2011 Sachsenring MotoGP Friday Roundup - Tires Cause Consternation Once Again

Bridgestone must be regretting getting that single tire contract around now, as once again, the only topic of conversation in the MotoGP paddock was the tires, and the tone of the conversation was a very long way from being universally positive. Four big crashes during the morning free practice session - two big enough that if circumstances had been otherwise, they could have resulted in serious injury - had everyone complaining of the cold temperature performance of the Bridgestones. But more of that later.

First, to the actual results: In the 125cc class, Nico Terol remains imperious, though Hector Faubel is snapping angrily at his heels and may well give his Bankia Aspar teammate a run for his money. Just seven thousandths separated the pair at the end of Friday. The gaps in Moto2 are similarly minuscule: Thomas Luthi leads Aleix Espargaro by the second-smallest of measurable margins, Luthi setting a time two-thousandths of a second quicker than the Spaniard. Yuki Takahashi is a further eight thousandths back, while Scott Redding lags a relatively massive seven hundredths of a second behind Luthi. Less than a second covers the first 26 riders at the Sachsenring, promising an exciting and probably chaotic race on Sunday.

In the MotoGP class, Marco Simoncelli was the fastest round the tight and technical Sachsenring, though the times are four tenths off the lap-record pace. Jorge Lorenzo was 2nd, less than a tenth behind, while the Repsol Honda armada followed a couple of tenths further back, Dani Pedrosa - his shoulder growing stronger as quickly as he had hoped - at the head, with Casey Stoner and Andrea Dovizioso following. Nicky Hayden is the fastest Ducati, his results giving him pause to reconsider whether to ride the GP11.1 next weekend at Laguna Seca, stick with the GP11 on which is clearly very comfortable, or use one of each as a less risky experiment.

Hayden's teammate Valentino Rossi - nine-time World Champion in all classes, seven-time World Champion in the premier class, with titles on 500cc two-stroke, 990cc four-stroke and 800cc four-stroke machines, in case you had forgotten - was 12th fastest in the afternoon, and continues to struggle with the weight balance of the bike. The GP11.1 has fixed the rear pumping, but the front remains the problem, with no feeling and no feedback, Rossi clearly not comfortable on the bike. The problem remains getting temperature into the front tire, and given the nature of the Bridgestones (more of which later) and the nature of the 800cc MotoGP machines, that is absolutely crucial to going fast.

Though Ducati's struggles have received the most publicity, things have not all been rosy over at Yamaha. Lorenzo's fortunes have improved radically since returning to much of the 2010 Yamaha M1, though the Spaniard remains cagey as to exactly what he is using. Informed opinion in the paddock says he is using the 2010 chassis and swingarm, with the 2011 engine and suspension, as well as the 2011 electronics package. Ben Spies is equally opaque about what parts he is using, but he is frank about why that is. "Honestly, I don't know what I'm using," Spies said in response to questions about whether he was using the 2011 or 2010 frame. His lack of speed at the Sachsenring is down to his health, not his bike, the Texan suffering with a nasty head cold which is clouding his concentration and giving him minor vision problems. But at 280 km/h, there is no such thing as minor vision problems.

The Monster Tech 3 Yamahas also continue to struggle, both Colin Edwards and Cal Crutchlow troubled by a front-end nervousness that manifests itself as a shaking through the handlebars, both at full lean and when straight. The cause of the problem is unclear, Crutchlow equally in the dark about which chassis he is using. "I have to ride what I've been given, so it doesn't really matter what chassis it is," Crutchlow said. It was clear, however, that his bike was different to Lorenzo's, as Lorenzo was able to get the bike to hold a tighter line that he was able to. "Obviously, Lorenzo would be quicker on my bike than I am," Crutchlow said, "but it's clear that he's on a different bike to mine." The Englishman was at least happy they had identified the problem, as that meant they could at least work on solutions, though he also said he was getting heartily sick of the volume of criticism and unwanted advice he was receiving. "I think my phone's been hacked, I've had that many messages," Crutchlow joked.

