Yamaha chassis alterations for Bridgestones

This is a precis of the Neil Spalding article from AMCN this month.

Yamaha has effectively built an M1 with Ducati style weight distribution: weight bias is set towards carrying more weight over the rear. The most successful Bridgestone tyres have been designed to work this way on the Ducati, and this has forced Yamaha to evolve the M1 this way and Rossi to change his riding style to suit.

The front forks are pushed as far forward as possible to move the weight away from the centre of the bike. Doing this makes the front end more flighty, and requires a very good tyre to cope with it. It is this characteristic that Bridgestone has designed its front tyres around as it is the way that Stoner preferred his GP7 set up.

The rear axle is moved as far forward in the swing arm as possible in order to get as much weight onto the rear tyre as possible. This reduces the chances of the rear spinning up and hence improves longevity.

In Qatar, Rossi discovered during the race that the Bridgestone rear tyre couldn't deal with the amount of stress he was giving it - although the bike initially worked well, the tyre needed more weight on it to stop it spinning and wearing out too quickly.

It is quite possible that Bridgestone will be able to build tyres to suit Rossi's preference but this isn't going to happen overnight, so Rossi and Burgess have built a bike that uses the current tyres in the best possible way until different ones are developed.

As soon as the bikes were rolled out in Jerez it was obvious that things were changing. The rear axle was sitting 30mm further forward in the swingarm than before and the front forks were similarly set further forward. The engine was moved back by nearly 35mm.

This is going to change things for the rider. He is going to have to trust Bridgestone's sticky front tyre completely because with the weight moved back that much the front is going to feel very loose and insecure. The shorter swing arm will also increase the anti-squat 'chain force' - the way the chain forces the rear wheel down during hard acceleration. This gives yet more force pushing the rear tyre into the surface of the track.

Rossi ran a very similar setup in Estoril, but there the rear axle was at the very front of its adjustment, fully 40mm further forward than the other Yamahas on Michelin tyres; the front forks were also at the front of their adjustment. And on a bike that must have felt totally different to anything he has ridden before, Rossi ran at the front before the tyres went off. As at Jerez there wasn't another Bridgestone runner anywhere close.

Rossi didn't want to say too much. "The chassis is very much in evolution, but on paper here (Estoril) we have a small disadvantage compared to the good Michelins. We try to save a lot the rear tyre; we try not to stress it too much so we don't create too much temperature. The bike is a little bit different to ride but the front tyre from Bridgestone is okay so now I feel confident with the bike - its stable, it's good to turn, but it's a little bit different to ride. I have had to change my style a bit."

Come China and Yamaha had it sorted. It was Rossi's first win in eight months, but the work is far from over.

With Yamaha giving Bridgestone a win for 2008 and a glimmer of hope for a second world title, you can be sure they will be hard at work trying to tailor a range of tyres to the Yamaha chassis and Yamaha will be building frames and swingarms that let the current Bridgestones work at their best.

These two photos illustrate what Neil has to say beautifully, as well as showing that Rossi has, IMO changed his riding position to be much more over the front than he used to be.

3316:lemansrossi.JPG]
3317:lemansjorge.JPG]

<div class='quotetop'>QUOTE (yamaka46 @ May 19 2008, 09:20 AM) <{POST_SNAPBACK}><div class='quotemain'>This is a precis of the Neil Spalding article from AMCN this month.

Yamaha has effectively built an M1 with Ducati style weight distribution: weight bias is set towards carrying more weight over the rear. The most successful Bridgestone tyres have been designed to work this way on the Ducati, and this has forced Yamaha to evolve the M1 this way and Rossi to change his riding style to suit.

The front forks are pushed as far forward as possible to move the weight away from the centre of the bike. Doing this makes the front end more flighty, and requires a very good tyre to cope with it. It is this characteristic that Bridgestone has designed its front tyres around as it is the way that Stoner preferred his GP7 set up.

The rear axle is moved as far forward in the swing arm as possible in order to get as much weight onto the rear tyre as possible. This reduces the chances of the rear spinning up and hence improves longevity.

In Qatar, Rossi discovered during the race that the Bridgestone rear tyre couldn't deal with the amount of stress he was giving it - although the bike initially worked well, the tyre needed more weight on it to stop it spinning and wearing out too quickly.

It is quite possible that Bridgestone will be able to build tyres to suit Rossi's preference but this isn't going to happen overnight, so Rossi and Burgess have built a bike that uses the current tyres in the best possible way until different ones are developed.

As soon as the bikes were rolled out in Jerez it was obvious that things were changing. The rear axle was sitting 30mm further forward in the swingarm than before and the front forks were similarly set further forward. The engine was moved back by nearly 35mm.

