Cycling

Tire Pressure: Rolling Resistance vs Comfort

PUBLISHED: 2026-08-01|READ TIME: 5 MINS|AUTHOR: FRANCESCO CASTALDI

FIGURE: Bicycle Tire Pressure Gauge

The Myth of 8 Bar (120 PSI)

For decades, cyclists pumped their ultra-thin 23mm tires to frightening pressures, convinced that "the harder, the faster". On a perfectly smooth wooden velodrome, physics confirms this theory.

But real-world roads are full of cracks, rough asphalt, and potholes.

Impedance Losses

When a tire is inflated to 8 bar, it's a rock. Every time it hits a small asphalt imperfection, the bicycle (and your body) are pushed upwards. This micro-bounce dissipates forward energy by transforming it into vertical energy. In physics, this is called *impedance*.

If the pressure is lower instead (e.g., 5.5 bar on a 28mm tire), the tire deforms, absorbing the obstacle. The bike continues to move forward in a straight line without bouncing.

Pressure / Width	Surface	Efficiency (Rolling Resistance)	Comfort
23mm at 8.0 Bar	Smooth track	Excellent	Terrible
23mm at 8.0 Bar	Rough asphalt	Terrible (High impedance losses)	Terrible
28mm at 5.5 Bar	Rough asphalt	Excellent (Absorbs vibrations)	Superior

[ NOTE ]

To find the perfect pressure, you must calculate it based on total weight (cyclist + bike) and internal rim width. Online tools like the *SRAM Tire Pressure Calculator* use empirical algorithms to give you the magic number.

Embrace comfort: wider tires at lower pressures are mathematically faster in the real world.

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