MotoGP Test in Malaysia - Racing

New machines, new tires, new problems.

MotoGP Test in Malaysia - Casey Stoner

MotoGP Test in Malaysia - Casey Stoner

The first preseason MotoGP test has just taken place at the Sepang International Circuit in Malaysia, giving us a look at how the jump from 800 to 1000cc changes things. Although bigger engines can make more power, the factory prototypes get the same 21-liter fuel allowance as before. If the races stay the same length, every use of more peak power must be paid for by more economical fuel use on part throttle. Were any of the teams running their full 2012 fuel economy systems? We can't know, and this can easily make bikes look faster in these tests than they will be once racing begins.

Just on lap times, Sepang test results could easily be finishing order of the 2012 MotoGP World Championship. Casey Stoner on a Repsol Honda was first at 1:59.607, 0.57 of a second clear of Jorge Lorenzo on a Yamaha YZR-M1. Then came the second Repsol rider, Dani Pedrosa, followed by Ben Spies on another Yamaha. Last of the top five and 1.2 seconds down from Stoner was Valentino Rossi on the latest twin-beam aluminum-chassis version of Ducati’s GP12.

First of the “Claiming Rules Team” bikes (essentially prototype chassis powered by hopped-up production engines) was the Suter/BMW of Colin Edwards at 2:04.722, more than five seconds back. Bringing up the rear were the Kawasaki-powered Avintia-BQR bikes on FTR British-made chassis, which were 8, 9 and 10 seconds down from Stoner. The Aspar-Aprilia “ART” bikes, which tested last fall at Valencia, Spain, were not at Sepang.

Now for the complications: Last year, Stoner and Honda were completely dominant. Stoner adapts to conditions, such as the now highly developed Honda. In his words, “I ride each bike as it must be ridden.” That means he is not wasting time, as so many others have, trying to make his present ride feel and handle like what he rode at the beginning of his career.

On the 2012 Bridgestone tires, Stoner’s bike is chattering. He said, “Chatter is something very difficult to fix. Surely, they are on it.”

With chatter, you cannot just “man up” and ride through it. The harder you push, the more violent the chatter becomes and the faster your bike heads for the outside of the turn. As veteran rider Mick Grant once said, “Chatter occurs under conditions of good grip and heavy load.” As the front tire is pushed near the limit of its grip, it occasionally begins to slide and then re-grip. The dull impact of re-gripping compresses the tire, slightly bends the fork legs, twists the steering head and deflects the front of the chassis. If the bending/unbending frequency of any of these parts is close to the front tire’s slip/grip frequency, the two can reinforce each other until the chassis is “ringing” and the front tire bouncing in unison. The more the rider tries to “ride through it,” the more intense becomes the vibration.

This is further complicated by the fact that the front of the chassis must be deliberately made laterally flexible to act as a “sideways suspension” when the bike is near full lean in corners (and the normal suspension is mostly pointed sideways). Get that lateral chassis frequency wrong and you invite chatter.

So, not only is Stoner 0.57 of a second ahead of Lorenzo’s Yamaha, he is in that position while dealing with chatter. Stoner said, “Considering we’re still going pretty fast without having this area completely dialed-in is a positive.”

This chatter is not affecting just Stoner; teammate Pedrosa had it, as well, and his crew was changing tire pressure and suspension settings in efforts to reduce it.

Lorenzo and Spies were not prominent in the chatter discussion. Remember that before the 2006 season, the Hondas had bad chatter in the tests but Yamaha did not. Honda’s problem yielded to countermeasures, but when racing started, Yamaha suddenly had severe chatter that kept Rossi from earning early-season points.

It has been pointed out that Rossi and teammate Nicky Hayden have, historically, rarely complained of chatter. In Hayden’s case, when both he and Max Biaggi were on Repsol Hondas in 2005, Biaggi was plagued with chatter but Hayden was not.

Bridgestone’s goals for this test were to speed tire warm-up at the starts of races and, in the words of engineer Tohru Ubukata, “...make their grip characteristics easier to manage...”  In the days of racing tires with grooved tread, the flexure of unbraced tread elements caused tires to heat up quickly after the start and begin to grip. But when slicks arrived in 1974, their smooth, self-bracing tread flexed much less, slowing warm-up enough that many riders crashed on cold tires in the first three laps. Warm-up laps were soon provided, and electric tire warmers came next. Yet even if tire warmers are turned up hot enough to damage the tires, performance on lap one is still tricky, because a full distribution of temperature in the tire takes time to establish itself.

For many years in GP racing, there have also been riders or machines that had trouble getting rubber to its best operating temperature and keeping it there. Edwards had this problem with Michelins at Mazda Raceway Laguna Seca in 2006. Part of the physics of rubber is a limited temperature range of best grip. Cold rubber is stiff; overheated rubber is greasy. If the tires are designed to perform optimally for top riders, slower riders, certain riding styles or particular machines may not work the rubber hard enough to reach grip temperature. If the tires are made to suit mid-pack riders, those at the front may find their rubber overheating and sliding. Bridgestone has, therefore, sought to widen the temperature range of best operation. This is one of the problems with a spec-tire series: With more than one tire maker competing, there can be a wider menu of tire choice.