But of course the real news at the Sachsenring was the four big crashes at Turn 11, the fast right-hander at the top of the hill, taken in 4th or 5th gear before the riders swoop down what has been nicknamed "The Waterfall", the back straight onto the final two corners. Toni Elias, Casey Stoner, Valentino Rossi and Dani Pedrosa all went down there, a fast and terrifying place to crash. Elias and Pedrosa came away relatively unscathed - in Pedrosa's case, very luckily, given that he is still recovering from the surgery to fix the collarbone he broke in the notorious Simoncelli incident at Le Mans - but Rossi and Stoner were less lucky. Rossi fell awkwardly on his shoulder - the one he had surgery on over the winter, and which had troubled him all last year - and that shoulder is giving him some pain again. He also caught his leathers on the kerbstones, which ripped slightly, then wore a hole through his leathers and then into his forearm. The sight was more serious than the discomfort, he said, it looking a little too much like an anatomy lesson. Stoner fell heavily on his right forearm, suffering contusions on the bone, much to his relief, as he had feared it was broken. Both will be fit to ride again tomorrow, though Stoner admitted the crash had shaken him up a little, and made him rather cautious.

The cause of the crash was simple: the right side of the Bridgestone front tire was not getting up to temperature in the cold and windy conditions. The wind had been a factor, Stoner said, as the wind chill had cooled the right side during the long section between the second right-hand corner (Turn 3) and the next right hander (Turn 11), and the front had simply gone away from him in the crash. Stoner's mistake, he said, was to try and save it - which he did a few more times later on - as the rear then dug in and flicked him over the handlebars. Rossi also attributed the problem to the improved grip of the soft rear that Bridgestone had brought, putting even more pressure on the front at a point in the track where there is little for the front to grab a hold of.

Casey Stoner described the problem in detail: "Well, we're accelerating pretty hard off of that hill. It's coming off a flat plateau, and then sort of drops down, and as you come on, you're on the gas in 4th or 5th gear, and the front wants to lift a little bit. The front is coming light, and that's why it wants to go. There's also a point on the track where we have to stay inside to get the correct line, but then you have to lift up and over another part of the track. All these things just make the bike too light, and you can't get enough weight on the front."

Different riders had different solutions to the problem, each from their own perspective. Dani Pedrosa wanted the Friday morning session scrapped, and to go back to three 1-hour sessions of practice, but he was alone in this desire. Casey Stoner wanted to have a tire with a much wider operating temperature, but retaining the characteristics of the current tire. Valentino Rossi, Ben Spies and Andrea Dovizioso all wanted an extra tire to choose from, a softer tire to be able to cope with cold conditions in the morning. And this, according to Matt Birt of MCN, is what they are going to get. Birt posted an update on his Twitter page, saying that all of the riders except for Karel Abraham had attended the Safety Commission, and they had persuaded Bridgestone to bring a third option of tire from Brno onwards.

Such a move would require both a revised contract between Bridgestone and Dorna, and also a change to the MotoGP regulations. The Grand Prix Commission will have to be convened to rubber stamp the move, but if the parties can agree, then it should not be a problem.

Another solution put forward would be to have an asymmetric front to go with the asymmetric rear. Rossi, Spies and Dovizioso were enthusiastic about such a move, Rossi saying that it would only be needed at a couple of tracks, such as here at the Sachsenring and at Phillip Island. Casey Stoner was less enthusiastic, saying that he was worried that such a move might compromise stability under braking. But the definitive answer as to whether this was a good idea was given by the one man with experience of such tires, Nicky Hayden, who had used asymmetric Michelins during his time at Honda. "Just like the rear tire's good, the front here would be awesome," he said.

That, though, would be a good deal more complicated than just bringing an extra option to the races. Given the PR nightmare that this year's unseasonably cold weather has caused Bridgestone in MotoGP, a quicker fix is needed, and producing some more tires in Japan and using up the softer compounds while they arrive by ocean freighter might help silence the constant stream of criticism leveled at the Bridgestone tires.

