Bike Tire Pressure Calculator for Road, MTB, Gravel and E-Bikes

Four things, and none of them is the brand. The number on the sidewall is a structural limit, not a recommendation.

Load on the wheel. A tyre is a spring holding up a weight, so pressure scales almost linearly with it. Your front wheel carries less of you than the rear, which is why it should always run a few psi lower.

Measured width. Air volume rises fast with width. Use what the tyre actually measures on your rim, often 1–3 mm more than the label.

Surface. Past a point, more pressure stops the tyre absorbing bumps and starts throwing the whole bike upwards, which costs far more than it saves. Rough ground is faster at lower pressure.

Construction. A stiff casing carries part of the load itself. A tube can pinch flat so it needs a margin; an insert takes the rim strike so it does not.

Road pressures have come down a long way — the 120 psi that was normal on 23 mm tyres is slower on any real road, not just harsher. On 28 mm tubeless, a 75 kg rider is usually near 70 psi front and 75 rear.

Measure the tyre rather than trusting the label, run the front 2–5 psi below the rear, and ignore the maximum printed on the casing. For racing on genuinely smooth tarmac, set the surface to new tarmac — that is the one case where higher really is quicker.

Mountain bike pressures sit in a narrow band where one or two psi separates grip from a dented rim. A trail rider at 90 kg total on 2.4in tubeless tyres lands around 20 psi front and 23 rear; XC on 2.25in a few psi more, enduro on inserts a few less.

Widths convert straight over: 2.3in is 58 mm, 2.4in is 61 mm, 2.6in is 66 mm. Wheel size barely matters — a 29er wants about a psi less than a 27.5 at the same width, while your weight and tyre width move it twenty times as much.

Rough ground pulls two ways: rocks want lower pressure for grip, hitting them at speed wants higher for the rim. That is why surface and riding style are separate boxes. If you are consistently under 18 psi chasing grip, fit an insert or a wider tyre rather than letting more air out.

Gravel is where pressure matters most, because one tyre covers a huge range of surfaces. The same 42 mm tyre might want 40 psi on a road transfer and 32 on chunky gravel — and on the rough stuff the lower figure is the faster one. An 80–90 kg system weight on 40 mm tubeless typically lands in the low-to-mid 30s at the rear.

Cyclocross runs lower still: 33 mm tyres on grass and mud in the low 30s, tubulars lower again because a glued tubular cannot pinch flat. Set the surface to soft ground.

Tubeless lets you run roughly 5–8% less than the same tyre with a butyl tube, because there is no tube to pinch. The failure you are avoiding at low pressure changes from a snakebite to a dented rim. Below about 16 psi a hard corner can burp air; an insert buys you lower again.

Hookless rims cap you at 72.5 psi (5 bar). Unlike everything else here that is a hard safety limit, not a preference — above it a tyre can blow off the rim. If the calculator gives you more than that, fit a wider tyre rather than exceeding it, and check your tyre is approved for hookless use.

E-bikes and e-MTBs. Most of the adjustment happens by itself, since the motor and battery go into the total weight. On top of that, more torque and more unsprung weight favour a little extra pressure and a tougher casing — tick the e-bike box. A 105 kg total on 2.6in tyres lands in the low-to-mid 20s at the rear; do not copy the figure off your unpowered bike.

Fat bikes. Single digits. On snow or soft sand 5–8 psi is normal, and one psi is the difference between floating and digging in. A low-pressure gauge is worth owning.

Loaded touring. Put luggage in the kit box and drag the front/rear split towards 40/60 if the load sits over the back wheel. A loaded rear can want 15 psi more than the front.

The physics does not change with the logo. Load, measured width, surface and casing set the pressure, and any calculator asking for those lands in the same place. Three things that do vary by brand:

Casing names are the real difference, and the casing box is where you enter them. Maxxis EXO is light reinforcement, EXO+ and DoubleDown tougher, DH heaviest; Schwalbe runs Super Race through Super Ground to Super Gravity and Super Downhill. Pick the row matching how tough your tyre is.

Maximum pressures bind. Continental prints conservative maximums on some road tyres; Schwalbe publishes a minimum as well. Put whichever is lower — tyre or rim — into the max pressure box.

Hookless approval is per tyre. Enve, Zipp and Giant all sell hookless road rims and the 72.5 psi ceiling applies to all of them. The brand tools from Specialized, Bontrager and Trek, SRAM AXS, Silca and Wolf Tooth are good but mostly single-discipline — the road ones return dangerously low numbers for a 2.4in trail tyre, and the mountain ones do not cover road at all.

Front / rear psi for an 85 kg total on tubeless tyres with a standard casing. A sanity check only — the calculator adjusts for your weight, surface and setup, which moves these a lot.

Divide by 14.5 for bar.

1. Get a gauge you trust. Floor pump gauges are often 5–10 psi out, which at mountain bike pressures is a third of the total.
2. Set the calculated figures and ride your usual loop. Bouncing and numb hands mean too hard; vague steering and the rim finding rocks mean too soft.
3. Change one wheel at a time, by one psi. Changing both tells you nothing about which one was wrong.
4. Check before every ride. Tubeless loses a few psi a week, latex tubes lose that overnight.

If you came looking for a RockShox or Fox fork pressure calculator, this is not it. Tyre pressure is set by load and volume; suspension is set by sag — how far the fork or shock settles under your static weight. Aim for 15–20% on a fork and 25–30% on a rear shock, starting from the manufacturer's chart for your exact model, because the air spring differs with every fork and travel length. Sort tyre pressure first either way — suspension tuned around bad tyre pressure will never feel right.