Dunlop Sportmax Roadsmart II Review
Dunlop's sporty sport-touring tire gets updated and improved
When Dunlop launched the Sportmax Roadsmart in early 2008 the venerable tire company stressed the wet-weather performance of its all-new sport-touring-oriented rubber. Dunlop got more than it bargained for during the launch of the Roadsmart: it rained nearly all day during the press ride.
We couldn’t have asked for more ideal conditions to put to the test Dunlop’s claims of the tire’s ability to handle the wet; I came away content the Roadsmart was a capable wet-weather tire. Unfortunately for the Roadsmart, that day’s deluge left no real opportunity for getting a sense of the tire’s dry grip performance.
Now we’ve come full circle, from a rain-soaked tire evaluation ride nearly four years ago, to a rain-free (albeit brisk!) day of riding during the recent launch of the new Roadsmart II.
Sport-Touring Tires: The Swiss Army Knife of Motorcycle Rubber
Developing a tire for the sport-touring crowd presents a tough set of parameters for tire manufacturers. A modern S-T sled, like Kawasaki’s Concours 14, brings the challenges of weight (688 lbs wet sans rider, passenger or loaded saddlebags), sportbike-levels of rear-wheel horsepower and torque, and handling performance that can mean footpeg-grinding lean angles. Salting the wounds are the S-T rider’s demands of high-speed stability, reliable grip in the wet and thousands upon thousands of miles of durability. A sportbike tire is easy by comparison: warm up as fast as possible, and sacrifice virtually all other qualities for Super Glue levels of grip.
Perhaps with the exception of the recent proliferation of traction-control technologies for sportbikes and sporty type bikes, we haven’t seen huge leaps forward in motorcycling in the past few years.
Despite the status quo in moto tech along with the long-running economic slump that’s put the chill on many companies, forcing them to conserve development resources until consumer confidence gets a full head of steam, Dunlop has continued to forge ahead. President of Dunlop North America, Joe Rosen explained that over the past few years the company has invested upwards of $30 million in its Buffalo, N.Y., facility.
Part of Dunlop’s multi-million dollar investment in itself resulted in the DOT-legal Sportmax Q2 and Sportmax D211 GP-A roadrace tires. Parlaying knowledge gained from experience with the Q2 and D211, Dunlop made a reinvestment of sorts into improving the Roadsmart – Dunlop calls this its “race to road” strategy.
The first (visual) tipoff to the RS II’s evolution is the new tread pattern on both front and rear tires.
The front tire still incorporates Dunlop’s cosecant-curve groove pattern, but the shape and placement of these grooves are newly designed to promote even tire wear up front while also stiffening the pattern for reduced tire squirm and extended tire life. Additional grooves also help improve wet-weather performance thanks to a greater sea-to-land ratio for increased water dispersion. Increased tread depth further promotes water channeling while also extending tire mileage.
Dunlop product and marketing manager, Mike Manning, stated that testing of the new front pattern revealed the front tire was so efficient at shedding water that the rear tire pattern could now employ a higher land-to-sea ratio compared to the previous tire. Simply put, the rear tire now has less tread grooves and more rubber for improved handling and traction in dry conditions.
Also unique to the rear tire is Dunlop’s Multi-Tread tech, or more commonly, it’s a dual-compound tire with a harder, longer-wearing center flanked by softer, grippy edges.
While the first-gen Roadsmart rear was also dual compound, the rear Roadsmart II’s compounds are newly developed and incorporate high-traction resins derived directly from Dunlop’s racing tire compounding technology. Manning said during testing the company discovered using dual compounds in the front tire never showed an appreciable advantage, but the front (and rear) utilizes silica which helps improve wet grip and extend wear.
To further improve linear handling and deliver high cornering performance, the Roadsmart II now incorporates the same Intuitive Response Profile (IRP) technology currently used in Dunlop’s racing Sportmax D211 GP-A tires, and the sport-focused Sportmax Q2. Dunlop says IRP technology uses a steep “tread drop” – the height measured between the tread center and the shoulder edge – to put down a bigger footprint at extreme lean. The objective with this new profile is to allow greater selection in line choice while cornering, as well offer linear steering at various lean angles.
