Dunlop Refines the Roadsmart IV Series

[darrell]

A little more than a year after bringing its Roadsmart IV tire line to market, Dunlop is now refining its touring-oriented series, creating two sub-lines.

When introduced in August of 2020, the Roadsmart IV tires came in with a two-compound design on the tire’s exterior, which enables the tires to last longer on the highway straights while still retaining grip on the shoulders for aggressive cornering. Then, there’s a third compound beneath the tires’ surface, intended to help them get to peak operating speed more quickly. The Roadsmart IV line also came to market with the usual talk of improved tread and tire profile offering heightened performance. Originally, the tire came in 17-inch and 18-inch front sizes. Rear tires were only available in 17-inch sizes.

A little over a year later, Dunlop is tweaking the Roadsmart IV:

In the most popular sizes (120/70ZR17 front; 180/55ZR17 and 190/55ZR17 rear) Dunlop has developed two distinct versions of the RoadSmart IV. The SP variant is optimised for lighter and sportier road machines, whereas the GT variant is tuned to bring greater handling prowess to larger touring bikes.

Dunlop says the Roadsmart IV is designed to fit 17 of Europe’s 20 top-selling bikes, including the BMW R1250 GS as well as crossover touring machines like the Yamaha Tracer. While obviously not a dirt-oriented tire, it would be a possible option for road-biased travelers, particularly now that there’s a version developed that’s intended for heavier machines. Presumable, the tires intended for heavier bikes have a slightly different compound and beefier carcass, although they may look the same.

The updated design joins the Mutant, the street-legal K950 trials tire and the reintroduced D605 dual-sport tire in Dunlop’s US lineup. Despite COVID supply chain issues, Dunlop seems keep its touring/ADV/dirt/dual sport lines healthy.

[Grumpy Goat]

Cool. Thanks for sharing this Darrell.

With this change they are even more directly competing with the Michelin Road 5 which comes in Standard and GT forms. I guess the RS would still take the standard RSIV. Interesting that they mention the Tracer as well, since I have both bikes which are the intended targets for the RSIV.

[Ray]

Reply to this news from the road -

[Lee]

Presumable, the tires intended for heavier bikes have a slightly different compound and beefier carcass, although they may look the same.

I wonder why they would use different compounds on beefier carcass tires.
Does Michelin use different compounds on the GT version?

[Chris216]

Thanks for the news Darrell, do you know what the bike weight suggested for the std and GT versions is?
Chris

[darrell]

Thanks for the news Darrell, do you know what the bike weight suggested for the std and GT versions is?
Chris

Once I get a chance to visit with Dunlop I'll let you know what I find out.

[Lee]

When the R1250RS is fitted with Michelin at the factory are they the GT version?
In 2016 one of our R1200RS bikes came with Michelin and it had the non GT version.[/i]

[darrell]

When the R1250RS is fitted with Michelin at the factory are they the GT version?
In 2016 one of our R1200RS bikes came with Michelin and it had the non GT version.[/i]

I’m not positive on your Michelin version question as it has been some time since I used a set of Michelin tires but having run a few sets I believe it is indicated on the sidewall of the tires.

[Lee]

I’m not positive on your Michelin version question as it has been some time since I used a set of Michelin tires but having run a few sets I believe it is indicated on the sidewall of the tires.

Yes, it will show GT on the sidewall.

[Duccrazydave]

Does this mean the SP version is identical to the original RS IV?
I'm completely satisfied with the current set.

[darrell]

The SP and GT versions are the European versions of the Roadsmart IV tires. The tires we get in the US are the Japanese version and will not change from what we have today. The GT tire is a more robust construction so should generate higher mileage. The GT will be recommended for bikes over 550 lbs and for riders who want higher mileage from their tires.

There is some discussion to bring the 19” front and 17” rear sizes to fit the GS models in to the US.

[Lee]

It's interesting Dunlop claims longer tire life from the GT version.
I don't think Michelin makes any claims of longer tire life from their GT.

[Duccrazydave]

Thanks for clarifying that, Darrell

[Ray]

It's interesting Dunlop claims longer tire life from the GT version.
I don't think Michelin makes any claims of longer tire life from their GT.

I think the claim was the Dunlops have a longer life than the Michelin GT.