This is going to change things for the rider. He is going to have to trust Bridgestone's sticky front tyre completely because with the weight moved back that much the front is going to feel very loose and insecure. The shorter swing arm will also increase the anti-squat 'chain force' - the way the chain forces the rear wheel down during hard acceleration. This gives yet more force pushing the rear tyre into the surface of the track.

Rossi ran a very similar setup in Estoril, but there the rear axle was at the very front of its adjustment, fully 40mm further forward than the other Yamahas on Michelin tyres; the front forks were also at the front of their adjustment. And on a bike that must have felt totally different to anything he has ridden before, Rossi ran at the front before the tyres went off. As at Jerez there wasn't another Bridgestone runner anywhere close.

Rossi didn't want to say too much. "The chassis is very much in evolution, but on paper here (Estoril) we have a small disadvantage compared to the good Michelins. We try to save a lot the rear tyre; we try not to stress it too much so we don't create too much temperature. The bike is a little bit different to ride but the front tyre from Bridgestone is okay so now I feel confident with the bike - its stable, it's good to turn, but it's a little bit different to ride. I have had to change my style a bit."

Come China and Yamaha had it sorted. It was Rossi's first win in eight months, but the work is far from over.

With Yamaha giving Bridgestone a win for 2008 and a glimmer of hope for a second world title, you can be sure they will be hard at work trying to tailor a range of tyres to the Yamaha chassis and Yamaha will be building frames and swingarms that let the current Bridgestones work at their best.

These two photos illustrate what Neil has to say beautifully, as well as showing that Rossi has, IMO changed his riding position to be much more over the front than he used to be.

3316:lemansrossi.JPG]
3317:lemansjorge.JPG]

Great post.

you can see rossis rear wheel is forward compared to lorenzos. just shows what a great rider vale is, that he can alter his style to suit. not many riders can do that imho.

<div class='quotetop'>QUOTE (roger-m @ May 19 2008, 10:30 AM) <{POST_SNAPBACK}><div class='quotemain'>you can see rossis rear wheel is forward compared to lorenzos. just shows what a great rider vale is, that he can alter his style to suit. not many riders can do that imho.

As impressive as Rossi's adaptability is, there is currently a rookie just 3 points behind him going through a significantly bigger adaptation.

<div class='quotetop'>QUOTE (roger-m @ May 19 2008, 10:30 AM) <{POST_SNAPBACK}><div class='quotemain'>you can see rossis rear wheel is forward compared to lorenzos. just shows what a great rider vale is, that he can alter his style to suit. not many riders can do that imho.


I agree Roger, but for me it is the change at the front that shows a greater level of adaptability and that can't be seen in the pics.

Anyone who rides knows the different feeling cause by tyre pressure changes, surface changes, tyre profiles and new tyres. Never mind getting used to a bike with an adjusted steering head, different weight distribution and then having to do the foreign art of putting total trust in a 'new' (to him) front tyre.

It is impressive (but not unexpected at all for VR) but I would suggest that at this level, all riders should be able to adapt, just that some will do it quicker and better than others. Those that cannot adapt will be stuck and become yesterday's racers.




Garry

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 10:35 AM) <{POST_SNAPBACK}><div class='quotemain'>As impressive as Rossi's adaptability is, there is currently a rookie just 3 points behind him going through a significantly bigger adaptation.

I'd think it's a lot harder to change your riding style than adapting to a new bike.

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 10:35 AM) <{POST_SNAPBACK}><div class='quotemain'>As impressive as Rossi's adaptability is, there is currently a rookie just 3 points behind him going through a significantly bigger adaptation.
i hate to say it but lorenzo has not adapted that well. he has impressed but he has also had quite a few get off's. skill or mad man ?
i would say rossi has a bigger adaptation to over come because of the years he has ridden the yam on michilins and now he has had to alter his style to suit the tyres and new geomatary of the bike. its been said the 250's and 800's are very similar to ride .

<div class='quotetop'>QUOTE (phleg @ May 19 2008, 11:20 AM) <{POST_SNAPBACK}><div class='quotemain'>I'd think it's a lot harder to change your riding style than adapting to a new bike.

Really? please explain

Changing your style to suit new tyres is harder than changing your style for a different bike, tyres and class?

<div class='quotetop'>QUOTE (roger-m @ May 19 2008, 11:30 AM) <{POST_SNAPBACK}><div class='quotemain'>i hate to say it but lorenzo has not adapted that well. he has impressed but he has also had quite a few get off's. skill or mad man ?
i would say rossi has a bigger adaptation to over come because of the years he has ridden the yam on michilins and now he has had to alter his style to suit the tyres and new geomatary of the bike. its been said the 250's and 800's are very similar to ride .

I would say being the highest scoring rookie ever after 5 races is about as good as an adaptation gets, although he has not been without his mistakes. The 880's are said to be similar to the 250 cc bikes, but not nearly as similar as an 800 Yamaha is to another 800 yamaha.

