You’ve heard it time and time again: inflate your tires to the correct tire pressure.
And no wonder! A full tire is one that rolls effortlessly, absorbs shocks from the ground gracefully, and wears out slowly and evenly as it should. (In the case of clincher and tubular tires, it’s also one that’s less susceptible to pinch flats.)
So there’s no doubt whether or not you should keep your bike tires properly inflated. Rather, the question is how hard they should be.
If you’ve ever wondered are bike tires supposed to be hard, you’re not alone. There’s some finesse to finding the perfect amount of air in bike tires to get the best ride. No matter what the terrain, you want a tire that’s firm to the touch—but not so hard that it’s likely to blow out.
Hardness isn’t the best indicator for tire pressure. PSI, as measured by a tire pressure gauge, is. But when you don’t have a pressure gauge or bike pump handy and hardness by feel is all you have, here’s how to know when your tires are in the sweet spot.
The “Sweet Spot” on Bike Tires
As a general rule of thumb, your bike’s tires should be firm, with just a little bit of give to them. This rule, although greatly oversimplified, applies to most situations and most types of bike tires, including clinchers, tubulars, and tubeless.
There is a “sweet spot” to every tire. And, when you’re there, you will know.
The ride will be firm, but not bouncy. The tires will be supple enough to take hits from bumps and foreign objects, but not so soft that they would pass their force to the rims.
The rubber on the tires will sit firmly on level ground and will make even contact with it, without the shoulders protruding to the sides (a sign for underinflation) or the center sticking out (a sign for overinflation).
On a road bike, you will fly over asphalt roads and glide along with inertia. On an off-road bike, you will have the grip and the traction you need to climb uphill, ride downhill, take sharp, challenging turns, and leap over moderate to extreme heights without hesitation.
How This Differs From One Type of Bike to Another
The tires on a road bike, lightweight and narrow, must be inflated to a higher tire pressure than those on a hybrid bike or mountain bike. Typically, that tire pressure is between 90 and 120 PSI. As such, they should feel the firmest.
Hybrid bikes make the best of road bikes, touring bikes, and mountain bikes, though some would say they’re not particularly good at substituting either. As such, their tires are normally inflated to 50-70 PSI. They should feel softer for rocky, rough terrain and harder for paved, easy roads.
Meant for rough terrain and extreme cycling, the tires on mountain bikes are inflated to a low inner pressure, between 30 to 50 PSI, sometimes even less. They should feel softest to the touch, and their hardness will vary with the type of tire used.
How It Differs From One Type of Tire to Another
Clincher tires, as a golden rule, should feel harder than tubeless tires. When the tire’s overly soft, the inner tube can get pinched between the beads and the edges of the rim and go flat from snakebite punctures (pinch flats).
Many think that tubular tires, a special type of tires with the tube stitched to the carcass and rubber glued to the rim, are immune to pinch flats and can therefore be inflated to a lower PSI than clinchers. While there is some truth to this, tubulars are not 100% immune to pinch flats.
Know When the Tires Need Topping Up
We’ve already established that there is such a thing as a perfectly topped tire.
The best way to determine this is to measure the tire pressure. But the look of the tire, the stance of the bicycle, and the overall feel of the ride already give us a lot of information when we don’t have a gauge or pump at our disposal.
Chances are you will always be in pursuit of this elusive “perfect” level of tire pressure. Even once you have your tires perfectly inflated, there are plenty of factors that can cause shifts in tire pressure over time.
Check your bike’s tire pressure before you go out for a ride.
You will notice that tires tend to deflate in cool weather because the air inside them contracts. Conversely, they will inflate in warm weather as the heat causes the air inside them to expand.
This natural fluctuation in pressure is normal, but you may need to top off the air more often during cooler months of the year. If you get on your bike and notice that the tires are puddling a bit—or the tire gives way on bumps and passes on shocks to the rim—chances are your tires need air.
A quick way to check if your bike tires need air is to pinch the sides right where the tire meets the rim. You should be able to squeeze it in a little bit, then be met with significant resistance. If it feels too soft and allows you to pinch it between your fingers, your tires probably need air.
Is There Such a Thing as Adding Too Much Air?
Most bike tires will have a pressure rating listed right on the sidewall, so you should have an idea of how much air they will need to be filled properly.
As a general rule, mountain bikes need 30-50 PSI, road bike tires need 90-120 PSI, and hybrid bike tires need 50-70 PSI. Always check your specific tires instructions and follow those, but those are the most common ranges.
When you are trying to make sure your bike tires are full, it’s important to make sure you don’t overfill them. As you’re filling them up, check every so often for firmness until you get the desired level with just a little bit of flexibility.
How Bad Is It If You Overinflate Your Tires?
There’s more than one reason why you don’t want to overinflate your bike’s tires.
In part, it comes down to safety. But it’s also about comfort, especially for commuters and recreational cyclists. Even if your tires are punctured, worn, and losing a little more air than they should, don’t over-inflate them for the reasons listed below.
When you have a bike tire with too much air in it, you are at a higher risk of the tire blowing out while you’re riding. Overfilled tires tend to wear unevenly and quickly. This can be a potentially dangerous situation because it can cause an accident and/or injury when you expect it the least.
Overfilled bike tires can also make your ride very (and I mean very) uncomfortable.
When they have too much air in them, they will be hard and have little ability to absorb impact as you ride. This means that you will feel every single bump you go over with very little cushion, which would make for a pretty uncomfortable ride.
Bike tires should be pretty firm and hard to the touch no matter if you are riding a mountain bike, road bike, or a hybrid.
Although the tires may be different on different types of bikes, you still want a tire that can withstand whatever the road or trail throws at you during your ride.