Dunlop Roadsmart Tire Review

Dunlop's newest tire put to the test, in the wet!

story by Pete Brissette, Photograph by Kevin Wing, Created Feb. 11, 2008
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"I'll never ride in the rain again!"

That's what I said to myself as I ended my L.A. motorcycle messenger career. Sure, I did it for years, and even got pretty good at it, but that didn't mean that I was okay with it. It can be a miserable experience, in my opinion, not to mention the multiplication of danger to what many already consider an overly dangerous way to transport one's self.

I should have figured it wouldn't have been long before I was eating those words...

Here in SoCal the official rainy season is longer than most would expect, stretching from July to late spring of the following year. The reality, though, is that the best chance of rain is from about late October to roughly March, and the 2007/08 season seems right on schedule. Yep, right on schedule and just in time for press the introduction of Dunlop's newest tire dubbed the Roadsmart.

Although Dunlop has targeted the sport-touring segment (VFRs, FJRs, RTs, etc.) with the new Roadsmart, it performed very well on this 2008 Suzuki GSX650F, a bike favoring more of the sporting and commuting side of things.I hate to admit it, but a day of rain couldn't have been a better setting to sample these buns. One of three areas of focus for Dunlop in developing this new tire was wet-weather performance; the other key characteristics are good handling and long tread life.

The tire company focused on these areas for the Roadsmart after it queried sport-touring riders to see what they wanted in a tire. In Dunlop's words, sport-touring riders are "very experienced and skilled" with thousands of miles behind them, and "their knowledge of tire design and capability is significant." In order to meet the lofty requirements of the sport-touring segment, Dunlop "globalized" its efforts and employed all four of its design centers in Buffalo, NY; Birmingham, UK; Montluçon, France; and Kobe, Japan. No beef was used in the making of the Roadsmart.

Coincidently, in light of the worldwide effort used in making and marketing this tire, development was trickier than normal, according to Dennis Tweed Director, Marketing and Operations for Dunlop. "Since the tire is the same as found in the U.S. and in Europe where it's been available for the past couple of months, it presented a big challenge for us in this category," he told Motorcycle.com.

"Going global slowed down the whole [development] process. Performance in the wet is extremely important for them [Europe]. Trying to market the performance and mileage in the tire for two different markets was challenging for our engineers not to compromise any one aspect or characteristic."

The Roadsmart isn't an OEM replacement tire, at least not yet, but when and if it does become replacement spec, more challenges will arise for Dunlop. According to Tweed, bike makers want to “tune” the tire in. This means that there is potential for the OEM version of the Roadsmart to be quite different from the aftermarket version that's built for a wide array of machines.

Flex Steel-Joint-Less Belt is the yellow colored layer just underneath the tread. Dunlop says this radial construction gives the Roadsmart much of its stability, grip and long tread life
Here you can see that the longer wearing compound that makes up the center tread serves as a base layer with the softer side compounds laid on top. The purported advantage is better heat dissipation.
For the Roadsmart, Dunlop created a new radial carcass construction process called Flex Steel-Joint Less Belt (FS-JLB) that's used in the making of the front and rear - an apparent first for Dunlop production tires. In simple terms, a zero-degree joint-less steel belt makes up the layer underneath and two plies of rayon - used for its excellent damping qualities - are laid at opposing angles just below. This type of construction, says Dunlop, minimizes distortion of the carcass helping the tire keep its shape when you've packed your FJR1300 like a rented mule, are mercilessly flogging your bike down the canyons or sailing the super-slab at crazy speeds.

Tire profile is an important factor, especially for the performance side of things. The Roadsmart replaces Dunlop’s old D220, and the new tire has a higher “tread drop,” that distance as measured between tread center and the tire's shoulder edge. With a slightly milder or more round edge and narrower profile, the Roadsmart offers a bigger contact patch as well as quicker steering transitions.

