Let us say you've been driving for a couple of hours and stop for gas. You ask yourself, "Did that bump back there damage a tire? Do I have a slow leak?" Or something else makes you wonder whether your tire pressures are correct. You want to check them, but the tires are hot. How do you do it?
The answer that most people will give, if they are honest, is "I don't know."
A few safety questions illustrate the danger this presents:
Question
Most People's Answer
Does guessing make it any safer?
Maybe.
Does the old rule of thumb "count 1 PSI for every 10 degrees above cold-tire temperature" work?
If I am on the road, do I have 2 hours to wait to let my tires cool in the shade (which shade may not be available) before I check and set their pressures?
Rarely if ever.
How fast do my tires heat up once I start rolling?
I don't know.
In the morning, can I ride to a gas station 1 mile away and set my tire pressures to their cold-tire pressures?
I don't know, but I have done it.
Does living with "I don't know" and hoping it won't be a problem ensure my safety?
Certainly not.
While this may sound scary, read on to find out the real answers to these questions. The good news is that it is very easy to correctly measure and set your tire pressures while they are hot. If you care to learn, follow me and I will show you how.
For those readers who do not care how I derived the solution to this problem, you can go directly to the Method Varies with Season section, or if your climate is similar to Colorado's, you can jump directly to the Derived Rules of Thumb section.
