Mountain Bike Glossary

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[edit] Tyre Compounds And How To Understand Them

Considering the multiple threads recently, I have decided to write this article on tyre compounds in relation to each other.

As well as tread pattern and width, an important thing one must pay attention to when selecting a tyre is the DUROMETER. This will appear as a two digit number, somewhere on the tyre's sidewall - accompanied by a small letter 'a', which just means that it falls within the softest group of plastic compounds. More info on the durometer device itself can be found here: http://www.matweb.com/reference/shore-hardness.asp

Now, the higher this number, the higher the durometer and therefore the harder the rubber compound. Hence 40a (Slow Reezay if you are using Maxxis) is softer than 42a (Super Tacky, Maxxis again) and 60a (again with Maxxis, Maxxpro).

Other companies use different names for their compounds, but it is the durometer reading you need to compare them, rather than their fancy marketing spiel. For example, the Marzocchi (and in fact, most Nokian tyres) are advertised as 55a, placing them in between Maxxis' Super Tackys and Maxxpro compounds.

Now as a general rule, the softer the tyre compound, the faster it should wear, but the more it will grip - as always, a compromise. Again, this means that 40a should grip better than 42a, with all other variables being equal - but of course, there are many other variables to consider... tread pattern, tyre wear, riding surface, weather conditions.

Anyway, I hope this article has been of some help.

-Tim

[edited by Dicky]

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