Panic is too strong a word to describe Wayne Rainey’s state of mind in the middle of the 1991 500cc World Championship.
The weight of the number 1 plate on his Yamaha YZR500 hadn’t slowed down the defending world champion when the season began. He finished third in what many consider the greatest 500cc race of the modern era, the 1991 Japanese Grand Prix at Suzuka. Kevin Schwantz won from Mick Doohan with Rainey third and John Kocinski fourth, all covered by 0.556 seconds.
A continent and two weeks later Rainey beat Doohan on the Queenslander’s home track at Eastern Creek. Another two weeks later and on the third continent in a month, Rainey beat Doohan by nearly seven seconds on his own home soil, Laguna Seca Raceway. The blonde-haired kid with the surfer’s good looks from southern California was on a roll.
The battle for the 1991 500cc...
The battle for the 1991 500cc world title came down to Rainey and Doohan, Yamaha versus Honda, but more importantly: Dunlop versus Michelin. Here Rainey leads Doohan during their battle at Jerez, before Rainey dropped back due to front tire problems.
Then began the heart of the championship, the 11-race European swing, starting at Jerez. From the pole position, Rainey could do no better than third, 13.5 seconds behind Doohan, and 4.5 seconds behind his teammate, the mercurial Kocinski. The pattern repeated at Misano; Rainey on pole, Doohan winning big over Kocinski. But this time Rainey was down in ninth, and over a minute behind. It would be his worst finish of the year. Rainey regained his form in Germany, but lost out to Schwantz in an epic battle. Then Rainey lost out to Doohan by 0.185 seconds in Austria. By now he’d gone four races without a victory, the longest stretch of the past two years…and he knew why.
“I remember we were having some tire issues with tires out of round in some previous races,” Rainey recalls. “I remember I blistered a front tire in Jerez, when Kocinski beat me. And just in general, the performance, there was a problem there. And Kenny (Roberts) was sniffing around about Dunlop’s commitment and wondering what Michelin was up to,” and not for the following season — but to finish out the 1991 campaign. “When you’re in the championship battle, you want the best, especially of the tire companies.”
At the end of the 1990 season,...
At the end of the 1990 season, Michelin announced that it was not only temporarily halting development of its motorcycle racing tires, but also that it would only supply the Rothmans Honda team. This put both Yamaha’s Wayne Rainey (left) and Suzuki’s Kevin Schwantz (center) on Dunlop tires, as they battled Mick Doohan (right) and his Michelin-shod Rothmans Honda.
Dave Watkins was in charge of Dunlop’s racing efforts at the time (and up until his retirement a year ago, after 46 years with the company). A former bicycle racer, Watkins is a soft-spoken Englishman from just outside Birmingham, where Fort Dunlop is located, who’s been blessed with a marvelous equanimity; he sees problems as challenges to be solved, a chance to learn, to expand your way of thinking. Nearly 18 years since Rainey’s retirement, Watkins speaks with reverence of the three-time world champion, who he calls “Wayner” (Rainey is prominently featured in a gallery of champions on the stairwell in Watkins’ home in Sutton Coldfield).
“As far as my tire engineers go, I really had a special connection to him. He was fun,” Rainey says. “Even if we were in a good situation with our tire combination at a particular race, I still knew he was doing everything possible to try to give me the best chance of winning. His passion for winning was as strong as mine. And he knew that tires were going to be a huge part of the win or the loss. And so we won together and we lost together; he was a part of my team.”
The string of tire problems...
The string of tire problems suffered by Rainey early in the season persuaded Marlboro Yamaha team owner Kenny Roberts (foreground) to approach Michelin about switching to the French brand in midseason. Although Dunlop responded and Rainey won the 1991 title, Roberts switched the team to Michelin in 1992.
Watkins believes Rainey was one of his most insightful riders, able to quickly analyze a tire’s benefits and able to detect the smallest variation. “Wayne didn’t need a big difference to find a difference,” Watkins said. “And that’s basically the difference between a great champion and someone who isn’t. They get down to the detail much quicker. They know what’s happening underneath them.”
The making of a tire is a mixture of components, experience, and black magic, in equal parts, and Rainey knew this. He didn’t always know what made the tire different, only that they were measurably different. And that heightened his appreciation of Watkins and Dunlop.
In what many consider one...
In what many consider one of the greatest races of the modern era, Doohan leads Schwantz, Rainey and Kocinski through the chicane at Suzuka, 1991. Just over half a second would cover the quartet at the line.
