However, like most tyre based guides, the nature of the subject is quite complete, so it’s not as easy as saying this causes that, or that causes this (especially when talking about suspension adjustment) so please take this as being a somewhat simplified guide to motorcycle tyre wear, not the definitive resource. When the tyre is overinflated the contact patch on the ground is too small so it cannot generate heat that is widespread enough to bring the carcass of the tyre up to operating temperature.Instead what happens is the surface of the tyre super heats very quickly while the carcass stays below operating temperature, so the surface of the tyre is ripped straight off.What happens in this instance is that when you start to turn the bike into a corner, because of the excessive weight on the front it will actually plough across the ground (rather than rolling), and it’s only when you have finished turning the bike and you get back on the gas that you take the weight away from the front end and the tyre is relieved.As well as having too much weight on the front, this type of tear can often be caused by the front end being too soft in conjunction with too much weight.You often see the question come up ‘why are my tyres blue’ or ‘what’s this blue stuff on my tyres’ with people suggesting that when you see it the tyres are done. – After the tyres have been used to the point where they gain significant heat, when they cool down again (this is one heat cycle) the oils in the tyre will often come to the surface.When you go back out and ride the bike these surface oils are scrubbed off and it’s only when you come back in and let the tyres cool down again that you’ll see more oils coming to the surface.
This means it cannot get proper grip or traction and as a result the front tyre pushes and drags across the ground when the rider gets on the throttle, rather than rolling over it as it should.
Also, it will typically be uniform all the way around the tyre.
Too much weight on the front – As the above heading would suggest, the other type of geometry tear is too much weight on the front.
– If you have a raised area on either the leading or back edge of the tread, this is a strong sign that rebound damping on the forks or shock is set either too fast or too slow.
Usually if it’s on the leading edge rebound is too slow, and if it’s on the back edge it’s too fast.
In this guide I have gone over some of the different types of tyre wear that you can expect to find on track day tyres around the circuit paddock.