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How to Change a Bicycle Inner Tube.

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How to Change a Bicycle Inner Tube.

31 Aug 2015 21:01

Back to basics for those new to cycling.

Some good reading on bicycle inner tubes: -

Your bike's inner tube is an inflatable tube made of synthetic rubber which sits inside the tyre and makes it airtight. Most bike wheels – road, city bike, MTB etc. - still use inner tubes to hold the air, although in recent years car-style 'tubeless' tyres have grown in popularity.

Your inner tubes are one of those things on the bike that you are never aware of until things go wrong – i.e. you have a puncture that has gone through the tyre and pierced the tube. If this happens, your inner tube can be patched using a puncture repair kit, but if the hole is too big (or you can't be bothered, let's face it), you'll have to get a new tube.

There are two things to bear in mind when replacing a tube:

1. Wheel size: This will differ between bike types – generally there are a limited number of standard sizes between road and MTB bikes but there can also be deviations in width and volume etc.
2. Valve type: The tube is inflated via a valve which fits through a hole in the rim of the wheel – there are a few different types of valves so when replacing a tube it's important to ensure you have the right one, or it may not fit through the rim hole.

WHICH INNER TUBE IS RIGHT FOR ME?

Which size for my bike?

Firstly, determine the size you need – this will be decided by the size of your wheels and tyres.

In most cases, you can look at the sidewalls of your tyres and see a series of numbers printed there which represent the size of your tyre – this is the size tube you need too. Most tyres will display both an ETRTO (European Tire and Rim Technical Organisation) or ISO (International Organisation for Standardisation) size as well as the 'traditional' size in Metric (mm) or Imperial (inches).

(The ETRTO and ISO are organisations which aim to standardise tyre and rim sizes globally and remove some of the confusion caused by the use of different standards – most manufacturers still use the 'traditional' sizing as well)

So the 'traditional' sizing will show the diameter of the wheel and the width of the rim in the form 'Diameter X Width'. In this case the typical road bike wheel of 700c in diameter might have a sizing of 700x23 (700c is the diameter, 23mm is the width). A mountain bike wheel (with dimensions measured in inches), may show the size 26x2.1 (26 inches being the diameter, 2.1 inches being the width).

In each case you will need a tube to fit – in the case of the road bike a 700 x 18-23/25c tube will be ideal (with 18-23/35c being the range of tyre widths it can fit) and for our MTB we will need a 26 x 1.75-2.5” tube.

Still with us? Good.

In reality it's not that complicated – most road bikes take a standard-sized tube to suit a range of the most common rim widths (700c), and will likely say 'road bike tube' in the description anyway. Same for BMX tubes (20”). However with MTB and hybrid/city bike tubes it's worth remembering that a number of different rim diameters are in common use, so be mindful of whether your bike has 26”, 27.5” or 29” rims.

Which valve type do I need?

Once you have the size of your wheels you'll need to know which valve type your tubes have.

There are two main types, Presta and Schrader.

Schrader valves are also sometimes known as 'car-type' valves as they are the same type used on motor vehicle tyres. Schrader valves are often found on MTB tubes, commuter bikes, kids' bikes and BMXs. To inflate or deflate a Schrader valve you simply remove the valve cap, press the pump nozzle against the valve until the central pin depresses, opening the valve, and off you go.

Presta valves are usually found on road bikes and some higher-end mountain bikes. They are available in different lengths so can be used to fit tubes on aerodynamic, deep-section racing wheels. Presta valves typically feature a threaded exterior onto which is wound a circular locknut, which keeps the valve tight to the wheel rim and prevents it twisting off or becoming damaged during inflation. Inflating a Presta valve also involves unscrewing a small nut at the very tip to open the valve before then attaching the pump nozzle – to deflate the tube you unscrew this nut and press it in to let the air escape.

Presta valves will sometimes feature a removable valve core, which allows riders with deep-section rims to use valve extenders, or which enables latex sealant to be put into the tube as added puncture protection.

