20 Inch Bike Tire Pressure – The Complete Guide


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If you’re looking at what pressure your 20-inch bike tires should be, then there’s a simple answer and a more complex one. The simple first:

20-inch bike tires would generally use a PSI between 30 and 50. The exact optimal PSI would depend on the manufacturer’s suggestions, the terrain, and the type of riding you will be doing.

In this article, I’ll go over everything you need to know about bike tire pressure for your 20-inch bike, particularly the following factors:

  • The type of terrain you will be cycling on
  • Your weight
  • The manufacturer’s suggestions
  • Temperature
  • Riding frequency
20 inch bike tire pressure

Tire Pressure – The Basics

Tire pressures exist to make sure your bike rolls smoothly and quickly while avoiding as many flats as possible.

If you have typical narrow road tires, they would be optimal at about 80 to 130 PSI. On the other hand, mountain tires require 25 to 35 PSI. Moreover, hybrid tires settle at a comfy in-between of 40 to 70 PSI.

However, with that being said, almost all tires would come with a recommended tire pressure or range. These exist to minimize wear but aren’t necessarily efficient.

Plus, there are a few rare cases where the recommended pressure is not indicated. As a rule of thumb, you should then pump your tire until it’s firm but slightly squeezable.

You can read on for more details on respective tire pressure for the various types of bicycles:

20-Inch Mountain Bikes

20-inch mountain bikes would be designed to fly over bumpy and loose terrain. So, if you keep tires with too much air, you’d experience too much bounce.

Hence, the ideal mountain bike tire pressure would lower pressures for more shock absorption and traction.

Due to this, the recommended pressure is around 30 to 50 PSI for most 20-inch mountain bikes. This is considered a good balance between an on-road tire pressure (approximately 50 PSI) and an off-road riding pressure (closer to 30 PSI).

Why Is Tire Pressure Important?

As somewhat discussed earlier, tire pressures can have two substantial impacts on your bike’s performance. These include grip and rolling resistance. The following are details on each:

Rolling Resistance

Rolling resistance is defined as the amount of friction between a surface and a tire. This friction increases with resistance in movement and increased contact with the ground.

So, if you have an underinflated tire, this causes too much contact with a surface. Therefore, in consequence, it’s too much rolling resistance.

Although, you may be surprised to know that an over-inflated tire would also have the same effect of increased rolling resistance.

This is because too much air results in your tire becoming too bouncy, rather than encouraging a smoother journey.

Grip levels

Grip levels are determined by how much contact a tire makes with a surface. It ensures that the tires conform to the route they’re rolling over.

And this grip level would increase with more contact.

As a result, if the tire is overinflated, it’d just bounce off the surface or roll on the central strip only.

20 inch mountain bike tire pressure
30 to 50 PSI is the recommended tire pressure for a 20-inch mountain bike (depending on the type of cycling you intend to do on it)

Factors That Influence Tire Pressure

When it comes to tire pressures, nothing is really as simple as it seems. Though I’ve already indicated a few aspects to think about, there’s still a lot worth considering.

In consequence, the following are a few factors that influence the ideal tire pressure.

Temperature

This isn’t a well-known fact, but the temperature does play a significant role in dealing with air pressure. In particular, physics explains that increasing temperature leads to higher pressures.

So, if you’re cruising along the beaches of Miami during summer, you’re bound to experience higher pressure than someone on a bike in Alaska during winter.

Likewise, rapid deceleration can generate friction which also increases the temperature. Fortunately, this has a quicker cool-off period, but it’s still something to be aware of.

Weight

You should know that more weight results in more pressure. So, if you’re planning on going on tour or cruising, you need to account for load.

For example, heavier riders would use a higher PSI than lighter riders for the same riding quality. In particular, a 200-pound load would need about 20 PSI more than a 160-pound load.

With that said, there isn’t really any rule to determine this PSI difference. Your only option is to experiment with what you have.

You can play around with the pressure to figure out what’s best for you. You should also keep in mind that rear tires tend to carry most of the load, so you should adjust accordingly.

Riding Frequency

A common question by beginners is how often you should inflate your tires.

Well, for starters, this depends on your riding technique and style.

If you’re a merciless cyclist, you may need to pull out the pump every few days. Meanwhile, more gentle riders would inflate their tires only once a week or month.

If your bike is left in storage for months between use, you still may not need to inflate your tires as much. Air usually seeps out at an excruciatingly slow rate anyway.

So, the most ideal practice is to just check your tires before a journey. If they feel too soft, inflate them until they’re stiff again.

Over-inflation or Under-inflation

As crucial as tire pressure may be, it’s equally vital to find the right balance. You shouldn’t over-inflate because that increases the risk of blowing out a tube by pumping or sudden impact.

 Likewise, you shouldn’t underinflate either, as the low pressure encourages pinch flats. This occurs upon hitting a bump with underinflated tires.

