SportBiKeZ

The penultimate pre-season test came to a conclusion at the Circuito de Jerez in southern Spain on Monday afternoon after three days of intermittent track activity courtesy of unusually turbulent Spanish weather. Rain and wind prevented teams, riders and tyre manufacturers from conducting uninterrupted running over the entire three days, including a damp official practice on Sunday in which Ducati’s Casey Stoner was fastest. A dry final day offered some meaningful running with more useful information collated by Bridgestone’s engineers.

A flurry of late qualifying runs shuffled the timesheets on the final afternoon of practice with Valentino Rossi ending the session as the fastest rider on Bridgestone tyres with a time of 1m39.568s. Several other Bridgestone riders were present in the top ten over the course of the test with some solid performances on race tyres. However, the final timesheets show that Bridgestone’s qualifying performance still needs to be further improved ahead of the season start in Qatar in three weeks’ time.

Q+A with Tohru Ubukata - Bridgestone Motorsport – Manager Motorcycle Race Tyre Development

What has Bridgestone managed to achieve over these three days with the mixed weather conditions?

“It was a difficult test for everybody with tricky track conditions over all three days. After the dry first day, we were able to carry out some wet weather tyre testing on Sunday, which was the first occasion for some of our riders to sample our wet specifications. In spite of those conditions, Casey did an exceptional job to set the quickest time and to win the car. On Monday, we had a brief shower at the start of the morning, but from then on it stayed dry, although with some quite gusty wind which was not helpful. We worked on evaluating tyres with a lower temperature compound range compared to the last tests in Sepang and Phillip Island to prepare for the Qatar night race and the Spanish GP in Jerez. We also continued to look closely at our qualifying tyres with many riders conducting detailed evaluation of different specifications.”

Has Bridgestone obtained all it needs from this test?

“Of course, we would have preferred a dry day on Sunday, but our riders worked really hard to get many laps in over the three days and we are grateful for their efforts. Today in particular we have seen some progress that we are sure will prepare us better for the race in March.”

In what specific areas does Bridgestone still need to improve qualifying tyres?

“We are quite happy with the durability of the qualifying tyres at this circuit, but it is clear that we are still in need of more grip to allow our riders to make an important step up in terms of lap time. Although our rivals continue to be very strong in this area, I believe we have made improvements since last year and even since the first test of this year. We tried several different specifications on Monday with different riders so we are sure that the variety of detailed feedback will benefit our development in this area.”

What is the plan for the next test in Qatar?

“Qatar test is going to be valuable, not only because it allows us to prepare our tyres for the opening race of the year at the same circuit, but also we will be following a night schedule for the first time. We will understand more clearly exactly what track temperatures we are likely to face and how that will affect our tyre performance by racing so late into the night. This will aid the tyre selection process on the Thursday of race weekend when our teams and riders must finalise the 22 rears and 18 fronts that they will have at their disposal according to the tyre restrictions.”

Published by Tasha Crook

To say Honda raised the bar within the middleweight sportbike segment would be an understatement.In our 2007 Supersport Shootout V, the ‘07 CBR600RR stood head and shoulders above the other Japanese 600cc offerings. Name the category and the Honda had it locked. Since completing that test, we’ve logged hundreds of additional track miles on the championship-winning platform, but the question on our mind was: how much better could this bike get?
A phone call into Tim Saunders, principal of Corona Extra Honda Racing, and just like our favorite Food Network Chef, Emeril Lagasse would say, ‘Bam!’ We were going to have a go on their ultra-trick Corona Light 600 race bike. At long last, we would get our chance to check out the CBR600RR in proper AMA Supersport racing trim.
Saunders assembled his crew and with the bike and supplies in tow, they met us at the Fastest Road in the West - aka Willow Springs International Raceway. If 2.5 miles of wide-open asphalt isn’t the perfect playground to see what a bike like the Corona Honda has to offer, then we don’t know what is. In an effort to fully grasp the difference we also procured a stock 2007 CBR600RR fitted with a set of Bridgestone BT-002 DOT race tires.
Conditions were perfect, with a light wind and mid-70s registering on the thermometer as we suited up for our first taste of Corona’s supersport brew. With the Dunlop D208 N-Tec DOT race tires baking beneath the PowerStands digital tire warmers, we strolled towards the white with lime-accents Corona Light machine. The pungent aroma of VP race gas saturating the mild desert air was a reminder this was no ordinary CBR.
“Man, this is going to be good,” I said inside my helmet.

