Announced last week in a major coup for the World Supercross Championship (WSX), Haiden Deegan is poised for a highly-anticipated SX1 debut at the Buenos Aires and Australian GPs, which raises the question – should he just stay on the 450 full-time entering 2026? There’s a bit to unpack.

The proposition is something that’s been on race fans’ minds throughout this year’s SMX World Championship, and gained additional traction when Deegan and Jett Lawrence were dominating their respective divisions in the Pro Motocross Championship.

A match-up between the Monster Energy Yamaha Star Racing rider and the 450 field is intriguing, with Deegan due to make his full-time 450 transition in next year’s Pro Motocross series outdoors. After clinching the western division in 2025, this would allow him another season of 250SX, a chance to perhaps add one more indoor title and a touch more experience.

It’s widely recognized that the Californian’s aggressive riding style translates better outdoors, and the high-speed, grueling races in Pro Motocross are a discipline that even he favors over the more technical stadium racing of Supercross. Therefore, one would say that experience – especially indoors – is the name of the game for the 19-year-old during these formative years of his career.

Image: Octopi Media.

Enter World Supercross. Although initially announced to be starting in the SX2 division, the Deegan camp, along with WSX, came to the agreement that Haiden would line up on the 450 and make his first premier class starts during his wildcard appearances this year in Argentina and on the Gold Coast.

This is a win-win for each party. WSX will get the eyeballs – because everyone has been waiting for this moment – and Deegan will get experience in a low-pressure, low-expectation environment, which is critical in Supercross development, even for a rider with the pedigree of Haiden.

WSX isn’t seen as the premier race series for Deegan or any of Supercross’ top contenders in the United States – that position remains firmly with SMX. What this means is he can race these events, without the narrative emerging of ‘Why didn’t you beat such-and-such?’ and ‘Are you as good as Jett Lawrence?’, and so-forth.

Deegan can gauge his speed against riders like Ken Roczen, Jason Anderson, Justin Cooper, and Eli Tomac, before reverting to his more familiar YZ250F for either region of 250SX, where another run on the smaller motorcycle will ensure he gets as much experience as he can before making a full-fledged, Monster Energy Supercross 450SX assault.

Image: Octopi Media.

So, to answer the question, should Deegan stay on the 450 full-time, beyond this initial WSX transition? No, I don’t think he should, because I believe that he should instead use these races as tryouts to gain information and – that term again – experience, before making a full-time transfer for the 2026 Pro Motocross series as previously intended.

In fact, I’d support any rider preparing to make the transition to start with Pro Motocross, as we saw with Jett, as well as the likes of RJ Hampshire do in recent seasons. It allows riders to learn the 450 class – the riders, the intensity – without the amplified chaos of Supercross, as well as providing a little more margin for error.

This can be a net positive from a confidence angle, knowing that you have been on the 450 grid, which takes the edge off the nerves when the lights are on in Anaheim the following January.

One final piece of the puzzle could be that Deegan contests select 450 races during Supercross next year, in between his title commitments on the 250. This is a possibility that we have seen done a number of times before, and another opportunity for invaluable experience. There’s also the possibility that he rides A1 – and the opening west coast rounds – in 450SX, before deciding to revert back to 250SX once the series goes east.

Image: Octopi Media.

Regardless, what we are set to see is the young prodigy equipped with an extra 200cc’s worth of power come both the Argentine and Aussie World Supercross rounds, which is a massive moment for him, the promoters, and the sport as a whole, as we look to see how the polarizing teenager fares equipped with the YZ450F.

It’ll be no walk in the park, either, with the aforementioned Roczen, Anderson, and Cooper trio headlining Argentina, while multi-time 450SX champion Tomac will also be on hand in Australia among a who’s who of well-credentialed WSX regulars, giving Deegan plenty of competition to cut his teeth against.

For a full-time American debut, though, let’s leave this for next year’s Pro Motocross Championship, meaning we’d have to wait to see him behind the gates in 450 Supercross come Anaheim 1 in 2027. Time will tell.