Anything else I need to know?

While most inner tubes are pretty standard – balloons to hold air – you can get heavy-duty versions that are more suited to the rigours of disciplines such as downhill racing (DH), but with a weight penalty.

Finally some tubes are available with liquid latex sealant already inside, the idea being that in the event of a puncture, the sealant hardens around the hole without the need for the tube to be repaired or replaced. These are more expensive and a little heavier than standard tubes, but have their fans among city commuters and road riders/tourers who swear by them.

here are a couple of YouTube clips that are well worth watching if you're new to changing punctured inner tubes, or need to install a new tyre.

https://www.youtube.com/watch?v=fwwfV99VV8I

Plus, if you want to repair that inner tube rather than buy a brand new one
this clip is great viewing.

https://www.youtube.com/watch?v=Q2sKMqB9QCg
User avatar JackRabbitSlims
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24 Nov 2017 17:58

You usually are a bit more detailed, you completely left out how and what to use when patching a tube.
froze
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Re:

28 Nov 2017 13:02

froze wrote:You usually are a bit more detailed, you completely left out how and what to use when patching a tube.


The thread title is "How to change an inner tube" not repair one.

Perhaps you could regale us with you anecdotes and reveal your mad-styles on "tube-patching"??

Go on then!!
User avatar JackRabbitSlims
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Posts: 1,491
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Location: On The Road.

28 Nov 2017 18:26

What's weird is that sometimes, at least 50% of the time I can fix a flat without removing the wheel! How's that you scream? It's a trick I learned 50 or so years ago from an older guy in his 70s. If I can find the offending object, and or hole, without removing the tire, I simply remove about a third of one side of the tire with the hole in the center of that section, then pull out about a fourth of the tube with the hole in the center of that section. I then take out the offending object if visible out of the tire, if not I try to find it with my finger, some use a cloth and let the cloth catch the object but since I know where the hole is I can find the object without sticking myself, I may have to poke my small phillips driver into the hole from the tread side to push the object out from the inside, but that's sort of rare. I then buff the tube like normal with an area a bit larger than the patch, then use an alcohol pad and clean the section where the hole is in a larger area then the patch will cover. I only use Park or Specialized Fatboy glueless patches because once on they don't come off ever unlike a couple of other brands I've tried, though I haven't tried the new Lezyne patches yet. I peel the patch off being careful only to handle just a tiny area of the corner of the patch, lay the patch down and press the patch on as hard as I can between my fingers and thumb for 30 seconds, observe the patch to see if there are any frosty looking areas if so repress that area. I put a tad amount of air into the tube and then reinstall.

Same routine goes if I have to remove the wheel of course; about 90% of the time I can fix a flat faster then replacing the tube even if I have to remove the wheel, because replacing the tube takes time to get all the air out of the old tube so it will roll down to a small enough size to stuff in the seat bag, that and using glueless patches makes fixing flats for me a bit faster then a tube swap; plus it has the added benefit of not going home, finding the hole, and patching it, which means I save time at home.

Now if for some reason I can't find the hole, then I replace the tube and look for the leak at home, but about 90% of the time I can find the leak pretty fast.

Tools used, well there are a lot of good tools, I use Soma Steel Core levers because they don't break no matter how cold it is, or how tough the tire is.

Sometime, though again rarely I may have to boot a tire, they only make glueless boots, but these will only get you home, they will not stick more then a couple of days. Though someone mentioned to me once a person can use a boot patch, go home and use black Gorilla tape and tape over the boot to help it stay in place, I haven't tried that yet. That same person said the black Gorilla tape will patch tubes, I tried that one but it didn't hold for more then a day, great in a pinch though, it may hold up longer in lower PSI tires then road tires use.

There it is, you asked for it, unfortunately! LOL. It's just the way I do it, others do that differently like they don't believe in glueless patches, that's fine, whatever works for them and gets the job done.
froze
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Joined: 23 Feb 2017 15:52
Location: NE Indiana


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