Following his near-perfect performance at Texas’ Circuit of the Americas for round two of 2015 MotoGP, Marc Marquez was the immediate favorite for this past weekend’s round three at Argentina’s Termas de Rio Hondo.Marquez had won during the circuit’s debut last season, and was quickly up to speed, earning his second-straight pole of 2015 MotoGP.
The 22-year-old Repsol Honda pilot then ran a near-perfect 23 laps in Argentina. But too bad the race consisted of 25 laps; Marquez crashed out with two to go while battling with nine-time World Champion Valentino Rossi.Marquez was riding smoothly, but Rossi had better longevity due to choosing an extra-hard rear Bridgestone slick while Marquez slipped around on the hard-rear tire. Rossi started from eight, but fought his way to take the lead from Marquez on lap 23. The youngster attempted to counter, but ran into the back of Rossi’s YZR-M1 and flopped to the ground, crashing out.Marquez sprinted to his RC213V, but the bike wouldn’t start. This caused a DNF, and a win for Movistar Yamaha MotoGP’s Valentino Rossi. This was Rossi’s second victory in three rounds, including the season opener in Qatar.Rossi ran effortlessly for the final two laps, taking the win ahead of Ducati Team’s Andrea Dovizioso and CWM LCR Honda’s Cal Crutchlow.Following the race, spec-tire manufacturer Bridgestone offered some analysis. Bridgestone says that the entire race weekend was dry yet the first day was marred by poor track conditions that resulted in low grip and accelerated tire wear. Conditions improved as each session passed and although track temperatures reached 116°F during qualifying on Saturday, it was cooler for the race with track temperatures in the high-90° range.Following is some Argentina MotoGP Bridgestone tire analysis from Masao Azuma – Chief Engineer, Bridgestone Motorsport Tire Development Department.Q. The Argentina Grand Prix was the debut for Bridgestone’s new extra-hard specification rear slick. Did this option perform as expected last weekend?Masao Azuma says: “The extra-hard rear slick was developed specifically to meet the extreme demands the Rio Hondo circuit places on rear tires and it performed very well level. There are two challenges at this circuit, extremely high temperatures on the left shoulder of the rear tire, and high rates of wear on the right shoulder.“With this in mind, using the data we acquired during last year’s race, we completely revised our rear tire allocation for this year – the medium and hard rears this year were also different to 2014 – and also developed a new extra-hard rear. In regards to the performance of the extra-hard rear, Valentino Rossi showed the potential of this tire by being able to lap quickly through the race. His second half of the race was particularly strong as set a new race lap record on the twentieth lap of the race and beat last year’s race winning time by four seconds.”Q. Given the strong performance of the extra-hard rear slick, was it the best race tire for the factory Honda and Yamaha riders?Masao Azuma says: “Based on our analysis over the race weekend, our recommendation was for the factory Honda and Yamaha riders to use the extra-hard rear for the race but in the end each rider had to make their own decision based on their race strategy and bike setting.“Making a final decision on race tire choice was difficult for some riders as conditions for the race were cooler than on Saturday when they did their race simulations. Rossi’s quick, consistent pace on the extra-hard rear slick was impressive but Marquez also rode a very strong pace and challenged for the win on the hard rear.“Also, Crutchlow was third and set his fastest lap on the last lap of the race with the hard rear, so it is obvious that this option also performed well. Tire management in this race was key, with either rear slick option for the factory Honda and Yamaha riders capable of producing race-winning performance.”Q. In Free Practice 1 on Friday morning many of the riders experienced graining on their rear tire. Can you explain what this means?Masao Azuma says: “Graining is a particular type of wear that is associated with a track surface that has very low grip, yet is abrasive. It causes excessive tire wear and creates a rough appearance on the tread of the tire. This phenomenon often occurs when there are large amounts of dust on the circuit which causes excessive spinning and slipping of the rear tire.“We expected graining to occur during the first session and knew that as more rubber was deposited on the racing line, the problem would go away. In the second practice session on Friday afternoon the graining was greatly reduced and by Saturday had completely disappeared and tire performance returned to normal. The dirty track conditions that cause graining is something that occurs at racetracks that aren’t used regularly and therefore don’t have a clean racing line, the most obvious example apart from the Rio Hondo circuit being Qatar’s Losail Circuit.”
This week we ride two genre-departing motorcycles from the established American manufacturers. Jess McKinley gives us his thoughts on the all new Harley-Davidson Pan America Special, and Ron Lieback gives his on Indian’s latest version of the FTR 1200 S.