Rossi may struggle with his adaptation because he is older and has been in relatively stagnant position longer but those differences are personal to him, not the change he is going through.

<div class='quotetop'>QUOTE (roger-m @ May 19 2008, 11:30 AM) <{POST_SNAPBACK}><div class='quotemain'>i hate to say it but lorenzo has not adapted that well. he has impressed but he has also had quite a few get off's. skill or mad man ?
i would say rossi has a bigger adaptation to over come because of the years he has ridden the yam on michilins and now he has had to alter his style to suit the tyres and new geomatary of the bike. its been said the 250's and 800's are very similar to ride .

I think Yamaha and Michelin are doing their very best to make sure Jorge can make the most of this style and talent...

And over time if needed the team and factory will change him to suit the bike.... oh sorry that is the Honda way of working with riders, not Yamaha...

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 11:36 AM) <{POST_SNAPBACK}><div class='quotemain'>I would say being the highest scoring rookie ever after 5 races is about as good as an adaptation gets, although he has not been without his mistakes. The 880's are said to be similar to the 250 cc bikes, but not nearly as similar as an 800 Yamaha is to another 800 yamaha.

Rossi may struggle with his adaptation because he is older and has been in relatively stagnant position longer but those differences are personal to him, not the change he is going through.
hear we go again, how many times do we have to go through this with you tom ? your such a bore

Hard to argue that anyone has been as adaptable as rossi, although eddie lawson did win premier class races on 3 different makes, including (unbelievably) a cagiva. Guess they were all 500 2-strokes though.

<div class='quotetop'>QUOTE (roger-m @ May 19 2008, 12:04 PM) <{POST_SNAPBACK}><div class='quotemain'>hear we go again, how many times do we have to go through this with you tom ? your such a bore

The peak age for learning is not 29.

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 12:30 PM) <{POST_SNAPBACK}><div class='quotemain'>The peak age for learning is not 29.
really proffessor tom ?

there are many mature students who excel in education and there are many mature athletes also. your comments are totally unfounded, there just your opinion not fact.

Depends on your abilities Tom. Might not be your own individual peak but still be far ahead of younger people of lesser ability. Also depends on what form of intellectual or physical endeavour you are talking about. There seems to be general agreement that the younger you are the better for higher mathematics or theoretical physics, and hence in your field you are correct, but I think 29 is below the age of significant intellectual or physical decline in many fields. Some artists remain creative or even improve when much older, and marathon runners for instance seem to peak in their 30s, although I admit this may reflect a dulling of sensibilities with advancing age and hence a greater ability to put up with the pain .

Regardless, in rossi's individual case he is obviously still more adaptable than most if not all even at his advanced age .

In general though, as I have said before in this context, all things considered I would rather be young .

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 11:33 AM) <{POST_SNAPBACK}><div class='quotemain'>Really? please explain

Changing your style to suit new tyres is harder than changing your style for a different bike, tyres and class?


i have found that it is often easier to adapt to big changes all in one go than little changes one by one.
its a familiarity thing IMO and so, i think adapting to new tyres can be very challenging as would be adapting to a new bike...but in a different way...

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 12:33 PM) <{POST_SNAPBACK}><div class='quotemain'>Really? please explain

Changing your style to suit new tyres is harder than changing your style for a different bike, tyres and class?

Well, according to the team he didn't change his riding style until he got hurt and then it was to avoid pain, allthough it might be a permanent change in the future.
So, yes he had to adapt to a new bike but largely kept his riding style. Says a lot about how close to a 250 the bike is?

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 12:30 PM) <{POST_SNAPBACK}><div class='quotemain'>The peak age for learning is not 29.


what does one really have to learn when they have mastered the art of something?

what your seing rossi doing is nothing more rite now other than using "expierience" he already knows what he is doing, im sure there are many people who will agree with me....

what lorenzo has done is jump to a higher CC, what rossi is doing is going back to the drawing board and doing something which has never been tested, so for baseline lorenzo already had a head start by going to yamaha and riding a bike that has almost been honned to perfection (apart from top speed) by the master...

its alot harder for rossi to use a untested formula where as lorenzo is just adjusting to something which is already good and been tested.

<div class='quotetop'>QUOTE (Tom @ May 19 2008, 01:30 PM) <{POST_SNAPBACK}><div class='quotemain'>The peak age for learning is not 29.

I guess it's 42 then as everything else.

<div class='quotetop'>QUOTE (BigAl @ May 19 2008, 02:26 PM) <{POST_SNAPBACK}><div class='quotemain'>i have found that it is often easier to adapt to big changes all in one go than little changes one by one.
its a familiarity thing IMO and so, i think adapting to new tyres can be very challenging as would be adapting to a new bike...but in a different way...



But then again, we just learned that the whole bike were changed to fit the b.stones so I guess he took the easy path