The ridiculous myth about letting bike tyres down when flying.

[fenlandpsychocyclist]

If you look at the galaxy c5 aircraft, that has 28 tyres to take its weight of 350 tonnes ... thats a seriously big aircraft.

Now compare to the space shuttle that has 6 tyres to take its weight of 100 tonnes ... meaning those tyres have to be filled to
a very high pressure. And they spend up to 16 days in the vacuum of space without going ... pop!!

 

[Globalti]

Bike tyres are already pumped up hard and are immensely strong so another few percent of relative pressure isn't going to bother them.

A crisp packet is nowhere near inflated at sea level; at 10,000 ft they can be quite well inflated and being completely inflexible and designed for easy opening I expect they would burst at a seam at much higher than that.

 

[frank9755]

Have fun taking the piss out of people who man airport baggage handling operations by telling them that there is a risk that a bike tyre could explode while on a plane and that it needs to be deflated. Occasionally one will believe this and prove his or her stupidity by proclaiming this gospel to members of the public.

Ironically, what does make tyres explode is the high temperatures encountered inside a parked car on a hot day. It's not that uncommon to have tyres go 'pop' - it happened to me last summer when I couldn't be bothered to take my racing bike out of the car when I got home. Happily the car wasn't a write-off

Given that aircraft holds are generally a bit chilly, I suspect that tyres are less likely to explode in a plane than they are in everyday use.

 

[Globalti]

Interesting point. In an aircraft hold your tyres might be at 10 degrees C or lower; in a car in sunshine they could reach 50 or more.

 

[Globalti]

Does this mean I should keep my rubber in the 'fridge?

 

[byegad]

Aircraft that will fly at higher altitudes, in the main use nitrogen.

Nitrogen won't entrain moisture, so the vast majority of jets require either nitrogen for the tires. While some compressors and storage tanks may exceed the industry standard, for compressors, of 125 psi, and may get to the ranges required for jets, dryers for regular air and the expense of maintenance makes it far less expensive to have nitrogen delivered virtually on demand by the AirGas, coming in cylinders with 4700psi crammed into them and allowing a mechanic to quickly, efficiently and easily service the tires of a jet up to the 225 or better psi that's required as determined by the manufacturer of the aircraft and the tire.

You also have the added safety of nitrogen being, as I mentioned before, an inert gas. Air contains, as well as nitrogen, oxygen, which is not an inert gas. Not only is it corrosive, in the form of a pure gas, it will spontaneously combust in the presence of petrochemicals, which are typically found in airplanes, in the wings, to which the landing gear is attached, and which most aircraft leak.
to sum up:
1. its non corrosive
2. its non flammable
3. it less likely to change its volume due to temp
4. it is less likely to change its volume at altitude.

Thus no one has to inflate the plane tyres when it decending.

And Nitrogen makes up around 80% of air.

Frankly the rules is stupid, even an unpressurised hold would not add 1 bar of pressure and would be a lot colder than the cabin so reducing pressure rather than increasing it. P.V/T remains constant so is you drop the temperature from 20C to -30C this is a drop of approximately 20% whereas a high pressure tyre at 100psi would only go up by 15% in a vacuum.

So a requirement to reduce trye pressure by 15% or 20% of full sidewall rating would be an ultra cautious and less inconvenient precaution. I'd like to see Ryan air test a few bike tyres in their hold rather than their testing of flying conditions near volcanoes.

 

[frank9755]

And Nitrogen makes up around 80% of air.
I'd like to see Ryan air test a few bike tyres in their hold rather than their testing of flying conditions near volcanoes.

To be fair to Ryanair, last time I looked, their rules explicitly stated that tyres do not need to be deflated.

The deflation thing is an urban myth amongst the baggage handler community and, it has to be said, some cyclists.

 

[Globalti]

To be fair to Ryanair, last time I looked, their rules explicitly stated that tyres do not need to be deflated.

The deflation thing is an urban myth amongst the baggage handler jobsworth community and, it has to be said, some cyclists.

Fixed that for you.

 

[Bromptonaut]

If you look at the galaxy c5 aircraft, that has 28 tyres to take its weight of 350 tonnes ... thats a seriously big aircraft.

Now compare to the space shuttle that has 6 tyres to take its weight of 100 tonnes ... meaning those tyres have to be filled to
a very high pressure. And they spend up to 16 days in the vacuum of space without going ... pop!!

Both are designed to fly though, bike tyres are not. I suspect it's one of those marginal things where some airlines risk managers regard as requiring a control and others dont. If asked why not just do it?

On the Galaxy the tyres can be inflated/deflated in flight. High pressure for departure from base, lower for landing on rough/ready forward airstips - where all the wheels are needed to spread the weight.

A laden Galaxy can land and stop in 1200m. Even medium size commercial airliners need around 2000. Any less and it's special briefing and Captain's landing

 

[fenlandpsychocyclist]

On the Galaxy the tyres can be inflated/deflated in flight. High pressure for departure from base, lower for landing on rough/ready forward airstips - where all the wheels are needed to spread the weight.

A laden Galaxy can land and stop in 1200m. Even medium size commercial airliners need around 2000. Any less and it's special briefing and Captain's landing

Whoo .. clever, i didn't know that about their in-flight tyre management!!
I've seen the c5's land/takeoff at mildenhall (only 32 miles by bike from home).
Love the noise of those engines, especially when they come over wisbech at 8000 feet and and make "adjustments" to the engine revs
as one did a few weeks ago.

This video from 1min 45secs is the sort of noise i'm on about:
View: http://www.youtube.com/watch?v=LvNwiczJ69k

 

[Little yellow Brompton]

If you look at the galaxy c5 aircraft, that has 28 tyres to take its weight of 350 tonnes ... thats a seriously big aircraft.

Now compare to the space shuttle that has 6 tyres to take its weight of 100 tonnes ... meaning those tyres have to be filled to
a very high pressure. And they spend up to 16 days in the vacuum of space without going ... pop!!

The C5 can change it's tyre pressures mid flight, so the problem of going pop ( or not ) doesn't arrise

 

[Little yellow Brompton]

Both are designed to fly though, bike tyres are not. I suspect it's one of those marginal things where some airlines risk managers regard as requiring a control and others dont. If asked why not just do it?

My money is more on outdated risk controls from the days of Rapides or DC3s, it's comparable to the decades out of date ban on mobile phones in hospitals.

 

[Little yellow Brompton]

Both are designed to fly though, bike tyres are not. I suspect it's one of those marginal things where some airlines risk managers regard as requiring a control and others dont. If asked why not just do it?

On the Galaxy the tyres can be inflated/deflated in flight. High pressure for departure from base, lower for landing on rough/ready forward airstips - where all the wheels are needed to spread the weight.

Although they were designed with that in mind it's very very, rare that a C5 would end up on a forward strip . The cost too much to risk compared with the alterative of transhipping to cheaper AC

 

[dragon72]

I want to know why I can't listen to my iPod Nano on a plane...

 

[frank9755]

A laden Galaxy can land and stop in 1200m.

My Super Galaxy can stop far quicker than that, even with a full touring load, going downhill!