Tyres

Discussion in 'Touring and Adventure Cycling' started by yorkshiregoth, 14 Nov 2007.

  1. yorkshiregoth

    yorkshiregoth Master of all he surveys

    Location:
    Heathrow
    On the BA website it suggests that one deflates the tyres when travelling with a bike but it doesn't state that it is necessary. If I don't deflate them; is it likely or just remotely possible that they will explode due to the air pressure?
     
  2. Elmer Fudd

    Elmer Fudd Miserable Old Bar Steward

    <pedantic mode on>More likely to explode due to the lack of air pressure</pedantic mode off>
     
  3. OP
    OP
    yorkshiregoth

    yorkshiregoth Master of all he surveys

    Location:
    Heathrow
    Thank you kind sir for your elucidation.
     
  4. Tim Bennet.

    Tim Bennet. Entirely Average Member

    Location:
    S of Kendal
    The pressure in the hold of an aircraft is at about the equivalent of 8000ft. This is lower than the top of many alpine passes including the Col de Galibier.

    Until you see Tour de France riders stop and let pressure out of their tyres before the climb, I would leave your tyres alone.
     
  5. I think someone many moons ago had this strange idea that they would explode if still pumped-up because the aircraft hold is unpressurised (which they were on older aircraft - modern ones may be presurised the same as the cabin - say 8000ft).

    But assuming your tyres were inflated to 90PSI (say), that's 4 atmospheres (well, 4-and-a-bit, but...).
    And assume air pressure on the ground is 1atm

    If there were absolutely no pressurisation in the hold (there is a bit even at 36000ft) that's only the equivalent to your tyres being inflated to 5atm, or 105 PSI

    Which will be well within safety limits for the tubes, tyres & rims, so yes they're highly unlikely to explode.

    No more so than the aerosol cans of shaving foam, hairspray, etc which people are allowed to put in their luggage.


    As User says, deflate em and you'll just have to pump em up again at the other end.

    And having air in the tyres will help protect the rims if your bike is knocked-about (if :blush:) by the baggage handlers.
     
  6. OP
    OP
    yorkshiregoth

    yorkshiregoth Master of all he surveys

    Location:
    Heathrow
    Just what I wanted to hear. Thanks
     
  7. Pets go in the hold too and they tend not to explode.
     
  8. jags

    jags Veteran

    talking of shaving foam,after arriving in spain last year ,when i opened my bag in hotel that night ,the can of shaving cream had exploded ,leaving me with a bag full of foam , messy .and it did explode on the plain ,
    so make of that what you will.
     
  9. Hurricane Steve

    Hurricane Steve New Member

    Location:
    Hamburg
    Hi Guys
    With a gain in altitude the Air gets thinner!!!! this means things do not explode but implode, this is why your bag decided to shave lol.:blush:
     
  10. Hurricane Steve

    Hurricane Steve New Member

    Location:
    Hamburg
    Hi Mr Paul, yess I believe you to be right.
    I think its Boyle's Law but only if the Temp stays constant:P1 V1(over)T1 = P2 V2(over)T2.
    Therefore, at constant temperature, as the pressure increases the volume decreases or the volume of a gas is inversely proportional to the pressure applied on it.
     
  11. Hurricane Steve

    Hurricane Steve New Member

    Location:
    Hamburg
    Hi Mr Paul, yess I believe you to be right.
    I think its Boyle's Law but only if the Temp stays constant:P1 V1(over)T1 = P2 V2(over)T2.
    Therefore, at constant temperature, as the pressure increases the volume decreases or the volume of a gas is inversely proportional to the pressure applied on it.
     
  12. jags

    jags Veteran

  13. jags

    jags Veteran

  14. HJ

    HJ Cycling in Scotland

    Location:
    Auld Reekie
    I have just had a look at what the BA web site actually says, "You may wish to deflate the tyres to reduce risk of damage." this seems sensible if you have you tyres pumped to high pressure (my are usual at 7bar). Cabin air pressures are usual lower than surface air pressure, although not by much, but it there was a problem during the flight, and it can happen to any airline, you tyres might burst.

    You don't have to let all the air out of the tyres, just drop them a couple of bar to allow for expansion. You can always pump them up again when you get to the other end, or is there anyone here who would seriously suggest going touring with out a pump or inflator?
     
  15. HJ

    HJ Cycling in Scotland

    Location:
    Auld Reekie
    I have just had a look at what the BA web site actually says, "You may wish to deflate the tyres to reduce risk of damage." this seems sensible if you have you tyres pumped to high pressure (my are usual at 7bar). Cabin air pressures are usual lower than surface air pressure, although not by much, but it there was a problem during the flight, and it can happen to any airline, you tyres might burst.

    You don't have to let all the air out of the tyres, just drop them a couple of bar to allow for expansion. You can always pump them up again when you get to the other end, or is there anyone here who would seriously suggest going touring with out a pump or inflator?
     
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