TT Tech changes for 2023


Nothing stands still in the world of motorsport and the Isle of Man Races are no different. Team and rider changes typically grab the headlines, but the bikes they use and the specifications they run to also change, as the rulebook – officially known as the Technical Regulations – evolve year on year.

This year is no different, so we caught up with Dave Hagen – the TT’s Technical Director – to talk through the changes coming for TT 2023.

Working for the Race Organiser under Clerk of the Course Gary Thompson, Dave is responsible for the Technical Regulations across all classes at the TT. He’s spent his entire professional career working at the top level of motorsport, including overseeing operations at Crescent Suzuki when they took on official Suzuki support and progressed up to a World Championship outfit.

His first experience at the TT was in 2004 as Crew Chief to John McGuinness and Jason Griffiths, with John taking his first ever ‘big bike’ win that year. Dave’s been in the role of Technical Director since 2017 and, in his own dry sense of humour, explains that he’s “not managed to get sacked yet, and must try harder…”


The headline change to the regulations for TT 2023 is that slick tyres will be permitted in all the solo classes.

Road-legal treaded tyres have had to be used in the Supersport and Superstock classes for many years, and the Supertwin class has mandated their use since it was introduced in 2012. However, decisions affecting production from some of the tyre manufacturers as well as changes to the regulations at World Championship and British Championship level mean that the three categories will be able to use slick tyres for the first time.

Dave explained the decision-making process:

“Dunlop and Metzeler are the two brands used by almost everyone at the TT, both for slicks and treaded tyres. The treaded tyres used across Superstock and Supersport racing are a road-legal tyre, so they have to be DOT homologated for regular highway use. That’s an expensive and timely process for tyre manufacturers to go through, particularly when you consider that these tyres will then almost exclusively be used for racing.”

“Understandably, Metzeler have made the decision to focus development on their slick tyre range for road racing activities, bringing it into line with the transition to slick tyres that is being mandated in all major series around the world. Their treaded tyres will still be available but as with all things in racing, tyres are constantly being developed and, in time we would have effectively been left with just one supplier to these classes. Ultimately it’s a manufacturer decision with the rules then changing to follow.” 

Treaded tyres might become a distant memory now that slicks are permitted in all solo classes.

With the change to slick tyres also coming in to the British Championship classes, it means there is parity for competitors across short-circuit racing and the TT. But will the change result in lap records tumbling?

“You might expect there to be some performance gains on track, but the TT isn’t quite as tyre critical for either wear or ultimate edge grip, so I don’t anticipate a marked increase on lap speeds, but we’ll see.”


Tightening emissions criteria have seen some manufacturers buck the trend of building 1000cc sportsbikes, increasing to as much as 1100cc in efforts to meet regulations without sacrificing performance. As a result, these bikes – namely the Aprilia RSV4 and the Ducati Panigale V4 – have been ineligible to compete in the Superstock class which has had a fixed capacity limit of 1000cc for 4-cylinder machines

In line with changes to the regulations in the British Superstock Championship, the rules for 2023 have been opened up to allow these larger-capacity bikes to compete, provided that they are equipped with a control ECU to ensure balanced performance, as Dave explained:

“We want to align with the national championship regulations, both so that we can open the class up to allow other manufacturers in, but also to ensure the same specification of bike can be run at both events without modification and associated cost.”

“It’s all done by the ECU. This year, bikes can use the standard ECU, a flashed ECU (manufacturer-developed reprogramming of standard unit), a KIT ECU (manufacturer-developed unit specifically for racing), and now the standardised Motec ECU with the British Superstock Firmware.”

Any machines over 1000cc have to use the Motec unit, but it’s anticipated that some competitors using 1000cc machines may also opt to use the system:

“There isn’t an ultimate performance difference between the Motec unit and a flashed or KIT ECU, but it does allow for more control over certain elements which some teams may look use; engine braking control for example”

There are, however, a number of areas where the TT regulations will differ from the British Championship rules given the unique challenges of the TT:

“Usually, Superstock bikes have to use standard, OEM parts such as the screen and fuel tanks. The sustained high speeds at the TT mean the riders need better protection from the wind so larger screens can be used, and fuel tanks need to be made larger to make sure they can complete two laps of the Course.”

Evolution rather than revolution for the Superstocks, with rule changes affecting the use of ECUs


2022 saw the biggest overhaul of the Supertwin regulations since the class was introduced in 2012. The 650cc capacity limit was increased to 700cc, opening the door to two motorcycles of note: the Yamaha YZF-R7 and the Aprilia RS660.

It was somewhat of an experiment in the first year, with the larger-capacity bikes having to run 10kg heavier. Further changes to the regulations in the following years were anticipated to reach parity of performance, so for 2023 the minimum weight limit for all Supertwins will be 150kg and there are a number of other technical revisions:

“The Yamaha is similar to the Kawasaki in that it’s a platform based on a commuter bike, so their performance in year one was perhaps more predictable. But the Aprilia was more of an unknown quantity as it’s an out and out sportsbike with, essentially, an engine that’s half an RSV4 superbike.”

“These commuter-based bikes are designed for low-end grunt and fuel economy, whilst the Aprilia has strong peak horsepower but lacks in the mid-range – it’s designed to be revved harder. So for TT 2023, the Aprilia will be given an extra 500rpm and allowed to run to its homologated limit of 11,500rpm; the rest of the class will keep the 11,000 limit.”

“The Aprilia will then have to use standard throttle bodies and injectors, but the 650cc bikes can run different or modified throttle bodies and multiple injectors. The Yamaha has the smaller throttle bodies as standard (compared to the Aprilia), but because it has a larger engine capacity we’re only allowing modifications to the standard throttle bodies.”

For Dave and his technical team, developing the class in a balanced but progressive way is somewhat of a challenge:

“We only get one go at this so it may change again [for 2024]. We want to bring other manufacturers up to speed because we want to see competition between Kawasaki, Paton, Aprilia, and Yamaha, so change is unavoidable.”

Tweaks to the Supertwin rules should allow the Aprilia RS660 to catch up to the dominant Patons


2022 also saw revisions to the Supersport class following changes at World and British Championship level and the development of Next Generation regulations.

The middleweight category has almost exclusively featured 600cc 4-cylinder machines for over 30 years, but declining sales have impacted the market to such an extent that only Yamaha and Honda are currently producing new models – albeit as race-only versions.

The Next Generation regulations have seen the category move away from a displacement-based rulebook to a performance-based one, opening up the field to a broader range of bikes in similar sector of the market, and applying rules that ‘level down’ to provide fair racing.

In 2022, only Peter Hickman and his PHR teammates took advantage of the new rules, running the 3-cylinder Triumph ST765RS. But after securing two podium finishes last year, it’s expected that more Next Generation Supersport machines will be on the TT startline this year.

As with the Supertwin class, the regulations are continuing to evolve, but Dave is confident the Next Generation is good for the class:

“Details are still coming out for the World Championship and British Championship this year, so there may be more changes to the 2023 TT regulations as was explained when they were first issued.”

“It’s a difficult nut to crack as to how successful the Next Generation rules would be, but at the World Championship level at least, all manufacturers bar one won races in 2022. Ducati, the one manufacturer that didn’t win a race, were still in the fight for podiums. All that level of competition will eventually transfer to the TT.”

“Levelling down is great for the sport because it brings costs down. These new models are only allowed to be modified for strength and reliability reasons, not performance, so there’s far less stress on the motors. Some can do whole seasons without needing a refresh whereas a tuned 600 might need a rebuild after a couple of rounds.”

Peter Hickman championed the Next Generation of Supersport machines in 2022. Will we see more on the grid this year?


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