C
cpannarbor
Guest
A given amount of air in a tire will produce a different pressure reading at different temperatures. So a "recommended" pressure has two values: a pressure reading in pounds per square inch (p.s.i.) or in Bar, or some other standard; and, a temperature.
BMW specifies recommended "cold" pressures at 20 degrees Celsius, which translates to 68 degrees Fahrenheit. BMW actually specifies pressures in Bar (1Bar = 14.56 p.s.i.) such as 2 Bar, or 2.1 Bar, or 2.2 Bar etc. Those specifications in Bar are converted to p.s.i. in U.S. publications.
BMW specifies pressures to the nearest .1 Bar = 1.46 p.s.i so are actually less fussy that many riders tend to be.
So the short answer is that to be precise, "cold pressure" ought to be at 68 degrees. When checking add a pound if it is a bit warmer and subtract a pound if it is a bit colder. You will likely wind up within 1/10th Bar.
Owner's Manual of my '12 GSA says 68 degrees. I run 36F/38R. Don't ask me what kind of oil I use or how often I change it!