- Location
- London
twas a reply to tin pots point.
Agree that many of these things, including "the rules" are OCD bonkers.
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Agree that many of these things, including "the rules" are OCD bonkers.
Tin Pot
Guru
...Back in the real world someone had recently stopped riding their bike leaned it up, then a short time later their tyre burst.
With no other information available they take the only apparently unusual aspect of the event - that it was an unusually warm day - and ascribe meaning to it.
We’re just lucky that a black cat hadn’t walked past in the previous few minutes. Both tyres would have burst then.
OP
OP
Lozz360
Veteran
- Location
- Oxfordshire
Who, me?
Crankarm
Guru
- Location
- Nr Cambridge
Yebbut when you get a flat it's only flat at the bottom.
OP
OP
Lozz360
Veteran
- Location
- Oxfordshire
Interesting anecdotes about tyres exploding in the heat, but from memory the advice from old men back in the day, was to avoid leaving your tyres in direct sunlight otherwise they would “go down”. Deflate in other words. It just seems very strange to me now. I realise that tyres just going soft in the sunshine is much more boring than spontaneously exploding with the local community thinking that it was a gun shot, but I was only wondering if others had received similar advice? I can understand heat causes air to expand but then causes air to leak out due to increased pressure and then carry on leaking so that tyres have considerably less pressure than before. It seems unlikely and I was interested as to whether the advice was based on reality.
The same happened to me a month or so ago - in the indoor coolness of my house, and it wasn't even sunny outdoors.
nickyboy
Norven Mankey
- Location
- You want hills? We got hills
I guess the theory is that air in the tyre gets hotter, expands, increasing pressure. Increased pressure increases rate of escape of air from tyre. Later tyre cools when not in sun and air in tube cools. Smaller volume in tyre than at start of ride so lower pressure
Sounds like bollox to me. I suspect the only risk is if the tyre gets really warm it may affect its structural integrity
subaqua
What’s the point
- Location
- Leytonstone
may raise the pressure to a point where the valve passes , but thats more of an engineering guess than any solid science . I suppose if i observed enough tryres at a specific pressure then the data set might prove the theory.
anyways if you want to make your brain melt then chuck Daltons law together with Combined gas laws to work out what the partial pressures , and final cylinder pressures and temps will be if you had 230bar of 32% oxygen 68%nitrogen at 30 degress c and decanted into a cylinder with 27% Oxygen 73% nitrogen at 15 degress c .....
I use a gas blending app on the piephone now...
Accy cyclist
Legendary Member
- Location
- The hills of Accrington
[QUOTE 5359355, member: 9609"]when heat goes up pressure will go up, and it could be enough to do damage
THESE FIGURES NEED CHECKED by someone who does science stuff
tyre left in the sun, goes up from 20c to 100c
therefore
(273+100) / (273+20) = 27% increase
so tyre with 100psi could go up to 127psi ?[/QUOTE]
This is why i pump my 23mm tyres up to 90 psi maximum if i'm going out on a very warm day. I normally have them at about 100 psi.I've always thougth the air inside the tube would expand,making too much pressure for the tube to take/hold.
THESE FIGURES NEED CHECKED by someone who does science stuff
tyre left in the sun, goes up from 20c to 100c
therefore
(273+100) / (273+20) = 27% increase
so tyre with 100psi could go up to 127psi ?[/QUOTE]
This is why i pump my 23mm tyres up to 90 psi maximum if i'm going out on a very warm day. I normally have them at about 100 psi.I've always thougth the air inside the tube would expand,making too much pressure for the tube to take/hold.
