A microscopic inner tube puncture can turn even the most expensive bicycle into an unusable machine.
If the tools necessary for repair are present, the inner tube can be patched or replaced, but the procedure is fairly slow, dirty, and can sometimes even be dangerous depending on the territory where you are.
For that reason, responsible cyclists do their best to minimize the chances of a flat tire.
In most cases, the focus is on the tire since it’s the inner tube’s defense shield. However, the condition of the inner tube itself is of high importance too; it doesn’t matter how puncture-proof a tire is when the tube in it is faulty.
This leads us to an important question — do inner tubes have an expiration date?
A standard inner tube protected from external influences such as UV light, petroleum fumes, water, and contrasting temperature changes can last more than a decade.
What Are Bicycle Inner Tubes Made Of?
The material of an inner tube is very important when predicting its longevity and outlining a proper storage protocol.
Option 1: Butyl Rubber
Most inner tubes are made of polyisobutylene or butyl rubber for short.
Butyl rubber is a tough elastomer utilized in many industries due to its robustness, satisfactory elasticity, and very high resistance to chemicals and gas diffusion.
Two popular examples of butyl use would be protective clothing (e.g, gas masks, gloves..etc.) as well as roof sealing.
Initially, bicycle inner tubes were made of natural rubber (polymers of the organic compound isoprene), but the impeccable air retention of butyl rubber incentivized the industry to make a switch.
Another motive behind the use of butyl rubber is the lower price.
How resistant is butyl rubber to the elements?
Butyl demonstrates great environmental resistance and has been utilized for the lining of emergency water tanks in tropical and subtropical countries without signs of degradation after 10+ years of use. (read more).
Similar examples clearly illustrate that butyl is very resilient to sunlight.
However, the butyl employed for similar applications tends to be a lot denser than an inner tube.
An inner tube cannot be super thick because the extra thickness would hurt its elasticity and add weight to the wheel.
Therefore, one cannot expect an inner tube to have the same resistance to environmental factors as industrial butyl designed for applications where extra weight isn’t a problem.
A Butyl Inner Tube Can Last a Long Time If Stored Properly
The following protocol for storing inner tubes will increase their shelf lifespan:
1. Coat the inner tube with baby or talc powder to prevent it from sticking to itself.
2. Place the inner tube in a protected container (e.g., а zipped plastic bag, а cardboard box, а plastic box…etc.)
Note: If the tube is new, you can skip steps 1 and 2 as most tubes are covered in powder in the factory and placed in a cardboard box.
If you want extra protection, you can put the tube in an airtight vacuum bag and then into its original cardboard box.
3. Store the tube at room temperature.
In most cases, it’s best to avoid car garages due to the temperature changes (Мost garages are super hot in the summer and ice cold during the winter). The fumes in the air don’t help either.
An inner tube stored similarly can remain as good as new for many years to come.
However, if a butyl inner tube is exposed to the environment (temperature shifts, rain, ozone, fumes…etc.) it will degrade over time even though the material is pretty tough. Hence why it’s not recommended to store inner tubes at exposed locations.
Common Signs Of a Degraded Butyl Inner Tube
1. Cracks
Visible cracks are a clear indication of a heavily deteriorated inner tube.
Such tubes cannot be used safely because the areas with the cracks are too thin and close to total disintegration.
2. Color changes
A change of coloration indicates degradation too. A degraded butyl inner tube is often darker than usual.
3. Lack of elasticity
An inner tube at the end of its lifespan could also display poor integrity when stretched.
4. Uneven inflation
Some damaged tubes do not showcase external signs of wear, but once you start inflating them, they expand unevenly because certain regions of the tube are damaged.
In some cases, such tubes burst when inflated to the necessary pressure.
What About Already Installed Inner Tubes?
If the inner tube is already installed, then there are two main courses of action for extending its life:
a. Remove the tube and store it in the aforementioned manner.
If the exploitation of the bicycle has been postponed indefinitely, then it may be worth it to remove the tubes and store them as described above.
b. Inflate the tire periodically
If you’re occasionally using the bicycle, then removing the inner tubes simply to store them could be an impractical approach.
In that situation, it will be necessary to inflate the tubes periodically to preserve their integrity and elasticity.
If you let the tires go completely flat due to loss of air, they will rub against the inner tubes along with the rim and cause cracks over time.
You don’t have to inflate the tires to high pressure. Just put enough air until they’ve reached their proper shape.
Another problem that you may experience even if you do the necessary inflation would be bondage between the inner tube and the tire.
You could minimize the chances of this scenario by coating the inner tube in powder before installing it.
Note: Areas of the tube that have been patched after a puncture are the most likely to stick to the tire.
Option 2: Latex Inner Tubes
Some racing-oriented inner tubes are made of latex which has the following benefits over butyl:
Greater Elasticity
Latex is more elastic than butyl. This property is important for the rolling resistance of the tire because the extra elasticity allows the tube to quickly regain its shape upon deformation.
In consequence, the tire spends less time in a “deformed state” after contact with the ground and rolls better overall.
Tests have shown that when a tire is pumped to 80 PSI, a latex inner tube can save about 1.9W per tire or 3.8W in total. If your power output is 145W, the savings amount to 2.6%.
The gains are marginal but significant enough for racing situations.
High Resistance to Flats
It’s believed that latex inner tubes are more resistant to puncture, especially the “pinch” type also known as “snakebites”.