It has to be emphasized that nobody has anything but the highest praise for the tires once they get up to temperature; but getting to that point can be a treacherous path indeed. Push too hard, and a cold tire will let go, flinging you off your machine. Don't push hard enough, and the tire never reaches its operating temperature, flinging you off your machine. Riding an 800cc MotoGP machine with Bridgestone tires is truly walking the razor's edge.

Total votes: 236
Total votes: 46

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Comments

We had summer here in Europe during April. Lovely warm consistent sun filled days. Now we've reverted back to spring with temperature spikes and heavens that continue to open on G.P weekends. Perhaps God does ride a Harley after all, over ruling Jesus Christ superstar burning 'round the corner on his Yamaha......

Total votes: 225

Does anyone else find absurd the notion that even a particularly stiff wind could possibly affect the temperature of the non-used portion of a MotoGP tire that is simultaneously spinning and traveling through the atmosphere at over 100mph? I'll leave the math to someone else, but the contribution of the atmospheric wind to the overall velocity of air flowing over the tire seems to me either minuscule or entirely insignificant from a thermodynamic perspective.

Total votes: 240

Perhaps indicates the margins they're operating with - CS states it as it is.
CS VR DP down at the same (very fast) corner !! Bridgestone could have had a much bigger PR problem if the above were not able to race.

Total votes: 232

as a brisk breeze under the skirts of these tempestuous ladies perhaps. Stoner "I had gone left and just gone over to the right and it was already gone, the front closed and I was trying to keep it up and it just wouldn't come back and then the rear came around.". Wind is the most cursed unpredictable weather condition of all to deal with on a motorcycle.

Total votes: 236

Perhaps its too much global warming thats causing the problem. Rain and cold seems to be the norm at the races in Europe this year .

Total votes: 218

I hope you're joking, David? Ocean freighter? Considering Bridgestones status at the moment they should fly them in, first class!

Total votes: 213

Stoner's comment of a few weeks ago that he wouldn't have ditched the GP11 so fast and that Hayden would do better if he just rode the bike they way he did last year instead of waiting for the thing to be 'fixed' looks more and more like a well-considered and reasonable opinion, rather than the dig at Hayden that it was taken to be by some at the time - especially as Abraham is doing quite well on the most original GP11 on the grid.

Whoever blocked the 'soft tyre' option at Mugello is probably not on the Christmas card list of a growing number of riders. When three 'aliens' go down in the same corner within a few minutes of each other, the issues can't be ignored.

Total votes: 229

Bridgestone counseled strongly against a single tyre supplier rule as they wanted the competition. Bridgestone also said the riders will have to put up with what they supplied as it was going to be too expensive to have several options. Michelin was copping a lot of flack at the time and Bridgestone were cornered in to being the supplier. I think Motogp is a victim of it's own manipulation of the sport, and those that had no choice in the matter are now suffering for it. The only answer is for Bridgestone to supply more options as the finger is now being pointed at them. A stupid situation imo

Total votes: 219

The 'official' comment from Bridgestone, quoted in GpOne:

"The front tire, though, is the same used here last year - a Bridgestone technician explained - and it wasn't a problem in Malaysia during the winter tests, with ambient temperatures of 38° and track temperatures of 55°."

From the FP1 results at motoGp.com, it was 16C ambient with a track temp. of 21C. How can Bridgestone believe that they should be taken seriously by saying the front was fine at another track at more than twice the temperatures, so therefore it wasn't their problem? And as for saying it was fine last year - FP1 was held in temps. of - guess what? - ambient 36C and track 55C.

That's pretty much like saying 'your spiked football boots were fine in Florida, so it's not the boot's fault if you're going arse over head while walking across this glacier'.

