BMW’s unlikely winner
The revelation in Motor Sport that Adrian Newey’s engineering brilliance may find a different outlet in the America’s Cup put me in mind of another racing engineer whose genius crossed frontiers.
Udo Gietl is the man who helped achieve some of the most unlikely successes in motorcycle racing history. In 1976 the German-born American took BMW’s R90S – a sports-touring machine with shaft drive and thus largely inappropriate for racetrack use – and won the first Daytona Superbike race and US Superbike championship.
Up against Gietl’s boxer twin was a new wave of four-cylinder sports bikes from Japan; machines such as Kawasaki’s 900cc Z1 and Honda’s CB750, for which the term ‘superbike’ was coined. The battle looked hopeless, but not to Gietl, who had already achieved considerable success in other areas of engineering.
During the 1960s he worked on the Apollo space programme as a senior electronics engineer, and the Polaris submarine project.
However, Gietl’s love of bikes was too strong and he came back to earth to work on powered two-wheelers. He got a job with BMW importer Butler & Smith, which had started in the 1900s as a fur-trading concern on the corner of Manhattan’s Butler and Smith streets.
At first he worked on road bikes, but his engineering prowess and his competition background – he raced off-road – led to him being transferred to the race department. Or rather, he was the race department.
“It was a one-man show,” recalls Gietl. “I did the engine, the transmission, the chassis and I tested the bikes, too.”
Butler & Smith owner Peter Adams wanted to go racing because BMW needed an image makeover in the US, where most motorcyclists considered the German twins rather staid, not a great selling point in 1970s America. At first Gietl’s R75 ran in low-key races. Then step by step it got faster and faster until, by 1974, the 50hp twin had become an 86hp twin, revving 4000rpm beyond its original peak.
“I worked it all out on the dyno – I ran the dyno every single day for years,” he says. “You have no idea how many motors I blew up. There was a rod stuck in the ceiling. Peter Adams wasn’t too happy when he came in the next morning. Hey Peter, don’t look up…”
Gietl bought in all kinds of trick kit including Crane camshafts infused with NASCAR tech and BMW titanium connecting rods and valves, designed by Porsche.
More important were Gietl’s own modifications. “We used twin-plug heads because the BMW plug is at the top of the cylinder, so it doesn’t burn the fuel so well at the bottom. Then we went to staggered ignition for better flame propagation and played with fuel injection, dry sump and ram air.”
And he learned some more from the automobile industry. “BMW car engineers designed the R75 engine, so they used connecting rods, valves, bearings, springs and so on from the four- and six-cylinder cars. Then I looked at Porsche and learned how to deal with an opposed engine because an opposed engine is a very interesting thing – it has forces that are totally different from a vertical engine. It has a lot of issues with basic design: the crankshaft, oil sealing, crankcase pressure, all this stuff, so it kept me busy.”
A full-race chassis came from Britain, designed by Rob North, the man who built the seminal frames that made Triumph and BSA triples mostly unbeatable in the early 1970s.
“The air scoops on the side of that bike’s fairing were for the ram air. I picked that up at NASA. I saw those [NACA] ducts on rockets and said, yeah, I need those on my motorcycle!”
The hard work all came together in the inaugural 1976 US superbike championship, essentially two-wheeled tin-top racing. Adams told Gietl to prepare three R90S road bikes for the new series, which kicked off with a 100-mile race at Daytona.
“The good thing was that everything I’d done could be easily adapted to the superbike,” says Gietl, who nevertheless designed some clever new pistons. “Everyone was using slipper pistons, but the R90 engine had so much distortion that it needed a very flexible piston, and a slipper piston isn’t flexible. So I used a full-skirt piston. I’d machine out the inside to make it even lighter, until you could literally squeeze it with your hand, so it would distort with the cylinder.”
The first man Gietl called to race the bike was multiple US champ Gary Nixon. “Gary said are you crazy? I’m not going to ride a BMW!”
Eventually he found three riders who were prepared to ride BMWs: Gary Fisher, Steve McLaughlin and US-based Brit Reg Pridmore. The trio dominated Daytona qualifying and ran away with the race, McLaughlin taking the win from Pridmore with a classic last-lap slipstreaming move off the banking. The first of the glamorous Z1s was a distant fourth.
Gietl’s creations went on to finish one-two-three in the championship: Pridmore from Fisher and McLaughlin.
Later Gietl worked for Honda US. “Butler & Smith spent $250,000 in 1976. When I got to Honda I wrote a budget that I thought would never fly. It was for $10.6 million and they said, ‘Yeah, it’s good, go ahead’. But for that they expected nothing but domination.”
After retiring from bikes Gietl got into sailing, just for fun, which is where Newey comes back into the story. “It was great relaxation, then one day I decided, ‘You know what, these things are too slow’, so I decided to build a boat.”
Gietl’s 56-foot carbon-fibre yacht dominated racing off the Californian coast for several years, proving that a really clever engineer can make anything work better.
Matters of Moment, June 1966
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