Another enhancement to the RS II is what Manning called greater “hoop strength.” In lay terms the carcass was stiffened somewhat in order to prevent premature wear in the rear tire’s center tread.
A Dry Ride, Four Years In The Making
A miserably cold downpour greeted us on ride day for the first Roadsmart in 2008. This time, for the Roadsmart II, we had nothin’ but blue skies and bone-dry roads. Morning temps were brisk, hovering in the upper 40s, but this meant we’d have an opportunity to get a sense of how quickly the new tire would warm to operating temps.
A diverse selection of motorcycles, including GSX-R600s and 750s, Honda’s NT700V and VFR1200 and BMW’s new full-boat tourer K1600GTL, as well as other standard-style and sport-tourers, were fitted with the new tire. The variety of bikes was Dunlop’s way of implying the new tire’s ability to serve a variety of roles: from sport riding to touring, the RS II aims to please an array of riders.
From city surface streets to freeway droning to long runs through the canyons, our ride route included everything a street-going motorcyclist might encounter. No matter which bike I rode, the Roadsmart II provided quick warm-up and reliable grip; a lack of trust in the tires was never an issue. The RS II stuck like glue while zipping around sweeping canyon roads, even at speeds that caused the heavier sport-tourers like Yamaha’s FJR1300 or Kawasaki Concours 14 to occasionally drag a footpeg.
And courtesy of the Connie 14 and its hyper-fast engine I had a few opportunities to sample the RS II’s stability characteristics during tripl… er, high-speed runs. The big Concours remained steady and true, never once exhibiting disconcerting shudders or weird vibrations, while front-end feel was consistently positive rather than vague. The bike was equally stable during heavy braking.
Dunlop development rider Rich Conicelli said that one of the goals for the new Roadsmart II was lighter and quicker steering feel. I can’t say any of the motorcycles I rode felt quicker steering than usual, but neither did they feel heavier steering than what I was used to.
Stints down the Super Slab at typical L.A.-freeway cruising speeds aboard the big bomber BMW K1600 was the perfect setting to get a sense of the tire’s comfort level – its ability to absorb bumps. The K bike sailed smoothly down the highway; the Roadsmart II gobbling up expansion joints and crummy pavement along the way, but not at the cost of a lower degree of feel or a squirmy ride.
After riding the various types of motorcycles during the day I was inclined to think the heavier bikes might’ve had just a little more ride comfort than the lighter weight bikes – ride quality on the smaller machines occasionally felt firmer. I attributed this sensation to the tire’s increased carcass stiffness, which for the heavier motorcycles should mean increased life – approximately 20% more than the previous Roadsmart according to Dunlop. Of course, tire durability is heavily influenced by the type or riding you’ll do.
After a full day’s ride the most prominent impression I was left with, beyond the RS II’s good grip and overall feel, was how linear steering action was when transitioning from full upright to full lean. This equates to a wonderfully predictable tire, and a predictable tire can instill confidence in the rider. And a confident rider is happy rider who’s not thinking about tires, but is focused on, and enjoying, the motorcycle and the ride.
|Roadsmart II Sizes|
|120/60ZR 17 (55W)||Front|
|120/70ZR 17 (58W)||Front|
|110/80ZR 18 (58W)||Front|
|120/70ZR 18 (59W)||Front|
|160/60ZR 17 (69W)||Rear|
|160/60ZR 17 (69W)||Rear|
|160/70ZR 17 (73W)||Rear|
|170/60ZR 17 (72W)||Rear|
|180/55ZR 17 (73W)||Rear|
|190/50ZR 17 (73W)||Rear|
|190/55ZR 17 (75W)||Rear|
|160/60ZR 18 (70W)||Rear|
|MSRPs on the fronts will range from $201.59 to $213.54 and rear tire MSRPs range from $266.62 to $292.95. Actual prices at retail will vary.|