The bike itself was supposed to spend the year competing in the AMA Pro Honda Oils 600cc Supersport class. But after the season opener at Daytona, then-rider Gary Mason and the Corona team parted ways and the bike was left collecting dust in the team transporter until Cycle News super-scribe Steve Atlas was presented the opportunity to race the machine at the Corona AMA Superbike season finale at Mazda Laguna Seca Raceway. Atlas did the journalists proud by finishing 17th in the race, his virgin outing with the team.

There’s no question Honda engineers found the sweet-spot between racy track use and daily street-ability in the ergonomics department of the stock CBR. Once aboard the lime-logoed race bike, however, you realize that this ain’t no streetbike. The thin black seat foam atop the jacked-up Hot Bodies racing tail section, lower Vortex Racing clip-ons, and raised TiForce adjustable rearsets instantly positions the rider’s body into a proper track attitude: Tail high and nose down. This would be the first of many differences.

Unlike our user-friendly road going stocker, this bike is devoid of anything associated with proper street accoutrements, including an ignition key. Instead, two separate run/off engine control switches are mounted on each handlebar. The left switch controls what would normally be the key-style ignition, while the right one functions the same as stock. Switch gear, mirrors, horn, and keyed gas cap are all gone. The GP-style shifting pattern makes gear changes easier at full lean, but takes a bit of getting used to when switching from a stock pattern.

Walker Jemison, crew chief for the Corona squad, gently warmed the machine before we wrapped our overly excited hands on it. He forewarned us to not let the bike idle too low due to the upgraded oil pump, which doesn’t build enough oil pressure at low rpm. As a reminder, an orange arrow is placed at the 3000 rpm mark on the tachometer. Climb on, blip the throttle, grab the clutch and drop it into gear - it’s time to ride.

Once underway, we immediately notice just how rigid the Supersport machine feels. Where the stocker feels like it’s blissfully gliding over road imperfections, the Corona Honda lets the rider know it’s a proper race bike. Every single bump, crack, and pavement ripple is transmitted directly through the controls to the rider. In, fact there’s so much feedback that initially it feels somewhat overwhelming compared to the plush accommodations of the road-going version. Our first handful of laps consisted of just acclimating to both the flowing nine-turn road course and the 130-horsepower rocket underneath us. Riding a machine in this state of tune in cruise mode made it very clear to us that we better up the pace, or get off.

By noon we had the track layout down reasonably well and started to ride the bike more akin to its tire-shredding design. In stock form, the CBR is already renowned for its potent set of binders. We went blasting down Willows front straight-away to test the racing set. A single finger pull of the adjustable Active folding brake lever slows the Corona Honda with amazing voracity. Although outright power and feel was never an issue with the stocker, stopping force and feedback through the coated, Galfer steel-braided lines is simply off the charts. Wouldn’t it be great if these brakes came standard on every sportbike? Supersport rules reflect changes which can be implemented by the riding public rather easily. Simple brake pad and line modifications are the key to taking the OEM CBR brakes to the next level.

Unlike our user-friendly road going stocker, this bike is devoid of anything associated with proper street accoutrements, including an ignition key. Instead, two separate run/off engine control switches are mounted on each handlebar. The left switch controls what would normally be the key-style ignition, while the right one functions the same as stock. Switch gear, mirrors, horn, and keyed gas cap are all gone. The GP-style shifting pattern makes gear changes easier at full lean, but takes a bit of getting used to when switching from a stock pattern.

