Castle Combe was the venue for Avon Tyres to let me try their new 3D Ultra Sport and 3D Storm X-M (Extra Mileage) tyres. It was actually my fourth visit to the track, and the second in May. Having said that, I’m actually a fairly slow and careful rider on the road.
After arriving to the usual handshakes and introductions we were dragged off for breakfast while the new tyres were fitted. I’m pretty familiar with the Castle Combe safety briefing, which mainly features Quarry. Not surprising as 25% of UK circuit accidents are attributed to it, with the adverse camber on the next chicane. So it makes sense to take care till your tyres warm up, and take it easy for the first two laps.
Taking to the track, the first two laps were following the leader. Quarry was uneventful, but the first chicane with cold tyres gave a little sideways moment to wake me up after the briefing!
Two laps down and it was time to pick the speed up and see what these tyres could do. The other testers were flying, and made me think I had stopped. After my track session, Avon reckons I have 5-6,000 miles left on the tyres they fitted on my ’99 Fireblade.
Over lunch I was talking to the tyre developer, and asked ‘how do you come up with the tyre tread patterns’?
Tread exists to clear water but causes uneven wear, so you have to compromise. A good pattern for clearing water will fail when the tyre wear starts. To get good, even, wear on the tyre, the tread groves need to be in the same direction as the forces on the tyre, which varies depending on what the tyre is doing. When upright in a straight line the tread grooves are round the circumference of the tyre. When you are banked right over in a corner the forces on the tyre are now across the tyre. This is why your tyre tread has a nice curve from the middle of the tyre to the edge. Avon took one pair of slicks and cut fan shapes all over the tyre to see how the tyre wears round the cuts.
Avon have taken this one stage further and added some snow tyre tech, in the form of Sipes. Sipes are cuts in the tyre to speed up the heating process, 3D Sipes have interlocking teeth to control the amount of heat generated as straight cuts will cause the tyre to overheat. Silica for the wet and 3 different angles to give a larger footprint on the road at all lean angles.
The 3D X-M also has different compounds so that the middle is a harder compound to the edges giving a longer life to the tyre. Avon says you can expect at least 20% longer life.
The afternoon was spent on the 3D Storm X-M which isn’t available for the Fireblade (16” front wheel), so they said you will have to use our bikes. Well, I thought take it easy, these are touring tyres for big heavy machines. Having started out carefully and getting overtaken, I was starting to get used to the tyres and moved up a gear. The Storms took it and I felt firmly attached to the track. I am going to get a pair of these for my ‘big heavy’ blackbird! With a tyre life of over 10K miles, sounds good to me.