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A Beginner's Guide to Bike Tire Pressure

By Spencer Powlison

Here’s a riddle: Your bike has a component that costs nothing and weighs nothing. But it is essential if you want to go ride. What is it?

Well, this story’s headline probably gave away the answer. It is the air in your tires.

Depending on your experience level, you might be able to gauge your PSI with a quick pinch of the tire. Or, you might be a little surprised to hear that bike tires need to be checked far more regularly than those on your car. This how-to guide is geared toward the latter group of cyclists, beginners. But hopefully, riders of every ability level can learn a little more about the precious pressurized air that keeps us all rolling.

Gravel bike tires

The basics

Pneumatic tires on any vehicle are supported by pressurized air in an airtight chamber. Higher PSI (pounds per square inch) makes the tire harder. Lower PSI makes it feel softer. Tire pressure has a huge impact on how a bike performs. Checking your tire pressure is the simplest and most important piece of regular maintenance you can perform.

So where do you begin if you’re new to cycling and just got a road, mountain, gravel, or cyclocross bike? Conveniently, every bike tire has recommended PSI stamped into the rubber on the sidewall. (Pro tip: If you’re mounting a tire, align that pressure rating next to the valve for easy reference.)

“Recommended tire pressure is about the intended use and the best range for that use,” says tire expert Johs Huseby, WTB’s Director of Global OEM Sales and Product Vision. “You need to find the sweet spot for a tire and figure out where the high pressure doesn’t have any risk of blowing off the rim and the low pressure won’t burp or rip off the rim.”

Most mountain bike tires are rated for 25-50 PSI. Road tires are usually 80-120 PSI. Gravel tires are often 40-80 PSI. While they are a good starting point, those ranges are too broad and conservative for most riders. Here are some more specific recommended starting points for your tires:

Mountain bike tires: 25 PSI
Gravel bike tires: 40 PSI
Road bike tires: 90 PSI

These pressure suggestions are based on an average-sized male rider (about 160 pounds) riding moderate terrain. Heavier riders may prefer higher pressures and lighter riders may prefer lower pressures. Read on to learn about the variables that might lead you to add more PSI or take a little out.

Tire pressure gauges

Having an easy-to-read tire pressure gauge is key to setting up your tire pressure. A lot of pumps will have built-in gauges. There is a chance these gauges are a bit inaccurate. If you suspect yours is off, that is fine, as long as you know what to expect and are consistent in checking your tires before each ride. If you’re really concerned, try comparing it with a pump that you know will read true, like one at your local shop or an accurate digital tire pressure gauge.

Mountain bike tires

Key considerations

Ready to start tweaking your tire pressure for optimal performance? Let’s start with the basic principles of tire pressure so you can determine the right PSI for your bike. The key considerations are tire width, rider weight, terrain, and tubeless.

Generally, narrow tires, heavier rider weight, and rougher terrain require a bit more PSI. On the other hand, wider tires, lighter riders, smoother terrain, and a tubeless set-up make for lower tire pressure. Here’s why.

Tire width

All tires require a certain amount of air pressure to prevent them from bottoming out on the rim. Wider tires have more air volume. This makes it possible to ride them at lower pressures for more comfort and traction. Conversely, a narrower tire, like a 28mm road tire has comparatively much less volume so it needs more air pressure to prevent bottoming out. If you have a 2.5” enduro tire on your mountain bike, you’ll be able to ride at pressures close to 20 PSI. Rolling out on the road bike with 28mm slicks? Anything less than 80 PSI would be risky.

Rider weight

You don’t have to be a physics Ph.D. to understand how your body weight interacts with tire pressure (heck, I didn’t even take a physics class in high school). Just sit on your bike’s saddle and watch how the tire compresses and deforms as more weight is applied. The idea is to strike a balance so the pressure supports your weight but doesn’t end up rock-hard. Therefore, more rider weight requires more tire pressure. For example, I weigh about 150 pounds and ride 30 PSI on my gravel bike. A rider who is 20 pounds heavier should definitely consider another 3-5 PSI of air. 

Terrain

Tire volume and rider weight are nice and predictable, but the terrain you’ll ride is not. This takes some trial and error to learn and mostly applies to mountain biking, gravel, or cyclocross. Eventually, you’ll be able to look at your local trails and tell which might require a little more air pressure (think: chunky rocks that might pinch your tire and smash your rim), and which are smooth enough to be ridden with softer tires for better grip in corners.

