The basics

Why

Pressure is a trade-off. Schwalbe sums it up: the higher it is, the lower the rolling resistance, wear and puncture risk; the lower it is, the higher the comfort and grip. Too low, the tyre pinches against the rim and the tube punctures (two small slits side by side). Too high, the bike bounces and grips less in corners.

When to do it

• At least once a month, with a gauge: Schwalbe considers a tyre losing 1 bar a month to be normal. Ideally every week, as in the pre-ride check.
• Before every ride with latex inner tubes, which lose air faster.
• After changing a tyre, or before setting off loaded.

Reading the limits

Two limits, never to be exceeded:

• The tyre sidewall shows a range, minimum and maximum, in bar and often in psi (for example "4–6 bar, 58–87 psi"). Never go below the minimum, never above the maximum.
• The rim sometimes has its own maximum pressure, written on the rim or its sticker. On a hookless rim, the standard caps it at 5 bar, whatever the tyre.

Always keep to the lower of the two maximums.

(1 bar = 14.5 psi.)

Finding your pressure

There's no right pressure for a given tyre: it depends above all on the weight it carries (you, the bike, the luggage). The rules to remember:

• The narrower the tyre, the higher the pressure. A 25 mm road tyre runs far higher than a 60 mm mountain bike tyre.
• The heavier the load, the higher the pressure: heavier rider, panniers, child seat.
• Small wheels (folding bikes) run higher than big ones.
• Tubeless can run a little lower than with an inner tube.

The method:

1. Start in the middle of the range on the sidewall.
2. Ride your usual route. Does the bike bounce, slide in corners or rattle you? Go a little lower. Does the tyre squirm in corners, or can you feel the rim hitting on bumps? Go higher.
3. Change in small steps, and note the pressure that suits you.

Steps

1. Identify your valve

• Presta (thin, with a small nut at the tip): unscrew the nut a few turns, then press it once to free it.
• Schrader (like on a car): just remove the cap.

2. Fit the pump

Push the pump head fully and straight onto the valve, then flip the locking lever if it has one. A bent valve or a crooked pump head lets air escape.

3. Inflate and read the gauge

Inflate to the chosen pressure, reading the gauge. If you overshoot, let a little air out (on a Presta, press the small pin at the tip) and read again.

4. Remove the pump and close up

Pull the pump head off in one quick, straight move. On a Presta, screw the nut back down. Put the cap back on: it keeps dirt out of the valve.

Check it's done right

• The pressure reads within the sidewall range, and below the rim maximum.
• The tyre is even all the way round, with no bump.
• The valve sits straight in its hole.

Common mistakes

• Trusting your thumb rather than the gauge.
• Pumping to the maximum "to go faster": on rough roads or off-road, a tyre that's too hard bounces and loses grip.
• Forgetting the rim's limit, especially on a hookless rim.
• Only pumping up after a puncture: a tyre loses air on its own.

What next

Note your ideal pressure in your logbook, with the tyre width: you'll find it again after every change. If a tyre loses a lot of air within a few days, look for a slow puncture: see Fix a flat tyre.

Sources

This guide was checked against the following documents:

• Schwalbe, tyre pressure (trade-off, load, width, tubeless, check frequency, thumb test), in German
• Schwalbe, mounting (5 bar maximum on hookless rims), in German
• Schwalbe, pressures by rider weight and tyre width (road)
• BikeTips, Hookless rims explained (5 bar limit)

Values vary between models: your part's manual always takes precedence.