I heard/read multiple instances of people pondering if they should or shouldn’t change their tire and/or shock pressure for winter. This got me thinking how much of a change there is and should I take it into account?
Science to the rescue!
In this scenario the amount of gas ( nR ) does not change and also the change in volume is not significant. We can then derive the following equation to calculate the necessary fill pressure to achieve a desired riding pressure, based on the temperatures of filling and riding.
I have a 125mm RockShox Reverb (A1) in my Enduro bike. The bike was bought second hand and the Reverb had some sag and extended easily if bike was lifted from the saddle. So it was clearly in need for full rebuild but I was lazy and kept riding as it still mostly worked.
Then came winter weather with -10 degrees C, which was enough for the Reverb in its current condition and it didn’t stay up anymore. At home I took it from the bike and it had leaked oil (or something similar but more gooey) under it, no use trying to fix it by pumping more air.