High Mileage Sportbike Tires Come of Age... Pirelli's Diablo Strada and Metzeler's Roadtec Z6
Like most sportbike owners, I give little thought to the engineering and design of my bike's tires. Rarely do I look beyond the desire to have the stickiest tires regardless of the cost. The problem that high horsepower motorcycle owners face is the need for traction combined with tire wear. When a season of riding the street eats four or more sets of tires, that desire for a high performance tire is often met with an empty bank account.
When Bikeland.org was asked to try Pirelli and Metzeler's new high mileage sportbike products, we were sceptical. Reaction from our friends and fellow riders was similar. "You're nuts", "You're going to go down" and "Look, Dude, I'm afraid for you. Those tires won't stick the way you ride". To make matters worse, our previous experiences with other manufacturers' high mileage offerings were less than confidence inspiring.
We decided to repeat the age-old mantra, "trust your tires" and also to trust the engineers who made them.
This is what happened....
Warning! Extremely long read!
Too long for me to insert all the photos!
Recommended:
Click here to download FULL PDF
(390kb optimized for download)
PDF contain lots of additional content including photos, data and interviews with tire engineers from Pirelli and Metzeler...
PDF is formatted for printing!
Warning! 18 pages long!
It was a beautiful summer's day on our friend's ranch in mid-Oregon...
A dozen riders suited up for a several thousand mile round trip to California's Monterey Peninsula and the 2005 MotoGP at Laguna Seca. The group was made up of a variety of sportbikes: an '05 R1, some ZX10Rs, some 6Rs, some 12Rs, a handful of Hondas and Suzukis. The group's tire selection was equally diverse, however the general consensus of the riders was to utilize the stereotypical "stickiest tire possible" formula. By our own calculations, we already knew the ZX-12Rs should return showing cord. Two of the bikes rode from Vancouver, BC. This added an additional 600 miles to their journey, eliminating any buffer their owners might have left for tire wear.
Only two of the bikes in the group wore high mileage sport tires. Pirelli Diablo Stradas on frEEK's ZX-12R and the Metzeler Roadtec Z6 on Princesskiwi's ZX-6R. My 2004 ZX-10R had the softer Pirelli Diablos, and I was going to be the control bike.
We wanted to compare the high mileage tire wear against a softer sportbike tire to see if we would notice any differences. The ZX-12R, although similar in horsepower to the 10R, was much heavier, while the ZX-6R, similar in weight to the 10R, made less power. Between the models we had all the bases covered.
We brought along a tread depth gauge and measured the tires' tread and wear patterns at the end of each day's riding for the entire trip. The tires were inflated following Pirelli and Metzeler's tire inflation recommendations found in their consumer literature.
The rest of the bikes in the group wore the standard fair. A few bikes had race take offs, some had Dunlop 218s, Pilot Powers and one bike had a pair of economy tires from Maxxis.
The first day's ride took us across Oregon and through a rarely travelled park. Highway 34 crosses the western portion of the State, with an amazing detour through Alsea Falls County Park on a one-lane road with no centerline. Twisting and winding through the forest, the smooth surface translated to high speeds using all of the road, including the unmarked oncoming lane. It set the scene for what would prove to be two weeks of motorcycling heaven.
After lunch, Princesskiwi, frEEK and I had a chance to chat. All of us remarked at the excellent feel the tires provided. One surprising observation was that the edge of the high mileage tires seemed farther away. Leaning over as far as comfortable on the street, frEEK and Princesskiwi didn't find the edge, but I did on the Diablos.
As we head south alongside the Ocean we pull into Port Orford and the 12 of us set up camp at a Bikeland.org member's house. "Snail" lives on 300 acres of coastal land with a view that words cannot describe. Old country hospitality and a warm fire give all of us another chance to talk about the day's riding. Measuring wear of the tires provides some interesting results. The Strada front on the much heavier ZX-12R is wearing faster than the soft Diablo front on the 10R! The high mileage rears are wearing at the same rate, much slower than the softer Diablo.
