What is the Isle of Man TT? Explaining the classes and schedule

It's almost time for the world's most iconic road racing event: The Isle of Man TT.

Set on the picturesque island in the Irish Sea and taking place on the 37.73-mile Snaefell Mountain Course, the track is one of the most challenging in motorsport.

Four classes of motorcycle are used in the event, with more than 100 riders competing across six days of racing.

This year's TT starts on May 26, with five qualifying sessions during the first week before six days of racing between May 31 and June 7.

We'll be covering the TT build-up and event itself extensively on The Race and in The Race Members' Club this year - including exclusive podcasts with key players

Isle of Man TT history

The event was first held in 1907 over the Isle of Man St John's Short Course, before moving to the Mountain Course in 1911. With the exception of the duration of both World Wars, the 2001 foot-and-mouth outbreak and the two years of the COVID pandemic, the event has taken place every year since.

The course starts at the main grandstand on Glencrutchery Road in Douglas, the island's main town, before heading off along public roads towards Peel in the north.

Competitors then follow the main road through the villages of Kirk Michael, Ballaugh and Sulby before heading out onto the mountain.

After reaching the course's highest point at Hailwood's Height, riders descend into Ramsey before following the road back along to the start line.

Michael Dunlop has taken the most wins, with 29, after eclipsing his uncle Joey's longstanding record of 26 last year. John McGuinness is in third with 23 victories.

Racing the clock

Unlike in many motorsport events, at the TT, riders are not racing each other: they're racing the clock.

The time trial format involves riders leaving the startline at 10-second intervals, aiming to set the quickest time across the lap, rather than departing at the same time as in short-circuit racing.

The rider with the quickest time across the race wins.

Which classes race at the Isle of Man TT?

The TT races are split into four classes, with varying engine sizes.

Superbike: The "big bikes". Quick and powerful, with 1000cc engines and over 200bhp. Similar to the specification used in the Superbike World Championship, but without the performance balancing. For the TT, these bikes are equipped with an expanded 24-litre fuel tank and quick release equipment on the wheels which allows for pitstops.

Supersport: These bikes are lighter and less powerful than the Superbikes, with a mix of 600cc four-cylinder and 675cc three-cylinder bikes.

Supertwin: Twin-cylinder 700cc machines.

Sidecar: Double trouble - sidecars feature a driver and a passenger, one alongside each other. They must work together to get the most out of their 600cc four-cylinder, 675cc three-cylinder, or 900cc parallel-twin engines.

How can I watch the TT?

The best way to follow all the action is via TT+'s Live Pass. The official platform shows all the action from practice and race week live.

ITV usually broadcasts daily highlights throughout the two weeks on ITV4 and ITVX.

Full Isle of Man TT 2025 schedule