Tubular pressure on a wooden velodrome: the equation between grip, rolling and comfort at 65 km/h

For years the wooden-track mantra was "more pressure = faster". Lab and field data published since 2018 has dismantled that mantra. There is a sweet spot below the tubular's maximum pressure, and exceeding it costs both Crr and grip on banked corners. Here is the analysis for pursuiter, kilo and sprint.

Why wooden track is a different case from asphalt

The Siberian pine of a covered velodrome is laminated in 4-6 cm wide slats. Between each slat there is a microscopic joint. Although the eye sees a continuous smooth surface, the tubular at 55-65 km/h sees a succession of tiny 0.05-0.2 mm steps every 5 cm. An over-inflated tubular does not absorb these irregularities: it bounces, and bouncing is an energy cost.

This phenomenon is called impedance loss and has been documented by Bicycle Rolling Resistance Lab and AeroCoach in dozens of real-track measurements. The Crr-vs-pressure curve is not monotonically decreasing: it has a minimum between 8.5 and 10.5 bar depending on tubular, surface and rider weight.

The real shape of the Crr vs pressure curve

Example measured on Siberian pine (Continental Sonderklasse 22 mm, 74 kg rider):

Minimum sits at 9.5-10 bar. Going to 12 does not save: it costs 2.4 W. Going to 8 costs 1.3 W. And to 7, three watts. The minimum is not flat: it's a clear parabola. Setting the sweet spot to manufacturer max is a decision that costs seconds.

How the sweet spot moves with rider weight

A 60 kg rider deforms the tubular less than an 85 kg one. Their optimum drops 0.3-0.5 bar. Rule of thumb:

62 kg rider → 9.1 bar. 78 kg → 9.9 bar. 85 kg → 10.25 bar. As reference, not sacred formula. Each tubular has its own curve and you need to verify it if you have measurement access.

The cost in grip on a 42% banked corner

Pressure not only affects Crr in the straight. In a 42% banked corner (the standard geometry of a 250 m UCI Cat.1 velodrome), the tyre works under significant lateral load. An over-inflated tubular has a narrower contact patch and less lateral force capacity. At the limit it slips.

For pursuit riders in line, that margin is rarely explored. For sprinters in Keirin or 200 m flying TT, yes. A sprinter wanting to hold the black line on corner exit at 70+ km/h needs 0.5-1 bar below their Crr optimum. Loss in rolling is 1-2 W. Gain in grip can be a full lap of clean line.

Recommendations by discipline

A common mistake: cold-measured pressure vs race pressure

The tubular on the warm-up roller heats up and rises 0.3-0.5 bar over cold reading. If the UCI reference you want is 9.5 bar on track, you have to inflate to 9.1-9.2 bar cold to hit 9.5 after warm-up. This adjustment is forgotten more often than it seems and explains why some riders perform better on the second heat of the day than the first: on the second they have unknowingly hit the right pressure.

References: Bicycle Rolling Resistance Lab (2024) — Track Tubular Pressure Study. AeroCoach Track Optimisation Report 2024. Continental Sonderklasse Test Protocol. Debraux P. et al. (2011), Sports Biomech..