Indy Race Thread SPOILERS!

[povol]

I'm no expert, but its not as simple as being discussed above.

From experience with slicks on cars, there are three critical issues. The hardness / softness of the rubber compound, the rigidity of the construction of the tyre, and the tyre pressure. The stiffness of the construction, and the pressure are linked and must be matched.

Soft rubber compound will give more grip but will wear more quickly, fairly simple, but the structure of the tyre must match the grip level of the track, and the tyre pressure is then related to how the structure of the tyre reacts to the track. Lower pressure gives more grip, but too low will compromise the structural integrity of the tyre and the tyre rips itself to bits very fast.

I think this was the problem at Indy, and it seems like the construction of the tyres were too soft for the very high grip level of the track. Probably, the guys who burnt tyres went too low in pressure trying to get the best possible grip, and the structure of the tyres could not handle the very high grip level of the track.



Some riders (who were struggling for grip) might have gone for slightly lower pressure to try to get maximum grip, and in effect compromised the stability of the tyre, so the tyre just tore itself to bits (we are talking differences of only 2 - 3 psi).

Other riders (possibly like Stoner, Pedro, Spies, Bautista) who had plenty of grip through good bike setup / riding style, were able to run higher tyre pressures to ensure the tyres were as stable as possible, knowing that tyre life would be critical.

Its a known fact that the Duc's all struggle with front end grip, and this probably fits with why they were trying to chase maximum front grip from the tyre (probably with too low pressure), and they over did it. It also fits with why some of the Duc's complained of loosing big chunks from their front tyres.



So bottom line, probably the tyres were ...., but probably it is nothing to do with hard or soft rubber compound, and if you had a bike with good grip levels the tyres were ok withhigher pressures.

And probably the conspiracy theory about HRC getting better tyres is crap - they just had enough grip from their bikes, and so did not have to chase more grip from the tyres (particuarly from the front), and overload the tyres to the point of failure.

Very true, mechanical grip, or lack of it, will result in teams compensating with what you said, softer options or lower pressures. Despite its super fast straight, Indy is a relatively slow track that virtually eliminates what little aerodynamic grip a bike might have in the corners, leaving it almost all up to mechanical grip. It cant be dismissed that the bikes suffering outright tire failure were Ducati's, the bike with the most notorious lack of front end grip.

 

[mylexicon]

The only thing I could think of is that they felt Ducati was the biggest threat(thanks to Casey). The rules really have a bigger impact on the Ducati than anyone else, so they were probably an accomplice and sneaky Honda was setting things into place the entire time. People give way to much credit to Rossi for the rules and tires but these factories also have behind the scenes strategies in place and they really don't want things to be left to just the rider. The stiff tires we see today are the result of Yamaha, followed by Honda figuring out how to get the chassis to act as a suspension and not because of Rossi, a stiff tire will always be better than a softer tire as long as you have the chassis that can exploit it and so we've seen the tires getting stiffer and stiffer as yam and honda have them figured out. Ducati is forced into trying to figure out the chassis while their engine advantage and strategy to racing has been taken away. Even if they were able to get a softer tire made just for them it wouldn't be any help without the hp to make up for the lack of handling, the japanese have really hit them hard, but someone at Ducati should have seen it comming and did a bit more planning than an inverted swingarm. When the head honda guy says he's surprised ducati hasn't changed, it just makes the duc engineers look worst.

The tires are hard b/c of the fuel rules. Braking wastes energy. If the bikes have 24L, who cares? If the bikes only have 21L, it's a big deal. Hard front tires can handle higher cornering g's, and they allow for more aggressive profiles thus larger contact patches. During the 26L-24L 990cc era, hard tires were not necessarily useful b/c braking stability was more important than corner entry. During the 21L era, corner entry speed is paramount.



We know for sure that Honda wanted to make flickable, mass-centralized bikes from the outset of the 4-stroke era, but after the public spat with Rossi and the subsequent titles he won, I'm not sure we will ever know the motives behind the 21L 800cc formula. Considering how poorly Honda/Michelin prepared for the 21L 800cc era, I tend to think they were more anxious to slow the compeitition than to build a world class grand prix motorcycle. HRC's current form was only made possible after the old management team was fired, and expert personnel were poached from other teams (Stoner, Suppo, and the Yamaha data techs).

 

[birdman]

Terrible track conditions? Friend, was there some weather condition that I didn’t detect on the tele? Or are you talking about the new pavement? The new pavement is something that did NOT suddenly spring on the series was it? It looks to me that Bstone didn’t do their homework and bring out an acceptable tire, and the wear was certainly abnormal. You are certainly chalking it up to normal mismanagement of tire wear, though you are casing it as mismanagement of “track conditions”. The wear was so bad that there is no other way to describe the dichotomy experienced by riders as nothing short as shocking. We had rider retirement’s dude!