The tube gets squeezed by the rim and tire. This causes the tire to puncture and can even damage the rim.

In addition, flat tires would just slow you down and increase rolling resistance, so they’re not really the most effective.

inflating 20 inch mountain bike tires
Either over inflating or under inflating tires can cause different problems

What About 20-Inch Bikes And Other Factors?

20-inch tires can be considered the same as any other tire. They would equally be affected by conditions, such as weight, temperature, under-inflation, riding frequency, and over-inflation.

So, the most reliable way to get the best tire pressure is to just check the number stamped onto the side of the tire. This would be the recommended tire pressure I mentioned earlier.

Regardless of size, shape, or type, it’s always crucial to have tires within this designed range. They’re the safest bet when dealing with unfamiliar tire types.

However, if the range was removed or unreadable, you’d have to do extra work.

In these cases, I suggest going by trial and error. You can pump up your tires until they’re stiff enough to avoid pinch flats and maintain sidewall strength for stability and cornering.

There’s a logical limit for pressures in every tire type. And, when talking about 20-inch tires, I’d say it’s about 60 PSI with 80 PSI as a maximum limit.

Some people might consider 50 PSI as a “perfect” option. But this is just a matter of taste.

You may want an efficient, comfortable, or durable mountain biking style; different riding styles would just entail varying circumstances.

Changing tire Pressure for Wet Conditions

Wet conditions present unique adjustments to many riders. It isn’t safe to use standard air pressure, so cyclists usually drop their tire pressures for wet conditions.

With that being said, this isn’t really necessary, especially if you have the correct initial tire pressure.

But, if you decide to lower your tire pressure, I don’t recommend doing it by more than 2 PSI. Significant decreases in pressure might make your tire squirm, which results in instability on trails or roads.

Types of Pumps

Since we’re on the topic of tire pressure, it would be fitting to discuss the various types of pumps you might use.

There are two main bike pump options: hand pumps and floor pumps. The following are details on each.

Hand Pumps

If you’re an enthusiastic rider, willing to put in the extra effort while cycling, hand pumps should be your go-to choice.

Though they aren’t quick and need more work to function, they’re accessible for transport.

You can always have a hand pump on you. They are especially ideal for puncture repair kits during long-distance bike rides.

Floor Pumps

On the other hand, floor pumps are my recommendation. All of the pros use them, and they’re much easier to attach and pump.

You might even get gauges with some tires. These would eliminate any need to switch from a pump to a standalone gauge. Plus, you wouldn’t have to guess whether your tire is at functioning pressure.

Yet, some experts are still a bit wary of floor pumps with gauges.

In most cases, this is because the accuracy of these gauges can sway and end up even being off by 10 PSI or more.

But, on the bright side, you can always consider the difference between consistent inaccuracies and adjust accordingly.

If you think these calculations are exhausting, you might be considering using an air compressor at your local gas station.

But, since these are meant for cars, they tend to be less accurate and overinflate your tires. So, if you’re looking toward becoming a serious rider, investing in a small pump can go a long way.

And, if you can’t get your hands on some eco-friendly option, you can opt for carbon dioxide inflates as an affordable alternative.

Regular Check-Ups

At the end of it all, tires would still leak air over time. Even with a proper set-up for butyl or tubeless tires, leaks would only be less common.

But, they won’t ever be permanently stopped. Whether we’re talking about a few PSI a week or dramatic changes overnight, air always seeps out at random times and due to various reasons.

For example, the depreciation rate could increase due to factors such as increased pressure because of lower temperatures outside.

And some models have even predicted a 2% decrease for every 10-degree drop in Fahrenheit.

So, if you really want to make sure you’re at the optimum riding pressure, I recommend checking your tire pressure as often as possible.

You could check it before every ride, or maybe you’d prefer once a week.

The crucial takeaway is that you should get into the habit of regular top-offs and check-ups, because, if you don’t, your tire pressure is probably going to be wrong for most rides.

Final thoughts

20-inch bikes are relatively new on the market. So, many people haven’t really come up with the perfect range for every type of 20-inch tire bike.

As a result, my recommendation for finding the perfect pressure is to just play and experience with multiple pressures.

Depending on the road, type of bike, and load, you’d have to adjust accordingly. Road cyclists prefer rear-heavy pressure distributions.

However, some people make it work with a 50/50 front and rear distribution.

The bottom line is that tire pressures are unique and personal to every individual. As long as the pressure is within the recommended range of the tire, there isn’t really a perfect PSI for everyone.

If you really want to know what air pressure works for your 20-inch bike tire, you’d just have to go out and find that out on your own. Good luck and happy cycling!

Martin Williams

Martin has been tearing up all sorts of trails on a range of bikes ever since he was young. He once cycled across France, and once fell into a canal on a hybrid. He writes about everything to do with cycling on our site. You can find out more about him at bicycle2work.com/about-martin-williams/

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