Does HKS’s New Tsukuba Record Count?

For me, Tsukuba is, and always will be, the benchmark for time attack.

For years, we’ve watched on from afar as the times fell. Over 10 years ago, a 55-second lap was breathtaking. Today, we’re talking about the HKS TRB-03 setting a barely believable 49.445-second lap around the 2.0km-long circuit in the Ibaraki Prefecture of Japan. A new lap record, but is it one that we should recognise?

Despite the incredible performance developments that time attack cars have made over the years – both from a power and aerodynamic perspective – there was always one thing that kept the playing field level, and that was the tyres. ‘Was’ being the operative word here.

With news of HKS’s new Tsukuba record, also came mumblings of the lap time being set on slicks, and not the traditional semi-slick (and street legal) tyres used by time attack competitors the world over. For a lot of us, this raises a question about the legitimacy of the lap time.


There’s absolutely no doubt that the HKS TRB-03 is an incredible piece of machinery, as Dino has documented since it was unveiled early last year as the HKS GTS800. Nobody is taking that away from HKS or saying otherwise. However, the rumoured use of a slick tyre would – for me – completely invalidate that sub-50-second lap time. For comparison’s sake, Under Suzuki ran a 50.366 lap in December of last year in the Scorch Racing S15, 0.9 of a single second slower than the time set this week by HKS, while on semi-slicks. Any reasonable person would judge that time difference to solely be down to the choice of rubber, and some might even question why the difference isn’t larger.

Again, in December, the TRB-03 did run 50.259 at Tsukuba on semi-slicks, which almost begs the question why did they – allegedly – move to slicks when a sub-50 was within touching distance on semi-slicks?

It’s an interesting situation and I can’t wait to see how Under Suzuki and others respond to it. In the interest of balance, with cars so far removed from their original form, maybe it is time that time attack went to slicks and that we accept the change?

One thing is certain, the battle for supremacy at Tsukuba just got a whole lot more interesting.

Paddy McGrath
Instagram: pmcgphotos
Twitter: pmcgphotos



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Was there ever a rule against using slicks? whether competitors were using them or not.


I've always thought it was a gentlemen's agreement when outside of specific events that enforce tyre regulations.


Gentlemen's agreement...LOL


I thought the tires were the 'control' aspect of time attack? Or is that more so just the different events put on have a control tire?


In official TA events the tyres are controlled. As this was HKS just going out to attempt to set a best lap there's no official control. The controversy or 'invalidation' would then come from everyone else setting their laps on semis and this (potentially?) on slicks and going against a gentlemans agreement.


So, potentially, 'IF' this was completed on slicks, there is no reason other teams couldn't run a set of slicks for a fast lap for 'unofficial' lap record bragging rights, correct? Then any 'official' times would be performed during an event on semis.


Basically, yeah

Jay Soh Tsu Chung

While there are no hard and fast rule about the type of tyres that can be used, it would have made things more interesting to watch HKS go under the 50-second lap with street-legal tyres.


To be honest, these rules are what's holding back time-attack from growing further. If people were allowed to build the craziest cars without a higher body restricting their capabilities, passing the 49 mark could be a piece of cake.


then it would be a pissing contest of who has the most money


That's what's happening anyway, so why not encourage it?

There will always be the lower classes in TA for the lower budget builds. Let the open class builds go hard.


can anyone tell me why they haven't been using slicks this entire time?

just seems like if you're going to try and go as fast as possible, with the amount of money they put into them, might as well use them


Maybe HKS went for overall fastest "car" record instead of fastest "car" with Semi-Slick? I'm surprised to hear it's still faster than Under Suzuki's S15 with Semi-Slick, makes me wonder how far TRB-03 can push with Semi-Slick?


If that's the case, they're about 5 seconds shy and they won't touch it


There's a reason I said "car", consider the other 3 faster "vehicle" were "open wheeler"...

43.304s - Dallara SF14
46.935s - Formula Nippon Reynard 99L
48.072s - F3000 Reynard 94D


Over here in the states the Unlimited class cars all run slicks so idk why the guys over in Japan don't. I know they all build their cars to comply with WTAC rules which is kind of the gold standard. That being said, Under should throw some slicks on :)


Maybe time to make a difference between street legal vehicles (in my opinion they should have an valid MOT) and real racecars. I for one think the street cars are more exciting!


this sounds like a problem with the rules more than a record.


It's not even a rule as such, more of an unspoken agreement.


Do you differentiate between someone setting times on trofeo r vs say a Michelin cup then?


I don't, because they're both street legal tyres made with the same principles and are comparable in performance. Going full slick is another level of performance.


