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Thursday, 22 September 2005 |
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Donut testing by Mike Emery ~ Donut shooting by Kevin Wing
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Traditionally street rubber and racetracks don’t mix very well. The problem is, a track dwelling tire has to put up with a lot more activity at any given time due to tremendous and consistent braking forces and track friction. Consequently they tend to come apart at the seams, like a cheap leather suit. The invite from Dunlop to come ride this new street tire showed some pretty good faith in their product and some balls too... not only were we offered that track day sample but we were offered two whole days of it too. Surely they’ve lost it, a two-day journalist GP on weekday rubber? My tail bone was hurting just thinking about it.
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Having missed the initial briefing for the tire in Las Vegas due to a bird dive-bombing our Boeing en-route, I settled for a quick scan through the press kit and some wise words from Dunlop’s product and marketing manager, Mike Manning. He explained a little about the prior history of street tires in the US, starting with the 364 which was replaced with the 207, a quantum leap forward in design and grip, he told me. The 207 begat the 208 and although not quite the jump forwards that they were hoping for, a better tire anyway. Next up the 209... whoops, I mean, the Qualifier. Apparently this tire represents a similar leap forward in design as the original 207 from that 364.
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Dunlop’s development manager, Mick Jackson, a bruiser looking British guy who looked like he’d kick your arse if you didn’t like the results of his work (or if you call his new tire a 209), confirmed to me that specific targets were incorporated into this new tire, obviously dry grip, wet grip and wear characteristics were up the top end of the developmental list, but more importantly, they were looking for a streetable version of their multi championship winning race tire, and a tire that would be significantly better than what was already on the market - basically a race tire for the street.
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Technology-wise, the new rubs have a smaller molecule/particles in a compound very similar to the Sportmax GP race series. A sticky three polymer blend is reinforced with lots of carbon black, and a secret sticky resin sauce thrown in to maximize the wet and dry grip. This also offered these tires a quick warm up time and better overall traction dynamics than the previous 208.
The build style of these tires incorporate a jointless belt rear carcass that inhibits growth and distortion at speed. Improvements in that belt design and construction have a great additional side effect too - It’s almost a pound lighter than the 208 - Unsprung weight reduction is like free horsepower and your bike will change direction quicker, win, win.
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The icing on that big rubber donut is a triangulated front tire that is a similar aspect ratio to the GP spec tire, offering a bigger footprint than the old’n, and an aspect ratio that promotes quicker turn-in and lighter steering. The bigger footprint, an 18% improvement at a 45-degree angle of attack, and the rear, an 11% increase, tells us (on paper) that the bike’s going to be able to run deeper into a corner, offering better stability and more grip. Tests on two continents prove that on some tracks (VIR as an example) there’s a 3.5 second advantage to the new tire. Data acquisition shown to us also confirmed that improved side grip translated into higher corner speeds and a consequent superior drive out from that point on. In some points of the track, especially through transitional sections the speed differential was a little over 8mph faster.
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OK, so it all sounds good, but a potential fly in this rubbery flavored soup, is the profile. If distant memory serves me correct (which would be remarkable as it’s been pounded around my cranial cavity a few times since) but wasn’t the 207 a little “flighty” back in the day? I distinctly remember the head-shake experienced on these originals especially on bumpy A and B roads rather than billiard table smooth racetracks. Tire wear was also an issue, and in some cases it was recommended that you run the tire backwards to cure the strange wear that verged on cupping. So, a step backwards? Lesgofindoot...
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