I completely disagree that Bridgestone can be held responsible in any way for what has happened. I work as an asphalt designer. There are safety issues which can apply to new asphalt. For a new surface the 'stone' is still covered in 'bitumen' or 'tar'. This is an oil extract, therefore its very slippery. In any case where the film of bitumen is quite thick, safety standards warn that the surface may become hazardous. Hence FP1 comments form the riders the track was very slippery.



To rectify the problem the surface either must be worn in or treated with sand to improve friction. This is just for public roads, not racetracks. Its absolutely crazy, boardering on irresponsible to send motogp out on a new asphalt surface imo.



The 'slick' or 'grease' Stoner was complaining about is a liquid tar used on joins between layers. This also wears off over time and he was correct in saying its slippery because its an oil derivative.



Next problem occurs when the bitumen film does wear off. New stone is exposed and it has intitial friction properties that would tear any tire appart. The reason is because the new stone has a highly irregular, jagged surface due to being mechanically crushed at a quarry to a certain size. This is the cause of the graining issue on the front tire. The action of the tire on the stone over time polishes the stone smooth. Like polishing a marble table, or even wood, the first few strips of sand paper wear through quickly, then after time you can move to finer grain sand paper. Same thing with the tires. Only once this has happened will there be a consistent surface suitable for racing. Bridgestone were at a hiding to nothing. Theres no solution other than wearing in the track with cars, go carts or whatever.



The fact that all the above occured during a motogp race and the responses and finger pointing is highly amusing to me. I have worked in a couple of race track situations so I know the people who run them can be preoccupied with other things, mostly making profit, and thus the obvious gets overlooked.



Anyway, there will be 18 races this year. If the tire catastrophy is limited to Indy, then statistically thats pretty good odds pointing to something perculiar at Indy being the cause, rather than the tires that were used successfully at the other 17 venues.



Moving along to the riders, its as much down to 'luck' as 'good management' who will suffer the most, just like in a crash. I dont expect them to know what the hell is going on, though as usual the 'lucky' ones were on the best bikes and are the best riders. Ducati are just plain 'unlucky' at the moment and they still dont have a good handling aluminium frame. But Suzuki went ok.

 

[Jumkie]

Birdman, thanx for ur techincal explanations, though i failed to see how this made Bstone blamless. This is not the first time in history a track has been repaved. Bstone is tasked to bring tires that will perform for a diverse group under general to specific conditions. Its the reason they adjust their compounds and bring out certain specs for certain tracks. In this case a green track was to be considered. For ther to be multiple tire failures points to one common denominator--the tire. Not sure how u can get around that.

 

[birdman]

Birdman, thanx for ur techincal explanations, though i failed to see how this made Bstone blamless. This is not the first time in history a track has been repaved. Bstone is tasked to bring tires that will perform for a diverse group under general to specific conditions. Its the reason they adjust their compounds and bring out certain specs for certain tracks. In this case a green track was to be considered. For ther to be multiple tire failures points to one common denominator--the tire. Not sure how u can get around that.

The 'green track' is a condition equivalent to riding around on pieces of broken glass. It actually cuts into the tire. Thats what caused graining. Its not a normal tire wear issue and I cant think of how Bridgestone or any other company might make a tire that resists 'cutting' since tires are made from rubber compounds?

 

[povol]

Birdman, thanx for ur techincal explanations, though i failed to see how this made Bstone blamless. This is not the first time in history a track has been repaved. Bstone is tasked to bring tires that will perform for a diverse group under general to specific conditions. Its the reason they adjust their compounds and bring out certain specs for certain tracks. In this case a green track was to be considered. For ther to be multiple tire failures points to one common denominator--the tire. Not sure how u can get around that.

I think he is saying that regardless of the compound Bridgestone supplied, there was goint to be a problem with tire degradation.

 

[povol]

double

 

[birdman]

I think he is saying that regardless of the compound Bridgestone supplied, there was goint to be a problem with tire degradation.

Its like giving Bridgestone a rough diamond and telling them to cut and polish it up with a piece of wood. Wrong tool for the job. Dont scrub in a green track with a motogp bike.

 

[Jumkie]

The 'green track' is a condition equivalent to riding around on pieces of broken glass. It actually cuts into the tire. Thats what caused graining. Its not a normal tire wear issue and I cant think of how Bridgestone or any other company might make a tire that resists 'cutting' since tires are made from rubber compounds?