“Imagine being a tire technician like David,” Rainey said. “You’ve got to figure where you are going to get the performance from the tire. There’s a hundred different parameters; if you just change one of them it can hurt the other 99 of them.” Finding the decisive factor was often a matter of trial and error, and sometimes luck.
“When you design tires, what you’re looking for is what we call a neutral line, stress-free line,” Watkins explained. “And you try to build the tires so the components, when they become stressed, they become equally stressed along their periphery or across their cross section. So what you don’t want is pinpoints of stress.
“Probably a year before at Daytona when we were testing with Yamaha, we were looking at tires without high stress levels in them in pinpoint areas. And we sort of escalated on from that. So by the time we’d finished the 1990 season, we got a pretty good idea. We tried various constructions, but stability was always a problem in the heat. The softer construction worked OK in temperate conditions.”
Rainey (center) won convincingly...
Rainey (center) won convincingly at his home round at Laguna Seca, with Doohan (left) second and Schwantz third. Doohan seems increasingly disgusted with Rainey’s building momentum (the American finished third at Suzuka, and won at Doohan’s home race at Eastern Creek), but it wouldn’t last when the series went to Europe.
He took the problem to a colleague in Dunlop’s textile lab who told him, “Well, it’ll be one or two things. Either you need a high-weight Kevlar or you simply just put a lower twist in it to increase the modulus [of elasticity] that way.” So tires were made with both types of strands and a preparatory test was done. “We found that the higher-molecular-weight Kevlar wasn’t as good as the low twist (the number of twists you put into it). And lower the twists, it becomes very stiff. If you get too stiff, you get no grip, so it’s a balancing act.”
Even more important are the initial stages when the tire is formed. Says Watkins, “It’s the most important bit, because if that’s wrong everything can’t be put right after that, so it has to be made very accurately.” Start to finish, a race tire was made in about 45 minutes, roughly the length of a Grand Prix race. As Schwantz said on a visit to the factory in 1991, “I can burn them more quickly than you can make them.”
Rainey (1) leads teammate...
Rainey (1) leads teammate John Kocinski (19) and Schwantz (34) during the initial laps at Eastern Creek, Australia, where Rainey won his first race of the season. The Dunlops’ grippy qualities in the first few laps would allow Rainey the chance to build an early lead.
“Obviously nowadays with the N-Tech, forms are already curved,” Watkins reveals. “And Michelin lay cords on separately and Pirelli do a similar sort of thing with their method,” Watkins said. “And then that tire goes to the press (where the layers are fused together), and then [much depends on] how it goes in the press and how volatile the rubber is. It’s quite crucial…you can mess this up after all this beautiful hard work in about 15 minutes, because that’s how long the curing time generally would be.” The tires would normally be cured at about 350 degrees Fahrenheit in about 15 minutes, but Dunlop found the best results with Rainey to be a half-hour cure with a much lower temperature. That seemed to give better consistency. “I don’t know the process on how they cured their tires, but I could generally tell there was something different about a batch of tires,” Rainey said. “I was pretty fortunate in my era that I got to test so many bloody tires. So I had a certain feel out of these tires that I was able to use when I went out and analyzed tires.”
“And then suddenly next thing...
“And then suddenly next thing I know, my rear tire is trying to pass the front…” Rainey and Schwantz compare notes at trackside while waiting for their mechanics after a practice plug-chop.
“Compound is a very complex thing,” Watkins says. “I wouldn’t want to tell you all that goes on, but you have a list of components. Carbon black, silica maybe, there’s fillers. Then you’ve got polymers, which can be natural rubber or can be synthesized.” Then you have oil, which can be used to modify grip level. “Alternatively you lower the black and put more oil in and get the same result, but that affects the abrasions. And then there’s plasticizers, peptizers. Then you’ve got your accelerators, which help your curing. Then you’ve got your curing medium, which is sulfur. Sulfur itself comes in many forms. It’s another science within the science. And of course there’s restrictions on what you can do in time and you need a lot of space for a lot of components.”
In the days before the era of control tires, manufacturers often custom-built tires for both teams and some individual riders. Rainey liked a tire with 2.5mm thick sidewalls, which gave a stiffer spring rate. Schwantz liked a softer tire — his had 1.5mm sidewalls. “The differences in the tires were quite small, the result in the spring rate was quite big,” Watkins says.
Schwantz leads Rainey and...