When you’re out riding, try to monitor the way your bike feels on bumpy terrain. Can you feel a harsh clunk when your wheel strikes a sharp rock? Your pressure might be too low. Does your bike seem skittish in loose corners and bouncy on rough stretches? Perhaps try dropping your PSI a bit.

For road riding, tire pressure won’t vary as much. However, the conventional wisdom of pumping up tires to a rock-hard 120-130 PSI has been debunked. Unless your pavement is glass-smooth, pressures in the 90-100 PSI range will be faster. The tire will absorb slight bumps and vibrations, which is faster than an unyielding, hard tire. You’ll also get more grip in the corners. If you ride in wet weather, slightly less pressure would also be prudent to improve traction.

“Over the last few years, we’ve dropped our PSI ratings even on the narrower tires by 10-15 PSI,” Huseby says. “WTB, coming from the dirt side of the spectrum, we’ve always erred on the lower side.”

Tubeless

Tubeless technology is now widespread in the cycling world, with the exception of some road wheels and tires. This can also affect your tire pressure. Because tubeless systems don't rely on an inner tube, you will be able to run a little less pressure and not worry about pinch-flatting your tire. You’ll get better traction and comfort with less pressure which is beneficial for mountain bike trails and gravel roads. To learn more about tubeless systems, see our Beginner’s Guide to Tubeless. 

How to find the right bike tire pressure

Performance

The final consideration when it comes to tire pressure is worth its own section in this article, and even that won’t be enough space to truly explore every nuance of how tire pressure influences a bike’s performance. The primary factors are traction, rolling speed, and comfort. Ride with the correct tire pressure and you’ll be able to maximize all three variables. Too much or too little pressure can compromise tire performance.

As hinted at earlier in this article, lower tire pressure usually improves traction. This is because it increases the tire’s contact patch on the ground. A tire at lower PSI better conforms more to the ground it is rolling on, also improving grip.

Traction is essential in many situations, from cornering to climbing to braking. In each case, better traction lets you overcome your bike’s inherent tendencies. Forward momentum makes cornering more difficult, but if your tire grips well on a loose dirt corner, you’ll be able to change direction with the right technique and rider input. Momentum also works in opposition to braking forces. With the right tire pressure to achieve grip on loose surfaces or wet pavement, you’ll be able to stop or slow down quickly and more safely.

Your bike will feel more comfortable with the correct tire pressure. Like traction, this performance quality improves with lower pressure. The comfort afforded by lower pressure can be noticed on all of your bike’s touchpoints, from your feet to your saddle to your hands and shoulders.

There is a limit to how soft we’d want our tires to be, though. We love the increased traction that comes with low PSI, but eventually, a tire gets so soft that it has too much rolling resistance, making our bike feel slow. This will be most noticeable on hard, smooth surfaces like pavement. Too-low tire pressure can also hamper bike handling by making the front end resistant to steering input or causing the tire to roll excessively on the rim during cornering.

Mountain biker shredding around a corner

Advanced tire-pressure nerdery

The first step you can take toward totally geeking out on tire pressure is to adjust your PSI mid-ride to tinker with how your bike feels. This is something that’s most applicable to mountain, gravel, or cyclocross riding, but there’s always a chance you might encounter a surprise rain shower on a road ride that will necessitate a little less pressure.

It’s always easier to take air out of your tires during a ride than to add air back. When in doubt, start a ride on the high end of the PSI scale and let out air little by little, going off of feel. See if you can notice an improvement in traction. Be careful not to take too much out if you’re riding rough trails.

Mountain bikers often like to run slightly less pressure in their front tires, and that’s something you can experiment with too. The idea is that, due to body position, you have less weight on the front tire, so you can get away with lower PSI, thereby enjoying more traction for cornering. With more air volume in a 2.2-2.5” mountain bike tire, pressure can be fine-tuned with great effect.

“On a drop-bar bike, I tend to run pretty similar pressure, maybe in the front, I have two to three PSI less if I can even control that,” says Huseby. “On a mountain bike, I definitely run less in the front than in the rear, up to five PSI.”

The last thing mountain bikers can consider when playing with pressure is a new technology generally called a tire insert. The category’s “Kleenex” brand is CushCore, so you might hear fellow riders refer to inserts that way. No matter the brand, the general idea is to put a foam ring inside a tubeless tire, which will reduce air volume and protect your rim from damage. Inserts allow you to run lower pressure with fewer drawbacks. If that rabbit hole looks enticing, check out our recent article on tire inserts.

