Black, round and very important

Tyres matter… especially at the TT

While the Isle of Man TT is undoubtedly a race of man and machine, neither bikes nor riders would be out on course without tyres to help them get around not just quickly, but safely too. TT tyres are designed especially to cope with the stresses of this unique event, so we thought we’d take a look at what they’re all about.

Just as Entire Cover is the official insurance partner of the Isle of Man TT races, Metzeler is the official tyre partner of the event. That means that as well as providing rubber to the racers (although they’re free to use whichever brand of tyres they want) like us, Metzeler will be at the heart of the event.

You’ll find them in the paddock area, with some cool activities and photo ops for fans on their stand, as well as on the track and (they hope) on the podium as well. Like us, they’re sponsoring one of the Supertwin TTs (the Metzeler Supertwin TT Race 1 takes place on Tuesday June 3 while the Entire Cover Insurance Supertwin TT Race 2 is flagged off on Friday June 7), so we thought who better to speak to about rubber than our supertwin buddies?

Metzeler take some 1400 tyres to the TT, along with dozens of staff and several trucks – creating a kind of village in the paddock, which is a hive of activity as mechanics (and sometimes riders themselves) bring wheels with worn out tyres along to be fitted with new rubber.

The teams remove the wheels from the bikes and take them along to the Metzeler truck in small carts. The competitor’s name and number is chalked on the tyre, as well as if the tyre should be kept or not. Teams will often keep their old tyres, either to use in practice sessions or to sell to track day enthusiasts as second hand tyres, or ‘scrubs’ as they are known, so they’ll collect the old ones when they go to pick up their freshly reshod rims.

Metzeler’s fitters remove the old tyres, fit new ones and balance the wheels, although the team mechanics refit the wheels to the motorbike and set the tyre pressures.

Because all riding at the TT is carried out in dry conditions, there’s no need to stock wet weather tyres. All tyres are smooth slicks, which don’t have any tread in order to get as much rubber on the road as possible. This gives maximum grip and feel. There are different widths of rear tyres, the 1000cc superbikes and superstockers use wide tyres, while the less powerful supersport and supertwin machines utilise narrower rears.

Despite all being black and round, there are different specification tyres to choose from, which come from differing rubber compounds and the internal steel construction. These give different levels of grip, feel and longevity, but all have to withstand the unique challenges of the TT course, where races are longer and faster than on the short circuits.

Front and rear tyres have to last the full race in the shorter three and four lap supertwin and supersport races, but in the six-lap superbike TTs the top riders generally change the rear at the two refuelling stops. Privateer riders usually do the full 220+ mile race on just one set of tyres, for reasons of cost, and they’ll usually choose the more durable options (which trade outright grip for greater endurance). More well healed teams can go for the grippier rear tyres, but change them after 75 miles when they come in to pit.

The TT is unique, with very high speeds (up to 200mph) and long races. The tyres are constructed like the opposite of your favourite chocolates, being hard in the middle and soft on the outside. The soft shoulders of the tyre give good grip and feedback to the rider when leaned over, while the hard centre is needed to cope with the extreme temperatures generated by the speeds.

Tyres get as hot as 95°C during a race and as much importance is placed on making sure the tyre delivers maximum safety as much as it does grip. The consequences of a tyre flying apart at 200mph do not bear thinking about. There’s a lot of clever engineering involved, and what’s learned at the TT goes into the next generation of street tyres we’ll be riding.

Metzeler are not the only tyre brand you’ll see at the TT. Dunlop is the other supplier in the solo classes and both companies have won in recent years. In the sidecar class, the outfits use their own unique tyres with American company Hoosier being a new manufacturer for this year.