Schwantz leads Rainey and Doohan during the Assen TT round. Doohan would crash out, leaving Schwantz and Rainey to duel to the last corner, where Rainey’s “rookie mistake” (in his words) caused him to run off the track, gifting the win — and lap record, that would stand for 15 years until the track was reconfigured in 2006 — to Schwantz.
With Rainey going four races without a victory during that span in 1991, Watkins and Dunlop knew they had to help get him back in the hunt. Planning for the latest tire design began just days after Rainey’s off-finish in Misano, and the first meeting was held and first designs drawn up on May 27, the day after Germany and less than three weeks before Jarama. The Friday of the Jarama race weekend the race tires were being tested at Donington Park — likely by Niall Mackenzie, Watkins believes — before being put in a van for the approximately 750-mile drive down to Madrid, which included a ferry crossing of the English Channel. Dunlop had a new front tire at Jarama as well.
The new tires arrived late Saturday, too late for pole qualifying, which went to Schwantz. But race day dawned bright and very hot — the track temperature was 140 degrees Fahrenheit — which worried Dunlop.
Watkins’ notes show Rainey’s comments from morning warm-up, the first run on the new tire. “More stable up the hill. Better side grip.” The thing with Rainey, Watkins points out, “is that he — and only a few people, Scott (Russell) was one of them and Doug (Polen) was another — could go for five or six laps and tell you if that tire would be a race tire or not. Wayne could do that and that was typical.”
Rainey (center) celebrates...
Rainey (center) celebrates his victory at the French GP at the Paul Ricard circuit. Doohan (left) finished second after front tire issues forced him to back off, while Eddie Lawson (right) scored a popular (and hard-fought) third place after barely holding off Schwantz.
Watkins could always tell when Rainey was going to win. “Where other riders might get upset by upsets, when Wayne was confident he was fireproof to any interjection of problems. If that bike was wrong, a millimeter out, he could tell you it was a millimeter out. But when it was spot on, he knew, and he was very, very difficult to beat.”
As Rainey remembers, “When they bolted that tire in and I tried it, it just felt like the bike was not battling itself. It’s like all of a sudden it started steering better. It was changing lines easier. It had good side grip. It had good acceleration grip.” Rather than thinking about tires, he could concentrate on the rest of the machine and his riding. But as the race approached, the heat increased, and Rainey and Watkins grew concerned.
Then came a possible break for Rainey and Dunlop. Watkins had seen Doohan struggling with the Michelin front in practice.
“Doohan was in real trouble with the front tire,” Watkins says. “He’d come up the straight, he’d make the turn and then the front tire would start pushing up to 100 yards. That was impossible for him, because he was not in control. So our guys knew that unless they could fix that,” which meant building tires overnight in Clermont-Ferrand and trucking them down, “[and in morning warmup it looked like] they didn’t fix it fully, it gave the guys even more confidence for the race.”
Doohan led until a few harrowing slides convinced him to back down. Rainey took the lead and sped away. With the track broiling the tires, there was concern that they wouldn’t last. But Rainey’s skill was such that he could make the tires better as the race progressed. “It’s the way he rode them,” Watkins said. “Sometimes if a tire was going off, sometimes instead of easing off and bogging it, he’d go the other way. And it got better. What he was doing was actually cleaning the surface of the tire. He’d take off all the rough by abusing it, so he’s got a good new surface.”
Rainey’s margin of victory over Doohan was 7.767 seconds. Rainey would finish on the podium for the next six races, winning three times and clinching the title at Le Mans.
Still, it wasn’t enough to convince team owner Kenny Roberts to stick with Dunlop in 1992. Rainey won that title on Michelin, but was back on Dunlop in 1993. He was leading the championship when he crashed out of the lead in Misano, his career coming to an end in a gravel trap.
“Who knows how that last season of mine would’ve turned out?” Rainey asks. “In racing, nothing’s for sure.”
Dave Watkins (left) was lead...
Dave Watkins (left) was lead development man at Dunlop UK’s motorcycle motorsport division for an amazing 46 years, up until his retirement last year (ironically just after similar Dunlop icon Jim Allen — at right — retired from Dunlop’s US motorsport division after a stellar career).
Even though he was at the mercy of the team owner when it came to tire choice, Rainey had respect for both tire companies, but with Dunlop it was, and remains, personal. “Normally, everybody that’s working on your team at any given time, they’re doing what they can to make sure they have the best chance of winning,” he said. “I always looked at it as we win together, we lose together, but whatever it is we’re going to do it together.” sr