Bridgestone Press Release: Shinji Aoki Explains Why Asymmetric Front Tires May Not Have Helped At The Sachsenring

Bridgestone today issued their usual post-race debrief discussing how their tires held up at the last Grand Prix, this time at the Sachsenring. There was much controversy at the German racetrack over the number of crashes, with riders responding positively to media suggestions that an asymmetric front tire may help. Bridgestone's Motorsport Tyre Development Manager Shinji Aoki addresses this, and other questions in the press release.

German MotoGP™ debrief with Shinji Aoki

Wednesday 17 July 2013

Bridgestone slick compounds available: Front: Soft & Hard. Rear: Soft, Medium & Hard (Asymmetric)
Bridgestone wet tyre compounds available: Soft (Main), Hard (Alternative)

Repsol Honda’s Marc Marquez won his second race of the season at Sachsenring after overcoming the challenges of Monster Yamaha Tech3’s Cal Crutchlow and Yamaha Factory Racing’s Valentino Rossi who placed in second and third place respectively.

Weather conditions at Sachsenring were typical for the German circuit, with cool, overcast morning sessions giving way to warm and sunny conditions in the afternoon. This large difference in track temperatures between sessions made finding a setup more of a challenge than usual and tested the riders, teams and tyres to the limit. Conditions for the race were fine and sunny with a peak track temperature of 39°C.

Q&A with Shinji Aoki – Manager, Bridgestone Motorsport Tyre Development Department

Sachsenring has a reputation of being a very tough track for tyres. Can you summarise the reasoning behind Bridgestone’s tyre allocation for this race and how the tyres performed?

“Yes this circuit is challenging for tyres - especially for the rear - and so our tyre allocation for the German Grand Prix is quite different to what we usually supply. This circuit features many large-radius, left-handed corners and so the riders are at large lean angles for long periods of time which is what generates very high temperatures in the left shoulder of the rear tyre. As a result, the difference in the hardness of rubber used on the left and right shoulders of the asymmetric rear slicks is the largest for any circuit. There is also a larger gap than usual in the hardness of our two front slick options at Sachsenring, with the soft compound being offered alongside the hard compound front slick. These two front slick options provided the riders with a very wide operating range to manage the cool morning and warm afternoon sessions and we could see that in the morning sessions, the softer front option was more popular as it gave better warm-up performance while in the afternoon, the hard option was used so these front slicks worked exactly as intended.

“The weekend started out being quite tough for some riders as the cool right side of the tyre caused by the infrequent right-hand corners resulted in a few incidents. However, we were always confident that our tyre allocation was up to the task and we saw that as the race weekend progressed, the pace improved and fewer incidents were recorded and Sunday passed almost without any incidents. This was the result of the teams, riders and Bridgestone engineers working closely together to find a bike setup and tyre combination that allowed the riders to find a good rhythm around this technical circuit.”

With such a high demand placed on the rear tyres at this circuit were any problems encountered with the rear tyres this weekend?

“Sachsenring is one of the circuits where we have supplied heat-resistant rear slicks for quite some time, but this year was the first time we provided this option in the soft compound option solely for the CRT riders. We kept a close watch on the wear characteristics of these soft rear slicks in case excessively high tyre temperatures were recorded and in general, this option worked very well and stood up to the demands of this circuit. It was pleasing to see three CRT riders in QP2 and again the performance of Aleix Espargaro using this soft CRT-specific tyre option was very impressive. Overall I was pleased with how all our tyres performed at Sacshenring as it really is a severe track for tyres and the pace during the race was very fast with no signs of excessive wear after the race.”

As Sachsenring only has three right-handed corners would asymmetric front slicks solve the problem of having the rubber on the right side cooling excessively?

“We may investigate developing an asymmetric front slick, but good front-end feel from the motorcycle is very important to a rider feeling safe and confident, so many factors need to be considered. Having rubber of different hardness on the left and right shoulders of the front tyre can affect the feel and balance of the bike, especially under braking and changes of direction. In this case, such handling problems would outweigh any benefit so an asymmetric front tyre might not be the best solution. In any case, an asymmetric front tyre wouldn’t solve the problems encountered at Sachsenring as the right shoulder of the tyre would still lose temperature as the distance between right-handed turns at Sachsenring is so vast. The layout of this circuit means that riders will always have to take extra care when negotiating right-hand corners and on Sunday they proved that there are ways to ride this circuit at a competitive pace without incident.”

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I wonder if Lorenzo, Pedrosa, Dovisioso and Crutchlow's definition of 'wide operating range' isn't somewhat different from Aoki's!

"In any case, an asymmetric front tyre wouldn’t solve the problems encountered at Sachsenring as the right shoulder of the tyre would still lose temperature as the distance between right-handed turns at Sachsenring is so vast. "


Why do they do dual compound rears then?

He assumes the leading MotoGP riders could not consider the differing performance of an asymetric front tire...yet they produce an asymetric rear for precisely this reason! The aliens know exactly where they are, what the machine can do in that INSTANT, and are gambling traction vs drive vs performance life, a running 3-variable equation, and this "product manager" thinks he knows better. He should go for a ride with Randy Mamola at every track, and issue his press reports after changing his soiled underpants.

