Trackday: Sportbike Tire Comparison
The joy of riding a fast motorcycle on an inviting canyon road or the occasional track day is well known.
However, it doesn’t take much of that type of mileage before your tires become decidedly worn and you face the question of replacement.
The original-equipment tires ordered by the manufacturers are mere shadows of their aftermarket siblings, hobbled by less rubber and lighter construction.
Manufacturers often supply several different tire brands on the same model, and which one ends up on the bike you buy is a random choice.
Nevertheless, you are quickly going to need some replacement rubber and we were determined to find out which tires will best satisfy riders oriented toward maximum performance.
A brace of Honda’s excellent CBR600RRs were the test platform, and the precision services of Danny DiNardo at Peak Performance in Simi Valley were enlisted to weigh, measure, and mount the tires to the Honda wheels; his findings fueled some interesting speculation.
The stock Dunlop Qualifiers (at a combined weight of 21.1 pounds) and the Michelin Power Pures (21.3 pounds) were easily the lightest.
The Dunlop Sportmax Q2s were heaviest-some 2.8 pounds extra for the pair-and for sportbike enthusiasts obsessed with saving unsprung weight (especially if that weight is distributed around the outside of the wheel) we presumed that the Q2s, by comparison, would make the usually sweet-handling Honda 600RR turn like a truck.
Once fitted to the bike, DiNardo measured the circumference of each tire and the axle heights to discover if there were any changes to the Honda’s chassis geometry.
Most made negligible change, however the Michelins dropped the front by 2.4mm and the Pirellis raised the rear by 5.3mm.
Both of these alterations to axle position would reduce the rake angle a little, implying that the steering of the 600RR would be speeded up considerably, particularly with the Pirellis.
Clearly, to eliminate as many variables as possible a controlled track test is mandatory.
Southern California’s Willow Springs Raceway was chosen for its high speeds and demanding technical corners-certainly a tire-shredder if ever there was one.
The ambient temperature on the appointed day was a balmy 72 degrees, and the test concluded before the notorious afternoon Antelope Valley winds had a chance to interfere.
We drafted the prodigious mechanical skills of Rick Wall and Danny Coe to facilitate wheel fitment in the pits and ensure that all tire pressures were consistent with the manufacturer’s recommendations.
Because of the high speeds involved, we stiffened the 600RRs’ stock suspension slightly at both ends of the bike, and to ensure the stock steering geometry was maintained, each adjuster was cranked up one-half turn.
Representing faster riders in the test was Tristan Schoenewald, a respected ex-AMA 600 Supersport racer with a National and several Regional WERA Championships to his credit. He is fast, precise, and smooth.
Schoenewald can evaluate tires at the limits of their traction while putting in consistent laps, always hitting his lines and braking points.
Associate Editor Jess McKinley is a highly accomplished off-road racer, but a racetrack novice. His years of experience pushing two-wheelers to their limits enable him to feel the differences in the tires, but his lack of racetrack experience gives us a regular-guy impression of the tires by lapping Willow Springs at speeds more familiar to mere mortals.
The Hondas started out the day on new stock tires to give the riders a comparison baseline. After several sessions and a best lap time of 1:41.0, the OE tires were clearly not particularly fast and the riders reported some vagueness over bumps as well.
Schoenewald generally liked the tire, but felt the grip was a bit lacking and had a couple of mild mid-turn slides to prove it.
After the initial sessions on the stock tires, the test was conducted blind, with the riders unaware of which brand of tire they were riding on, and at no stage did Schoenewald and McKinley discuss their test results with each other.
Comparisons of each set of tires were made against their impressions of the stock Dunlop Qualifiers.
Bridgestone Battlax BT-016
As the sole tire supplier to MotoGP since last year, Bridgestone has certainly carved out an enviable reputation.
Who can forget 2008 when Valentino Rossi-having floundered the year before- successfully changed to Bridgestone tires, prompting Dani Pedrosa to insist mid-season on switching to Bridgestone as well?
