 160mm
- 165mm
- 167.5mm
- 170mm
- 172.5mm
- 175mm
- 177.5mm
- 180mm
That’s a total of 8 different crank lengths.
Shimano Road Cranksets and Their Crank Length Availability
The current lineup of Shimano road cranksets offers the following crank length options:
| Crankset | Series | 160mm | 165mm | 167.5mm | 170mm | 172.5mm | 175mm | 177.5mm | 180mm |
|---|---|---|---|---|---|---|---|---|---|
| FC-R9200 | DURA-ACE | ○ | ○ | ○ | ○ | ○ | ○ | ○ | - |
| FC-R9100 | DURA-ACE | - | ○ | ○ | ○ | ○ | ○ | ○ | ○ |
| FC-R8100 | ULTEGRA | ○ | ○ | - | ○ | ○ | ○ | - | - |
| FC-R8000 | ULTEGRA | - | ○ | - | ○ | ○ | ○ | - | - |
| FC-R7100 | 105 | ○ | ○ | - | ○ | ○ | ○ | - | - |
| FC-R7000 | 105 | ○ | ○ | - | ○ | ○ | ○ | - | - |
| FC-4700 | TIAGRA | - | ○ | - | ○ | ○ | ○ | - | - |
| FC-R3000 | SORA | - | ○ | - | ○ | - | ○ | - | - |
| FC-R2000 | CLARIS | - | ○ | - | ○ | - | ○ | - | - |
DURA-ACE offers the widest range, with seven crank length options—fitting for a top-tier race component designed for professional athletes of all body types.
The older FC-R9100 model included an 180mm option, but this was replaced by a shorter 160mm option in the newer FC-R9200 generation.
For ULTEGRA and lower series, the crank length options are typically limited to 4–5 sizes. This means that riders who need more precise adjustments may need to choose across series.
For example, shorter riders—especially women—seeking the shortest crank length of 160mm should consider DURA-ACE, ULTEGRA, or 105, as these are the only series that offer it.
Meanwhile, entry-level groups like CLARIS and SORA offer fewer length variations. Riders requiring finer adjustments should consider upgrading to at least the 105 series.
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What Happens When You Use Longer or Shorter Cranks?
Since crank length essentially determines the radius of your pedal stroke, a longer crank means a larger pedaling circle, while a shorter one creates a smaller circle.
At first glance, you might think, “It just slightly changes the way you pedal, right?” — but in fact, crank length can significantly affect your overall bike fit.
For example, switching from a 170mm to a 175mm crank adds 5mm to the crank length. That means:
- The top dead center (highest point of the pedal) rises by 5mm
- The bottom dead center drops by 5mm
- The distance between the saddle and the pedal changes
- Your pedaling arc moves 5mm forward and 5mm backward
As a result, you may need to adjust your saddle height and fore-aft position.
If you’ve ever had a professional bike fitting, you’ll know that even a 1cm difference in saddle height can noticeably affect your ride. So a change of 5mm or even 2.5mm can make a subtle but real impact.
In general:
- Longer cranks = Feels like you can push a heavier gear, but cadence tends to drop
- Shorter cranks = Easier to spin at higher cadence, but you might lose torque leverage
That said, these are only general guidelines. Your leg length and riding style also play a big role.
How to Choose the Right Crank Length for You
A Common Rule: “(Your Height ÷ 10) − (2.5 to 5mm)”
Traditionally, people used the formula:
Crank length = Your height ÷ 10
But in the last few years, the trend has shifted to:
(Your height ÷ 10) − (2.5 to 5mm)
Examples:
- 170cm tall → 165mm or 167.5mm cranks
- 175cm tall → 170mm or 172.5mm cranks
- 180cm tall → 175mm or 177.5mm cranks
That’s why complete road bikes generally come with 170mm cranks — designed to suit the average male rider around 170–175cm tall.
Is “Shorter” the New Trend after 2024?
In the past year or two, shorter crank arms have become increasingly popular, even among pro cyclists.
A notable example is Tadej Pogačar, who won the Tour de France twice. At 176cm tall, he was seen using 165mm cranks on his bike during the 2023 Saitama Criterium — something that caught a lot of attention.
Looking at his Strava data, Pogačar’s:
- Average cadence is around 90rpm
- Max cadence can approach 140rpm
It’s likely that the shorter cranks help him maintain high cadence efficiently.
What About Women Riders?
Crank length can pose a challenge — especially for women riding road bikes.
Take a woman who is 159cm tall, for example. Using the same formula, the ideal crank length would be between 155mm and 157.5mm. However, Shimano’s shortest available crank is 160mm. So in this case, either:
- Choose a 160mm Shimano crank, or
- Look for other brands that offer shorter options.
Women often have to pedal in a larger arc compared to men of the same height, which can place more stress on the knees and feet.
To offset this, it’s a good idea to:
- Use a lighter front chainring (like a 46T outer ring)
- Reduce the overall gear ratio for easier pedaling
These tweaks can help make riding more comfortable and efficient.
The Best Crank Length Varies by Individual
That said, there’s no one-size-fits-all rule when it comes to crank length. Even among professional cyclists:
- Some follow standard crank length formulas
- Others opt for shorter or longer cranks based on personal feel
The best way to find what works is by comparing how different lengths feel during actual rides or using ride data.
Since most people can’t easily test multiple crank lengths, your best bet is to visit a bike shop that offers test rides or fittings for different crank setups.