All Maintenance Tasks · Every ride
Check Tire Pressure
Tires leak through the tube and around the valve continuously, and narrow tires at high pressure lose a noticeable fraction of it in a few days. Pressure that has drifted low is the leading cause of pinch flats, it makes the bike feel vague in corners, and it wears the sidewall from the inside. Pressure set too high is not free either: it skitters over rough surfaces and gives up grip.
Interval
Every ride
Before you roll out, every single time
Time on the job
2 minutes
Once you have done it a few times.
You or a shop
Anyone
The stop signs further down are the real answer.
Applies toRoadMTBHybridE-bikeKids
How often, really
Squeeze the tires before every ride and put a gauge on them once a week. Narrow, high-pressure road tires need the gauge more often than fat, low-pressure tires, simply because the same volume of lost air is a bigger share of a small tire. Cold weather drops pressure on its own, so a bike that lives in an unheated garage reads lower on a cold morning than it did in the afternoon.
The interval on this page is Every ride. Before you roll out, every single time.
What you need
- A floor pump with a gauge, or a portable inflator with a digital gauge
- A valve adapter, if your pump does not fit both Presta and Schrader
Doing the job
Read the sidewall first
Every tire has a pressure range molded into its sidewall, and that range is the boundary of this whole exercise. It is set by the tire manufacturer for that specific casing on a rim of the right width. Nothing on this site, and no calculator anywhere, overrides it. If your rim manufacturer publishes a lower maximum than the tire, the lower of the two wins.
Know which valve you have
Schrader valves are short and wide, like a car tire valve, with a spring-loaded pin in the middle. Presta valves are narrow, usually longer, and have a small knurled nut at the tip that unscrews. A Presta valve has to be unscrewed before air goes in and screwed shut afterward. Pump heads either fit both or need a converter.
Use a gauge, not a thumb
A thumb tells you a tire is flat. It cannot tell the difference between the number you want and fifteen psi below it, and fifteen psi is the difference between a comfortable ride and a pinch flat. A floor pump with a built-in gauge is the cheapest way to make this routine, and a separate stick gauge is the most accurate.
Set front and rear differently
More of your weight sits over the rear wheel than the front, so the rear tire wants more pressure than the front, typically a small step of a few psi rather than a dramatic difference. Setting both wheels identically is the single most common way a bike ends up with an overinflated front and an underinflated rear.
Adjust for the surface, within the printed range
Smooth pavement rewards the upper part of the range. Broken pavement, gravel and packed dirt reward the lower part, because a tire that can deform absorbs the surface instead of bouncing off it. Cargo, a rack, a child seat or a trailer all push the number up. None of this ever moves the number outside the sidewall range.
Check the valve after you pump
Close a Presta valve nut finger tight and put the dust cap back on. Then listen at the valve for a hiss, and if you suspect a leak, put a drop of water on the valve and watch for a bubble. A slow leak at the valve is a common and undramatic reason a tire is soft every few days.
Stop and take it to a shop
If any of this shows up while you work on check tire pressure, put the bike down and let a mechanic look at it. None of these are things to ride out and see how it goes.
- The tire will not hold pressure for a day, or it goes down again within minutes of being inflated. That is a puncture or a valve failure, not a pressure problem.
- A bulge, a blister, a cut deep enough to show the casing threads, or a section where the tire is not seated evenly on the rim. Deflate it and do not ride on it.
- The pressure you need to make the bike feel right is outside the range printed on the sidewall. That means the tire is the wrong size for the load, and no pressure setting fixes it.
- A rim brake bike whose rim shows a hollow or a crack. High pressure loads a worn rim wall, and this is a job for a shop, not a pump.
Where this usually goes wrong
- Inflating to the maximum on the sidewall because it is the number that is printed largest. The maximum is a ceiling, not a target.
- Trusting a gas station air hose on a bicycle tire. The volume comes out fast enough to overshoot a bike tire before the gauge catches up.
- Setting pressure once in spring and leaving it, when temperature alone moves the reading through the year.