Latex inner tubes come with many downsides preventing them from being the universal standard.
The main problems are:
Low Room For Error During Installation
Latex inner tubes require more sensitive installation when using a clincher tire (the most common type) as it’s easier to pin the tube between the rim and the tire and puncture it.
Not a Back-up Tube
Many people avoid using latex inner tubes as a spare because it’s difficult to install them properly on the side of the road or trail.
Latex inner tubes require a “calmer” environment to avoid making small mistakes that may unfortunately puncture the tire.
Dangerous When Paired With Rim Brakes
Intensive and prolonged braking can heat a rim if the bike uses rim brakes.
The heating is the result of the brake pads rubbing against the outer layer of the rim.
This is a problem when using latex inner tubes because the extra heat can blow the tube. The effect is particularly pronounced when using carbon rims because carbon dissipates heat slowly.
For that reason, some producers of latex inner tubes explicitly say not to pair them with carbon rims.
The likelihood of this issue is significantly lower when using alloy rims because aluminum is a better “heat sink”. That said, even alloy rims can reach very high temperatures during long descents and destroy a latex inner tube.
Poor Air Retention
Latex inner tubes do not hold air nearly as well as butyl tubes. As a consequence, they require very frequent inflation.
CO2 diffuses through them very quickly too. This is problematic for people who want to use CO2 cartridges and another reason why latex inner tubes are not a popular choice as a spare.
Poor Environmental Resistance
Latex inner tubes are sold sealed in zip-bags because they’re highly prone to degradation caused by environmental factors such as ozone, sunlight…etc.
If you plan on stacking up latex inner tubes, it’s best to keep them in the original package and away from the elements.
Storing Inner Tubes In a Saddle Bag or Kit
The general cycling protocol says to always carry a spare inner tube with you.
Most cyclists put one either in their backpack or somehow attach it to the bicycle. A small saddle bag is the most frequent choice.
It’s of high importance to defend the tire from punctures caused by sharp objects in the spare kit (e.g., a multi-tool).
Personally, I no longer use a small saddle bag because it fights for space with my Carradice SQR. For that reason, I rely on a Zefal tool bottle.
To protect my tube from the rest of the kit which includes a multi-tool, tire levers, a handful of zip-ties, and patches, I placed the tube in a cotton sock.
Also, my multi-tool has its own pouch made out of an old inner tube.
Tip: If you’re using a saddlebag, you may consider putting duct tape on the inside of the bag if bolts and nuts part of the mounting mechanism are sticking out.
How Many Patches Can an Inner Tube Take Before Becoming Unusable?
A tube cannot be patched indefinitely because the patches are thicker and less elastic than the tube itself.
As a result, an “over-patched” tube is often imbalanced and acquires an uneven diameter across its body when inflated.
In consequence, the wheel itself could start to feel lumpy. Having said that, there isn’t a precise number of patches after which the tube deforms with certainty.
I usually retire a tube after six patches – a number that should take a lot of time to reach if the tires are intact, and the bicycle isn’t used for extreme mountain biking.
Additional Tire Patching Tips
1. If the puncture is too close to the valve, I prefer to replace the tube because that area is sensitive and unstable.
2. If a tube needs multiple overlaying patches, I retire it because it makes the wheel too uneven.
3. If a tube has too many patches, I don’t use it as a spare because patches get old and come off more easily when the tire is folded which is the case for spare tires in a toolbox or bag.
The Condition of The Tires Is Very Important Too
Back in the day, I had the misfortune of cutting a brand new tire on a piece of glass after dropping off a small gap. It wasn’t the tire’s fault. There isn’t a bike tire that could have survived this scenario without damage.
Since the tire was new, I patched it as best as I could and exploited it for over a year. Unfortunately, however, I got 6-7 flats during that period because the cut of the tire was continuously opening and exposing the inner tube. As a consequence, I had to retire a couple of inner tubes prematurely.
If you want to expand the lifespan of an inner tube to the maximum, it’s necessary to rely on “healthy” tires preferably with some extra protection against punctures.
Note: Tires deteriorate over time even if they’re not in exploitation because the rubber loses its elasticity and cracks. The effect is sped up when the tire is exposed to the elements.
Due to that factor, old bicycles often need tire replacement.
What To Do With “Retired” Inner Tubes?
Inner tubes are cheap in comparison to other bicycle components, but throwing them into the bin after retirement is a little wasteful and somewhat disrespectful to the environment because synthetic products could take centuries to dissolve.
Luckily, inner tubes can be very useful for other tasks besides their original purpose. The list below contains a few examples:
1. Chainstay protection
If your rear derailleur does not have a clutch, chances are that the chain will consistently hit the chainstay when riding on uneven terrain.
The result is a scratched and weakened chainstay. You could prevent this problem by making a chainstay protector out of an inner tube. You can secure the chainstay protector with zip ties
2. Tool Pouch
An inner tube could also be used to make a pouch for your multi-tool or another pointy object that you carry in your kit.
3. Mounts stabilizer
If an accessory (e.g., а flashlight) that you have on your handlebars is moving too much, you can stabilize it by wrapping a piece of an inner tube around the installation spot first and then mounting the bracket.
The inner tube increases the friction and minimizes movement.
4. O-rings
By cutting small pieces of an inner tube, you can make O-rings too. The wider the piece, the stronger the hold of the O-ring will be. I use those to secure and silence the folding lock on my bike as explained in this post.
