Knowing the correct mountain bike tire pressure is one of the most important things for you to learn. Too much or too little tire pressure can cause all kinds of problems, none of which you want to experience firsthand.
But with all the different recommended ranges it can be really hard to try to figure out what the right psi for you is. Hopefully, when you are through reading this article you will know just what to put the psi of your tires on.
As you can see from the chart, there are a lot of different factors that go into determining what psi you should ride with. But just knowing that these affect your tire pressure may not be enough to let you know exactly where you fall at on this graph.
Factors To Consider
While there I will go over each of the three main factors in just a moment, one of the first things that you should look at is your tire’s rating. Most of the time this is conveniently found on the side of the to and is which tells the recommended tire pressure for that specific tire is.
Mountain bike tires are made with a particular range of pressure in mind, most of the time this is somewhere between 30 to 65 psi. Going over or under this amount is something that you should try to avoid doing.
1. How Much You Weigh
The more you weigh, the more pressure you are putting down on the tires of your bike. This weight pushing down on means that you will need to have a higher amount of air pressure in the tires in order to hold up your weight.
If you hit a bump too hard with an amount of pressure that is too low for your weight, then you’re the rim of your wheel can hit the obstruction. This is bad for your rim to have to deal with and it can bend, bent, or otherwise damage your rims.
If you are doing jumps or are riding down a trail that has a drop of any kind, then you really have to watch your psi and make sure that it is not too low or you risk damaging your rim. Sometimes your rim can even fold and form a taco shape.
At the same, if your tire pressure is too high then when you land on it you risk bursting your tire if you are on the heavier side. This is why getting the right psi is all about balance, just as you have to balance yourself on those two wheels of your bike.
Keeping your weight in mind also applies if you are bikepacking and have bags and extra things on your bike. This added weight should be taken into consideration and your psi levels raised accordingly.
2. The Size And Width Of The Rim
While the size does make a difference in the tire pressure you need to use, the width of the rim makes a very noticeable difference as well. While you might think that a wider rim like you find on a fat bike would need more air pressure since there is more air needed to fill the tire.
Actually, it is the complete opposite. The wider the rim is the lower the psi that you can safely use. This is in part because there is more of the tire touching the ground and therefore your weight is more spread out.
It is the thinner tires that are going to need a higher psi because all of your weight will be on a smaller area and you will therefore need more air pressure in the tire to keep you off of your rims.
3. High Pressure Vs. Low Pressure
Along those lines, you should also do your best to find out if you prefer a tire pressure on the higher end of things or on the lower end of the psi spectrum. Each has its own advantages and disadvantages, but most mountain bikers tend to prefer a psi that is slightly towards the lower end for those rough trails and slightly higher for racing.
Advantages Of High Pressure
You may have noticed that the tubed tires have a generally higher psi than their tubeless counterparts and this is for good reason. If your psi is too low with a tubed tire then you risk getting what is commonly referred to as either a pinch flat or a snake bite.
A pinch flat is what happens when your tube inside your tire gets folded and pinched hard enough to make holes in it. When this happens, the whole tire has to be taken off and the tube replaced before you can keep riding on your bike.
This can be really time-consuming and it is certainly not something anyone enjoys doing on a nice day when they are there to ride the trails. Since a high enough psi can prevent this from happening, it is one reason why you should definitely consider having a higher psi.
However, there are other advantages that even mountain bikers with tubeless tires can appreciate. The first one of these it the fact that a tire with high pressure in it has a great amount of what is called rolling resistance.
Better rolling resistance means that you can go faster will as little effort as possible because the tire is not resisting your forward movement. This is great for races and those times when you just want to go fast. It is also nice when you might be already tired and don’t want to have to expend any extra energy on pedaling.
However, you should know that having too much pressure in your bike tire will result in you “bouncing” far more than you should be. Bouncing will cause you to lose traction among other things, so you never want to go too high with your tire pressure.
Advantages Of Low Pressure
Having a low psi for your mountain bike tires is something that comes with its own advantages. One of the first things that you will likely hear about is that low pressure gives you a much better grip on the trails.
This grip can be vital if you are going at fast speeds over bumpy areas on a trail where your tires would bounce if they had any more air in them. Sandy or other “loose” trails will need this extra grip, and so will other things like snowy conditions.
As long as you are not going too low with it, having a low psi can even help you climb those steep sections and is even needed to climb them in wet conditions to prevent your tires from slipping back while you are trying to go up.
Final Thoughts
The fact that tubed tires have to have a higher psi on the low end, giving tubeless tires a wider range of tire pressure options that you can choose from. If you like the higher pressure than this will not matter to you, but if you dislike a high tire pressure then you will want to have a tubeless tire so that you can go lower.
Another thing that you should keep in mind is the temperature. Hot air moves around more and this can literally increase your psi levels if you aired it up in your cool garage. This being the case, you should check the air pressure in your tires when your bike gets to the same temperature as the area where you will be riding at.
This will help to make sure that your tires do not burst on you because you inflated your tires to a high psi while your bike was cool and then set your bike outside where it was hot. The reverse is also true if the weather is cold, so a good mountain biker checks their psi often.