Total votes: 228

I think, what Bridgestone are saying, is that they have to rely on data from previous years. After all, if they supplied tyres that worked in super cold conditions, everyone would be bitching that they were useless in super hot conditions.

That's one of the problems with the one tyre supplier contract, and the rules limiting number of tyres. All done to reduce the cost of racing. Now, they spend the savings on doctor's bills and new body work on the bikes. Wonder how much the fairing on Rossis bike will go for on eBay ?

http://www.motorcyclenews.com/MCN/sport/sportresults/MotoGP/2011/July/ju...

Total votes: 214

Basing this reply solely on the official comment you've posted above, I don't see where the Bridgestone official said "it wasn't their problem".
He said "it wasn't a problem in Malaysia". Big difference.
They obviously know a problem with their tyres exists, otherwise they wouldn't agree to supplying extra (softer) ones at Brno - they are under no legal obligation to do so, as has been stated by Dorna before.

Total votes: 218

The other thing I read at GP One was Simo saying he thought the problem was a dirty track and not a tyre issue.

Total votes: 210

Hopefully Bridgestone realise that tyre wear in MotoGP races isn't all bad. I would love to see tyre management genuinely play a role in results more than it does at the moment.

More importantly though, is rider safety. If injuries to Rossi, Pedrosa and Stoner were a result of yesterday's crashes, dare I say this would be an even bigger issue today and there would probably be cries of negligence on Bridgestone's part.

Thankfully though the injuries are minimal and there is a window of opportunity for Bridgestone to resolve the issue once and for all.

Total votes: 226

Having a extra tire to choose from this weekend may be a temporary fix although if it's a softer tire than the ones they have will we see grip go away big time late in the race? Bridgestone is using, to my understanding, data collected last year and in very different weather conditions.

The solution to prevent weekends starting like this in the future, stop with the stupid supposed money saving test limits and let these guys test the bikes and tires in the off season more. The more they ride and collect data in variable conditions the better prepared they'd be. I mean the limited testing has not helped close the racing at all and the guys at the back are just as far back as ever.

Total votes: 217

Elimination of a spec tire rule! Most people correlate the end of Stoner's 2007 Ducati dominance with the intro of the CF frame but it also coincided with moving of Rossi to BS and the elimination of bike-specific tires with the spec rule the following year.

Maybe Rossi's 2008 development input to BS tilted the balance of the resulting spec tire from the Duc's hard to heat needs to a those that benefited the Japanese style GP bikes. There also was the rise of Lorenzo as a big talent so more true competition for the win.

There is a pic from Mugello of the GP12 naked at http://twitpic.com/5l35h3/full and from a side profile it is almost exactly the same as their superbike with a nearly horizontal front cylinder and huge amounts of empty space between the front wheel and the crankshaft. No wonder why they are having a hard time loading it to get heat into it. However, this same layout in the superbike is working just fine against strong competition with the easy to warm up spec Pirelli tires. I think their problem is not the CF frame but how the orientation of the cylinders keeps the heavy parts of the engine very far back from the front axle and low. The lower the C of G the less load transfer under braking and acceleration and the less heat that goes into the tires. The further back the C of G is reduces the weight on the front in the first place. Each bad characteristic compounds the other. Not good.

Looking at the RC211V at http://www.superbikeplanet.com/image/honda/rcv211v/4/6.htm and the M1 at http://www.motorcyclenews.com/upload/252229/images/225306.jpg you can see that Ducati's mass centralization is poor and and possibly their resulting high yaw moment of inertia makes the bike slow to turn simply from a mass distribution perspective regardless of C of G position or steering geometry. Its like adding insult to the injury of above and explains both of Rossi's problems of hard to heat tires and a hard to turn bike.

It also makes their decision to go with the same subframe-chassis style design for the new production superbike much more reasonable. With the Pirelli tires heat generation is not an issue and maybe the reduced load on the front tire helps with reduction of front tire wear late in the race. Now the low and rearward C of G is a benefit and not a problem! I suspect that production road and even club race tires are more like the Pirellis then the BS so us mortals won't have to worry about warm tires as we go to the cafe or turn a lap at the local track on our 1199.

