Posted in Cycle

What are inner tubes?

Let's start with the basics... what is a bicycle inner tube? An inner tube is a balloon-like structure, which can be inflated and deflated using a valve. The inner tube is your air-cushion, and when inflated beneath the tyre it provides you with a comfortable, safe ride.

Unless you've converted your bike to tubeless (read our blog on the The Benefits of Tubeless Road), then the chances are your bike has inner tubes. However, with so many wheel and tyre sizes out there, it can be tricky to identify the correct size for your bike.

What inner tube do I need for my bike?

Inner tubes come in a range of sizes, as well as two main valve types. These are the two key factors to consider when making your choice of inner tube.

Size

Inner tubes vary in size depending on the circumference of the wheel, and the width of the tyre:

  • Wheel Diameter/Circumference: Depending on whether your bike is a road bike, touring bike, mountain bike, or child's bike, the diameter and circumference of the wheel can vary. Then, within these categories there are further sub-divisions, such as 26 inch, 27.5 inch and the 29ers commonly used in mountain bikes. 
  • Tyre Width: To add to the variety, you also have different tyre widths. There are wide road tyres and narrow road tyres, wide downhill mountain bike tyres and narrow cross-country mountain bike tyres. Get the wrong size, and you could have too much tube to fit inside the tyre, or too small an inner tube to fill it out.

So how do you know what size you need?

There are two fool-proof ways to ensure you get the right inner tube size:

  1. Check your tyre sidewalls: The best way is to look at the markings on the sidewall of your tyre. Printed onto the tyre should be something like "700x23c" on a road bike, or "29x1.9" on a mountain bike. The first number in this sequence refers to the circumference of the wheel, the latter refers to the width of the tyre. Additional markings on the tyre sidewall may include the International Standards Organisation (ISO) size. This would look like "23-622" for a 700x23c tyre, or "50-559" for a 26"x1.9" tyre. 
  2. Check your bike's specifications: The other way to identify your wheel and tyre size is to look at the product page of your bike. Assuming you haven't changed the specification from when you originally bought the bike, then look for the tyre size in the product description, such as "Tyres: Continental UltraSport 700x25c".

Valve type - Schrader or Presta

The valve is used to inflate and deflate the inner tube. There are two main valve types available; Schrader and Presta. It is quite easy to identify from looking at your existing tube what kind of valve you have.

Presta valves, pictured left in the image below, are narrower and longer. Schrader valves, pictured right in the image below, are shorter and fatter (found on car and wheelbarrow tubes).

 

The right inner tube for you...

Now you know your tyre size and valve type, you can consider the extensive Inner Tube range at Wiggle.

We have a particularly fantastic value range from LifeLine, in all the sizes you could need:

We also have even better value 5 packs of LifeLine Tubes available, for a bulk-buy discount.

 

 

What are the advantages of latex inner tubes?

Latex inner tubes are an alternative to the standard butyl rubber inner tubes that are commonplace in the market.

The benefit of a latex tube, is that they save weight, and the more supple nature of the material can give a smoother ride feel as it reacts better to road surface changes.

The disadvantage of latex tubes is that they are a little trickier to fit, with a tendency to get caught between the tyre bead and the rim. They also leak air more than butyl, so you need to top them up more often.

Wiggle sells a variety of latex inner tubes but our top three road latex inner tubes are:

 

 

Tyre pressure

On the sidewall of the tyre, you may also find the recommended pressure for tyre inflation. This can be in pounds per square inch (PSI) or BAR (1 BAR = 14.5 PSI).

Weather and riding conditions can effect how much you inflate your tyres. For road riding in the wet, a pressure of 10-15 PSI under the recommended level provides extra grip, particularly when cornering. Mountain bike riders will also often under inflate their tyres, sometimes quite significantly, to maximise grip, cornering, and shock absorbance. 

A floor pump with a pressure gauge is very useful for making this kind of adjustment.

 

How do I change my inner tube? 

It's a skill all cyclists need to master; changing a punctured inner tube - or at least, removing and replacing it during a quick repair - is an inevitability, so it's a good idea to be capable of doing it quickly and with ease. 

Here's a quick lesson from Wiggle High5's Amy Cure to help you change a tube like a pro...

 

Cycle guides