Since 1979 Metzeler has produced only motorcycle tires. This singular focus has yielded significant firsts. In 1978, the company created the first tubeless motorcycle tire. The first tire with transversal grooves rolled out of the Metzeler factory in 1982, and the first mass-production tire with a Kevlar belt came out a year later. The first rear tire with a 0° steel belt came in 1992, and four years later, the first set or radial tires with 0° steel belts was released in the form of the Metzeler ME Z4. The march continued in 2008 with the patent of Interact technology for the Roadtec Z6 Interact. Now, Metzeler has released the heir to the popular Roadtec Z8 Interact throne, the Metzeler Roadtec 01.
While the Roadtec Z8 Interact tire was well-received by both riders and the media, the company believed the role sport-touring tires play is changing. The market has grown beyond just traditional sport-touring motorcycles to include both urban naked bikes and larger, more touring-focused rigs. With this change of job description in mind, Metzeler set three design parameters to surpass the Z8 with the creation of its next generation sport-touring tire:
- Enhanced grip in widely varied environments, including dry, wet, and low-friction surfaces.
- A 10% mileage increase over the Roadtec Z8.
- Increased steering accuracy, stability, and handling predictability on the road.
Crafting a Successor
In the past, when a manufacturer discussed grip in press briefings, the focus was almost exclusively on the compound. While tread compound does play an important role in traction, Metzeler says the most improvement in the tires’ grip in the environments outlined in its first parameter would come from the tread design, offering the most room for improvement as the surface varied from a high-friction coefficient to a low-friction one. In fact, Metzeler decided the change in approach was so profound that the result would be released as a new line of sport-touring tires rather than an update to the Z8. Consequently, the Roadtec 01 signals a new beginning.
A quick glance at the 01 reveals that Metzeler has broken with its Pi groove pattern, where there were significant variances in the land/sea ratio as the tire rotated. On the new front tire, transverse grooves cross the centerline at regular intervals. The grooves themselves become wider as they move away from the centerline. Not surprisingly, this improves their ability to displace water. However, Metzeler discovered through its testing that the groove design also helps to improve braking grip in low-friction situations. Additionally, Metzeler claims the new tread design also offers better interaction with ABS – an improvement that we would get to experience first-hand, during the riding portion of the tire introduction. Moving toward the edges of the tread surface, the groove spacing widens to twice that at the tire center, providing larger tread blocks for improved grip. The longitudinal groove angle was fine-tuned to allow better drainage without negatively affecting handling.
While the emphasis in the new design was on the tread profile and grooving, the compound still plays an important role. In the change from he Z8 to the Roadtec 01, the front tire’s compound remains a single-compound construction with 100% silica for wet-weather grip. The rear, because of its differing demands, features a dual-compound construction consisting of a center stripe of 80% silica for better durability over the center 20% of the tread. The remaining 80% of tread surface is constructed of 100% silica and split evenly between the two sides of the tread for maximum grip while leaned over.
The rear tire’s tread design includes a center stripe with no grooves for maximum traction during acceleration. However, Metzeler claims this does not compromise wet weather adhesion because the front tire will have already forced the water away from the pavement surface. Once leaned, the tread begins what Metzeler describes as “drops and sabers.” As with the front tire, the space between the saber-shaped channels – and the grooves themselves – widens as they track towards the edge of the tire. However, a series of unconnected drops, following a similar path to that of the sabers but in the opposite direction, combine with the grooves to offer improved grip in medium- to low-traction conditions. The grooving also promotes quicker compound warmup.
|Metzeler Roadtec 01 Sizes|
|120/60 ZR 17 M/C (55W) TL||160/60 ZR 17 M/C (69W) TL|
|120/70 ZR 17 M/C (58W) TL||180/55 ZR 17 M/C (73W) TL|
|190/50 ZR 17 M/C (73W) TL|
|190/55 ZR 17 M/C (75W) TL|
|Heavyweight Motorcycles (HWM)|
|120/70 ZR 17 M/C (58W) TL HWM||180/55 ZR 17 M/C (73W) TL HWM|
|190/50 ZR 17 M/C (73W) TL HWM|
|190/55 ZR 17 M/C (75W) TL HWM|
|Enduro Street Sizes|
|110/80 R 19 M/C 59V TL||150/70 R 17 M/C 69V TL|
|120/70 ZR 19 M/C 60W TL||170/60 ZR 17 M/C 72W TL|
In addition to the changes in the tread and groove design, the Roadtec 01 also features a shorter, wider contact patch which, according to Metzeler, is 5% larger. The reshaped contact patch combines with the new grooving, promoting a land/sea ratio in which more of the grooving is in contact with the pavement, again for increased grip. The reshaped contact patch altered the pressure distribution within that area, focusing more in the center. Additionally, pressure in the rear of the contact patch is reduced since, according to Metzeler, this is prone to slipping.
When combined with Metzeler’s 0-degree steel-belt technology, the changes to the tread pattern and contact-patch shape play a role in Metzeler achieving its second goal of a 10% mileage increase in tire life. For those who aren’t familiar with Metzeler’s Interact technology, the steel thread that runs parallel to the tire’s rotation has its tension and spacing between the threads varied to tune the carcass’ stiffness for various sections of the tire profile, allowing for increased stability in the center of the tire and maximum grip on the edges.
The Roadtec 01 also has a Heavy Weight Motorcycle (HWM) construction. Because of the additional stability required of the tire under the higher weight, the HWM rear tires receive a two-ply casing instead of the standard’s single ply. Since the standard front already has a two-ply casing, a more rigid casing and flank material is achieved via a different compound in both the casing and flank material.
