Tyre pressure depends on the amount of air you pump into your tyres. For bicycles it’s measured in either psi – pounds per square inch – or bars – 100,000 Newtons per square meter.
Everyone will have a preference in regard to their ideal tyre pressure, just like everyone has a preference on gel flavours or rim brakes vs. disc brakes, but there are some empirical factors at play that should feature in your decision making process.
If you can’t be bothered to read any further and just need a number, we’ll start with some very approximate starting points for different types of bike. These won’t be the best pressures for you and you should absolutely give this more thought, but it’ll be better than just guessing.
Tyre pressures for different types of bike: A (very) rough guide
Road bike: 90psi / 6.2 barGravel/cyclocross bike: 40psi / 2.8 barHybrid bike: 50 psi / 3.4 barMTB: 30psi / 2.1 bar
If you want a more precise figure but don’t care about the theory, a good tyre pressure calculator is incredibly useful. We like the SRAM one. Want to understand tyre pressure in more detail? Read on.
Why does tyre pressure matter?
As with many things on a bike, tyre pressure is a balancing act, trying to cover all bases without compromising too much on any one of them. A better tread or rubber compound might get you more grip but negatively impact rolling resistance, while super racy tyres might feel amazing and save weight, but they’ll puncture more easily.
You may have seen the growing trend in recent years towards running lower pressures, but riding too low will put you at greater risk of a pinch puncture when using inner tubes – where the tyre flexes excessively and pinches the inner tube against the rim, causing a hole.
Both tyre and rim manufacturers set minimum and maximum tyres pressures for their products and straying outside of these ranges can cause them to fail.
A pro mechanic checks tyres pressure on a TT bike at the 2022 Tour de France. Matthew Loveridge / Cyclist
Professional cyclists have whole teams behind them to help them make such complex decisions. ‘We use the advice from the team’s experts’, says Will Bridgman, race mechanic for Team DSM. ‘Their job is to look into the best tyre pressures for each race and conditions. We also use an in-house software tool to see the road surfaces from every race, from there its basically picking from a menu.’
Without a panel of experts to help you, choosing the best tyre pressure for you can be a daunting task, so we’ve broken it down into the key areas to consider to help you decide.
Isn’t higher tyre pressure faster?
If you are riding on a velodrome that is routinely manicured and consists of perfectly flat wooden boards with zero imperfections, then yes, a higher tyre pressure will probably help you ride faster. If you are riding on a seemingly smooth road however, it’s a whole other matter.
This is because even the flattest of tarmac will still have minute lumps and bumps in it and these cause the bike to bounce up and down as it rolls over each of them. The air in the tyres acts as shock absorption and the higher the pressure, the less is absorbed. This translates to increased vertical and horizontal movement, requiring more power to be put down by the rider to maintain the same speed.
This also takes a bigger toll on your body, as your joints act as in-built shock absorbers. This absorption requires energy additional to that you are putting through the pedals. It’s a complex topic, so read our breakdown of wider tyres and lower pressure for a full dive into the nitty gritty.
How do you check your tyre pressure?
The most accurate way to check your tyre pressure is by using a pressure gauge. Most floor pumps – or track pumps – will feature a built-in gauge, as well as some mini pumps. Electronic gauges will give you the most precise reading (but not necessarily the most accurate one – that depends on calibration) but for the majority of people, this level of precision isn’t necessary.
You can also go by feel. While this isn’t the most scientific method, it can be useful to know what different pressures feel like on the tyres you’re using so that, if you get a puncture and only have a pump without a gauge, you know roughly what pressure feel to pump up to.
Why do tyres lose pressure?
In the same way that few jackets are fully waterproof, few inner tubes are fully airtight. Air can leak through the valve but the biggest loss of air over time is typically through the tube material itself.
Latex is more porous than butyl – the standard inner tube material – so latex tubes let out more air and lose pressure more quickly.
