bdcheung

Do I need to deflate my tires when flying with my bike?

DocRay

You should, the cargo hold is not pressurized.
You should not have any pressurized object on a plane.

bdcheung

Thanks!

Mo'Phat

If that's true...there'd be lots of dead pets.

darkmother

No, don't worry about it. Even if the cargo hold weren't pressurized (and it is), the maximum increase in pressure your tires could see is 10 psi or so.

Having air in the tires will protect your rims somewhat when the goon baggage handlers throw your bike around.

merlinextraligh

+1 on the last 2 posts.

I've never deflated my tires flying, and never had a problem.

The reason not to deflate them is the wheel, and the inner tube, are slightly less likely to be damaged if you leave pressure in the tire.

The only reason you might need to deflate them is an overly conscientuous airline employee, that didn't take Physics.

DocRay

Depends on the plane. Some have pressurized holds, some don't, some have both. Obviously, they put the pets in a pressurized hold. And you cannot transport pets on all aircraft.

Even though pressurized, the time to equilibrate can cause strain the tubes. I did this by mistake a few years ago, even though the hold was pressurized, and one tube developed a leak around the valve stem.

I guess the ban on pressurized object on airplanes is for no good reason.

urbanknight

Pets HAVE died that way, either because the employee was not properly trained (or fell asleep during the cideo), or because the traveller hid the pet in a plain loking carrier. Pets are kept in a different compartment where the air is pressurized.

One dog barely survived when a panicked woman asked the flight attendant if they had put her dog in the correct place. The plane landed at the nearest location and the dog was severely dehydrated. Not sure why a lack of oxygen would dehydrate you, but that's what the story read.

So in that case, I would deflate the tires before travelling. I wonder if you'd be able to hear the BANG! when the tires pop from inside the cabin.

merlinextraligh

My physics is limited to one semester of college physics, so I certainly stand to be corrected. Pressure at sea level is around 15psi. Pressure at 40,000 feet drops to around 3psi.

When the guage on your tire pump reads 100psi, it means 100psi above the ambient pressure. Thus 100psi at sea level would be the equivalent of 112 psi at 40,000 feet in an unpressurized cabin. (As alluded to by Darkmother.)

As for time to equilibriate causing stress to the tube, it wouldn't appear to cause more stress than pumping the tire up an extra 12 pounds.

bdcheung

So, uh, are you saying i don't need to deflate it?

cuda2k

Best of both worlds, pump the to 75psi.

bdcheung

I know. I'll pump one to 50psi, one to 100psi, and i'll report the results when I land.

gcl8a

Exactly. It's the equivalent of a couple of extra strokes of the pump.

gcl8a

Ummm...is the time to equilibrate shorter than the time to pump it up in the first place? That's just ridiculous.

badkarma

What results are you going to report? I'd imagine the tires would return to the original gauge pressure if you measure them when you land.

DrPete 

That's exactly what he's saying, and he's right. The inside of a plane isn't a vacuum, and the pressure difference isn't enough to cause a problem.

cydewaze

It's enough to make a mess out of my stick deodorant and shaving cream though, sheesh! I put them in ziplock bags now.

'nother

Yes, that is what he's saying.

Even in an unpressurized hold, the change in pressure in a normally-inflated tire is very small. The actual blow-off ("BANG"-inducing) pressure of your tires is much higher than the max stamped on the sidewall.


The "ban" on pressurized containers is actually not a full-on ban. You can (or at least, could...stuff keeps changing, those pesky terrorists) carry on pressurized containers of hair spray, shaving cream, and other aerosols. Some pressurized containers, such as scuba tanks, containers with flammable gases, and such are prohibited, because the effect of them rapidly losing pressure is extremely hazardous. But that effect is similar on the ground, too, which is why many tunnels, bridges, etc. also have bans or restrictions on these things. Going to 40,000 feet with them doesn't increase the chance that they'll rapidly lose pressure; it's the consequences of that possibly happening that is the reason for the ban. For example, if a scuba tank were to have its valve broken off, that rapid loss of pressure (thrust) could easily put a hole in the side of an aircraft, and the consequences of that are pretty bad, hence the ban. But the consequence of a bike tire rupturing is nothing more than a bang, at worst.

I_bRAD

Assuming your destination as at the same elevation above sea level, of course.

DrPete 

Even so, it's a few psi.

I_bRAD

Just sayin' is all!

'nother

If you are "just sayin'" that a few psi is a problem, you must be one sensitive fellow. Most people will barely notice a change of 5 psi, and even then they'd probably only notice upon having it pointed out to them.

labrat_62

On a similar note, could you guys recommend a bike case for flying your bike? Thanks

DrPete 

Trico Iron case. Cheap and gets the job done very well. Traveled to France with one just a couple months ago.

DrPete 

Here's a pic from the last time someone left their tires fully inflated on a plane flight: