Shorter cranks: plan a fit experiment, not a universal upgrade
A shorter crank changes the circle your foot travels through. Whether that helps you depends on your position and riding needs. Start with a specific reason for the change and a way to assess it, rather than assuming shorter always means better.
Know what the length changes
In a simplified geometry example, a 170 mm crank gives a 340 mm pedal-circle diameter; a 165 mm crank gives 330 mm. With the bottom bracket fixed, the top of the circle is 5 mm lower and the bottom is 5 mm higher. Those numbers describe geometry, not a prescribed saddle adjustment or a promised comfort improvement.
Keep the contact points in the assessment
Record the current crank, saddle and cockpit setup before changing parts. Discuss the intended adjustment with a suitable fitter, especially if the reason is discomfort. Do not copy someone else’s saddle-height change as a complete prescription. A shorter crank and a different saddle position are two changes that should be understood together.
An INCOLOR Speedster SR frame does not itself determine your ideal crank length. Your complete fit, available compatible components and manufacturer limits matter.
Use the stack and reach guide to distinguish the frame’s coordinates from your recorded contact-point setup. Keep that baseline when planning the crank trial: changing crank length and moving the saddle together makes it harder to tell which change helped.
Price the compatible change
Check axle and bottom-bracket compatibility, chainline, chainrings, front-derailleur requirements, power meter and frame clearance for the exact crank. A length option in a product family does not guarantee that every version fits your drivetrain. Use the matching manuals and get the complete installation quoted.
If the fit benefit is uncertain, discuss a practical trial before committing to an expensive crank or power-meter replacement. Keep the experiment focused on the original problem and assess normal rides with the resolved setup.
Sources
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