So you need to buy a bike tube? But you don’t know what to buy…This simple story explains bike tube sizes. It shows you where to find the information you need on your tyre. Then it gives you a quick explanation of valves and pressure so you can use your bike tube properly.
What is a Bike Tube?
A rubber inner that sits inside the bike tyre. It is this inner that gets filled with air and gives you a comfortable, smooth ride on your bike wheels, if it is pumped up correctly.
Why do I need a spare one?
A lot of people choose to carry a spare bike tube with them as part of their bike tool kit. This means if you happen to get a flat tyre you can simply replace the tube and get on your way rather than repairing the puncture with a puncture repair kit. Having spare tubes at home, that match all the bike wheel sizes you have, makes any repair/replacement jobs quicker & less frustrating.
The valves found on bike inner tubes
The sidewall of your tyre shows your TUBE size
What size is your bike tube?
Embossed on the side wall of your tyre you will find all the information you need to know about your inner tube. This is represented in diameter x width e.g. 26 x 2.0 (see the photos above & below).
The diameter is the diameter of your wheel – this changes depending on the type of bike and size of the bike e.g. kids bikes come in a range of wheel sizes starting at 12inches…16 inches..20 inches…up to 24 inches. This is where the adult sizes kick in 26inches, 27.5 and 29inches.
Road bikes are different again their diameter is 650 to 700C (this is not a cm measurement but millimetres, the C is an A to D system).
means the width of your tyre. Remember that your tube sits inside your tyre and when it is full of air it is the tube that allows the tyre to hold it’s intended shape. The width changes depending on the purpose of the bike – generally the wider the tyre the rougher the terrain it is used on. Skinny or narrow tyres give you smooth fast riding so are great for the road – flat, smooth, even surfaces.
This photo shows a kids size tube
This photo shows a road bike size tube
The wider the tube/tyre the more traction or grip you will have
Types of Bike Inner Tube
These inner tubes add an element of prevention to your ride. They will save you time out on the trail or on your way to work by either completely preventing a puncture or sealing the puncture immediately. This added advantage comes at a higher price point but is worth the investment for many types of riders – commuters, mountain bikers, tour riding or anyone that would rather be enjoying their ride than fixing a puncture. You should, in theory, not have to replace these types of tubes as often as you would standard inner tubes.
Self sealing inner tubes have a sealant inside them. When you puncture the sealant will fill your puncture hole and harden fixing your problem immediately. This system works on punctures up to 3mm wide so it is still recommended that you carry a spare tube incase of slashing type flats. You may also have to rotate your wheel to get the sealant to fill the hole then pump any air you have lost back in.
Thorn resistant inner tubes are 3x as thick as a standard inner tube. This makes them really durable and strong so they are less likely to puncture. This type of inner tube is popular with mountain bikers who often find themselves surrounded by gorse. These tubes are not designed to be carried as a spare tube in a bike tool kit, they are considerably bigger & heavier than standard inner tubes.
You can also get inner tubes that have been designed to match a certain type of riding. Downhill inner tubes are durable & strong, designed to handle hard impacts better than a standard inner tube. Lightweight inner tubes are all about reducing weight allowing a competitive rider to perform better.
More about your Bike Inner Tube
VALVES – PRESTA & SCHRADER
The valve is where the air goes in to inflate your inner tube. When you are buying a inner tube replace it with the same valve type that you have. You will either have a presta (skinny, high pressure) or schrader (fat, low pressure) valve.
Presta Valves – are French high pressure valves, they have a nut on the end of them that must be unscrewed to allow air to flow. They can also have a screw on cap over the end of the valve which keeps dirt and grit out. Another advantage of a Presta valve is the locking ring that screws down onto the wheel rim. This ring keeps the valve from disappearing back inside the tyre when you go to push on a pump…very handy. Presta valves also come in different lengths to match your wheel rim depth.
Schrader Valves – are German, they are the same type of valve that you will find on a car tyre. This can make it more convenient to pump up your tyre while out around town by using petrol station air pumps. Schrader valves are generally found on lower pressure types of bikes e.g. children’s bikes, mountain bikes. Air flows through the valve when the pin in the centre is compressed/pushed. You can do this with your finger nail to release air. Schrader valves are not covered in any way so can fill up with dirt.
Your bike pump needs to match your valve. Most bike pumps can work with both valves the process is just slightly different – watch our Pumping Up a Bike Tyre video to learn more. Also note that a presta valve has a nut on the tip that must be unscrewed to allow air to flow.
PSI – POUNDS PER SQUARE INCH
The pressure to inflate your inner tube to, is called PSI (pounds per square inch). You will generally find a range from a minimum to a maximum PSI, again, written on the sidewall of your tyre. Check out the photos below which show a minimum PSI to a maximum PSI on a range of different bikes. Again if you want to know more about pumping up a bike tube, watch our video.
get Ready and goRide – How to Buy a Bike Tube
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