Do inner tubes age?
 

Do you guys think (butyl-) inner tubes age and that rubber decay makes inner tubes more prone to leaks and punctures with time? If so, what time is the estimated half-life of a inner tube (1/2 way gone?)
Do you guys think that the attaching (self gluing of inner tubes to the clincher tire, which we often see in older tire/tubes is a sign of rubber disintegration?
The rubber of tires ages with time and gets harder an brittle, but that is more to exterior exposure- isn't it? Does the same (or different) apply to inner tubes?:rolleyes:

Anecdotally, yes. I would suspect that use, exposure to temperature extremes and other factors would come into play, but I have no hard evidence to my assumptions.

What I can say is if I get an old bike, I replace tubes. Cheap insurance.

I've seen 50 year old tubes that still work. Exterior exposure does indeed make a difference.

Generally, if the tire is okay, the tube shouldn't ever really "age". I've used tubes for years and many, many patches without experiencing any problems with degradation of the tube's rubber. I have, on the other hand, found tubes inside tires that had long since degraded that are also past saving. But those have also seen years of outside exposure and the tires are usually rotted shells.

I recently used a 35+-year-old tube whose tire tread had completely cracked and flaked off of the tire casing. I'm pretty sure that tube had been sitting in that tire for the tire's whole lifetime, and the tube was perfect.

I remember reading (Sheldon I think?) that if a tube is held in its "natural" shape inside a tire, it will be very unlikely to degrade at all, but if it is folded into a box, it will be prone to cracking at the folds.

I think that the self-gluing phenomenon is from extremely mild vulcanization due to heat in storage and on the road, not due to degradation of the butyl.

A few months ago I bought a couple of tubes from the local bike guy that were left under a leak in the roof of his garage with -40 deg C <-> + 40 deg C* temperature range for at least five years. They work fine.

*That is -40 deg F <-> 104 deg F in case there is a caveman reading this.

I have a set of tubes, and tires, that came originally on a 84 Fuji Club I bought with less then 5 miles on it about 3 months ago, and the tires and tubes are still on the bike, and I rode it just last week with the original tires and tubes! I've been riding it for a little bit and haven't had any issues with the tubes or tires and there are no cracks on the tires.

Odd thing was, I bought a 88 Miyata 712 last fall, it to had the original tires and tubes, the tires were cracked badly, but the tubes were fine...that is until one of the tubes blew out of the front tire due to a severely cracked tire.

Not sure why two bikes, the Fuji stored in a attic, and the Miyata stored in a garage, both stored since almost new (very little wear on the tread, the Fuji tires still had the nubs) had such different tire life.

Tubes do age, but it's slow enough not to make a difference. I've noticed that over time they become less elastic and a bit more brittle. It's never enough to cause a problem in itself, but I've noticed that older tubes sometimes split or tear when newer tubes would only puncture.

I've also had older tubes tear apart when removing them from flatted tires.

I wouldn't scrap a tube over an age issue, but if going on an extend trip might carry one more spare than I otherwise might.

"Not sure why two bikes,...had such different tire life." Exposure to ozone, created by the effects of sunlight on air pollutants or by electric motors, has severe effects on rubber items. The rubber manufacturing process and the additives used also have a great influence.

...like a fine wine.

:thumb:

I got out my dad's old Motobecane that hadn't been ridden for 15+ years. The cables are a mess (probably rusted inside), but I inflated the tires, and they still hold air, so I think it's all good! The tires are also in runnable condition.

Edit: I got the bike out to see how it rides about 6 weeks ago. There is still some air pressure in the tires.

I've used old ones that seem as good as new and others that lose pressure pretty fast. Probably related to the original quality of the rubber and the conditions it has been exposed to.

Tube is not exposed to sunlight, being inside the tire..

they are Butyl rubber, petroleum based, .. latex in ultra light tubes may age faster.

I too have seen tubes stick to the tire and the only way they were coming apart was to rip the tube, but if that's going to be happening then the tire and tube are shot anyways. None of mine ever got that way, even the one that had the severely cracked tires, those were slightly stuck together, but the tubes came out with no damage.

UV exposure probably doesn't have a large effect on aging of rubber. It does some damage but not all that much. Think car tires that are exposed to sunlight all the time. What dsbrantjr is talking about is the production of ozone via the exposure of other chemicals - unburned hydrocarbons and oxides of nitrogen -to UV light.

The formulations used for the butyl rubber will also make for a highly variable rate of reaction with ozone.

QUOTE=fietsbob;13180756]Tube is not exposed to sunlight, being inside the tire..

they are Butyl rubber, petroleum based, .. latex in ultra light tubes may age faster.[/QUOTE]

It's not just sunlight, it's ozone levels too.
IMO it is also the chemical mix, wall thickness and cure procedure from the OEM that also determine longevity of the tube. You will also have to factor in inflation level (over/under), heat and impacts.
I recently resurected my brothers 1970's Columbia. The Taiwan mfg. gumwall tires were disintegrating(cracked, flaking), but the original Carlysle tubes still had about 25psi in them. That's after sitting for over 40 yrs.
I've got newer tube, tire combo's that require airing up every week. No visible leaks in the tubes, so IMO it's the schraeder valves that are allowing air loss. As my budget allows I am replacing tubes, where possible, to presta valve tubes. Will see how that works.

I knew a guy that purchased a 1958 car with the original tires that sat outside for about 40 years or more and the tires still held air, they were cracked very badly, but they held air so he could roll it onto a trailer.

I use to store several patched tubes (700 x 23 butyl) in my garage high on a shelf. Then I discovered that they were developing big holes that looked like chemical deterioration. Nothing had come in contact with the tubes. Since then, I've had the exact type of tubes stored inside the house for many years with no problems. With 3 cars and extra gasoline stored in the garage I've suspected that higher ozone levels is the problem. Also our city is known for high ozone during the summer months.

I store my tubes and even tires in ziplock plastic bags to protect them from something accidentally getting on them and perhaps ruining them.