Are u saying that Bstones could not make a tire that would hav stood up to a resently repaved track? Interesting, do u remember what happened when GP came to a recently repaved Laguna Seca?



I must say, despite the standard tribalist posts (and it seems ther hav been fewer this thread, i might be wrong) its been interesting to see the different plausible explanations. Even the enthusiastic explanations dont seem all that out of wack considering the outliers of tire wear which if denied are equally enthusiastic).

 

[Mental Anarchist]

I completely disagree that Bridgestone can be held responsible in any way for what has happened. I work as an asphalt designer. There are safety issues which can apply to new asphalt. For a new surface the 'stone' is still covered in 'bitumen' or 'tar'. This is an oil extract, therefore its very slippery. In any case where the film of bitumen is quite thick, safety standards warn that the surface may become hazardous. Hence FP1 comments form the riders the track was very slippery.



To rectify the problem the surface either must be worn in or treated with sand to improve friction. This is just for public roads, not racetracks. Its absolutely crazy, boardering on irresponsible to send motogp out on a new asphalt surface imo.



The 'slick' or 'grease' Stoner was complaining about is a liquid tar used on joins between layers. This also wears off over time and he was correct in saying its slippery because its an oil derivative.



Next problem occurs when the bitumen film does wear off. New stone is exposed and it has intitial friction properties that would tear any tire appart. The reason is because the new stone has a highly irregular, jagged surface due to being mechanically crushed at a quarry to a certain size. This is the cause of the graining issue on the front tire. The action of the tire on the stone over time polishes the stone smooth. Like polishing a marble table, or even wood, the first few strips of sand paper wear through quickly, then after time you can move to finer grain sand paper. Same thing with the tires. Only once this has happened will there be a consistent surface suitable for racing. Bridgestone were at a hiding to nothing. Theres no solution other than wearing in the track with cars, go carts or whatever.



The fact that all the above occured during a motogp race and the responses and finger pointing is highly amusing to me. I have worked in a couple of race track situations so I know the people who run them can be preoccupied with other things, mostly making profit, and thus the obvious gets overlooked.



Anyway, there will be 18 races this year. If the tire catastrophy is limited to Indy, then statistically thats pretty good odds pointing to something perculiar at Indy being the cause, rather than the tires that were used successfully at the other 17 venues.



Moving along to the riders, its as much down to 'luck' as 'good management' who will suffer the most, just like in a crash. I dont expect them to know what the hell is going on, though as usual the 'lucky' ones were on the best bikes and are the best riders. Ducati are just plain 'unlucky' at the moment and they still dont have a good handling aluminium frame. But Suzuki went ok.

Thanks birdman. This confirms my points that the track was bad and it came down to how you rode it as to the degree that you suffered.

Birdman, thanx for ur techincal explanations, though i failed to see how this made Bstone blamless. This is not the first time in history a track has been repaved. Bstone is tasked to bring tires that will perform for a diverse group under general to specific conditions. Its the reason they adjust their compounds and bring out certain specs for certain tracks. In this case a green track was to be considered. For ther to be multiple tire failures points to one common denominator--the tire. Not sure how u can get around that.

Jum, about all Bridgestone could of done was bring wagon wheels. No matter what tyre they brought along if you pushed to hard or had a bad set up then you were going to suffer.



Hayden commented that he was stoked that he was able to run with the front guys in the first few laps. Why was he able to do this when under normal circumstances he has not been able to because of his bikes limitations? I will give you my explanation....because the guys at the front were taking it easy because they knew that if they stood a chance of winning they needed to have tyres left at the end.



The other consideration to look at as to why some riders lasted better than others is due to lines. If someones line was different to the majority then the little piece of track they were running on would have had less smoothing of the rocks and less rubber and could therefore add a percentage of extra wear. Stoner, Pedrosa at the front could run what ever lines they wanted. Those that were having to fight were probably forced to run lines they would not necessarily choose had they too had clear track. From memory Hayden diced it up quite a bit during the early stages.

 

[Mental Anarchist]

Are u saying that Bstones could not make a tire that would hav stood up to a resently repaved track? Interesting, do u remember what happened when GP came to a recently repaved Laguna Seca?



I must say, that despited the standard tribalist posts (and it seems ther hav been fewer this thread, i might be wrong) its been interesting to see the different plausible explanations. Even the enthusiastic explanations dont seem all that out of wack considering the outliers of tire wear which if denied are equally enthusiastic).

Jum, how often is Laguna used? Every weekend including track days, testing and local racing? How many events were run between resurfacing and MotoGP?

