What we learned from the first DTM/SUPER GT joint-race

After seven years of exasperating talk of Class One regulations, punctuated by a demonstration by SUPER GT at Hockenheim in 2017, the DTM and the Japanese series finally achieved the goal of having the two series go head-to-head on a racetrack.

But this was never going to be a true clash of Germany versus Japan at Hockenheim last weekend. Put simply, there were just far too many unknowns to make this a realistic contest at the very first attempt.

Instead, next month's 'SUPER GT x DTM Dream Race' at Fuji will act as the true unifying of the two series after what amounted to a 'fact-finding mission' for Honda - led by 2009 Formula 1 world champion Jenson Button - and Lexus and Nissan last weekend.

Button starred by qualifying sixth on Saturday in changeable conditions and battled back to ninth after a slow pitstop, while TOM'S Lexus pair Nick Cassidy and Ryo Hirakawa and NISMO-Nissan's Ronnie Quintarelli and Tsugio Matsuda struggled to overcome the learning curve.

But as the three Japanese teams head back home to complete their SUPER GT seasons and prepare for Fuji - Button aside, as he will not compete in the 'Dream Race' - there was enough evidence from Hockenheim to indicate how the real head-to-head will work.

Equalisation remains murky

Simply put, chucking a high-tech endurance car pushed to the limits by development wars and an advanced touring car fitted with a large number of common parts onto a track and expecting a true duel would be foolish in the extreme.

DTM and SUPER GT knew this, which is why - despite the DTM's well-known dislike of it - a Balance of Performance was expected.

But rather than force a BoP base, the idea was that SUPER GT's two hours of testing on Thursday would set a baseline that could then be tweaked through the weekend accordingly.

With no data being made public, Autosport took to the Sachskurve with a stopwatch and roughly worked out the pace of SUPER GT cars to be as low as a 1m29s lap and as high as a 1m35s tour.

But it was visual observations that proved most telling, with the three cars - the NISMO-run Nissan in particular - running at such a low ride height that taking the DTM line over kerbs would dramatically unsettle the car.

The late-braking of a SUPER GT car was a sight to behold but, despite more advanced aerodynamics than a DTM machine, the cars were a handful mid-corner on flying laps, contributing to times well off BMW driver Philipp Eng's pole position of 1m28.972s in dry conditions at the series' May Hockenheim visit.

The pace was also affected by mixed conditions in which the three SUPER GT cars drove on a track that cycled between dry, damp and mildly wet.

One of the highlights of the weekend was Button's continued eloquence in giving detailed answers on the differences between SUPER GT and DTM at a weekend where everyone entered somewhat blind

SUPER GT and DTM met last Thursday evening to discuss BoP and rightly decided not to enforce it considering all the outside factors hindering SUPER GT's preparations.

Autosport understands that SUPER GT did not push for a BoP that would allow it to go head-to-head with the DTM, instead focusing on learning the DTM's format and remaining out of influencing the DTM finale - though almost all meaningful titles had already been decided.

But the DTM and SUPER GT only have limited relevant data - from the weekend's odd spells of dry running - to work from for Fuji. When it comes to what will be the true head-to-head race, DTM technical partner DEKRA must get BoP right to avoid the celebration of Class One becoming a damp squib.

Differences between SUPER GT and DTM clearer than ever

One of the highlights of the weekend was Button's continued eloquence in giving detailed answers on the differences between SUPER GT and DTM during a weekend everyone entered somewhat blind.

Button was in a unique position in that he was the only SUPER GT driver competing in all sessions - as opposed to the two-driver entries from Nissan and Lexus - while his Honda is also the only mid-engined car in the field.

"The way the cars work are very different," he explained. "When they're not using DRS we have a bit more speed, but it's not as much as I thought. Braking with us is very strong, we're very good at braking. But it's the lateral loads, the traction, which we really struggle with.

"These guys [DTM] look like they're just planting their foot and it's just really good grip when laterally loaded, whereas for us when we touch the throttle it immediately goes to snap-oversteer, and I think that was some of our problems in the wet as well.

"So that's a big weakness for us, and it makes it very difficult to get on the power for that long straight down to Turn 6. And the high-speed corners as well.

"They're able to put the car places we can't really go because we can't get there. The car feels a bit lazy, and also I think we're running it a bit too low. So if we do get there we hit the kerb and we take off."

Where Button also proved fascinating was explaining how the Hockenheim weekend had sent the SUPER GT crews in set-up directions they had never needed to try in their own series.

SUPER GT's tyre war - as intense as Honda having three different specs of wet tyre available to it - means that mechanical set-up work is limited as the bigger gains come from optimising the series' specialised tyres. This wasn't possible with the spec Hankook DTM tyre, meaning elements such as ride-height were having to be considered as the Japanese teams tried to counter oversteer.

But while that situation pushed SUPER GT outside of its comfort zone, Button was adamant it could help the teams in their series.

"We've taken away so much really. In terms of set-up, we've done more set-up work than the whole SUPER GT season," said Button.

"But also, when you look at the driveability, these guys are running over kerbs and able to get on the power. They get oversteer, but it looks like you can hold onto it. With us, it's a sudden snap.

"There's a lot to look at with driveability of the power unit, which I think is quite exciting.