But that then begs the question, where do you draw the line? R888's are technically a street tire but at the same time have race rubber compounds in them, at that point its just a small step to slick with treads. I mean thats where the rub always is in a "gentleman's agreement" and also why we consider official rule sets to have merit (for example building to WTAC rules). Personally i tip my hat to HKS marketing division and their ability to keep their mouths shut, at least for a little bit.


why doesn't the fact that they "did" reset the fastest semi-slick tire record at tsukuba get covered as an article on its own..?
I just thought that was a pretty big least for me more so than this article's slick tire record legitimacy.
ofcourse, sharing of and opening a place for discussion is valuable as well. in this case whether using slicks is okay.
but let's give them credit where its due.
they did well!


For sure, nobody's taking that away from them. They were strangely quiet about that December time, I guess because their primary target was sub-50?


Never understood handicapping world class time attack cars with street tires. Semi slicks on the mild and street driven cars makes sense. The way I see it HKS has the record and if anybody wants to beat the record then step up to slicks.


I thought the point was the fastest time, do we need a * with cars running sub 55 second times, they are all super illegal race only vehicles, slicks or not none of them would pass any form of street worth inspection, without cheating or fraud.


There was something I could never get right when I made a local car culture website with some friends and it's something I gotta congratulate you on: saying things that may cause a big name to be upset with you. That takes guts and that is genuine journalism, bravo!

I fully agree with what you're saying Paddy: no control tyres, no record. Yes, it's not a formal rule set in stone but it's a gentlemen's agreement to make sure all this time attacking madness makes sense. Did HKS build an absolutely amazing and breathtaking car? Without a doubt. Are they still the major japanese powerhouse only rivalled by Trust/GReddy? Absolutely. Is this record valid? No sir, sorry.


Ridiculous...which manufacturer gets to be the "worlds fastest street tire"? And who and by what criteria is that even determined...bribes perhaps? and what if any competition is then left to produce more capable tires?

You seem to think the will to build such cars operate in a vacuum of profits and competition to acquire it, no it does not.

If you want to kill these companies and all that they are trying to achieve, outlaw them and replace them with corporate billboards and shared chassis too, I wonder how many NASCAR fans will come with it?

If someone wants to build a carbon fiber go kart with maneuvering thrusters and wild geometry that puts COG below ground, why stop them, isn't this the point, to be "the fastest"


The same basic arguments I've heard forever, NOS is cheating, nose cars is cheating, wheelie bars, 4 speed reverseless transmissions, inboard dampers, ground effects, active aero, 6 wheels instead of 4, motor swaps, tube frames, slicks, boost, displacement and on and on and on.

The record and limits to it is pointless, the pursuit of it is not.


I don't know if it should get the DQ. Slicks aren't cheating, they're just an advancement in tire* technology. If anything the lap time should just be considered outside of those set with semis.

For comparison's sake, what are some of the fastest lap times on slick tires?


The current lap times with street tires eclipses old records set on slicks, little grooves do little over time to stop progress just limit it for a time


Time Attack originated as road going, street legal vehicles with street legal tires going to the track on the weekend to see how fast they could run a single lap - 1 warm up lap, 1 hot lap, 1 cool down lap.
Rules as written:
[1] Commonly, as the cars are modified road going cars, they are required to have tires authorized for road use.

However, due to the nature of competition and ego's, it has now turned into a massive global event to see who can build the most over the top cars and put down extreme lap times. Just like drifting, it has now turned retarded...
Not a single one of the top time attack competitors is street legal, at least not where I live... So they may as well throw on slicks or just skip it and perform Time Attack with Formula 1 cars.

Just my opinion. I am a full supporter of grassroots racing, and run what you "drive" to the track!


I've been around long enough that issues like this come up often enough. We'll look back in a year few years and slicks will most likely be the norm.

HKS probably knew it would cause some stir up. They even added TRB in the name.


I would expect other teams to just strike back and beat them with slicks sooner or later. I understand the gentleman's agreement bit but the cars are already insane as it is, so why not...?

But what do I know


if suzuki puts on slicks it will go faster than a 49.4


interesting pic with the tilt shift , luv it ...


No two ways about it, it is an amazing achievement and a valid record....for a car on slicks. It's probably time to rank a car and the records on semi-slick tires or slick tires and not lump them all together.


What kind of slick tire and what kind of "semi slick"?

If there is nothing in the rule book saying he can't run "slicks" then he would be an idiot to not run the softest tire and if someone refuses to acknowledge that then they shouldn't go near racing lol. If it's not legal to run a real racing tire then how is the time valid in the first place?