 

[povol]

Jum, how often is Laguna used? Every weekend including track days, testing and local racing? How many events were run between resurfacing and MotoGP?

Good point. I was talking to a vendor at the official merchandising store, and was bitching a little about paying 3 bucks for a bottle of water. Told him i saved a bottle and filled it up out of a sink spigot and it tasted like ..... He started laughing and said, hell dude, that water has been in the lines since the Brickyard 400.

 

[birdman]

Are u saying that Bstones could not make a tire that would hav stood up to a resently repaved track? Interesting, do u remember what happened when GP came to a recently repaved Laguna Seca?



I must say, despite the standard tribalist posts (and it seems ther hav been fewer this thread, i might be wrong) its been interesting to see the different plausible explanations. Even the enthusiastic explanations dont seem all that out of wack considering the outliers of tire wear which if denied are equally enthusiastic).

Simply stood up to or rather performed perfectly evenly for 17 different riding styles? Stood up to yes, I actually think they did because more than half the field finished the race. Performed evenly for 17 different human beings no. Humans are inherently unpredictable, and on an unpredictable surface the effects are even more unpredictable. 17 robots maybe yes.

 

[hawkdriver]

The tires are hard b/c of the fuel rules. Braking wastes energy. If the bikes have 24L, who cares? If the bikes only have 21L, it's a big deal. Hard front tires can handle higher cornering g's, and they allow for more aggressive profiles thus larger contact patches. During the 26L-24L 990cc era, hard tires were not necessarily useful b/c braking stability was more important than corner entry. During the 21L era, corner entry speed is paramount.



We know for sure that Honda wanted to make flickable, mass-centralized bikes from the outset of the 4-stroke era, but after the public spat with Rossi and the subsequent titles he won, I'm not sure we will ever know the motives behind the 21L 800cc formula. Considering how poorly Honda/Michelin prepared for the 21L 800cc era, I tend to think they were more anxious to slow the compeitition than to build a world class grand prix motorcycle. HRC's current form was only made possible after the old management team was fired, and expert personnel were poached from other teams (Stoner, Suppo, and the Yamaha data techs).

I think those rules were an attempt to prevent the high revving machines we see today. Yamaha and honda both got caught out by Ducati, they were to conservative. I'm sure the calculations and simulations were done to set the fuel limit rule, in other words they didn't chose 21L as some arbitrary number. They knew that they didn't want to have anything to do with where racing technology was taking them and their engines wouldn't be able to keep up with the desmo without major work. The only problem was the calculations were wrong. They aren't going to make the same mistake for next year so we have the 81mm bore to tame revs. Giving these machines extra fuel is a big deal when Ducati can out rev(make more hp)them.



Yamaha used conventional valve springs in the engine for most of the '07 season with the belief that engine revs for the new-generation 800cc bikes would be limited by fuel consumption.We believed that the new 21-liter fuel tank regulation would mean that engine speeds could not exceed 18,000 rpm without running out of fuel in a race, Furusawa admits, and at these rpm it is still OK to use valve springs instead of a more complex alternative technology

This explains why Yamaha got smoked in the first race of the season at Qatar, when computer projections for fuel consumption caused them to back off engine speeds to 17,500 rpm, resulting in Stoner's D16 GP7 being timed at 202 mph down the Losail pit straight, against just 192.6 mph for Rossi's Yamaha. When it was discovered afterward that Rossi's bike still had more than a liter remaining in the fuel tank-against just a third of a liter for Stoner-Yamaha realized its mistake and raised revs to 18,000 rpm for the next race in Jerez, which Rossi duly won.



But even more revs weren't sufficient to keep up with the flying Italian bike that ran 209.4 mph versus the YZR-M1's 202.5 mph at Shanghai, where the Honda and Kawasaki were both faster, too. This forced Yamaha to accelerate development of a pneumatic-valve version of the motor, which debuted in postrace testing at Brno in August and was judged sufficiently promising for Rossi to race it two weeks later in Misano, only to DNF with a blown engine.



When a repeat failure occurred in testing in Japan, the decision was taken to park it on the sidelines for the time being, especially as Yamaha had by now developed a fourth version of the existing valve-spring motor, whose revs had been raised to 19,000 rpm without affecting fuel consumption and seemingly without any ill effects in terms of reliability. This proved a wise decision when Rossi won in Portugal using that uprated motor, delivering four percent more horsepower than at the start of the season.