For the street portion of the Roadtec 01 introduction, Metzeler assembled a variety of machinery to demonstrate the breadth of performance provided by the tires. I spent the most time on a BMW 1200GS but also got short stints on a pair of Kawasaki Versys (large and small) plus a BMW R1200R. Regardless of the bike, the Roadtecs delivered consistent performance.
The ride began with the temperature in the upper 40s, but the tires warmed up quickly. In fact, the pace of the Metzeler lead rider ramped up before my jet-lagged body had reached operating temperature. Still, from the first decreasing-radius corner encountered just a couple miles into the ride, the 01s delivered sporty steering characteristics and seemingly unflappable grip over pavement ranged in appearance (I didn’t get off the bike and actually inspect it) from grippy aggregate to slightly polished to tar patches.
The route planners certainly did their homework when developing the ride because in just a couple hours we managed to traverse billiard-table-smooth high-speed sweepers followed by tight, bumpy esses. Being in farm country, the pavement also had dirt-sprinkled sections with the occasional cow pie. (The tires handled the former while I completely avoided the latter since no tire can negate that slickness.) Riding on unfamiliar roads taxes rider and tires alike, and the Roadtecs willingly went where directed – at a moment’s notice – when the situation warranted it. The 19-inch front on the GS, not surprisingly, steered slower than the 17-inchers on the R1200R and the Versi, but the impression given by the Roadtec 01 tires is more sporting than touring.
Touring the Laboratory
The second half of the day took place at the Bosch Boxberg Proving Grounds which offer test facilities for manufacturers to put their machinery through the paces in a controlled environment. During our day there, we saw everything from super cars to cargo vans being run through testing routines while we took advantage of a banked oval, a wet braking area, and a handling course.
We were first given the opportunity to ride, in quick succession, a BMW S1000RR, a Kawasaki Z1000SX and ZX-14R, and a Suzuki GSX-S1000F on a 3-kilometer (1.9-mile) banked oval. While one of the two corners had a 160 kph (100 mph) speed limit, the other was left to the discretion of our right wrists. High speeds on a banked track put incredible loads on a motorcycle’s tires since the cornering force mashes the contact patches into the turn.
Although we were limited, for safety’s sake, to 2.5 laps around the course before we had to slow down and pit, giving the tires a moment to cool off, each of the bikes exhibited impeccable stability throughout this test – even when changing lanes. The highest speed I saw exiting the fast corner was 247 kph (153 mph) on the ZX-14 which had the biggest pocket of still air behind the windscreen. The tires weren’t the limiting factor in this environment. The flapping of my textile touring suit was. On the S1000RR, it was violent enough to blur my vision – not something I really enjoyed while riding just a few feet away from a metal barrier at elevated speed.
To test the Roadtec’s grip on low-traction surfaces, we got several passes on a pair of Suzuki Bandit 1250 ABSs which were identical except for the fact that one had Roadtec Z8s mounted and the other Roadtec 01s. Using the same data-acquisition equipment utilized during the development of the Roadtec 01, we got to make three passes on each tires. With repeatable recording accuracy to within 0.2 meters, we were able to see numerically how much shorter the 01 tread pattern allowed in a panic stop from 35 mph. Just for fun, the test took place on wet, Sett paving (Belgian Block).
The difference in braking feel was immediately evident at the lever. The Roadtec Z8 tires didn’t feel as planted, and the ABS kicked in sooner during the exercise. The Roadtec 01 tread offered a much clearer impression of what was happening at the contact patch. I could feel the impending lockup before the ABS intervention. The numbers bore out my impressions, with my shortest distances being 18.56 meters (60.9 ft.) on the Z8s and 17.31 meters (56.8 ft.) on the 01s for a 7% improvement. In a panic stop, every little bit helps.
The final test environment was a handling course in which approximately half of the track was soaked with water. The wet portion of the course featured a variety of corners: flat, uphill, downhill, off camber and decreasing radius. Additionally, the water was constantly spraying on the pavement simulating a rain storm. While again riding a variety of machinery, the Roadtec 01 tires delivered exceptional lean angles for wet street riding. The longer I rode; the more confident I became with their grip, particularly in the off camber and decreasing radius sections that had me quite tense in the first few passes. (Thoughts of how my last wet Metzeler tire introduction had me taking Spanish soil samples kept going through my mind.) The wet riding was so much fun that I was disappointed when we moved on to a dry, higher-speed handling track layout. I would’ve been content to have stayed on the wet track to further explore the 01’s wet pavement capabilities.
Metzeler put together a series of demonstrations of how a street rider could expect the new Roadtec 01 to perform, and the tires impressed on a variety of bikes of different weights and capabilities. However, a single day can’t reveal how long one can expect a set of tires to last. Given that the Roadtec Z8 Interact tires that the 01s replace have a reputation for decent longevity, we should expect the new Roadtec, at the bare minimum, to match the Z8s or perhaps meet the stated goal of a 10% increase in mileage.
The price range for the Metzeler Roadtec 01 fronts is $197.67 – $237.57, while the rears step in at $248.46 – $315.67, which slots them in between the Michelin Pilot Road 4 and slightly more than Dunlop Sportmax Roadsmart II. These are just MSRP, and much better prices can usually be found by shopping around. The Roadtec 01 is on sale at dealers now, and all sizes, with the exception of the 120/60-ZR17 will be available before mid–2016. The 120/60-ZR17 will ship in early 2017.