Data shows just how much quicker Jeff Williams was on the Dunlop "Q" tires at CTMP. Data shows just how much quicker Jeff Williams was on the Dunlop "Q" tires at CTMP. Photo by Richard Coburn

Trevitt's Blog: What's a Qualifying Tire Worth? Featured

Written by  Andrew Trevitt on Tuesday, 06 September 2016 11:23

At the final rounds of this year's Mopar Canadian Superbike Championship series, held at Canadian Tire Motorsport Park, Dunlop offered qualifying tires to the top 10 riders for a separate, 15-minute final qualifying session. This was new for many of the competitors, as qualifying tires have not been used in the series for several years. Jeff Williams was one of the riders in the top-10 session, and I was able to get some data from the Accelerated Technologies Honda CBR1000RR that he was riding for the weekend.

The data, gathered using an AiM EVO4 GPS-based system, showed just what the advantages were from the sticky qualifying rubber.

While many current watchers of the CSBK series may not be familiar with Jeff Williams, he was a top contender in the Sport Bike and Superbike classes 15 years ago, winning a Superbike national race at Calgary in 1999. While Jeff has been racing in the Pro Sport Bike class occasionally for the past year, this weekend was his first on the CBR1000RR, and his first time on a superbike in more than a decade.

Jeff set a time of 1:23.007 in the first part of the qualifying session, using a standard rear tire, to make it into the final shootout. His plan for the 15-minute session was to complete three laps at the beginning, again on the standard tire, before fitting the qualifying tire for the final few minutes. Only a rear tire is offered in a qualifying compound, and a standard-compound front tire was used through the session. It was anticipated that the qualifying tire would only be good for one lap at speed on the four-kilometre CTMP road course.

After a relatively slow warm-up lap (to avoid wearing the qualifying tire out too early), Jeff was immediately finding and taking advantage of the extra grip offered by the qualifying tire. In turn 1, he opened the throttle 13 metres earlier than his usual opening point, and likewise reached full throttle several metres earlier than usual. In turn 2, the difference was even greater, as Jeff opened the throttle more than 30 metres earlier than usual, and reached full throttle 50 metres earlier. This is repeated through the first half of the circuit, saving about a tenth of a second in each turn and succeeding straight.

Looking at the use of the throttle over time, on Jeff's previous best lap he used full throttle for 11.6 seconds over the first half of the lap; with the qualifying tire that increased to 12.2 seconds. More importantly, his time at closed throttle decreased significantly, from 9.2 seconds to just 6.7 seconds. A similar pattern was evident in the second half of the lap, with more throttle, and earlier openings, in every turn.

We can also look at slip and when the bike's Bazzaz traction control system is active for any differences between the tires. What's interesting here is that the data shows a bit more slip with the qualifying tire than without, and in the first part of the lap more activation of the traction control - a good indication that Jeff was up to speed and taking full advantage of the extra grip the tire offered right from turn 1.

In terms of outright cornering speed, the data indicates that the qualifying tire does not offer much in this respect. Apex speeds in most of the corners are actually less with the qualifying tire than with the standard tire, with one anomaly in turn 2 - here, apex speed was considerably higher with the qualifying tire. As you'd expect from using only a rear tire with more grip, as opposed to both front and rear, the big advantages come on the corner exits as the rider is on the throttle, with more speed on each straight. Part of this discrepancy may be the way Jeff has changed his riding to better suit the qualifying tire, but the suspension data does indicate that some setup changes to account for the now-mismatched grip levels would help.

Unfortunately, Jeff had a problem on the back straight and had to close the throttle momentarily, which hurt drive and lowered top speed from its usual peak of just over 275 km/h to 267 km/h. Ironically, suspension data shows that it was a big wheelie that forced Jeff to close the throttle, perhaps a side effect from the extra grip offered by the rear tire. In any event the miscue cost more than two tenths of a second.

According to the official timing, Jeff's lap time with the qualifying tire was 1:22.399, an improvement of just more than .6 seconds; without the issue on the back straight, the gap would have been closer to .8 seconds. This is in line with the riders at the front of the field: the top three all improved their times from the first part of the session by .9 seconds. As expected, the tire's performance dropped off quickly, and Jeff was unable to go any quicker after that first flying lap.

What's impressive about all this is that Jeff and the other riders, most with no experience with qualifying tires, were able to adapt so quickly to the different tire and take so much advantage of its extra grip right away in the lap. If the use of qualifying tires continues in the series for next year, it will be interesting to see just how the lap times shake out as the riders and crews gain more experience with the stickier tires.

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Last modified on Tuesday, 20 September 2016 17:44
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