Bridgestone Press Release: Hirohide Hamashima Talks Through What Happened At Assen

Press release from Bridgestone, discussing the problems that occurred at Assen, and what Bridgestone did to try to alleviate them:


Dutch TT debrief with Hirohide Hamashima

Round 7: Dutch TT – Post-race debrief
TT Assen Circuit, Tuesday 28 June 2011

Bridgestone slick compounds available: Front: Soft, Medium. Rear (asymmetric): Medium, Hard

Wet compounds available: Front: Soft. Rear: Soft

The Dutch TT marked the first MotoGP victory for Yamaha's Ben Spies, who becomes the tenth rider to win a premier class Grand Prix on Bridgestone tyres. Conditions all weekend made running very difficult indeed: the track temperature was a significant 29 degrees Celsius cooler than last year during the race, rain interrupted running every day and left the circuit very greasy, and an oil spill from the Moto2 category on Thursday cancelled the afternoon's running and although it was cleaned up, it didn't help track conditions.

Hirohide Hamashima – Assistant to Director, Motorsport Tyre Development Division

There was a great deal of talk of tyres all weekend. Firstly, what can you clarify what happened on Friday?

"Friday morning was the first dry running the teams got after the rain on Thursday, so it was the first day that riders used our slick tyres. We selected the same slick tyre compounds this year as we used at Assen last season, because our data and rider feedback suggested there was no reason to change. Track conditions on Friday morning were so bad though. Not only was the temperature cold but the track was slippery from the rain and I believe that some oil still remained from the spill, and that contributed to the riders feeling that grip was so bad on Friday morning. Riders requested a solution to their difficulty in warming-up the left side of the rear slick tyres at midday on Friday. Initially their request was for us to cut the slicks on the left side, which we were prepared to do, but finally there was no consensus between the riders so we were unable to proceed with this measure.

"Then we made a proposal of our own to bring a new rear slick tyre specification from our base in Germany overnight in time for warm-up and the race. This new specification featured a softer left shoulder, using our extra soft compound, so would have directly assisted with warm-up performance in this area. The right shoulder meanwhile was still the same medium compound as used in the original specification, which was performing well, so performance in this area would have remained the same.

"We were loading the truck in Germany, after the FIM asked all the teams and riders for their opinions and told us that the proposal was well received, however later on Friday evening we were informed that there was no unanimous agreement between the teams so we were unable to change the tyre allocation. Some riders didn't agree because they didn't feel there was a safety issue with our original compound selection. In the conditions we saw in the race on Saturday, I think the revised slick tyre specification we proposed would have been beneficial for the first few laps in terms of warm-up performance, but of course the trade-off of this would have been reduced durability over race-distance."

In the race a few riders, especially Crutchlow and Edwards, experienced high front tyre wear. Why was this?

"We have seen that most riders usually prefer the harder spec front slicks as they have improved stability and wear resistance, and can be pushed harder through a corner and resist graining. However, seeing as conditions for the race were so cold and slippery, almost all riders chose the softer option front to be safe. The trade-off of the improved low temperature grip provided by the softer option is that it is more susceptible to graining. Bike setup and riding style also play a significant role in tyre performance and extracting the maximum performance from the tyres. Certain rider, bike and tyre packages were more severe on our front tyres, and as soon as a situation leads to the front tyre starting to grain, the issue gets increasingly worse.

Assen has been resurfaced and remodelled many times over the years and so as a result it has a mix of tarmac, some of which is smooth and some abrasive. On the abrasive sections, especially through the long and fast right-handers, the wear resistance of the front tyre was really tested. For most riders it was not a problem, but clearly Colin, Cal and Andrea had a problem with front graining and wear rate."

Is there any more news about the vibration Dovizioso experienced during the race?

"Andrea's rear tyre had no problems – we have examined it and there was nothing out of balance with either it or the wheel, and nothing to indicate that the rear tyre was the cause of the vibration. Rather, all the signs point to front tyre graining being the cause of the vibration that Andrea felt through the bike. Basically, as the rubber grained, the right side of the tyre became slightly uneven, or not perfectly smooth, and this is what caused the vibration."

2011

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Comments

However, does it seem unreasonable for Bridgestone to check the weather 1 week ahead of each GP and to send an extra specification by road if the conditions are likely to be different from last year or from what they have foreseen?

Then with 3 specifications on hand they would be able to propose 2 of those 3 to the MotoGP riders and they would have better performance.

That would require what, to be ready to bring maybe a 100 extra tires ahead of each round with unforeseen weather conditions?

Would it be that expensive considering they have plants in Europe and Asia were most of the races (minus 2) take place? So they could store a certain amount of tires, ready to be brought by road ahead of some Grand Prix.

I don't know where the Bridgestone plants are but they have at least one in Germany which would be fairly close to all the european rounds and at least one in Japan where they can store the extra specifications.
Don't know about the US but the only real concern would be Indy since the weather in Monterey is very predictable (foggy in the morning, torrid in the afternoon).
Sepang and Losail also have very predictable temperatures.

All in all it would require to ship more than the extra tires they would eventually use during the year but it does not seem such an insurmountable challenge?

Total votes: 31

Are the CRT going to get tires like the current teams do next year? If so, this will just complicate Bridgestone's problems.

Riders are always going to complain about tires. It's just part of racing. the problem isn't really the tires anyway. It's the nut holding the handle bars.

Total votes: 32

If it was confirmed that Simoncelli had been the one naysayer to the new tire allocation offered by Bridgestone, I wonder if journalists ever asked him after the race about his decision. Talk about irony, if true.

Total votes: 23

None of the riders were intending to use the softer tire to race on, they just wanted the extra tire for the morning warmup. With colder temperatures, they could get some decent data and save a soft tire for the race.

Total votes: 31

that the tire allocation rules were supposed to provide for the teams, I wonder what it costs a team for one of their riders to miss a race or two or three. When you consider all of the cold tire injuries over the last two years, how is it even possible that this silly tire rule is saving teams or Dorna any money?

I agree with Frenchie. If you have to limit all of the teams to the same two tire choices, let's not set those choices in stone a month before the race! Or at least have a backup plan unless the weather report looks iffy a couple of days beforehand.

Total votes: 33

All a bit of a storm in a tea cup stuff. Certainly the previous days oil must have been a contributing factor. And as others have said fair enough for Simoncelli to veto, he was sorted, why give an advantage to his competitors.

Simoncelli's crash notwithstanding. Those that got their bikes set-up well in the short space available rode without issue. The time lost to the wet was the biggest issue of this particular strung out field.

As mentioned previously I wonder how much more of a logistical / cost exercise it would be to be better prepared (with more options to choose the allocated of two compounds) for these weather exposed circuits. Estoril, Assen, Philip Island..... 

Total votes: 28

Spoke to Bridgestone people. They said that there had been a request for a third spec of tire at Laguna, but they can't do that logistically. Bridgestone will be bringing a softer spec to Laguna, but still only 2. 

The proposal for bringing 3 specs has been put forward, and will be discussed tonight in the safety commission, but that is a very significant investment, and Bridgestone would be reluctant to make such a change. This story is going to drag on for a while.

Total votes: 30

The statement of Lorenzo on BS bringing 3 specs next year as disappeared in the english version but is still online in the italian version...
Does the safety commission have multiple meetings during a GP weekend?

Total votes: 29