Walker Jemison, crew chief for the Corona squad, gently warmed the machine before we wrapped our overly excited hands on it. He forewarned us to not let the bike idle too low due to the upgraded oil pump, which doesn’t build enough oil pressure at low rpm. As a reminder, an orange arrow is placed at the 3000 rpm mark on the tachometer. Climb on, blip the throttle, grab the clutch and drop it into gear - it’s time to ride.

Once underway, we immediately notice just how rigid the Supersport machine feels. Where the stocker feels like it’s blissfully gliding over road imperfections, the Corona Honda lets the rider know it’s a proper race bike. Every single bump, crack, and pavement ripple is transmitted directly through the controls to the rider. In, fact there’s so much feedback that initially it feels somewhat overwhelming compared to the plush accommodations of the road-going version. Our first handful of laps consisted of just acclimating to both the flowing nine-turn road course and the 130-horsepower rocket underneath us. Riding a machine in this state of tune in cruise mode made it very clear to us that we better up the pace, or get off.

By noon we had the track layout down reasonably well and started to ride the bike more akin to its tire-shredding design. In stock form, the CBR is already renowned for its potent set of binders. We went blasting down Willows front straight-away to test the racing set. A single finger pull of the adjustable Active folding brake lever slows the Corona Honda with amazing voracity. Although outright power and feel was never an issue with the stocker, stopping force and feedback through the coated, Galfer steel-braided lines is simply off the charts. Wouldn’t it be great if these brakes came standard on every sportbike? Supersport rules reflect changes which can be implemented by the riding public rather easily. Simple brake pad and line modifications are the key to taking the OEM CBR brakes to the next level.

Once slowed down, a slight tug of the bars brings the bike on its side, carving hard to the left through Turn 1. Like the stocker, its amazing how little effort it takes to get these Honda’s to turn, but it’s even more amazing when it’s lighter and tighter. Up front, the standard appearing 41mm Showa fork is anything but. Hidden inside, there’s Ohlins 25mm supersport cartridge internals. Only ultra trick-looking adjustable fork caps give you a clue to how much potential is in there. Unlike the stock CBR which has a tendency to blow right through fork stroke, as any stock bike will when pushed hard in fast sections and heavily loaded, the Ohlins setup is both firm and compliant, and never feels overwhelmed. Contrary to the stock suspension, which gets progressively more out of sorts when ridden to the edge, the Corona Light Honda’s racing-spec front suspension follows the surface of the road carefully yet precisely, all while delivering an enormous amount of feedback - rewarding the rider for having the balls to go harder, faster and deeper. The faster you go, the better it gets.

Pickup the throttle and the Ohlins rear shock squats a bit as the Dunlop 190/55R17 rear tire digs into the pavement - hooking up and driving the bike forward like an oversized paddle tire on a CRF450R in the sand. The howl emitting from both the intake and the raspy wail from its underseat Ti Force muffler will put any rider on the verge of sensory overload. Dropping the throttle for a moment before easing it back on through the banked Turn 2 is a lap-by-lap thrill. Get back on the pipe after the apex and the engine zings above 11,000 rpm and into the core of the power as the front end gets light and the next turn approaches fast.

Funny thing is, the more time we spent turning laps the better both bikes begin to feel. Sure, the stocker doesn’t pull with as much gusto, but it still is fast. The biggest difference lies in the massaged components: Brakes and suspension. The harder we push and the more we lean, the more the race-spec fork helps keep things in check. The more aggressive we get on the gas, the quicker the Corona bike responds.

