Isle of Man TT Sidecars will return in 2027 with major rule changes
Sidecars will return to the Isle of Man TT in 2027, but the class is getting a major overhaul after its 2026 suspension.
The Isle of Man TT’s Sidecar class will return in 2027, following a major overhaul of the technical regulations designed to make the category safer, more sustainable and more competitive.
The announcement comes just over two months after Sidecar racing was suspended for the remainder of the 2026 TT following a serious qualifying crash involving Ryan and Callum Crowe at Rhencullen.
That suspension triggered a Sidecar Sustainability Review, with the first stage concluding that there was a credible route for the class to return, but only if significant changes were made to the way the machines and races were run.
We now know what that return will look like.
The TT has committed to running Sidecars for three years from 2027 to 2029, with two races scheduled at each event. The 2027 races will both be two laps of the Mountain Course, with the distances for 2028 and 2029 set to be reviewed once organisers have seen how the new format and machinery perform.
The biggest change to the class is taking place within the engine casings.
Goodbye 600cc four-cylinder engines
The traditional 600cc four-cylinder engine formula will be replaced by a production-derived framework based around modern middleweight motorcycles.
Eligible engines will include units from bikes such as the Yamaha R7, Aprilia RS660 and Kawasaki Ninja 650, with other engines potentially eligible under the new regulations.
The move is intended to address two problems with the old formula. The 600cc four-cylinder supersport class is becoming increasingly difficult to source, while development costs can give better-funded Sidecar teams a significant performance advantage.
The new rules will also introduce controlled electronics using a common Mectronik ECU platform, allowing the TT Technical Director to have greater control over the performance of the outfits.
A Balance of Performance system will also be introduced, with the aim of bringing different engine configurations much closer together in terms of performance.
In other words, the fastest Sidecar should be determined less by who has spent the most money developing an engine. Well, that's the theory, anyway.
The TT says the intention is to put more emphasis on chassis set-up, preparation and the driver and passenger rather than outright engine performance.
The chassis rules are changing too
Existing Sidecar chassis designs will remain eligible, meaning teams won't be forced to build completely new outfits around a single approved chassis.
However, there will be tighter requirements covering chassis construction, identification, modification, repair and inspection.
The bodywork rules are also being tightened, with clearer restrictions around floors, undertrays, wheel arches and aerodynamic devices. Separate wings, aerofoils, fins and spoilers will be banned.
The changes are intended to limit the amount of aerodynamic development while also improving structural integrity and making the machines easier to inspect and access in the event of an incident.
There will also be further requirements covering minimum weight, fluid containment and general machine safety.
The sporting regulations are being changed alongside the technical rules. Competitor eligibility and qualification standards will be strengthened, with greater emphasis on recent racing activity, medical fitness and whether riders and passengers are ready for the demands of the Mountain Course.
A cautious return for 2027
The TT is deliberately treating 2027 as the first step rather than the finished version of the new-generation Sidecar formula.
The established qualifying period and Sidecar sessions will remain, but the two shorter races are intended to provide a more controlled return while competitors get used to the new machinery and regulations.
The organisers will then assess the new formula using technical data, incident information, competitor feedback and participation levels before deciding how the class should develop for 2028 and 2029.
That all means the Sidecar class is one hundred per cent coming back, but it won't simply be a case of dusting off the old rulebook and carrying on where 2026 left off.
The decision follows more than 460 submissions received during the Sustainability Review, alongside input from competitors, technical experts and TT officials.
While there was strong support for keeping Sidecars on the TT programme, there was also broad agreement that the class could not simply return under its previous guise.
TT Clerk of the Course Gary Thompson says the aim is to create a formula that can work for the long term.
“The move to the Sportbike engine framework and controlled electronics is a significant change, but it gives us a much greater ability to manage the performance of the class,” said Thompson.
He also pointed to the changing motorcycle market, with the traditional 600cc four-cylinder supersport engine becoming increasingly difficult to base a long-term racing formula around.
The new rules will now be finalised ahead of the publication of the 2027 TT Sidecar Technical Regulations, with further details on entries, sporting regulations and the race schedule to follow.
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Simon (AKA Toad) has been working within the motorcycle industry for more than twelve years, and a member of the motorcyclist family since birth. Growing up around British-built single and twins, it was inevitable that a life on two wheels was on the cards, from a very early age!
