How to use the calculator
- Pick your bike type. We load typical values for bike weight, tire width and rim that you can change.
- Enter your weight and your bike’s weight. Include clothing and bottles. If you carry a load (panniers, bikepacking bags), add it under More settings → Luggage.
- Enter the tire width as printed on the sidewall: on “28-622” or “700×28c” the width is 28 mm. If you know your rim’s inner width, add it: the same tire measures wider on a wide rim and needs less pressure.
- Choose the surface you ride most. Below you’ll see the same bike on every other surface, in case your plans change.
- Check the warnings. If your rim is hookless, the pressure will never go above 72.5 psi (5 bar).
With the Save to My bike button, you won’t have to type this data again in other calculators.
How we calculate tire pressure
We start from Frank Berto’s idea: a tire is properly inflated when, with your weight on it, it always compresses by the same fraction of its height. If it compresses more, it rolls sluggishly and you risk hitting the rim. If it compresses less, it bounces over every bump, loses grip and, on real roads, is slower.
To keep that compression constant, pressure has to rise with the weight on each wheel and drop with tire width:
Base pressure (psi) = 165 × load on the wheel (kg) ÷ width (mm)^1.4
We then apply, in this order:
- Weight distribution: the front carries 46% on road and gravel bikes, 45% on mountain bikes and 40-42% on city bikes and e-bikes, because you sit more upright.
- Use: on mountain, city and e-bikes we add 12-18%, since there are impacts, curbs and more weight in motion.
- Surface: from velodrome (+6%) to rocky trail (−22%). The rougher the ground, the lower the pressure: the tire absorbs instead of bouncing.
- Tube or tubeless: +4% with a butyl tube to prevent pinch flats.
- Casing: reinforced casings handle load a bit better and let you go slightly lower.
- Your preference: −6% for comfort and +4% for speed on smooth pavement.
- Wet: −5% for more grip.
Then come the safety limits: never above 72.5 psi (5 bar) on hookless rims, never above the max on your tire and never so low that the tube pinches. The full detail is on the methodology page.
Recommended tire pressure at a glance
Values in psi, front / rear (bar in parentheses), for three rider weights with a typical bike weight and 2.2 lb (1 kg) of bottles, calculated with the same defaults as the calculator, including the typical inner rim width for each bike type (21 mm road, 25 mm gravel, 30 mm mountain and 19 mm city). On a wider rim the tire grows 1-2 mm and pressure drops 3-6%: the calculator adjusts for it if you enter your rim’s inner width.
| Bike, tire and surface | 120 lb (54 kg) | 165 lb (75 kg) | 210 lb (95 kg) |
|---|---|---|---|
| Road 28 mm, tubeless, average pavement | 40 / 47 (2.8 / 3.3) | 53 / 62 (3.7 / 4.3) | 66 / 77 (4.5 / 5.3) |
| Gravel 40 mm, tubeless, hardpack | 24 / 28 (1.6 / 1.9) | 31 / 37 (2.2 / 2.5) | 39 / 46 (2.7 / 3.1) |
| Mountain 2.4 in (61 mm), tubeless, trail | 15 / 19 (1.0 / 1.3) | 20 / 24 (1.4 / 1.7) | 24 / 29 (1.7 / 2.0) |
| City 42 mm, butyl tube, pavement | 29 / 43 (2.0 / 3.0) | 37 / 56 (2.6 / 3.9) | 46 / 69 (3.2 / 4.8) |
On the road, with a butyl tube, add about 2-3 psi (0.2 bar). Watch out for hookless rims: at 210 lb (95 kg) on 28 mm tires, the rear already goes past 72.5 psi (5 bar), so you need 30 mm or wider. Many city tires also print a minimum pressure on the sidewall: respect it even if the table says less.
The full charts, with a wide range of rider weights and every tire width, are in road tire pressure, gravel, mountain bike and city bike. To hang next to your pump, use the printable tire pressure chart.
Hookless rims: the 72.5 psi limit
Hookless rims are increasingly common on road and gravel bikes. They hold the tire only with the shape of the bead and the air pressure, so they have a ceiling: 72.5 psi (5 bar) for any tire, according to the ETRTO standard and ISO 4210-2. In 2024 the UCI decided that, where the two standards conflict, ISO takes precedence.
On top of that, most manufacturers don’t approve tires narrower than 25 mm on hookless rims, and some (like ENVE) only approve specific models that pass their own testing. Before mounting a tire on a hookless wheel, check the wheel maker’s compatibility list.
Common mistakes
- Pumping up to the number on the sidewall. The sidewall max is a safety limit, not a recommendation.
- Same pressure front and rear. The rear carries more weight; at equal pressure, front grip suffers and the rear squashes.
- Trusting the thumb test. Between 45 and 70 psi (3 and 5 bar), a tire feels equally hard when you squeeze it. Use a pump with a gauge, ideally a digital one.
- Ignoring your luggage. 22 lb (10 kg) of panniers changes rear pressure by more than 7 psi (0.5 bar).
- Measuring hot. After a long descent on rim brakes or sitting in the sun, pressure goes up. Measure cold, before you ride.
If the pressure doesn’t feel right
It’s a starting point. Go for a ride and adjust 1-3 psi (0.1-0.2 bar) at a time:
- If the bike bounces, you feel every stone or the wheel slides in corners, let a little air out.
- If you feel the rim bottom out on bumps, the tire feels “squirmy” in corners or you get pinch flats, add a little air.
Frequently asked questions
What tire pressure should I run on a road bike?
With 28 mm tires, regular tubes and a rider weight of 155-175 lb (70-80 kg), between 52 and 68 psi (3.6-4.7 bar), a little more in the rear than the front. With 25 mm tires it rises to 58-76 psi (4-5.3 bar), and with 32 mm it drops to 46-60 psi (3.1-4.1 bar). The old 100-115 psi (7-8 bar) only made sense on 23 mm tires, and we now know it is slower on real-world roads.
Why should the rear tire have more pressure than the front?
Because when you sit on the saddle, roughly 54-60% of your weight is on the rear wheel. At the same pressure, the rear tire would squash more. Running a bit more air in the rear evens out how much both tires compress.
What is the max tire pressure on a hookless rim?
72.5 psi (5 bar), whatever the tire. That is the limit set by the ETRTO standard and adopted in ISO 4210-2. Above it, the tire can blow off the rim. If your weight calls for more, fit a wider tire.
Can you run lower pressure with tubeless tires?
Yes, a little lower, because there is no tube to pinch against the rim. With a butyl tube, go about 4-5% higher to avoid pinch flats. Latex and TPU tubes behave almost like tubeless.
How often should I check my bike tire pressure?
On the road, before every ride: a butyl tube slowly leaks air and a latex tube can lose 15 psi (1 bar) in a day. For gravel and mountain biking, at least once a week and always before a long ride.