Isle of Man TT 2025: What classes of bike will be racing?

The 2025 Isle of Man TT will run from 26 May to 7 June. Here are all the classes of bike racing in this year’s event.

For two weeks this year from the end of May through to 7 June, the Isle of Man will come alive with the sound of various different types of racing machines.

Officially, five classes will take part in the 2025 Isle of Man TT: four solo classes for motorcycles and the Sidecar class.

Each class will feature two races for a total of 10 contests.

Here are all the classes competing at the 2025 Isle of Man TT

Superbike

The Superbikes are the most powerful class of bikes racing at the 2025 Isle of Man TT. Unlike the other classes at the event, the two races for these bikes are labelled slightly differently.

The first race for the class is the Superbike TT, while the second is the Senior TT. The latter is the main race of the event and is the last one on the bill.

Superbike races are open to bikes derived from production models, with the class mainly entered by 1000cc machines that produce over 200bhp.

There are exceptions to the Superbike regulations, though this is at the discretion of the organisers. For example, in recent years we’ve seen the Honda RC213V-S raced and a two-stroke 500cc Suter take part in the class.

Slick tyres are used in the class.

The Superbike races are run over six laps, which equates to 226.38 miles. There are two pitstops scheduled in both races for the ends of lap two and four.

The lap record for the Superbike class is 135.970mph, set by Michael Dunlop in 2024.

Supersport

The Supersport class is one of the most competitive at the Isle of Man TT, with two races scheduled for 2025.

These will be run over four laps, with the opening Supersport race the first contest of race week at TT 2025. Where the Superbike TT used to open up race proceedings, the expanded schedule introduced in 2023 saw Supersport 1 positioned as the first race of the week.

The class was typically for 600cc four cylinder machines and three cylinder 675cc bikes. However, next-gen Supersport rules brought in after the COVID pandemic have opened up the class to a broader range of bikes.

Last year, the Ducati Panigale V2 made its way onto the grid in the hands of Davey Todd and made it to the podium twice. More riders will run that bike in the class in 2025.

Michael Dunlop holds the lap record in the Supersport class at 130.403mph, set on a 600cc Honda in 2023.

The four-lap races feature one pitstop at the end of lap two.

Where previously treaded tyres were mandated for the Supersport class, in 2023 slicks were permitted.

Supertwin

The newest class at the Isle of Man TT, introduced in 2012, the Supertwin class has come on leaps and bounds since its inception and has drawn a healthy entry list for 2025.

The idea behind the Supertwin class was to offer a more affordable platform for riders to enter under, though serious money has to be thrown at a package now if you have any hope of being competitive.

The bikes used are, as the name might suggest, twin cylinder machines, with a displacement of 700cc derived from road going engines. The booming twins produce around 90bhp, with the lap record standing at 122.750mph set by Michael Dunlop in 2018 on a Paton.

The class used to feature only once on the race bill, but expanded to two for 2023.

These are run over three laps, with a mandatory fuel stop set for the end of the opening tour. Slick tyres are permitted for the Supertwin class.

Superstock

The Superstock class is up there in terms of power with the Superbikes, with very little these days to actually distinguish these 1000cc machines.

As the name suggests, these are stock motorcycles run to strict technical regulations: effectively, these are Superbikes wheeled off the showroom floor and tweaked minimally to withstand the rigours of the 37.75-mile Mountain Course.

They don’t have all the bells and whistles a Superbike class machine does, with engine, frame and electronics standard production parts.

But such is the level of Superstock machinery now, the fastest lap in the class is also the outright lap record at the Isle of Man TT. That belongs to Peter Hickman, who put in a 136.358mph lap in 2023.

A lot of riders enter their Superstock bikes into the Superbike races if they can’t afford a full-blown Superbike-spec machine or if they’ve encountered any issues on their Superbike.

The Superstock races are run over three laps, with a mandated pitstop involved. As of 2023, there have been two Superstock races on the Isle of Man. Slick tyres are permitted for the Superstock class.

While Superbikes and Superstock machines look the same, the latter is easily identified by the red number background on the front of the bike.

Sidecar

Arguably the most jaw-dropping class of machinery at the Isle of Man TT, the Sidecars are the only non-two-wheel races at the event.

The three-wheelers are piloted by two competitors: one is the driver, while their passenger sits in a section of the machine to their left and is responsible for keeping traction and helping the outfit turn.

The machines are either powered by 600cc four cylinder engines, 675cc three cylinder engines or 900cc parallel twin engines.

There are two races for the Sidecars run over three laps, and neither of these contests feature pitstops.

The lap record for the Sidecar class is 120.645mph. Slick tyres are used in the class. For 2025, the usual top 10 seeded starters order has been replaced by a qualifying-based ‘grid’.