The same is true for some tubeless tyres. As there’s no inner tube holding the air inside the tyre, the tyre material is responsible for maintaining pressure when the tyre is fully sealed to the rim. Some tubeless sidewalls are more porous – most often tan walls – so will deflate faster. Air may also leak out at the valve, or past the tape that rims with spoke holes in the rim bed require.
‘We find that tubulars loose about 0.1 bar [1.5psi] per hour’, says Team DSM’s Bridgman, ‘and tubeless about 0.1 bar roughly every 3 hours. This informs the expert advice on what the ideal pressure is to pump up to pre-race.’
A more complex issue is external temperature changes. Temperature will directly affect the real-world pressure inside your tyres, though to what extent, experts disagree. Unless you are riding in extreme weather conditions, temperature fluctuations shouldn’t affect your tyre pressure that noticeably.
The last thing to consider is punctures. While most punctures become immediately apparent at the time of impact, some cause smaller holes which leak at a much lower rate.
Such punctures tend to deflate overnight and can be ridden for a whole day before needing pumping up again, so if you’re consistently waking up to a flat tyre, this is likely the culprit.
How do I choose the correct tyre pressure for me?
Recommended rangesTyre typeTyre sizeTraction and gripWeather and temperatureLoadPreference
Matthew Loveridge / Cyclist
Manufacturers put their tyres through rigorous testing before they are released onto the market. One of the tests is the pressures at which the tyres can be run safely at without failure. Too low and the tread won’t perform as intended and the tyres will begin to crack along the sidewalls. Too high and the tyre is at risk of failing completely or blowing off the rim.
Their findings will dictate the suggested psi/bar range of the tyre, which you can either find written on the tyre itself or on the packaging.
Rim manufacturers often only provide a maximum tyre pressure value. While most modern wheels and tyres should be cross-compatible, it is always worth double checking as running tyres at too high a pressure – especially when tubeless – can cause the tyre to blow off the rim.
There are three main types of tyres and, as a rule of thumb, they tend to have similar characteristics when it comes to tyre pressure.
Clinchers are standard ‘use with an inner tube’ tyres that are held onto the rim by pressure from the inner tube pushing the tyre outwards and hooking the tyre bead onto the rim bed. These generally cannot be run at very low pressures as there is increased risk of pinch punctures when doing so.
Tubeless tyres are similar in overall design to clinchers but rely the tyre and rim creating a sealed unit to maintain air pressure, using sealant to help make this air tight and fill holes caused by punctures. Tubeless tyres can be run at much lower pressures than clinchers as the tyre can safely deform without the risk of pinching an inner tube.
While tubeless tyres cannot get pinch punctures, they need a certain amount of pressure to remain properly mounted on the rim – too low and there’s a risk of ‘burping’, where the bead comes unseated suddenly and releases air.
Tubular tyres – also known as tubs, sew-ups or singles – are like a tyre and an inner tube rolled into one. The tyre is a fully sealed unit, with an inner tube-like liner, and it’s glued or taped onto a slightly concave rim.
As tubular tyres are literally stuck to the rim they can be run at extremely low pressures with a reduced risk of rolling off. They can also be run at very high pressures as they’re entirely self-contained and don’t rely on the interface of multiple components to maintain a seal.
The downside to tubular tyres is that they’re expensive and time-consuming to replace properly, ruling them out as a day-to-day option for most riders. Tubs are still widely used in pro road and cyclocross racing but they’re gradually disappearing from amateur competition and are now mostly the preserve of track cycling and cyclocross.
Wider tyres can be run at lower pressures as they have a larger volume. To break this down, think back to the pressure metric, psi.
For a given segment of tyre mounted on a rim, a wider tyre will have a larger internal surface area than a narrower tyre, as the total width from bead to bead is larger. This means that there will be more square inches inside a wider tyre than a narrower one.