Strange situation.


You draw the line at DOT approval. A DOT semi slick is what you run. It's the unspoken gentleman's agreement, much like the JDM power level that the OEMs kept to in the 90's. It's the Japanese way of fine tuning the car to extract max performance as opposed to just adding Hoosiers or 900 hp to go faster. Take a look at an FD RX7 and compare it to a Fox body Mustang. This "JDM mentality" is why those cars are so much different...


When you mount a set of AD08's, RE-71s or Star Specs on your sports car, don't forget to thank Japanese Time Attack culture for driving the years of tire technology development that went into sub 200 UTQG tires.


HKS went full slicks, man... Never go full slicks


Just a correction to the article, the december trb-03 time of 50.2 sec was also set using advan a005 full slick.


Maybe this was for a comparison of slick and semi-slick tyres, to see how the car handles. Maybe they are working with a tyre company to produce a better semi slick tyre.


Traditionally lap records only count if they are set during a race


Time Attack isn't racing though.


This is why racing does classes: if the slicks stick to “unlimited” class(es) relevant to engineers and the awesome (not sorry for the pun) and street legal tires stick to “street” class(es) relevant to the masses and manufacturers pumping out crossovers, then is there any issue here? The problem is when tryhard hipsters pretend that the carbon spaceframe one-off with their Car’s silhouette “panels” argue that their modded street car is faster than your exotic because Tsukuba times.


HKS went for outright tin top record, not time attack record. so why does it matter what tire they use? it seems a lot of people are trying to link the two somehow... not sure why


Any word on what Suzuki-San has said about this "record breaking" lap?


To me this article and first image mark the end of a “classical Time Attack” era in Japan. The first image after reading articles that came to my mind was the last cover of MAX Power magazine... Purple Pug from the rear.

Over the last years we have seen a massive decrease in Tsukuba race appeal... Dino wrote that the main focus is shifting on to HKS premium days, Fuji battles etc.
From one side, it’s sad because we have grown on it and formed some strange bond/like for this sort of racing – glorified true JDM way. Remember Japanese tuners building GTRs to get into 9sec club on street tires in the golden drag racing era, it’s the same.

Seeing what happens in WTAC and other countries around the globe it’s just a natural thing to evolve also a Time Attack “gentelmens agreements” I guess.
But the good thing is that it’s Japan and there will be the ones who’ll do it right or original way till the end of their lives same as Wangan, Kanjo racers.

>End of an era<



Clipping Creations India

Great, it seems to me an amazing car indeed. Really impressive. I wanna try this asap, thanks.


I dont see the point of using semi slicks, these cars a designed to go a fast as possible, so why hold them back by using a lower spec tyre. If the car is still road legal you could make a case for saying it needs to run on a road legal tyre but the top tier of Time Attack has very little road car relevance so why not go as fast as you possibly can
I'd say its up to everyone else to bolt on some slicks an chase that lap time harder.


Time attack cars use semi slicks. That's one of the limiting factors of a time attack car as opposed to a all out race car.
The story is that they used a R-compound tyre because the downforce is so much it's destroying the semi's. While driver safety needs to be paramount, the tyre is the limiting factor so needs to be part of the design


I just see this as a natural progression. The people who want to chase the fastest records should not be held back by tire rules. This is what makes F1 today booring vs the old time monster cars, wich people really enjoyed watching. Yes I know todays F1 cars are faster, but we all know they have tremendous potential if alot of the rules were looser, and how fun wouldnt that be.


The record stands, simple. HKS did what no one else wanted to do and broke the gentleman's agreement and congrats to them. Time attack has been classed for years and the pros have had the freedom to do whatever they want, so why haven't they been able to change their rubber? These tin tops are amazing as is so why not excel the sport and make s-compound tires legal for the pro class? They already have the money for the aero/engine mods, so tires seem to be the only thing holding them back. If this happens I'm still sure that time attack can thrive at the street legal spec which the normal person can afford, but please, lets let the big boys go hard and see what they can do! I've been hanging out for the day Under and his S15 switch to S-compound, just let it happen!


i honestly believe the matter of tyres should be in regards to the class. these are some serious cars with aero pieces stretching out larger than the cars width, so match the tyre to the class is my personal opinion. i also think its pointless to care about the tyre type unless its official TA events. if they were just setting laps on a random day, then there's no point in mentioning it. if it was a monitored official TA event and they were using slicks while everyone was using semi's, then its a problem.


The cars themselves are not street legal, so why even run them on semi slicks?