A Complete Analysis Using the Fizmoo Position Calculator

Clipless pedals and cleat positioning are among the most influential yet often overlooked elements of proper cycling posture. The cleat–pedal interface is responsible for transferring power, stabilizing the foot, and defining the movement path of the knee and hip. Even a small change in cleat position can alter the biomechanics of the entire pedaling cycle, affecting comfort, efficiency, and injury risk. This article examines popular pedal systems and their adjustment ranges, then presents a detailed experiment conducted in the Fizmoo.com application. The goal was to measure how cleat fore–aft changes influence knee angles, effective leg length, and saddle height requirements. The results are clear: every cleat adjustment requires a corresponding saddle height correction, regardless of rider height.

Pedal Systems and Cleat Adjustment Ranges

Different pedal systems offer different fore–aft cleat adjustment ranges, which directly influence effective leg length and knee tracking

Brand / Model	Fore–aft Cleat Adjustment	Notes
Shimano SPD‑SL	~12–14 mm	Stable road system, 3 float options
Shimano SPD (MTB)	~20–25 mm	Wide adjustment range in MTB shoes
Look Keo	~12–15 mm	Float varies by cleat color
Look X‑Track (MTB)	~20 mm	Large contact area, stable engagement
Time Xpresso / Xpro	~5–6 mm	Small range but generous natural float
Wahoo Speedplay	14 mm fore–aft, 8–15 mm lateral	Most adjustable system on the market
Crankbrothers (MTB)	~6 mm	More “floating” feel, less precise

Reference Bicycle and Drivetrain Configuration

To ensure consistent and comparable results, all Fizmoo simulations were performed on the same bicycle model: Specialized S‑Works Tarmac SL8 (2024)

factory geometry
identical cockpit and saddle configuration
170 mm crank arm length Using a fixed crank length is essential because crank arm length directly affects knee angle and pedaling arc. This setup ensured that the only variables in the experiment were:
rider height and limb proportions
cleat position (0 mm, +8 mm, –8 mm)
resulting saddle height changes

Experiment Setup in Fizmoo

Three Rider Heights, Three Cleat Positions The experiment analyzed three typical rider heights:

155 cm
175 cm
195 cm Each rider was tested with cleats in three positions:
0 mm – neutral
+8 mm – cleat moved forward
–8 mm – cleat moved backward For each configuration, Fizmoo measured:
knee angle at the bottom of the pedal stroke
effective saddle height (BB center to saddle surface)

Results: Knee Angle Changes

Height	0 mm	+8 mm	–8 mm
155 cm	149.8°	148.1°	151.6°
175 cm	149.9°	151.7°	148.2°
195 cm	150.0°	151.8°	148.6°

Interpretation

Moving the cleat forward (+8 mm) effectively lengthens the leg, altering knee angle by 1.7–1.9°.
Moving the cleat backward (–8 mm) shortens the leg, changing knee angle by 1.6–2.4°.
The effect varies with limb proportions: taller riders experience larger changes in effective leg length. Even a 2° change in knee angle is biomechanically significant and can influence comfort, power output, and joint loading.

Results: Saddle Height Changes

Height	0 mm	+8 mm	–8 mm
155 cm	648 mm	646 mm	651 mm
175 cm	752 mm	749 mm	756 mm
195 cm	850 mm	846 mm	854 mm

Interpretation

Cleat forward (+8 mm) → leg becomes effectively longer → saddle must be lowered by 2–4 mm.
Cleat backward (–8 mm) → leg becomes shorter → saddle must be raised by 3–4 mm.
Taller riders require larger corrections due to longer lever arms. These changes are not optional. They are a direct biomechanical consequence of altering the foot’s position relative to the pedal spindle.

The Most Common Mistake Cyclists Make

Changing Cleat Position Without Adjusting Saddle Height

Many cyclists adjust their cleats but leave the saddle at the same height. This leads to:

altered knee angles
changes in hip flexion
increased joint stress
reduced pedaling efficiency
discomfort or overuse injuries The Fizmoo experiment demonstrates that every cleat adjustment changes effective leg length, and therefore: Every cleat adjustment requires a saddle height correction. Ignoring this relationship is one of the most common causes of knee pain and poor bike fit outcomes.

Comparison of the Three Rider Heights

Rider 155 cm

knee angle change: ±1.7°
saddle correction: –2 mm / +3 mm
shorter limbs → smaller biomechanical impact Rider 175 cm
knee angle change: ±2.0–2.5°
saddle correction: –3 mm / +4 mm
most balanced response Rider 195 cm
knee angle change: ±1.8°
saddle correction: –4 mm / +4 mm
long limbs amplify effective leg length changes

Summary

Cleat positioning is a fundamental component of proper cycling posture.
Different pedal systems offer different adjustment ranges.
Moving cleats by 8 mm changes knee angle by 1.5–2.5°.
These changes alter effective leg length and require saddle height adjustments of 2–4 mm.
The effect varies with rider height and limb proportions.
Fizmoo provides a precise way to analyze these relationships and avoid common bike‑fit mistakes.