Manufacturer recommended inflation pressure is valid for tires before they warmed up when driven (at a normal outside temperature – 700 F). For every ten degrees Fahrenheit change in tire temperature, tire pressure changes above half a pound (see tire pressure chart below).
Tire pressure chart
So a tire with 32 psi at 70 degrees F will have about 35 psi at 100 degrees F and this is normal. If the tire is inflated at a temperature of 100F to the recommended pressure of 32psi, then at 70F it will be under-inflated. For every 10 percent tire underinflation it’s life decreases 10 percent.
According to the NHTSA – National Highway Traffic Safety Administration, about 1/3 of light trucks, SUVs and passenger cars are being driven with at least one underinflated tire.
An underinflated tire loses its optimal shape and becomes flatter than intended. Increased rolling resistance causes a reduction of up to 5% in fuel economy. Underinflation also causes a significant loss of cornering stability and steering precision.
An underinflated tire deflects more as it rolls and builds up internal heat, which can lead to tread separation, premature wear, and blowouts. A blowout can cause the driver to lose control of his vehicle. Other drivers may suffer from pieces of flying debris from the blown tire.
Getting the right tyre pressure is simple, right? Pump your tyres to the range recommended on the sidewall and away you go. Turns out it’s not quite that straightforward.
Tire pressure chart for bicycle tyres
Bicycle tyre pressure determines tyres compressing. If it compress too much, they will squirm on the rims, increase rolling resistance and make the bike harder to control. If tires don’t compress enough, there will be little rubber on the road and little grip.
In addition to pressure, the deformation of the tire is determined on cyclist weight. Optimal for common use tyre compressing is about 15 percent of its height.
Below you can see a tire pressure chart, showing the relationship between wheel load and pressure.