From their press release:

"Independent testing on a 2016 BMW R1200RT yielded more than 12,000 miles on the Dunlop RSIII, 3,000 miles more than the Michelin
Pilot Road 4 GT*"

"Like the RSIII, the RSIV delivers best-in-class mileage—up
26-percent compared to the RSIII—and stays close to its peak
performance throughout its lifespan.** Additionally, the RSIV offers
performance upgrades in both wet and dry conditions. Compared
to the RSIII, the RSIV has quicker steering response for more nimble
handling, and greater wet-weather performance—grip, stability and
overall response.***"

*As compared to the Michelin Pilot Road 4 GT tire in sizes 120/70ZR17 front and 180/55ZR17 rear on a 2016 BMW R1200RT in independent test performed by Texas Test Fleet, Inc. Individual results may vary.

**Testing performed by Dunlop in Japan on a 2018 Honda CB1300 SB with tire sizes 120/70ZR17 front and 180/55ZR17 rear on 40% public roads and 60% highways. Individual results may vary.

***Testing
performed at the Sumitomo Rubber Industries, Ltd. proving grounds in Japan on a 2016 Suzuki GSF1250 with tire sizes 120/70ZR17 front and 180/55ZR17 rear. Individual results may vary

[darrell]

Ray's information is from the marketing comparing the Roadsmart III and IV tires as well as against the Michelin Pilot Road 4 GT.

Below are my questions to Dunlop and the response as related to comparing their now confirmed to be Euro only version of the SP and GT variations of the Roadsmart IV tires.

1) when will these 2 different versions of the RS IV be available for US riders to install? Dunlop Response - They will not be available here. These are Euro versions and are different than the Japanese versions. We may bring in the 19” and 150 rear though for ADV fitments

2) is there a bike weight point that determines which of the 2 versions one should install on their bike model? For example my 2016 R1200RS weighs 525 lbs plus me and my gear when traveling. Dunlop Response - All the heavyweight sport touring bikes would run their GT spec, so basically bikes weighing above 550 lbs or people wanting to get higher mileage.

3) is there a specific marking on the 2 versions that identifies them? Dunlop Response - Their versions will say SP and GT

4) if I install a set of each on my RS BMW would you expect I would see different mileage performance for each version? Dunlop Response - SP would get less mileage. GT version is a more robust construction, so it will get better mileage.

[Ray]

Darrell -
Thanks for the clarification.

So I got this straight -
RS III longer life than Pilot 4 GT,
RS IV > RS III.
RS IV GT > RSIV SP....

I agree with Dave - happy with the current RSIV engineered, tested, and manufactured in Japan Sumitomo).

Where will the new European models be manufactured?

[VTBob]

Since I've gotten my RS I've always put on Michelin RP 4 or now 5. To my memory I've never had the GT version.
I'm happy about that.
It sounds to me the GT means more load carrying capability which implies at least a stiffer / stronger side wall and maybe a less flexible belt (less flex, temp build up).
These are my speculations , extrapolations from Darrel great info.
For my riding style, even when the RS's weight with me and luggage puts in in the GT spectrum, I prefer what I perceive as a more flexible, (road conforming, softer ride) and possibly a stickier (less milage) pair of tread compounds.
I'm sorry to hear the Dunlop SP will not be coming to the states. On my old RT in the past I had very good results with the early Dunlop version of the dual compound

[darrell]

The Dunlop Roadsmart IV has a more flexible sidewall then the RS III. Point 7 in the attachment mentions this. The mention Dunlop will not be bringing these to the US could change in the future. I base this comment solely on the fact the Dunlop Mutant version was released in Europe at least a year before it appeared in late 2020 or early 2021 in the US.

https://ultimatemotorcycling.com/2020/08...ast-facts/

[Grumpy Goat]

Since I've gotten my RS I've always put on Michelin RP 4 or now 5. To my memory I've never had the GT version.
I'm happy about that.
It sounds to me the GT means more load carrying capability which implies at least a stiffer / stronger side wall and maybe a less flexible belt (less flex, temp build up).

I have had a PR5 GT on my RS once when the dealer did not have a standard PR5 and it appeared to be no different than the standard one, may have been a little stiffer due to specs, but without scientific measurement (as opposed to subjective "butt-feel") it is hard to tell. Wore similarly as well.

[Ray]

Just smoked my 2nd set of RS IVs (it took only 2 weeks of fun). The sidewall is definitely more pliable than the RSIIIs I tried.

Not clear that what we currently have available from Japan is any different than the described SP (presumably to be manufactured in France?).