Bike tire pressure calculator

The right tyre pressure depends on how much weight sits on the tyre and how wide it is: more weight needs more pressure, a wider tyre needs less. Enter your total weight, measured tyre width, tyre setup and the surface you ride, and get front and rear pressures in psi and bar, with a safety cap for hookless rims.

Calculator

Bike

Rider weight

Bike and kit

Tyre width

Use the measured width on your rim if you know it; wide rims make tyres measure wider.

Setup

Surface

Wet conditions

Hookless rims

Hookless road rims are limited to 72.5 psi (5 bar).

Advanced

Max pressure printed on tyre or rim

psi

Enter a value between 15 and 220 psi.

Front

5.2bar

75 psi

Rear

5.6bar

81 psi

Starting range: front 73 to 77 psi, rear 79 to 83 psi. Adjust 2 to 3 psi at a time.

Base pressure by tyre width at 80 kg total weight, scaled with weight, adjusted for surface, setup and weather. Front about 4 % lower and rear about 4 % higher than the base.

How the tyre pressure calculator works

The right pressure lets your tyre flex enough to absorb the surface without folding over or hitting the rim. Two things decide it: how much weight sits on the tyre and how wide it is. More weight needs more pressure; a wider tyre holds the same weight at a lower pressure. This calculator is one of the free LeCoach cycling calculators and covers road, gravel and mountain bikes in one place.

It works in four steps:

Base pressure by width. Each width has a base pressure for a total system weight of 80 kg (rider, bike and kit), smooth surface, tubeless and dry. A 28 mm road tyre starts at 74 psi, a 40 mm gravel tyre at 43 psi and a 2.4 inch MTB tyre at 24 psi.
Scale with weight. 10 % more total weight means 10 % more pressure.
Adjust for conditions. Rougher surfaces and wet roads lower the number. Inner tubes raise it.
Split front and rear. The rear goes up and the front goes down by a fixed percentage.

Worked example. One 75 kg rider, three bikes. On a gravel bike (10 kg with kit, so 85 kg in total) with 40 mm tubeless tyres on mixed gravel, the base is 43 × 85 ÷ 80 × 0.94 = 42.9 psi, which gives 41 psi front (2.8 bar) and 45 psi rear (3.1 bar). The same rider on a road bike with 28 mm tyres on smooth tarmac starts at 75 / 81 psi, and on a 14 kg trail bike with 2.4 inch tyres on mixed trails at 24 / 27 psi. Same rider, same method, pressures that differ by a factor of three.

Example pressures for road, gravel and MTB

All rows: 75 kg rider, tubeless, dry. Bike and kit: road 9 kg, gravel 10 kg, MTB 14 kg (trail casing, no inserts).

Bike	Tyre	Surface	Front	Rear
Road	25 mm	Smooth tarmac	86 psi (5.9 bar)	93 psi (6.4 bar)
Road	28 mm	Smooth tarmac	75 psi (5.2 bar)	81 psi (5.6 bar)
Road	32 mm	Smooth tarmac	62 psi (4.3 bar)	68 psi (4.7 bar)
Gravel	40 mm	Hardpack	43 psi (3.0 bar)	48 psi (3.3 bar)
Gravel	40 mm	Mixed gravel	41 psi (2.8 bar)	45 psi (3.1 bar)
Gravel	45 mm	Rough gravel	31 psi (2.1 bar)	34 psi (2.3 bar)
MTB	2.4 in	Flow trails	25 psi (1.7 bar)	28 psi (1.9 bar)
MTB	2.4 in	Roots, mixed	24 psi (1.7 bar)	27 psi (1.9 bar)
MTB	2.4 in	Rocky	23 psi (1.6 bar)	25 psi (1.7 bar)

For tables built around one kind of riding, use the focused pages: the road bike tire pressure calculator for 23 to 35 mm tyres and hookless rims, the gravel bike tire pressure calculator for 35 to 50 mm tyres on different gravel, and the mountain bike tire pressure calculator for casings, inserts and trail types.