The BT-016 is a dual-compound front, and triple-compound rear tire that gets grippier as the lean angle increases. Bridgestone also prefers a steel (over other brands’ aramid fibers) mono-spiral belt construction to give the carcass added strength.
A significant two pounds heavier than the stock tires, the Bridgestones took 0.8mm height away from the front and 0.5mm from the rear, which lowered the bike slightly but made minimal changes to the geometry.
McKinley was very impressed, as he felt the Bridgestones were softer and more compliant than the stock tires, but a little slower to turn-in. “A big improvement over the stock tires,” he enthused.
Schoenewald’s best lap of 1:38.3 on the Bridgestones was almost three seconds a lap quicker than the stock rubber.
He felt the BT-016s were a little harsh over bumps, and he also noticed some front-end chatter at full lean angle.
Schoenewald complimented the tires on their reliable turn-in and mid-corner traction, and said he “felt comfortable and confident” on the BT-016s. However, he also noted that “when I pushed hard, the rear would lose grip quite suddenly,” and it was that lack of predictability that ultimately cost him the ability to go any faster.
Dunlop Sportmax Q2
In 2010, Dunlop became the specified tire for the AMA Championship, and the Q2 tire uses its proprietary N-Tec race technology.
The rear tire is a dual compound construction with softer shoulders for extra grip, while the front tire is a single compound.
The secret to the Dunlop Q2’s extraordinary and predictable grip seems to be its advanced compound and the Intuitive Response Profile at the rear, which creates a bigger footprint and allows more lean angle than the other tires.
The Q2s are a significant 2.8 pounds heavier than the stock tires. They raised the Honda’s axle height by 1.4mm at the front and 1.6mm at the rear; although the 600RR sat a little higher, the steering geometry was essentially unchanged.
However, the slightly taller bike would arguably give the riders a little extra leverage when turning in, thereby offsetting any negative effects of the extra rotating mass.
Carding a best lap time of 1:36.3 with Schoenewald at the controls, the Q2s were almost five seconds per lap quicker than the stock tires.
McKinley was full of praise for the Dunlops: “I love these tires! I found them very confidence-inspiring. I was able to ride comfortably at my limit, yet they were predictable and stable throughout the corner.”
Schoenewald felt equally at home on the Dunlops and said “I liked these tires, and felt very confident with them. The front was stable, turn-in was excellent, and the tire held its line perfectly.
Leaned over on the brakes-even over bumps-the tires stayed planted. Overall, steering input was minimal and once turned the bike felt like it was on rails.”
Michelin Power Pure
French tire-maker Michelin was the first manufacturer to develop dual-compound tires, and the new Power Pure tires claim that the soft compound rubber comes in at earlier angles of lean.
The Pures incorporate Michelin’s Light Tire Technology, which reduces weight without sacrificing tread depth, and saves a dramatic two pounds in weight compared to its rivals.
The Michelins were the only tires tested that weighed almost exactly the same as the Original Equipment. In theory, with less rotating mass, they should have offered nimbler handling than the others, but it did not work out that way.
The Pure’s lightweight carcass had too much flex, causing it to understeer; the Michelins also made the Honda a little nervous.
Lapping with a best time of 1:38.4, Schoenewald was ambivalent toward the Michelin Power Pures, feeling that they were grippy and competent over bumps, but he complained that “the bike wandered and wouldn’t hold its line.
I frequently found myself on the outside part of the track. Initial turn in was good; the tire felt stable and didn’t slide, but it just wouldn’t hold its line without increased effort.”
McKinley found the same problem: “This tire had good grip, but it was hard to keep a line and the tires felt squirrelly, but not from a traction perspective. The tire was very light to steer, so I lacked some confidence in the front. These tires may require a more deft hand than I have.”