The coastal air was cold and damp. The next morning's ride into northern California along the Pacific made me thankful that I'd brought along my electric vest. It felt more like October in Seattle or Summer in San Francisco (ha ha!) than the beginning of July. The people who laughed at me about the electric vest a few days earlier weren't laughing now, especially Dave in his fully perforated leather suit. As we made our way down the dewy, wet 101, the tires tracked the ocean soaked pavement with ease, and provided confident traction on the slick road surface.
The highway winds its way inland and we head through Humboldt State Redwood Forest. As temperatures begin to rise, the road widens. The highway opens into wide, two lane sweepers and speeds increase. The group fans out for some all out sport riding. The bikes wearing the stickier rubber seem to have no advantage over the Stradas and the Roadtecs. Unlike previous high mileage tires we had tried, these tires seemed to show no difference in street performance from their sporting counterparts.
If the first part of the day's ride was smooth, the next leg of the journey proved to be exactly the opposite.
Mattole Road, also known as the "Lost Coast Highway", leaves the smooth pavement of the 101 and heads west. The chopped up surface of the narrow twisty road that lay ahead resembled a paved goat trail. The potholes, frost heaves and cattle guards were enough to rattle the fillings out of your head, and a few of your wires on your bike loose. The pace was slow, but the view spectacular. The road spills out of the mountains, depositing our group on the coast with a panoramic view of the Pacific Ocean. We stopped for a photo and to the left we see cattle being herded up a cliff face, and to the right a small island with The Flag placed there for the 4th of July.
That afternoon we set up camp in a grove of ancient Redwoods. Six of us decided to take the bikes out for a real test on California's famously curvatious Highway 36.
Highway 36 is probably one of the most challenging and exciting motorcycle roads I have ever ridden. The sign which greets you at its start reads "Curves next 140 miles". The 36 stretches inland east of Red Bluff past, the I5 and winds its way westward to Highway 101 and the coast.
The 60 mile section from the coast to the one store town of Wildwood is riddled with blind, decreasing radius hairpins. It is a dangerous section of road that has claimed at least three Bikeland members' motorcycles on different occasions. The onslaught of 15mph corners really get the adrenaline pumping. If you had a chance to get a knee down on the street, this would be it. We left the rest of the group to set up camp and headed inland, the thermometer climbing to well above 100'.
Leaned over, the tires stuck to the ground like glue. PK and I turned around at the halfway point, overheated in our full leathers. All we wanted was an ice-cold beer after the long day's ride. FrEEK set off with Turboblew and Dino and completed the round trip while we sat back at the campsite, in the shade by the river, and chatted.
Measurements revealed that the wear on the Diablos was starting to show. The Roadtec and the Strada also showed some signs of wear, but nothing as pronounced as that on the Diablos. The hot, rough pavement and the hard, fast tight cornering had eaten up a layer of the softer compound tires.
Travelling down the 101, through the old hippy hideaway of Garberville leads us to yet another amazing section of road. SR9 from Legget to the Coast is the first of many traverses from the tiring and straight inland commuter highway, the 101 to the legendary Pacific Coast Highway 1 (PCH). SR9 is another 35 mile slice of motorcycling nirvana, and there is not a tire store for miles. FrEEK learned this the hard way on a previous trip. With minimal tread wear on the Stradas and the Z6's, both the ZX-12R and the ZX-6R continued to perform flawlessly. The Diablos, however, continued to wear themselves down.
As our group inched closer and closer to San Francisco, and Laguna Seca, the tires on all three bikes continued to show no signs of weakness in performance. Eventually both Princesskiwi and frEEK began to forget that they were riding "high mileage" tires. It was business as usual as we let the engineers at Pirelli and Metzeler do the thinking for us.
The first real red flag came at a stop on our last leg before we reached the outskirts of San Francisco en route to the track, and the fevered crowds of the MotoGP. After diligently measuring the tread depth on the different bikes for several days, we came to a shocking conclusion. We realized that my bike, the "control" bike, wearing the softer compound Pirelli Diablo's, simply did not have enough tread on the rear tire to make the return journey! It was basic math. Had we not measured along the way, we would have never known. I was already over ½ way through my total tread, but nowhere near ½ through our trip!