Accelerating hard out of the inside of Turn 2 to the left uphill Turn 3, the precise throttle, well-sorted suspension and warm, sticky tires give the confidence necessary to get on the gas much earlier than on the stocker. Blip the throttle, snag a shift and transfer weight to the left side of the bike as it snaps into position. With the bike carving left under acceleration, it’s time to maneuver past Turn 4,and downhill into the near 90-degree Turn 5. Trail braking into 5, with the added effect of gravity pulling the fork down, is one area showcasing the difference between stock and Supersport-spec suspension.

The brakes on both bikes are powerful, but the added feel and confidence that the Corona Light CBR exudes makes it easier to stay on a bit later and carry more speed. The transition is not nearly as abrupt on the racer as the stock bike because when the OEM fork is tapping out as the bike hits the apex, the Corona bike is in the sweet spot which again allows you to dial on the gas sooner.

Climbing uphill into Turn 6 the Pro-Link rear suspension is put to task, but the action is firm and responsive and resists the tendency to bottom out as the g-forces pull hard. Both bikes are in their element in the fast transitions but the stock bike feels almost couch-like compared to the racer. While the Corona Light bike is taught and flickable the stocker feels spongy and a bit less responsive when snapping it from side-to-side. Cresting the hill after Turn 6 while shifting and on the gas is a prime opportunity for the bikes to get nervous. The racer did more often than the stocker. The contributing factor here could be a number of things including a slightly more aggressive angle of attack, more mid-range torque lifting at the front wheel or the different steering damper.

While the stock HESD steering damper performs well, as you can tell, the original setup was jettisoned in favor of an adjustable GPR V1 gold-anodized unit. These aftermarket style dampers offer a range of adjustability which allows the resistance to be tailored to the individual rider. We have had plenty of experience with the GPR units in the past and they do a good job of keeping the unwanted movement in check, but it comes at a price. It requires a decision to be made regarding how much resistance will be dialed in where the HESD unit calculates the resistance on the fly, so in some cases it doesn’t even feel like it’s doing anything - and that’s the glory of the high-tech piece. The GPR on the other hand is always on. Motoring hard through Turns 6 and 7 loads the rear tire, un-weighting the front-end of the bike, but with the GPR damper we experienced a bit more head shake here. It never was an issue anywhere else on the track.

Compared to the stocker, the supersport-spec engine spools up extremely quick as we accelerate towards the notoriously high-speed Turns 8 and 9. Press down on the gearshift lever (GP-shift) through gears four and five and witness the precise-shifting glory of the Dynojet Quick Shifter, which facilitates throttle-to-the-stop, clutch-less upshifts. Neither of our test riders had ever ridden with one of these gizmos, but both came away believers. Sure, you can make clutchless up-shifts on the stock CBR, but it generally requires a moment of hesitation to engage while the race bike just keeps rolling on.
While the all-new for ‘07 Honda engine has plenty of pulling power around the 10-turn track, the Jett Tuning-built 599cc mill was exceptionally powerful with its seamless mid-range punch. The fun really begins when you hit that magic 13,000 rpm mark; suddenly, that beefy mid-range transforms itself into a thick surge flinging the bike forward at an incredible rate. Power keeps on coming up to 15 grand and another 1500 rpm of over-rev remains before you reach the limiter. Lap after lap we would drag these two rockets up the front straight with the Corona Light bike getting the edge on the stocker. Only a mistimed shift or an excellent drive on the standard machine would allow it to pull even at the finish line. The racer however, was just coming into its own and would start to pull a gap between there and the braking zone. It’s not really fair to the stock mill, but it taught us two more valuable lessons. The first is that the Jett Tuning performance upgrades give the CBR600RR a whole new personality. The second is that the CBR in stock trim is no slouch.

The man behind this wickedly powerful supersport mill is John Ethell. The name may sound familiar to AMA roadracing fans, since he’s the Honda engine-building guru that’s spent the last six years working in American Honda’s race shop building the motors for Red Riders like Miguel Duhamel, Josh Hayes and Aaron Gobert.