Chris
http://moto2-usa.blogspot.com/

Total votes: 233

i agree with u.having ridden a 1098s the bridgestones dont work on the front end, u get no feel,they understeer, there great for the back wheel but the perellis are better for the front but crap on the back.

Total votes: 225

Terrifiic piece of 'skul diggery' Chris.

Interestingly Wayne Garner in his lattest missive says >>

"On the subject of those major changes, a lot of people are asking why Ducati don’t ditch their carbon fibre chassis. But my question is: are the bike’s problems all down to the carbon fibre? Can they pinpoint this as the exact issue? If they can, then maybe they should. But I think it’s more than that. I think it’s also things like engine configuration and weight distribution causing the difficulties.

Whatever the cause, or causes, I think it’s now fair to say that Valentino has definitely underestimated the challenge of signing for Ducati. Sadly, we may even be faced with the possibility of the MotoGP legend not getting near the top of the rostrum again."
(David let me know if it's not ok to include this WG qoute).

Am I dreaming this? I seem to recall in '06 or '07 there was talk of the BS front (I've forgotten the designation) being so much better than the Michelin front PARTICULARLY on the light front end of the Duc. Or maybe that should read ... particularly on the LIGHT FRONT END of the Duc.

Total votes: 222

Nice links Chris and good comments. I agree totally on your point about tyres. They seem to be dictating the entire design of the bike now. What if Bridgestone quit? All the factories go back to the drawing board. Does not sound like keeping costs down to me.

The pic of the Ducati is fascinating. Now I can see the short and wide airbox that constitutes the riders connection to the remainder of his bike, ouch! It looks like nothing on Earth would make that thing flex. Looking at the picture, it seems they needed that airbox space and the steel tubing option was taking up too much of it. Perhaps they need not abandon the layout, just the materials. In any case, given the short and wide nature of that section, engineering in a smooth linear amount of torsional or fore/aft flex would seem to be at odds with the choice of CF. Any engineers want to put their 2 cents worth in? One would think, that with finite element analysis, a more suitable material or composite of materials could be chosen.
Assuming for example the lack of torsional flex is the problem, couldn't the sides be aluminum and CF top and bottom sections attached? This would enable the the amount of twist to be varied by attaching top and bottom plates of different section as required.

Total votes: 223

... is that you can get whatever amount of flex you want, in any direction.

Depends on how much, of what kind of carbon fibers, what direction they're laid, etc.

Determining *what* flex you want in *which* direction... that's the trick.

Total votes: 237

This has been covered before in many threads on this forum. I incorrectly made the assumption that most readers have read the articles regarding the fact that not only is carbon very resistant to flexing, but it also "snaps back" into shape which is not what is required.

Total votes: 221

... for an engineer to put his two cents worth in.

I'm a degreed mechanical engineer, and I've worked enough with CF to have a good understanding of it's fundamental characteristics, how it's used, and why.

Total votes: 230

I'm not an engineer, a mere mechanic, but Speeddog is right.

John Barnard used flexure joints instead of spherical bearings or rod ends on the suspension of the Ferrari F1 cars he designed back in the mid nineties, (and everyone else followed suit) and Cannondale's Scalpel XC race mtb has been around for nearly ten years with around 90mm of rear travel just using the flex of a CF chainstay and not a pivot in sight.

Total votes: 217

I know absolutely nothing about engineering but the new Pagani car (Huayra) uses something called "carbotanium" that is basically CF glued to titanium. Apparently it´s stronger and lighter than CF and more importantly it´s easier to regulate it´s flexibility.
What can you guys tell me about it? all I know is what I read in car magazines.

Total votes: 227

Well.. Can u enlighten us with more than two lines of ??? and >> im no engineer but ive ridden a lot of bikes so what do i qualify as?

Total votes: 222