Read more: http://www.sportrider.com/features/146_0804_motogp_ducati_yamaha_honda/viewall.html#ixzz1WaFDUM24

. http://www.sportrider.com/features/146_0804_motogp_ducati_yamaha_honda/viewall.html#ixzz1Wa8Sn1DJ

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[levigarrett]

disregard

 

[hawkdriver]

I wanted to also add that the 6 engine rule was another attempt to reduce the revs as a higher reving engine will wear out sooner, and that F1 engineers have said they can now exceed 20k rpm if it wasn't for the rules. I have heard rumors that the Duc engine is still the highest revving engine on the grid so it isn't hard to believe the japanese don't want this to turn into an all out horse power war.

 

[hawkdriver]

I'm no expert, but its not as simple as being discussed above.

From experience with slicks on cars, there are three critical issues. The hardness / softness of the rubber compound, the rigidity of the construction of the tyre, and the tyre pressure. The stiffness of the construction, and the pressure are linked and must be matched.

Soft rubber compound will give more grip but will wear more quickly, fairly simple, but the structure of the tyre must match the grip level of the track, and the tyre pressure is then related to how the structure of the tyre reacts to the track. Lower pressure gives more grip, but too low will compromise the structural integrity of the tyre and the tyre rips itself to bits very fast.

I think this was the problem at Indy, and it seems like the construction of the tyres were too soft for the very high grip level of the track. Probably, the guys who burnt tyres went too low in pressure trying to get the best possible grip, and the structure of the tyres could not handle the very high grip level of the track.



Some riders (who were struggling for grip) might have gone for slightly lower pressure to try to get maximum grip, and in effect compromised the stability of the tyre, so the tyre just tore itself to bits (we are talking differences of only 2 - 3 psi).

Other riders (possibly like Stoner, Pedro, Spies, Bautista) who had plenty of grip through good bike setup / riding style, were able to run higher tyre pressures to ensure the tyres were as stable as possible, knowing that tyre life would be critical.

Its a known fact that the Duc's all struggle with front end grip, and this probably fits with why they were trying to chase maximum front grip from the tyre (probably with too low pressure), and they over did it. It also fits with why some of the Duc's complained of loosing big chunks from their front tyres.



So bottom line, probably the tyres were ...., but probably it is nothing to do with hard or soft rubber compound, and if you had a bike with good grip levels the tyres were ok withhigher pressures.

And probably the conspiracy theory about HRC getting better tyres is crap - they just had enough grip from their bikes, and so did not have to chase more grip from the tyres (particuarly from the front), and overload the tyres to the point of failure.

I don't know if you are referencing my post but yes I did simplify it and it's in response to mylexicon on how we have arrived to the current set of rules and tires in GP and not in relation to why they caused problems at Indy. When I'm talking about the tires I'm talking purely about the stiff construction and it's advantages over a more flexible tire and why the riders always want the harder/stiffer tires. The stiffer the tire the more you have control over the contact patch against lateral and vertical loading. Better thermal wear(it's easier to control with a stiff construction and lowering pressure won't hurt it as much as an already softer tire), higher speed, and fuel efficiency. You need to have a good suspension/chassis to see the benefits of course. If you read the article on Kropo's site with his interview of Casey's crew chief you'll see they still intend on using the hardest tires for next year.

 

[hawkdriver]

BS is saying the problem was that the track improved so much and made the rear get much more grip for the race causeing the fronts to push. No wonder the Ducs ate their tires as they already suffer from the front end pushing and no wonder Casey had no issues as he has to be the master of not letting the front push after riding the Duc for so long.

 

[povol]

BS is saying the problem was that the track improved so much and made the rear get much more grip for the race causeing the fronts to push. No wonder the Ducs ate their tires as they already suffer from the front end pushing and no wonder Casey had no issues as he has to be the master of not letting the front push after riding the Duc for so long.





Thats the general consensus, then you have Rossi saying the polar opposite





[size="-1"]"In acceleration, I spin around. Unfortunately, after some laps, I started having some problems with the gear box. When I shifted down, I remain in neutral. So I made two or three mistakes for this reason on the first corner. And I wanted to stop, seriously. But I try to don't give up before I arrive at the end. I remained in neutral another two or three times and tried to take some points, but it was very, very sad."[/size]

 

[Keshav]

I think he is saying that regardless of the compound Bridgestone supplied, there was goint to be a problem with tire degradation.

Beat me to it. Between the fact that no two re-paved tracks are going to be exactly the same, and the inability to pre-test the tires

on the resurfaced Indy - combined with variances in rider styles, rider weights and chassis set-up - it's absurd to think that a choice of three different compounds are going to neatly cover the bases on all the combined variables. I thought we all made that base assumption a few years back when it was announced there would be a control tire. Tie all that together with the limitation imposed by Bridgestone's hardships in the wake of Fukishima disaster - I'd say they were doing an admirable job.