"We have so much grip on corner exits that we don't normally feather the throttle, we just plant it and it grips up and we can go. It's very different.

"So yeah, a lot of learning and I think it really helps the SUPER GT teams that are here for the future, racing in Japan. Helps them understand the power and areas we don't really delve into."

The mountains SUPER GT teams faced

One of the biggest talking points heading into the weekend was how the DTM and SUPER GT machines would match up, beyond a widely-held belief that the SUPER GT teams running without their tyre-war-developed compounds in favour of the DTMs spec-Hankook tyre would be a significant limiting factor.

Hockenheim was the first chance to grill both Berger and his SUPER GT counterpart Masaaki Bandoh over the next steps for Class One. The message? Mixed

Other theories suggested that the aerodynamics of SUPER GT cars would make them a fearsome proposition on the straights.

Even as late as SUPER GT testing, those observing had mooted to Autosport that the SUPER GT teams were struggling with oversteer but that their race pace had looked promising.

But two things proved decisive in relegating SUPER GT to the rear of the field - Button heroics aside - and it was the expected tyre deficit, but also the DTM's format.

Looking at it chronologically, the challenges were: getting the DTM Hankook tyre up to temperature for two flying runs in qualifying, taking a standing start for the first time in a SUPER GT car, completing a pitstop for tyre changes in 10 seconds - rather than 40s to change tyres, driver and refuel as happens in SUPER GT - and undertaking an Indianapolis-style double-file restart following a safety car.

In short, it was alien to the SUPER GT crews, but there was also the culture shock of wheelbanging, which Button explained was frowned upon in SUPER GT after clashing repeatedly with BMW's Sheldon van der Linde.

If the contact was surprising, so was the impact of the DTM's DRS and push-to-pass that effectively neutralised the SUPER GT cars' straightline speed advantage.

Flashpoints such as Nick Cassidy's crash in the finale after tagging WRT Audi's Jonathan Aberdein, Button's Kunimitsu Honda squad's disastrous 17.9s pitstops on Saturday and practice offs for Cassidy's TOM's Lexus and Tsugio Matsuda's Nissan will hopefully be resigned to the past at Fuji.

But will the DTM come out on top at Fuji?

The DTM had a clear advantage at Hockenheim, but a change of venue to Fuji and a reduced and revised line-up for the DTM throws up question marks.

BMW has deliberately chosen to focus on a line-up that would capture the imagination of the local market by signing Alex Zanardi - ahead of his attempt to qualify for the paracycling competitions at the 2020 Paralympic Games in Tokyo - and Toyota World Endurance Championship driver Kamui Kobayashi. The total of their DTM experience is Zanardi's guest outing at Misano last year in a 2018-spec DTM car. Their team-mate Marco Wittmann obviously has no shortage of DTM experience and will be expected to lead the charge.

Audi can at least count on two-time DTM champion Rene Rast, Mike Rockenfeller and SUPER GT veteran Loic Duval, making up for three-time Le Mans 24 Hours winner Benoit Treluyer's lack of proper DTM experience as he has just been Audi's reserve driver.

The 'dream race' will again use the DTM format but, although the SUPER GT rolling start will be used instead of the DTM's standing start, Fuji will throw up new challenges for the DTM line-up.

Button, who will not race at Fuji, was asked if he had any advice he could share with the Fuji DTM drivers.

"I don't really want to tell them anything! They're way too fast! But I'm not racing, so I will," he joked, before adding: "It's a lot bumpier [at Fuji] than here. This is a very smooth circuit.

"For us, racing in Japan, the cars bounce around a lot more. I think it's a similar circuit, there aren't corners like Turn 1 [at Hockenheim] where you can really run off and over the kerbs because there's big sausage kerbs there. We'll keep these guys on the track and we'll drive the same circuit - which is nice!

"But they'll find themselves changing the balance a little bit of the car to suit the circuit. Still running on their tyres, so it should be really interesting and I'm looking forward to watching it."

What's the next step for Class One post-Fuji?

Autosport has been critical of the fact Class One does not appear to have one large long-term goal, with DTM boss Gerhard Berger repeatedly playing down the most obvious idea of a 'world championship', sensibly pointing to the fact that previous series along those lines - such as the pre-WTCR World Touring Car Championship and the DTM's own 1990s International Touring Car Championship - proved unsustainable.

But Hockenheim was the first chance to grill both Berger and his SUPER GT counterpart Masaaki Bandoh - through a translator - over the next steps for Class One. The message? Mixed.

Bandoh spoke of a "World Cup" dream, without going into specifics, while Berger said the "final goal has to be to do more and more races together" but that he "would like to build it on very solid ground and not do too many things too fast".

Autosport has been told that IMSA SportsCar Championship personnel have visited the DTM, doing so at the Nurburgring last month, with interest in both the Class One regulations and the DTM's plan to go to hybrid power within the next decade.

Asked by Autosport if there were plans to expand Class One, Bandoh said: "We have to talk about the topic, like how we can achieve much more manufacturers and how we can get the costs down. This is the first big step for us.

"In the future, we would like to think on a global level and we can achieve more manufacturers from all over the world."

There is no sign of clarity soon, but post-Fuji there must become a clearer plan if both series intend on growing their manufacturer presence and using their joint rules vision to help their teams expand into other series.