The set-up secret to Keke Rosberg's 'ultimate' Silverstone F1 lap: 'It was common sense!'

F1

Keke Rosberg set a record for years to come with his smoking Silverstone lap of '85 in a Williams – Frank Dernie remembers the day and how the F1 team got there

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Rosberg at Silverstone in '85 – fastest man on the plant, for one weekend at last

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For many, it’s the ultimate F1 flying lap.

A British crowd baying for action, drizzle starting, and a fired-up Finn stubbing out his cigarette to get on with it and harness up to 1,250bhp of a terrifying turbo Honda engine. Keke Rosberg would pull out an absolute stunner of a lap at the ‘old’ Silverstone, in a layout which favoured the brave, free from the current chicanes and fiddly new sections.

His pole lap for the 1985 British GP, clocked at 1min 05.591sec with an average speed of 160.925mph, was then the fastest F1 lap ever, remaining unbeaten for the best part of the following two decades.

Recalling that momentous achievement to Motor Sport, then-Williams engineer Frank Dernie couldn’t be more Grove in his assessment of how they did it: “It was just common sense. Frank would have given you a dirty look if you’d got excited!”

For all that controlled fire and fury bottled in one brilliant lap though, it had been a circuitous route to getting back on top of the speed charts for the constructors’ world champions of ’80 and ’81.

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Engine issues persisted through ’84

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After becoming the new pre-eminent garagistas with the ground-effect FW07, Williams had been slow to catch on with the turbo era, and found results unyielding in its initial link-up with Honda in 1984.

Dernie points to a lack of experience which now sounds startlingly naive in the modern age.

“Basically, none of us at Williams, including the drivers, had ever run with a turbo car,” he says.

From the archive

“Honda had a super high reputation, an ‘amazement factor’. So it was sort of assumed that the engine was good, and therefore if we weren’t quick then the problem was the car.

“We accepted that and just assumed that we got a lot of understeer, with some other things to fix.”

After the team laboured through 1984, its new recruit from Lotus-Renault, Nigel Mansell, inadvertently brought about a revelatory moment for the then-Didcot outfit.

“When Nigel drove the FW09B at the end of ’84 at Donington, he came in and said ‘Ah the car’s much better than I expected, but I haven’t got any boost.’

“So they checked the engine over and it was running a perfectly normal amount of boost. We found that we had been racing about 0.6 of a bar less than Renault – which is about 180bhp!

“The engine also had phenomenal lag, which we hadn’t been aware of – we didn’t know what lag to expect from a turbo engine.

“To cut a long story short, the new engine, which was the ‘B’ engine for ’85, was phenomenal.”

Honda’s new monster had an incredible 200bhp more than its predecessor, and all of a sudden, Williams was in business. They say there’s no silver bullet in racing, but as Dernie describes, this time the team wasn’t far off.

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Improved Honda power unit transformed Williams fortunes

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“Though it sadly wasn’t quite as reliable as it needed to be, it had basically fixed all the performance faults of that previous engine. The throttle lag was much less, it was very powerful.

“We used an old FW09 chassis to develop the new engine whilst we also worked on the FW10 car at the same time, and sure enough, all the handling problems with the former car weren’t there anymore.

“The problems, literally all of them, were due to the old engine. With the lag it had, if you set it up not to spin when the power came in it, it had massive understeer.

“If you set it up to have a nice balance turning into the corner, as soon as the power came in like a rocket – some time after pressing the throttle – you couldn’t control the oversteer.

“The FW09 wasn’t an amazing car, but nearly all of its problems were solved with the new engine.

“We were reasonably confident that we were going to get there with the FW10 – it was starting to go quite well…”

Though there were still reliability issues to overcome, a few races into 1985 and the new pairing of Rosberg and Mansell combined with the car was potent.

The former won in Detroit, in what would turn out to be his penultimate F1 win. When the team rolled into Silverstone, drivers and machine were on song.

Such was the clockwise inclination of the 1985 layout, with only eight corners (five right-handers and three left kinks), Dernie had a simple approach to getting the car ‘just right’.

“I was quite into doing a particular set-up because Silverstone back then of course was just mainly pretty fast right handers. There were a few left-turns but they weren’t of any consequence.

“So, I felt perfectly comfortable making an asymmetric set-up with cambers and all the rest of it.

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Dernie hugely enjoyed working with Rosberg, one of the ultimate F1 charges

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“It was just common sense. I mean, I didn’t know anything about IndyCars back then [which are set-up on ovals to turn left of their own accord], so speculating about them would have been a bit silly.

“I know enough about it to know what my limits are – it’s amazing how many fans think they know everything about it when they know nothing!

“Keke was happy with it and drove it amazingly quick. I liked working with him, all drivers are different, but Keke was a unique sort of personality – he was pretty confident, macho.”

On that weekend at Silverstone, the FW10 set-up by Dernie with Rosberg behind the wheel really was dynamite.

“The attitude was to be ‘Well, this is what we came to do'”

As the Finn described to Adam Cooper back in 1998, he’d already set the fastest time on Friday before doing so again on Saturday, breaching the 160mph average speed mark with it.

Rosberg was enjoying himself though, and fancied one last go as the clock ticked down.

“Patrick Head said ‘We don’t really need to,’” remembered Rosberg. “I said ‘Give me the tyres, I want to go out again.’ I was just on a high.

“There wasn’t pressure, I was on pole anyway. So it was pure enjoyment. And I’m glad that somebody like Patrick or Frank would sometimes allow you to enjoy yourself. I don’t know if the current system would allow it, but in those days it was acceptable.

From the archive

“Stowe, Club… it was just fantastic. I can remember coming out of Woodcote with a completely blistered left rear, hardly able to keep it on the road any more in the last corner. But I beat my own time.”

The lap of 160.925mph was simply astounding, one for the ages set by a true F1 warrior.

Not that there was as much as a flicker of emotion noted in the Williams pits: “It was very Williams back in those days, where the attitude was to be ‘Well, this is what we came to do,’” says Dernie.

“The emotional involvement would be potential upset if we didn’t do well, rather than the elation if we did.

“I know it sounds a bit small but Frank’s attitude was very much that and so was mine really. We had gone there to do the best we could and yeah, we’d done a good job – that was what we were there for.

“Frank didn’t even like people getting excited on the pit wall – if somebody started bouncing about he give them a dirty look!”

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’85 progress laid foundations for title success in the following two seasons

WIlliams

Looking back even now Dernie is pragmatic to a tee in assessing perhaps F1’s greatest pole effort.

“At the end of the day, it’s important to have a car that’s fast over one lap, but it’s only one small step on a very tall ladder in terms of doing well,” he reasons.

“I’ve always tried to focus on winning races and trying to win the championship, not doing one fast lap.”

Though Williams might have been some way off the title in ’85, by ’86 and ’87 it was back on top of the F1 world again.

On that day at Silverstone, Rosberg had signalled that the team was on its way once more.