“Most of the power comes from the cylinder head, fuel injection mapping, and cam timing,” explains Ethell, owner of Jett Tuning. “Because of the rules in Supersport, we’re only allowed to clean things up a bit.”

In fact, AMA Supersport class rules only allow light modification in order to keep the cost factor down and elbow-to-elbow racing competition up. The engine itself has to retain both original displacement and stock internals. That means no aftermarket pistons, cams, valves, etc. So the real ingenuity comes from being able to maximize performance through the stock setup as rolled off the assembly floor by the manufacturer. This is the core of the Supersport racing philosophy. Take a bike the public can buy, do some minor modifications to push its performance envelope to the next level, then let the kids go play. That’s supersport racing, and with these Jett-Tuning powered Honda’s consistently running up front in both AMA 600 Supersport and Formula Xtreme-both companies must be doing something right.

So how much better is Honda’s amazing middleweight in race trim? The words magnificent, thrilling and heart-stirring all dart into our minds. In race trim, the Honda does everything with both precision and personality. It fuses rider and machine in a quest to achieve the lowest possible lap time. With the combination of hand-selected aftermarket components and meticulous attention to detail, the Corona boys have built something special.

On the flip side, in comparing the 2007 Honda CBR600RR to the race machine, it became quite clear that even though the stocker isn’t as sharp-edged or as refined as the Corona Light Honda on the track, it also doesn’t require as much focus or outright concentration at speed. Its comfort zone is anywhere between the stop sign and 80 percent. For a middleweight sportbike you can buy off the showroom floor, it is simply amazing how much performance Honda’s CBR600RR serves up. Then take that same platform, spend a week stripping off the unnecessary OEM gadgets, tweak the motor, suspension, brakes, top it off with a set of premium race rubber and voila, you have a motorcycle that is miles away from ordinary.

original location: www.motorcycleusa.com

Tires are the intermediary between a fastest lap and a trip to the gravel pit. And with Japan, Italy, England, Germany and now even the U.S. producing 1000cc-plus motorcycles that crank out upwards of 130 horses to the rear wheel, the time has come for a new generation street tire that can handle those mega-power outputs and the associated loads that accompany putting that much power to the pavement.

Tire development is all about compromise. Make a tire too sticky and we’ll burn them up in a few hundred miles. Make a tire too hard and we’ll get the mileage we desire but sacrifice grip and warm-time. Integrate numerous tread cuts and it displaces water but compromises our coveted contact patch. We could continue or dissertation on compromise, but Pirelli believes that it’s found the right middle ground with a tire that can meet the needs of both 21st century man and machine.

The Pirelli squad mounted up a set of Diablo Rosso tires (120/70-ZR17 front and 180/55-ZR17 rear) on our 2007 Honda CBR600RR. With the tire pressure set (36 psi front, 42 psi rear), we hit the streets of Ventura County. Once under way, it became immediately clear that the tires do not offer the greatest feel. Throughout the street ride we felt disconnected from the road below. However, steering was extremely neutral and side-to-side direction changes were no better or worse than the OEM Bridgestones that were previously fitted. The lack of feel from the rubber made it difficult for us to really push hard through the curvy, mountain route that Pirelli had laid out for us. The few times we were able to man up and actually work the tires, they performed flawlessly without a hint of instability or lack of traction. In fact, adhesion levels felt very consistent. During our photo shoot, a few times we locked up the rear wheel to speed up the turn-around process, sliding the bike around 180-degrees. The rear rubber consistently slid, making us look like we actually knew what we were doing. Normally our CBR600RR delivers a relatively plush ride on the street for a 600cc sportbike. But with the Rosso underneath us, that smooth ride was compromised. The CBR’s tires normally work in unison with the suspension to help soak up some of the irregularities and bumps in the pavement, but the Rosso tires have a stiffness to them that translated every bump and pavement ripple directly through the bike.

Tags: tires, performance, wheel, motorcycle, pirelli