Has The honorable Shinijni Aoki EVER done A SINGLE LAP on a MotoGP bike?

He sounds like a general who has never had a field combat command dismissing losses in an assault. "Yes, , there are many dead, and soldieres end up in the hospital, but this is their fault for not being good enough to defeat tanks with our rifles"

It's a press release that will always seek to put a positive spin on the company and the product. The nature of these press releases has been discussed before in that they will almost never admit a fault of the tires. And yes, Pedrosa's crash to me definitely indicates a poor tire for the conditions.

I also wonder how far out Bridgestone are deciding their allocations so they can make the tires, they might be stretching any ability to predict the conditions a little? I have a notion that the tires might be constructed more like 'production' tires to make it cheaper to supply, and that might be taking longer....I could be utterly wrong though.

Do you remember what happened at Sachsenring in 2007? All the Michelins fell apart, the Bridgestones were the only tyres that could still be ridden fast in the last 1/3 of the race.

It didn't make for a great race... and it was probably the decisive moment for the move to Bridgestone.

I saw something incredibly disappointing today at the Press Conference. A spanish speaking reporter from Univision, the big spanish-language channel we have here in the states asked Marc Marquez a question in Spanish, and wished for Marquez to respond likewise. Marquez asked whoever was running the press conference if he was permitted to answer in Spanish and they said t must be in English.

I understand the contracts and legal issues may have prevented it, but this was another missed opportunity to market the sport to the Latino population in the United States. I recall there being a good amount of Mexican motogp fans at Laguna these past few years too.

The official press conference is for the world market, in English. Any rider can use any language in private interviews, and those are generally the best to 'see', but the official interviews are English. If they can't speak it that's a big MotoGP contract issue and an interpreter ( usually Gavin Emmet, a polyglot as well as highly knowledgable and eloquent commentator, no relation to our host David ) is provided. Even Vale is required to use English, and his early press conferences are quite amusing. Biaggi , with his squeeky voice, is even better. This has been the rule for many years (Many Moto2 and 3 riders need an interpreter) and the Spanish reporter must be new, stupid, or arrogant. 20 years, at least, English at the official press conferences, like aviation or shipping world licenses. Marquez can speak for hours to the Spanish reporter in Spanish if he wants, the time-critical world feeds are English. I doubt MM93 is lacking any press exposure in Spain. Or Mexico. Or Argentina, yada yada yada. Oh, and I live in Mexico. I'm learning Spanish. Mexicans in the US need to learn English. My Mexican girlfriend is very proud of her children's English, it opens opportunities for them to escape the worst pay-per hour country in the world (according to Forbes/CNN). I am a ship engineer. In France, I try to speak French. In the Baltic and Adriatic, I'm lost. Though I studied Russian 6 months at university, just too different.

I don't know why so many are critical of the tyres. If the riders gamble on a cold tyre and crash then that is their fault. The track doesn't lend itself to the cause, mind you, but these are professional race riders. They can figure it out. The sport ain't for wimps and they know it.

The Bridgestone rep's remarks on the reason for asymmetrical rear but not front made perfect sense. They use them on the rear because of excessive wear and heat build up, not because they aren't getting up to temp. The front is obviously the reverse problem which is why his comments about the negative aspect of "feel" outweigh the alternative option.

If every time you rode out on your bike you had to push the tyres beyond what you know to be 'safe' (i.e. you are at risk of crashing) would you want to put that exact tyre on your bike at renewal time?
I think not.....

It is very clear from what Oxley has said in his blog on this site,and had said to him, that this is a problem, not a 'part of the game'.

Bridgestone have studiously ignored the problems - there may be engineers in-house who want to do something, but the bean-counters are probably controlling this, not engineers. It isn't what MGP should be about. Tyres are a relatively small part of the cost of racing, but a huge performance factor.

It seems quite clear that the riders effectively had/have no choice - you throw it in and hope it grips/you can catch it, or you look second-rate.

"If every time you rode out on your bike you had to push the tyres beyond what you know to be 'safe' (i.e. you are at risk of crashing)"

... then you would be a racer. Whatever tyres they have, they will push until they find the limit.

Agreed. But the point Oxley and others seem to be making is that these tyres are not being developed or the choices being provided to allow the racers to select/use them as they would wish.
I wasn't comparing road riding to racing, I was making the point (badly obv.!) that if you lacked the confidence in your tyres you would choose something else (assuming you had a choice....).

The difference between asymmetric fronts and asymmetric rears is that a lot more depends on the feel of the front tire. Braking and corner entry is crucial, and so having a consistent feel is the most important thing a tire can do. An asymmetric front would be slightly stiffer on one side than it would be on the other, and so the front would tend to squirm a little under braking, then hold that feeling as you enter the corner. It would not feel very pleasant. Rear tires are far less important in terms of feel, there is very little weight on the rear as you tip it in. By the time you are using the rear tire, you are completely leaned over, and so you do not feel the transition.