Why front and rear pressures differ

More of your weight sits over the rear wheel, so the rear tyre needs more support. The front carries less and does the steering, so a little less pressure gives it more grip. The calculator moves the front down and the rear up by the same percentage of the base: 4 % each way on road, 5 % on gravel and 6 % on MTB. Off-road, front grip matters most, so the gap is largest there.

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Tubeless, inner tubes, wet roads and hookless rims

Tubeless is the baseline: with no tube to pinch, you can run a little lower. Top up the sealant every few months.
Inner tubes add 6 % to protect against pinch flats.
Wet conditions take off 5 % for a little more grip.
Hookless road rims are capped at 5 bar (72.5 psi). The road bike tire pressure calculator explains the limit and what to do if you hit it.

Common mistakes

Pumping to the number on the sidewall. That is the maximum, not a recommendation.
Using rider weight only. The tyres carry the bike, bottles, bags and tools too.
Entering the printed width. On a wide rim a tyre often measures a millimetre or two wider than its label.
Ignoring the limits. Never exceed the maximum printed on your tyre or rim; enter it under "Advanced".
Running the same pressure front and rear. The front ends up too hard, the rear too soft.
Going too low for comfort. The tyre squirms in corners, and you risk rim strikes and burping air.

When to change your pressure

Rough or wet day: choose the matching surface and switch on "Wet conditions".
Bikepacking or a long day: add the luggage to your bike weight.
New tyres: enter the new measured width. Our guide on when to replace bike tires helps you judge wear.
Before every ride: tyres lose air over a few days, so check them each time.

To turn a faster setup into an event plan, the cycling speed calculator shows what your power gives on the road. And you can ask LeCoach how to pace and fuel your event, and it answers from your own rides and goals.

Sources

Berto F. Tire drop pressure chart. Bicycle Quarterly. https://www.renehersecycles.com/wp-content/uploads/2015/03/BQTireDrop.pdf
road.cc. How to choose your tyre pressure. https://road.cc/content/feature/how-choose-your-tyre-pressure-180830
ETRTO standards manual and ISO 5775: 5 bar (72.5 psi) limit for tubeless tyres on hookless road rims, as summarised by Schwalbe and BikeRadar.
Stan's NoTubes. Sealant service life guidance.

Frequently asked questions

What tyre pressure should I run?

It depends on weight, tyre width and surface. For a 75 kg rider with a typical bike, tubeless and dry, start at about 75 psi front and 81 psi rear on 28 mm road tyres, 41 and 45 psi on 40 mm gravel tyres on mixed gravel, and 24 and 27 psi on 2.4 inch MTB tyres on mixed trails.

Should front and rear tyre pressure be different?

Yes. The rear carries more of your weight, so it needs more pressure, while a softer front tyre grips and steers better. This calculator sets the front 4 % below and the rear 4 % above the base on a road bike, 5 % each way on gravel and 6 % each way on a mountain bike.

Why does my weight change my tyre pressure?

The tyre carries you, the bike and everything on it. More weight squashes the tyre further, so it needs more air to keep the same shape. That is why the calculator scales pressure in a straight line with total weight: a rider and bike 10 % heavier start about 10 % higher.

Which bike needs the most careful pressure setting?

Gravel and MTB, because the range between too hard and too soft is narrow and the surface changes all the time. On a road bike a few psi either way mostly changes comfort. Off-road it changes grip, rim protection and whether the tyre burps air in corners.

How often should I check tyre pressure?

Check it before every ride. All tyres lose air slowly through the casing and valve, and tubeless tyres often lose it faster than you expect. A tyre that has dropped a few psi since your last ride feels slower and is more likely to pinch-flat or strike the rim.

How do I convert psi to bar?

Divide psi by 14.5 to get bar, or multiply bar by 14.5 to get psi. So 75 psi is 5.2 bar, 45 psi is 3.1 bar and 28 psi is 1.9 bar. The calculator shows both units, with bar to one decimal place, and leads with the unit that matches your unit setting.