Panicked phone calls were made to try to arrange a tire at the track. I had no idea what to expect, hearing rumours of 120,000 people attending Moto GP. Would there be a tire there for me? After several calls, we had a tire squared away and on hold.
The next several days at the track were a blur of racing, drinking heavily, and meeting old friends and fellow members of the site. We visited Cycle City's tent at Laguna Seca and had a Roadtec Z6 rear mounted to my 10R. There weren't any Stradas available, and I didn't want to take the chance of running out of tire on the return leg, so I opted for the Metzeler high mileage offering.
Now it was I who drew the ire of many of our friends who were at the track. Yet another barrage of "those tires won't stick" and "you're going to crash if you use those tires!" followed. At least now I had something to gauge my experience against. I knew that Princesskiwi and frEEK had no problem riding aggressively on the same tires, so I felt partially assured that I would be "okay", but like any other sportbike rider I now had those voices in the back of my head.
With the race over and the group going separate ways, we headed out on our own journey, a return to Oregon through California and the Sierra Nevada mountains. We were tired of the coast's cold air, and desperately wanted a change of scenery.
My initial reaction to the Roadtec Z6 was surprise. Much like Princesskiwi and frEEK had reported, the tires felt no different on the street than the Diablos. As we approached the twisties just outside of Mariposa, I tried to put any negative thoughts about the supposedly not sticky tires out of my mind. It took a while, but after heading north and having to concentrate on the ride, I eventually forgot altogether that I was riding on a high mileage rear.
Pulling into the small town of Jamestown, California, we began the "saloon" leg of our journey. Hot and sweaty, we made a point of visiting some of central California's small town saloons. Jamestown is situated just outside of lake Tahoe and at the crossroads of two awesome roads. Jamestown has a few very small hotels, an excellent Mexican restaurant, and a real life saloon, complete with swinging doors and the three regulars staring at ya because they don't know who ya are.
SR 49 from Yosemite to Jamestown sports 100 miles of fresh twisty pavement. The road snakes its way along a river basin and canyons and has a nice combination of hairpins combined with wide sweepers and on camber corners. Exiting Jamestown puts you at the entrance to SR 108, Sonora Pass and SR 4 and Ebbett's Pass.
Ebbett's Pass redefines the phrase "blind corner". The road sports no centerline, no guardrail, a 24% slope and a cliff edge that will swallow you up, never to be seen again.
Ebbett's pass descends into the desert basin, and joins into Highway 395 heading north into Lake Tahoe. As the desert heat builds, the altitude takes its toll on the bikes. Good luck with a power wheelie here. The 6000' oxygen starved air sucked the power right out of my 10R.
From Tahoe, north across through Red Bluff we sit in construction traffic at the eastern junction of Highway 36 and the I5.
The road was so amazing on the way down that we wanted to ride it again on the way home. Little did we know that the week or so we'd spent riding around in the bay area had given road crews just enough time to tear up giant sections of almost all 140 miles of the 36, literally! From end to end the 36 was decimated... a giant grooved, gravelled and oiled construction site better suited to some KTMs than a group of sportbikes. Miles of gravel and no way out. This sucked.
At the coast a quick detour north and east set us back on track as we cut inland towards Weaverville.
Highway 299, which follows the river basin, was awesome. The tires were still holding up, showing little signs of wear and reacting predictably, smoothly and never breaking traction.
The only one who was concerned was Dave with his set of economy tires on his Yamaha. In Jamestown he noticed that he was running out of tire, and now at the end of this day he realized he had even less to show.
With the fear of Dave hitting cord and still having to make it to Oregon, and then Canada, we did exactly what we did NOT want to do. We called the remainder of the twisty part of the ride off.
This is precisely why I will never mount standard or soft compound tires to my sportbikes on the street again.
With several riding days left, in the middle of nowhere and without a single tire shop in site, the fact that there was no tread left on the Yamaha meant that Dave's trip was over. Meanwhile, the ZX-6R and the ZX-12R's tires looked like they could continue on for weeks.