It’s all about balance

You might be the type to tinker with your PSI, or you might prefer the set-it-and-forget-it approach. Either is fine if you have a grasp of the fundamental balancing act that goes into deciding on how much to pump up your tires. You find that balance point by going low enough to maximize traction and comfort without risking flat tires or sacrificing rolling resistance and handling.

Compared to most vehicles, a rider on a bike is very lightweight and slow-moving, making the correct tire pressure far more important from a performance standpoint. Remember, air is free, so make sure to use it to your advantage whenever you’re headed out for a ride!


15 comments


  • Can you tell me are flat tires faster than aired up tires?

    bikeandmore on

  • I’m an avid recumbent cyclist, so the psi situation can become even more of benefit during a ride. And, a bigger challenge. But, as a response to the individuals that were mentioning that they couldn’t get it to the max psi. That’s when I would have a bicycle shop check what you’re seeing, to what they get at the shop. So, you can feel more confident about what you’re next choice will be. And, then follow the advice provided above. And, then start to adjust your tires psi according to your riding preference.

    Zachariah West on

  • If you have a hard time getting tires up to pressure, get a skinnier pump. The pressure equals the force on the pump divided by the cross-section area of the pump (the area of the piston face inside). Make the piston area smaller and it takes less force . It will take more time, but we’re talking seconds to pump up a road tire.

    Dennis Mullen on

  • This is super helpful! Does it matter what size the tires are? I have a hybrid bike and I have 700c tires. I read that I should try to get 100 psi in my tires, but when I pump, it feels near impossible to get past 80. Should I try for 100 or is 80… fine? I am new to this!

    Elizabeth Lewis on

  • I’m a new road rider about 210lbs got a flat second ride out probably from low pressure. Max pressure on my tires are 90psi max is there any leeway on that .Max is max I would assume. Just wondering. Thank you !

    Michael McDermott on

  • Just picked up a Santa Cruz 5010 V4. It came tubeless from the shop and they inflated the tires F 24 / R 25. First ride out over some sketchy rock gardens and spirited descents the tires felt bouncy. I’m going down to 22 / 23 and see how that works.

    Joe S on

  • I weight about 335lbs and have a gravel bike. What psi should I be running? I have it at 60 psi because of my weight.

    TY on

  • Great read, thanks. I am so confused as I have a new bike with 26×2.1 tires and the max psi on the side wall reads 60. I use an automated pump and I cant get them past 22 psi without them being too tight. How can that be? How can it possibly say 60 psi when the tires can hardly hold 22? Thanks for any help

    LoriO on

  • Hey Matt,

    I’d start out by going tubeless if possible. It will let you try truly low pressures with a lower risk of punctures.

    If you’re using tubes at your weight I’d start out around the mid to low 30s for psi. Experiment with going incrementally lower until you feel comfortable, but you might not be able to go much lower without suffering flats.

    If you switch to tubeless then you can likely start experimenting in the mid to high 20s for psi. At around 200lbs I ran 25/28psi f/r on my XC bike and was able to go a bit lower on certain trails. At 240lbs you’ll likely need a couple more psi than me.

    Good luck!

    Bruce

    Bruce Lin on

  • So I’m an old school Mountain Bike rider. I’ve had the same bike for almost 20 years. I just bought a Scott Scale 950. I still run tubes. I’m 6’2 240lbs. What tire pressure do you recommend for an average xc rider??

    Matt HArmon on

  • Nothing here about riding wider, supple tires and lower pressures, and no data. Any comments on Bicycle Quarterly’s take on the subject?

    Mark Guglielmana on

  • I ride a Recumbent. Lightning P 38. In Fl. Keep tire pressure at 100psi. front&rear. Top off every week. No flats the last 2 years

    Doug on

  • Good baseline info and food for thought.
    Thanks

    vf calderon on

  • I like the idea but every time I use lower tire pressure (road bike) I flat easier. I usually run at 110. Love to hear some science around it.

    Kelly O on

  • This is a very timely article and I am always interested to read a new opinion. Largely this article contains a lot of useful information about tires/pressures etc. However there is one signification area that I feel can be improved and it doesn’t require you to be a PhD but it may require some high school physics to full grasp. The late Frank Berto has written the definitive article with a handy tire size, tire load to recommended tire pressure guide which you may find useful. there seems to be wide held confusion over the tire volume effects but in the end it comes down to pressure that is important.
    Have a read of Franks article, I think you and your readers will learn a beneficial lesson, then experiment!
    Kerry Harmon, P.Eng.

    Kerry Harmon on


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