Pirelli Diablo Rosso Corsa
Pirelli has been the original spec tire in World Superbike racing for some six years now, and have used it as their personal R&D lab.
According to WSBK owner Paolo Flammini, Pirelli has “done a superb job and delivered far more than we asked.” Like the Dunlop Q2s, the new-for-2010 Diablo Rosso Corsas have a single compound front.
However, the dual compound rear tire has Pirelli’s SC2 race-compound on the shoulders. Utilizing their proprietary Enhanced Patch Technology (EPT), Pirelli claims an enlarged and “optimized contact patch at any lean angle on street and racetrack.” Similar to the Bridgestones, they use a steel belted carcass.
The Rossos were 1.2 pounds heavier than stock and they raised the rear axle height by a whopping 5.3mm but the front only by 0.8mm, which certainly reduced the rake at the front end considerably.
But, despite the change in chassis geometry, without a doubt the Pirellis gripped well and were fast without being nervous.
They posted a decent lap time of 1:36.5-a dramatic 4.5 seconds per lap quicker than the stock tires.
Schoenewald said, “These tires worked well, but the problem was I didn’t have much feel with them, making me less confident to push. They didn’t do anything wrong-I liked them grip-wise and they were stable in corners-but they were a little sensitive over the bumps.” McKinley concurred: “These tires were so much better than stock. They gripped well, but they felt stiffer and a bit less compliant. They were also a little bumpy.”
When the tires on your sportbike need replacing, any one of these four replacement tires will be a marked improvement. However, tire performance is not just about the amount of grip it generates.
It is also about how the tires feel when the bike turns into a corner, how much they transmit the bumps through to the chassis, how they feel on the brakes, whether you can hold your chosen line throughout the corner, and, if you are really pushing hard, how they feel once their grip starts to let go.
It was interesting that our two testers, with different levels of track experience and an almost 15-second disparity between their lap times, generally agreed on how each set of tires felt.
Clearly, one does not have to be a racer or super-fast rider to notice the difference in feel between these tires.
The issue of tire weight is a fascinating subject. Logic and experience tells us that, for sportbikes, lighter-is-better. Yet, in this test, the opposite proved to be true. Certainly, there is a sweet spot in tire and wheel weight.
If a tire is too light, it can upset the suspension by not providing enough resistance to bumps, and it reduces the gyroscopic effect of the wheels, making the bike less stable.
Make the tires too heavy, and the tires can overwhelm the suspension in bumps and it can be hesitant to change direction. It is all about balance, and in this test, of the five pairs of tires, the heaviest clearly had the balance spot on.
In last place, were the OE tires. The best things we can say about them is that they are decent and come with the bike, but they are certainly not your best option for high-performance riding.
The Bridgestone BT-016 finished fourth, beating the best OE lap time by two seconds, and are clearly superior to the stock tire. They work well within a certain range, but are less competent at the edge of performance on the track.
The Michelin Power Pure tires finished third, a blink faster than the Bridgestones, but still some two seconds a lap down on the Dunlop Q2s.
Schoenewald and McKinley were divided in their opinion, with Schoenewald slightly preferring the Michelins and McKinley giving his nod to the Bridgestones.
The biggest complaint was the nervousness of the Michelins and their inability to hold a line through the corner, which was not caused by lack of grip.
The Pirelli Diablo Rosso Corsas came in second, a full 1.8 seconds quicker than the Michelins. The Rossos gripped well, but lacked feel-a difficult handicap for a rider to overcome.
Changing the chassis geometry the least, the Dunlop Sportmax Q2 maintains its line through corners, turned most predictably, handled bumps well, and gave good feedback in all situations.
Additionally, the Q2s showed the least wear at the end of the day. The Q2 was a little faster than its closest competitor, an undeniably important statistic for performance tires, but most importantly it was the tire that gave the testers the most confidence.
By both subjective and objective standards, the Dunlop Sportmax Q2 is our clear winner.Google+