If you run a 35mm tyre and a 25mm tyre at 80psi, the 35mm tyre will counterintuitively feel less comfortable as there are more square inches thus more pounds of air. Casing tension is also higher on a wider tyre, which contributes to increased tyre stiffness on a wider tyre run at the same pressure as a narrower tyre.
Wider tyres have historically been used exclusively for off-road terrain, where most more grip and shock absorption is needed, but with more recent research showing the benefits of a wider rubber on the road as well, it’s becoming more common to see the likes of 32mm tyres run on tarmac as well. For general road riding on mostly well-kept surfaces, 28mm tyres are a great all-round choice.
Traction and grip
The lower the tyre pressure, the more the tyre can flex and more of the tyre is in contact with the ground. The more contact with the ground, the more grip and traction you will have. This is because, where contact takes place, friction will occur which is what gives us grip.
The need for traction varies depending on which type of cycling you’re doing. If you’re riding on a flat road with gentle, sweeping corners on a dry day, being glued to the road isn’t top on your list of priorities. But if you’re riding on a dusty, bumpy gravel track where the ground feels like it’s sliding about beneath you, you’ll want as much grip as you can get your hands – or tyres – on.
This is one of the main reasons why you’ll see lower pressures used on mountain bikes and gravel bikes, compared to the road. As a general rule of thumb, the rougher the terrain, the more grip thus lower tyre pressure you’ll want to be running.
Traction over varying terrain features heavily when teams choose what pressure professional riders should be using. ‘We have to factor in that, in a large bunch of 150+ riders, you can’t always pick the perfect line’, says Bridgman. ‘We want to eliminate issues arising due to bad road surfaces, so this affects what tyre pressure we will choose to ensure the best balance of grip and performance in these scenarios.’
Weather and temperature
Temperature changes have a direct impact on the pressure in your tyres, though experts dispute the extent of that impact. While some will argue up to 1psi loss for every 2°C temperature drop, others claim the real world figures are closer to 1psi for every 5°C.
For most riders, this will not matter all that much, but if you ride in climates where the temperature fluctuates extremely, it is worth taking into consideration.
So too is the weather itself. Wet roads wreak havoc with tyre grip, as the water affects the rubber’s ability to gain traction. Given that a lower pressure gives a larger contact patch, it’s often advised to drop tyre pressure by around 5psi when you’re expecting rain.
Extrapolate this further for icy conditions, where road surfaces will be even slipperier. Dropping your tyre pressure will help to some degree but in most cases, anything short of studded tyres won’t provide you with enough grip and we’d strongly advise not riding when there’s ice about.
The more load that is put on a given tyre, the more that tyre will deform. When riding, there are several contributing factors to this load: the weight of the bike, the weight of the rider and the added weight of any accessories or luggage.
The more load is on the bike, the higher the tyre pressure will need to be to compensate for tyre deformation.
When in the saddle, there will be more load on the back tyre than the front one. If riding with panniers or a large rucksack, it may be worth increasing the rear tyre pressure by 5-10psi to account for the extra weight.
No matter how much science can tell you what the theoretical ideal tyre pressure is, if you don’t find it comfortable, you’re not going to enjoy it.
As discussed, a lower pressure will reduce the impact and exertion from your body which can help both your energy levels and your comfort. Go too low and you risk the bike feeling less stable as the tyre excessively flexes or creates too large a contact patch and excessive grip, slowing you down.
Traditionally, there has been the misconception that a higher tyre pressure will make you faster, and this lesson has been deeply internalised. While you may feel faster, the science shows that this is not technically the case in most situations.
‘Riders generally make a note of pressure they have used on particular courses and conditions’, says Team DSM’s Bridgman, ‘so they normally arrive at a race with an idea of where to start in regard to tyre pressure and we go from there.’
Feeling comfortable and confident on your bike can often be a case of trial and error, and experiencing a range of different tyre pressures, combined with the knowledge of how this feels, is usually the best way of finding a tyre pressure that works well for you.
Time to deck your bike out with some new rubber? See our guide to the best road bike tyres.