What this called for was a drink.
The saloon in Weaverville is on the west side of the street. According to the barkeep it was "the only saloon in town". After a couple of pints, we swung the saloon doors open, only to look across the street to see another saloon! We walked over to check it out, but there were even less people in that saloon, so we headed back to the first saloon to sit down and have a toast to the engineers from Pirelli and Metzeler.
Who would have thought that a high mileage tire would work on a big bore sportbike? I would have never believed it had I not tried it myself. So here I sit, feeling like I am in the future, riding bikes that make power unimaginable by standards even 10 years ago, riding tires that by all reasoning should be mounted on a "pipe and slippers" touring bike like a VFR or something of that ilk.
For those of you who thought the tires wouldn't stick (myself included), we were all wrong! And for those of you who made the trip to Laguna Seca from all points around the country, next year carefully consider your tire choice! Tinhead, you could have made your trip on one set of tires, not three!
Just like any other decision, choosing the right tool for the right job is imperative. Pirelli and Metzeler have done their homework and have solved a major problem for all of us that like to take a month in the summer and actually go somewhere with these beautiful bikes that we own. If you think that you can outride these tires on the street, then you're going to get yourself into a whole bunch more trouble than the tires not performing.
I can assure you that we tested them accordingly!
SO WHAT MAKES HIGH MILEAGE SPORT TIRES LAST LONGER?
At first we thought it was simply the compound itself, but after living with these tires for thousands of miles, and seeing that their performance was so similar to the "normal" street tires, we had to do a little thinking on it. The first clue to the long lasting nature of these tires was the tread depth measurements we took before we began our test. When reviewing the measurements we realized something very important. Our measurements revealed that both the Roadtec and the Diablo Strada Rears start their lives with 6mm of tread, while the street sport Diablo rear started with only 4mm. This means that right off the bat the high mileage tires have an approximate advantage of 50% more tread. Next we examined the compound and construction of these tires. Silica is incorporated into the compound to give better wet and cold grip. Steel belted construction keeps the compound temperature even, acting as a heat sink once brought up to speed. Pirelli and Metzeler offer sport tires with a slightly longer lasting compound and by coupling this with 50% more tread, both manufacturer's have come out with tires that out last their normal counterparts with more than double the life expectancy, and similar, if not identical street performance.
FrEEk's THOUGHTS ON THE PIRELLI DIABLO STRADAS...
"Great grip, great wear." The same claim made by every new tire to hit the market begot the usual sceptical and cynical response from me. Pirelli states their new Diablo Stradas have enough stick to keep your sportbike shiny side up, but also get close to sport-touring levels of mileage. If true, the Stradas would be exactly what I have been asking for years, but since I never get what I want, I wasn't about to hold my breath.
Well imagine my surprise when they did exactly what Pirelli said they would. In the 4000 miles it took me to get from my house to Laguna Seca and back, I never once felt the tires weren't up to the task, and at about 6,300 miles, the rear is just getting into the wear bars now. The trip consisted of a pretty standard mix of highway droning and railing through twisties, and as a reference I consistently got about 2,800 miles out of Dunlop D207s, Bridgestone 010s, and Bridgestone 014s. Frankly I'm having a bit of a hard time believing the results as I write this, but the numbers are accurate. Now to be fair, there were moments when the Stradas felt like they didn't quite have the level of grip the aforementioned tires did, but they never let go, just wiggled a touch more. Even the much adored Metzeler M1s my bike wore immediately before the Stradas went on felt only mildly more planted.
So in the end, the Pirelli Stradas are winners in my book. They may not be the right choice for a track day or for someone who frequently puts a knee down on the street as they aren't quite as sticky as most super sport tires, but for any sane street rider (including the 90% of us who are "above average") a set of Stradas will do you proud. They'll also save you 50% on tires, save 50% of your work and downtime for tire changes, and get you through that big trip without having to stop halfway through for new rubber in the middle of nowhere surrounded by understandably impatient riding buddies.
Source: Bikeland.org