Stoner bettered the lap record on only his second lap, an indication that the new Bridgestones are clearly not some “safety tire” but are genuine steps forward in overall performance. And the chatter? This is a cycle that has gone on as long as I’ve been watching. Each year, tire grip improves, and because more grip flexes chassis parts more, chatter is a possible result. The teams respond first with the time-honored band-aids, then with retuned chassis, and the problem comes under control. The following year, the cycle repeats, for no one has ever devised a complete “medicine” for chatter.

Suggesting that Bridgestone has succeeded in widening its tires' operating temperature range is the fact that Edwards had a giant chatter problem with his Suter/BMW CRT bike, while running four seconds off the pace. In general, there has to be good grip before there can be chatter.

"Right now, our issue is chatter," said Edwards, who went on to explain that if the chatter could be suppressed, he thought he could run a second to a second-and-a-half quicker. What might this imply for Stoner's performance, once his team deals with the chatter? Stay tuned for the next test, which begins on February 27 at Circuit of Jerez in Spain.

Lorenzo had other concerns and was quoted as saying, “I think we need to work on the electronics, especially on the exit of the slow corners.”

What about Rossi and the Ducati? A disappointing full second off the pace through 2011, Rossi and teammate Hayden spoke of lack of front-end feel and of understeer. This is unknown territory for Ducati, which burst on the scene in 2003 with the most power in the class and were soon finishing on the podium. Yet after Stoner’s masterful world championship on the red bikes in 2007, it was unclear whether Yamaha R&D overpowered Ducati or Ducati lost its combination as its chassis evolution continued.

Now that a full twin-beam aluminum chassis has replaced the extremely stiff carbon-fiber front frame/airbox used previously, Hayden said, “The front-end feeling is by far the best of any Ducati I’ve ever ridden.”

Rossi added, “Already this bike is better in braking and entry, better feeling with the front. Now, we have to make work for the acceleration, for the engine, for the electronics.”

Ducati Corse boss Filippo Preziosi said, “The next priority is to concentrate our effort in exiting the corner in the initial acceleration area before the bike starts wheelieing.”

This was the second area mentioned by Rossi’s crew chief, Jeremy Burgess, in the middle of last season: understeer. As the rider throttles up, weight transfer to the rear reduces the front tire’s ability to hold line and the bike runs wide. Some of the things Stoner and associates have said suggested that he used the Ducati’s naturally rough power onset to get the rear tire loose enough to steer with the throttle and not with the handlebars (shades of Kenny Roberts!).

Rossi commented that last year, most of the things they tried seemingly had no effect; but now, for the first time, the new bike is responding in a more normal way. Yes, Rossi is still 1.2 seconds back from the front, but now there seem to be tools at hand by which to improve.

Lorenzo and Spies seemed to take a longer view, that lap times in the first test are much less important than getting quickly and easily on the pace and gaining familiarity with how basic settings changes affect performance.

Honda is said to have weathered the depression of 2008 better than Yamaha. So, what we saw in 2011 and recently at Sepang could be just the effect of Honda’s greater financial ability to support development. Yet the next test could bring surprises either way.

And the CRTs? Even canny, experienced Edwards has a distance to go to “get amongst the chickens.” Dorna CEO Carmelo Ezpeleta has said he is happy to see “two races in one,” and that, if necessary, he will give the privately built machines other advantages to make them more competitive. At present, while MotoGP prototypes are limited to 21 liters of fuel per race and six engines for 18 events, CRTs get 24 liters and 12 engines.

To me, CRT just looks like an extension of Moto2—another opportunity for desperate small-team owners to stay in business by renting amusement rides in the top class to sons of wealthy families. It’s been a long tradition in Formula One.

MotoGP Test in Malaysia - Racing

MotoGP Test in Malaysia - Racing

MotoGP Test in Malaysia - Racing

MotoGP Test in Malaysia - Racing

MotoGP Test in Malaysia - Ben Spies

MotoGP Test in Malaysia - Ben Spies

MotoGP Test in Malaysia - Bridgestone

MotoGP Test in Malaysia - Bridgestone

MotoGP Test in Malaysia - Casey Stoner

MotoGP Test in Malaysia - Casey Stoner

MotoGP Test in Malaysia - Colin Edwards

MotoGP Test in Malaysia - Colin Edwards

MotoGP Test in Malaysia - Dani Pedrosa

MotoGP Test in Malaysia - Dani Pedrosa

MotoGP Test in Malaysia - Jorge Lorenzo

MotoGP Test in Malaysia - Jorge Lorenzo