As a bike fitter who works with a broad spectrum of triathletes and road cyclists - from complete beginners to seasoned professionals, I'm often asked for advice on tire pressure.

Optimal tire pressure isn't a one-size-fits-all number; it's a personalized calculation that balances rolling resistance, comfort, traction, and puncture protection. Get it right, and you could shave seconds off your bike splits while reducing fatigue. Too high, and you'll bounce like a ping-pong ball; too low, and you'll risk pinch flats or increased drag. Let's break down how to calculate yours based on key factors: your weight, bike weight, tire width, setup (tubeless or inner tubes), and terrain.

First, start with the basics: total system weight. This includes you (fully kitted in helmet, shoes, and hydration) plus your bike's weight. For a 80kg rider on a 8kg road bike, that's 88kg total. Heavier loads demand higher pressures to prevent the tire from deforming too much under stress, which increases rolling resistance.

Tire width is crucial. Narrower tires (e.g., 23-25mm) need higher pressures for stability, while wider ones (28-32mm or more) excel at lower pressures for better compliance and grip.

Tubeless vs. inner tubes makes a big difference. Tubeless setups allow lower pressures (5-10 PSI less) because there's no tube to pinch, improving traction and reducing rolling resistance on imperfect roads. With tubes, err higher to avoid flats—sealant in tubeless also forgives minor punctures. Always check manufacturer max/min ratings; exceeding them risks blowouts.

Terrain tweaks the equation. Smooth tarmac? Higher pressures (e.g., +5 PSI) minimize deformation for speed. Rough roads or gravel? Drop 10-20 PSI for cushioning and grip. Wet conditions? Lower slightly for better contact patch. For elites chasing marginal gains, test with a pressure gauge and power meter: ride segments at varying PSIs and note wattage vs. speed.

Sounds complex? It is, and that's why I recommend using a tool like the Silca tire pressure calculator

In summary, optimal pressure is dynamic: calculate based on weight and width, adjust for setup and terrain, and iterate. As a fitter, I recommend quarterly checks or post-weight changes. Ride smart, stay inflated, and enjoy the efficiency boost.

Happy pedaling!

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