In another first for Dunlop production street tires, the company has created a dual or "multi-tread" compound for the rear. You can probably guess what that means: a harder and thusly longer-wearing section of rubber in the center with a softer compound on either side for better grip. But don't think of the dual-compound construction like a peanut butter sandwich with three distinct layers. Nope, the rear Roadsmart uses the harder stuff as something of a base layer with a large lip that makes up the center portion while the softer compound on both sides of the center tread are layered on top. The idea here was to use the harder compound underneath to help dissipate heat build-up during long straight runs or when the wifey (or hubby – don't get nasty on me, ladies!) is on the pillion.

Finally, we come to the wet. Capping off the final key characteristic of the Roadsmart was the use of a new extrusion process and a whole bunch of chemistry to get the right blend of polymers, resin, silica and ultra-fine carbon black for improved wet grip and quicker warm-up times, all without reducing mileage. To further enhance wet-weather performance, engineers did a little tweaking to what's called the "void to tread" groove distribution. It gets a bit techie and rather uninteresting, so just know that there's deeper  grooves and the groves are a bit longer in the tread center in order to better drain water from the tire. Conversely, there's slightly less "void" or groove on the tire's shoulder so you've more rubber for better dry grip when leaned over.

Here's a small sampling of the bikes the Roadsmart can be used on: BMW R1200RT, Yamaha FJR1300, Honda VFR and a Suzuki GSX650F. This photo is also proof that it does rain in SoCal.

With all the right ingredients in place there was one last step before Dunlop unleashed its newest tire on the world. Finite element analysis (FEA) and 3D finite element modeling (FEM) were used to "pretest" the tire in various virtual constructions under various simulated conditions. This allowed Dunlop to narrow its focus, developing only the best possible prototypes before real-world testing began. When it was time for the rubber to meet the actual road, the tire maker discovered that test riders gave feedback very similar to what pre-testing in the lab had predicted. The benefit to FEA and 3D FEM: Developers could zero-in on fine-tuning the prototypes, spending less time back at the drawing board.

Rain Time, Ride Time

As I mentioned earlier, the weather may have created the perfect setting for evaluating the new tire. A storm that brought cold, days-long midwinter rain prior to our ride had softened the canyon walls enough to cause mini rock slides and little islands of sand and mud that covered countless corners and sections of road. That same storm lingered in the area long enough to bring strong on-again-off-again downpours about half way through our ride. Conditions were bad enough at some points that I had forgotten this was a tire test, confusing it for an intro of the latest adventure-touring machine wherein the bike maker had crafted one gnarly environment.

Although I didn't get any miles on the GSX650F with its stock tires for comparison, I was satisfied with the handling dynamics of the middleweight Suzuki with the Roadsmarts. They reacted well to steering inputs, offering a predictable turn-in rate that aided confidence in the dicey riding conditions.

The new Roadsmart's performance in wet conditions was just as advertised. Grip was consistent and predictable. Handling remained neutral, and stability at higher speeds was excellent.In the end, we all made it back in one piece, and I'm happy to have nothing negative to report. No unexpected loss of traction under braking. No hydroplaning or instability at freeway speedways. No little slips or drifts while cornering. No ill-effects to the bike's handling. Nope, nothing. Nothing but a tire that performed just as Dunlop suggested it should.

There is one caveat worth mention: An opportunity to sample the Roadsmart's dry conditions performance never really surfaced, as our route always had some degree low-traction and the weather deteriorated as the day wore on.

However, we don't have much reason to think this latest tire from one of the biggest names in rubber should perform worse in a perfect setting than it did when all the elements were stacked against it. And, in dry conditions, the softer compound in the tire’s shoulder area will undoubtedly improve edge grip. 

Sizes and U.S. MSRP for the Dunlop Roadsmart
Front:

120/60ZR17  $183.14
120/70ZR17  $188.53
 120/70ZR18  $193.99 

Rear: 150/70ZR17  $230.33
160/60ZR17  $231.21
170/60ZR17  $231.85
180/55ZR17  $242.43
190/50ZR17  $247.84
160/60ZR18  $238.81



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