should ask the dogs that fly there.
Even if the luggage compartment is pressurized, most planes are pressurized to only about 8-10,000 feet. That is why your ears pop on the plane. The pressure at 10,000 feet is 10.2 PSI, or about 30% lower than sea level, which is 14.7 PSI. So, in theory, a tire could be damaged if it was inflated at max PSI at SL and then transported in a plane. So, better safe than sorry–just let some air out and give it a few extra pumps before your next ride.
From Wikipedia:
Aircraft that routinely fly above 10,000 feet are generally equipped with an oxygen system fed through masks or canulas (typically for smaller aircraft), or are pressurized by an Environmental Control System (ECS) using air provided by compressors or bleed air. These systems maintain air pressure equivalent to 8000 ft or less, even during flight at altitudes above 43,000 ft.
So if you leave from sea level, it is possible that mid air the pressure in the cabin will be that of 8000 ft (maybe even higher in the luggage compartment). Also, ever fly from sea level to Denver and open up a bottle that you capped before you left? Can get messy.
Just my guess. I’ve never flown with my bike and probably wouldn’t even have thought to let air out.
The pressure at 10,000 feet is 10.2 PSI, or about 30% lower than sea level, which is 14.7 PSI.
The percentage doesn’t matter. It’s the absolute pressure that matters. Assuming the 10.2 PSI figure is correct, it would be like over-inflating your tires by only 4.5 PSI, say from 120 to 124.5 PSI. Unless you’re pushing the envelope with your tire pressure, it shouldn’t be a big deal.
You’re much more likely to have problems leaving your bike in the hot sun after a race if you pump your tires up to max while it’s still cool before the swim.
I agree it is not that bad at the pressures we are talking about, otherwise air travel could be somewhat uncomfortable–I have been up to 40K in a hypobaric chamber, and believe me, it didn’t feel good. Any air/gas trapped inside (gut/tooth/sinus/etc.) becomes quite painful.