Re: 1991 ranger brake problem - CO2 & O3

On 14/11/2024 19:31, Bob La Londe wrote:

On 11/13/2024 4:58 PM, Jim Wilkins wrote:

"Bob La Londe"  wrote in message news:vh38u5$2dg8a$2@dont-email.me...
>
On 11/13/2024 3:09 PM, Snag wrote:
>

   I thought it was exposure to sunlight/UV that caused most of the sidewall degradation ... or are those aftermarket tire covers (in particular for RV's and campers) just another scam ?

>
>
Yeah I don't know for sure.  UV is certainly capable of damaging a lot
of things.  I do know CO2 is an issue with some rubbers.  I was told
by... well somebody... that tires were among them.
>

 Nobody likes to be wrong, so I did some look ups.
 CO2 is said to contribute to the breakdown of rubber on several sites. Some say "distressed" CO2 and others just generically say CO2. 

I have no idea what "distressed" CO2 is, but CO2 dissolves in tyre rubber, kind-of. It seeps into spaces between the molecules in the rubber, and can seep through the rubber. This doesn't normally do much damage to the rubber, but because of this seepage a tyre filled with CO2 will deflate quicker than a tyre filled with air.
That said, rubber in high pressure CO2 will absorb more CO2 - and if the pressure is suddenly released, as in a CO2 gun, the CO2 can bubble out, damaging the rubber, perhaps severely.
Another thing CO2 does is actually react with rubber, which can cause damage. However the amount of CO2 in normal air isn't likely to do much harm to car tyres - the normal oxygen in air will probably do more damage, long term - but it could well damage rubber in CO2 guns and airguns.
An aside, people put lampblack (carbon) in rubber for several reasons, but a major one is to slow the reaction with oxygen in the air. The oxygen still reacts, but (somewhere between greatly simplified and lies-to-children) reacts with the lampblack instead of the rubber... producing CO2, which permeates out to the atmosphere... But overall, the rubber lasts longer.
Rubber should not be used to seal CO2 long-term, especially under high pressure.
UV and O3 are very different animals!! Both will aggressively attack rubber. And almost anything else, including humans.
Peter Fairbrother