Tyre Wear

Tyre Wear

We are often surprised to find bicycles coming into our workshop with under inflated tyres, or those with worn tyres. But what exactly constitutes worn tyres and what are the risks of riding on them?

Worn tyres?

With cars and motorcycles, the general rule is that tyres are worn when the tread is less than 1mm.

However, these rules don’t apply to bicycles and some tyre types, such as those for certain road bicycles, have no tread at all.

Rather unhelpfully the Highway Code simply provides that you bicycle tyres should be in good condition and inflated to the pressure shown on the tyre.

So what does ‘good condition‘ mean?

Tyre Tread

There are obvious cases when is it clear a tyre is worn and must be replaced, for example when the puncture protection belt (if your tyre has this feature) or the carcass threads can be seen through the tread. Looking at the pictures below: on the left you can see the green puncture protection belt where the tread is worn. On the right, you can see the tyre carcass threads where the tyre tread is worn and peeling away.

However, as puncture resistance also depends on the thickness of the tread layer, we strongly recommend you replace your tyres before the extreme levels of wear described above is reached (unless of course you enjoy practicing your puncture repair/inner tube replacement times!).

Therefore, we look for the following when judging whether a bicycle tyre tread is worn:

  • Tyres originally with tread. When the tread/grooves are no longer visible on any part of the tyre;
  • Tyres originally without tread (e.g. road bikes). Some tyres such as Continental road tyres have a ‘Tread Wear Indicator’ (TWI). These are two small holes in the tyres (see the picture below). When you can no longer see these holes, you should replace your tyres.

  • If road bike tyres don’t have the tread wear indicators we look for other signs that the tyre is worn, for example the shape of the tyre. A worn road bike tyre will no longer look round in the cross section. It will have a squarer profile or have ‘flat spots’.

Tyre Sidewalls

The tyre “sidewalls” are the sides of the tyre where the manufacturers’ logos, sizes and recommended tyre pressures are printed (see picture below).

This part of the tyre often fails before the tread is worn out. In most cases, this premature wear is due to prolonged use of the tyre with insufficient pressure or, if your bike has been sat for long periods in the garage and the weight of your bike, on flat/low pressure tyres can damage the sidewall. Sometimes, this cracking, damage, arises simply because of ageing (see the image below).

Is there anything you can do to prolong the life of your tyres?

  1. Regularly check your tyres at least monthly and inflate them as necessary – see our previous blog on how to do this: http://www.havebike.co.uk/news/post.php?s=2017-06-12-pumping-up-your-tyres-the-basics-updated-for-the-summer
  2. Avoid locking up your rear brakes/skidding on your rear tyre by applying your front and rear brakes evenly when coming to a stop – remember skids cost quids!
  3. If you are not going to use your bike for long periods of time, you should hang your bike to avoid the weight of your bike sitting on under inflated tyres. This will help prevent sidewall damage.
  4. Choose an appropriate tyre dependant on use – if you are commuting on a daily basis, you should opt for a more hardwearing tyre with built in puncture protection rather than a lightweight performance tyre designed for racing.

We hope you found this useful. Please do feel free to share it amongst your friends and/or on social media.

Best wishes and happy cycling!

The havebike team

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