- The sidewall number is the maximum the tire can hold, not the pressure you should run.
- Correct pressure depends on your total loaded weight and how wide the tire is. Wider tire, lower pressure.
- Rear carries more weight than front, so it runs a few psi higher.
- Lower pressure is more comfortable and grips better, until the tire squirms in corners or you start pinch flatting.
- Check every two weeks. Tires lose pressure sitting still, and an e-bike tire at half pressure handles badly.
Most commuter e-bikes leave the shop pumped to the number on the sidewall, because that is the fastest defensible thing for an assembler to do. It also produces a bike that skitters over expansion joints, transmits every crack to your wrists, and grips worse in the rain than it should.
What the sidewall means
That number is a rating: the maximum pressure the casing is built to contain safely. It says nothing about what suits your weight, your tire width, or the surface you ride. Treating a ceiling as a target is how a comfortable tire ends up riding like a wooden wheel.
Total loaded weight is you, your gear, and the bike itself. E-bikes are heavy, so a 180 lb rider on a 65 lb bike with a loaded pannier is a very different load than the same rider on a 25 lb road bike.
Starting pressure
Pick your tire width and your total loaded weight. These are starting points to ride and adjust from, not final answers, and they never override a lower maximum printed on your tire or rim.
Starting pressure
Total loaded weight means rider, gear, and bike together.
Weigh yourself in riding clothes with your bag on, then add the bike's listed weight. Guessing low is the most common mistake here.
Set the sliders to see a starting point.
Adjusting from there
| What you notice | Meaning | Do this |
|---|---|---|
| Harsh over cracks and seams | Too high | Drop 2 psi. Repeat until it stops improving. |
| Tire squirms in corners | Too low | Add 2 psi and reassess. |
| Pinch flats on curbs and potholes | Too low for your weight | Add 3 to 4 psi, and consider a wider tire. |
| Feels slow and skittery on rough pavement | Too high | Drop 2 psi. Smooth beats hard on real roads. |
| Rim strikes on big hits | Well under pressure | Add pressure now. Rim damage is not repairable. |
| Poor grip in the wet | Often too high | Drop 2 to 3 psi to increase contact patch. |
Change one thing at a time and ride the same route. Two psi is a noticeable step on an e-bike tire. Four is a different bike.
Front and rear are different
Most of the weight sits on the rear: the rider is behind the middle, the motor and pack are usually back there too, and any cargo goes on a rear rack. That is why the rear runs a few psi higher than the front.
Running the front slightly lower is what buys you comfort and steering grip. The front tire is the one that has to hold a line in a wet corner, and a bit more contact patch there is worth more than the rolling resistance it costs.
Carrying a full pannier or a passenger changes the math. If you commute loaded some days and empty others, set for loaded and accept slightly firm on the empty days.
Habits
- Check with a real gauge, not a thumb. Thumb pressure tells you nothing above about 15 psi.
- Check cold, before you ride. Warm tires read high.
- Look at the tread while the gauge is on: glass, cuts, and embedded grit come out easier before they work through.
- Keep a pump at home and a mini pump or inflator in the bag. A flat at pressure zero is a walk.
Parts in this guide
Puncture Resistant Commuter Tire, Reflective Sidewall
Floor Pump with Accurate Low-Range Gauge
E-dirt bikes run knobbies at much lower pressures and have their own guide.
