Pirelli 2013

[autogyro]

Bring back Max.

The kerb issue brought up By Garry Anderson is very valid if not the full picture.

I do not see the sharp inner kerb angle as the reason for the tyre explosions.
I do see it as the main contributory factor.
I do not think the tyres would explode unless they are subject to high impact force on a small area of the sidewall.

[rssh]

Can the uni-directional tyres be the problems that causing these problems in the races because in 2011 and 2012 after qualy teams used to change the left tyre to the right side & vice-versa in races ? Could the max loaded tyres (max wear ones) explode when put through racing .

[Huntresa]

Can the uni-directional tyres be the problems that causing these problems in the races because in 2011 and 2012 after qualy teams used to change the left tyre to the right side & vice-versa in races ? Could the max loaded tyres (max wear ones) explode when put through racing .

I thought teams did left on right etc this year aswell ?

[Huntresa]

http://www.autosport.com/news/report.php/id/108479

[WhiteBlue]

http://www.autosport.com/news/report.php/id/108479

It sounds like the fudging has already started. All analysis of the failure mode will not escape the simple truth that the tyres were not fit for the purpose. If we can believe the preliminary analysis we still have to conclude that Silverstone simply puts high stresses through the tyres and that can happen at Spa and Monza equally or worse. Whether it is stress concentration or shock waves that ultimately kill the construction will have little impact. The new tyres need to be simply stronger to provide an acceptable level of safety.

Kevlar is still likely to be part of the solution. It has higher ductility compared to steel which helps a lot in cases of stress concentration or shock waves. It was also said that the 2012 Kevlar belt dissipated less energy and hence gave a wider operating window than the 2013 steel belt.

[Huntresa]

http://www.autosport.com/news/report.php/id/108479

It sounds like the fudging has already started. All analysis of the failure mode will not escape the simple truth that the tyres were not fit for the purpose. If we can believe the preliminary analysis we still have to conclude that Silverstone simply puts high stresses through the tyres and that can happen at Spa and Monza equally or worse. Whether it is stress concentration or shock waves that ultimately kill the construction will have little impact. The new tyres need to be simply stronger to provide an acceptable level of safety.

Yeah but that concrete in that pic, not good work from Silverstone and the BRDC

[WhiteBlue]

Yeah but that concrete in that pic, not good work from Silverstone and the BRDC

I bet you can find similar pics from Spa or Monza if you do some research. I cannot believe that Silverstone has sub standard track and curb surfaces. The FiA would have intervened long ago. To me the particular curbing sections were just generating high stresses, but on a level that the design was supposed to cope with.

http://www.marca.com/2013/07/01/motor/f ... 72736.html
Marca seems to claim that the improved bonding process involved the use of a Kevlar layer which wasn't communicated and should have been. When I look at the pictures of the exploded tyres I must admit that the visible fibres look more like the pale colour of Kevlar than the dark colour of steel that has bonded with rubber. It would mean they tried a hybrid construction from steel and Kevlar. It sounds like a plausible thing and like something Pirelli could have fudged in their communications to appear like a minor change.

[FW17]

Most European circuits have grasscretes lining the kerbs and has never been an issue

Spa 2009

http://www.marca.com/2013/07/01/motor/f ... 72736.html
Marca seems to claim that the improved bonding process involved the use of a Kevlar layer which wasn't communicated and should have been. When I look at the pictures of the exploded tyres I must admit that the visible fibres look more like the pale colour of Kevlar than the dark colour of steel that has bonded with rubber. It would mean they tried a hybrid construction from steel and Kevlar. It sounds like a plausible thing and like something Pirelli could have fudged in their communications to appear like a minor change.

Quiet clear that kevlar has been used on the thread




Pirelli seems to be resting totally on kevlar belt as a solution but it is quiet clear that fundamental design of the tyre are not suitable to F1 racing.

[stefan_]

[youtube]http://www.youtube.com/watch?v=6shR0qYWxoc[/youtube]

[garygph]

To me there is an important difference between a delamination problem which they have had
and hence the chat about improved bonding, and the failures we have seen this week end.

where the whole center portion of the tyre tears away from the sidewalls. I seem to remember that when making tyres and different rubber blends the higher the percentage of natural rubber in the blend the better "cut resistance" the tyre had. This may explain why other tyres have not suffered on the same track and kerbs like this one has. One of the other chemicals used is Silica in road cars for supposedly better wet weather grip as well as fuel economy but not cut resistance. I was just wondering if in their quest for wear rates etc they have now have a compound that is not good at all with cut resistance and hence the problems we saw yesterday with this tracks high speed corners really exposing that flaw?

I know we have some tyre experts on this forum and love to know their opinion on this.

[turbof1]

http://www.youtube.com/watch?v=6shR0qYWxoc

They could smoothen the edge of the kerbs for an intermediate solution. Anything that helps stop the tyre failures but does not hamper racing should be used now.

That said, the emphasis on the kerbs is too big. It damages the image of the circuits, while they did nothing wrong. It is effectively Pirelli who designed tyres this year which aren't suitable for that kind of work.

So yeah: as an inmediate solution smoothen the kerbs' edges, and for Hungary or no later then Belgium new tyres.

[WhiteBlue]

http://www.auto-motor-und-sport.de/form ... 50495.html
AMuS has an interesting theory about the tyre failures. They remind us that similar things have happened to Michelin tyres in Spa 2004 and Indy 2005. They say that the failure mode at that time was the build up of a standing wave in the tyre shoulder. At that time the waves had also been induced by kerbs and Michelin used a steel belt in the shoulder.
https://en.wikipedia.org/wiki/Standing_wave

This is a standing wave of the first order on a disc geometry.

And this is a standing wave of the second order for the same geometry.

I find some plausibility in this explanation. A standing wave is something similar to what we know as resonance. If a dynamic system gets excited to oscillations that are not in the design calculation you do get stresses that massively exceed the design parameters.
Combined with the use of a hybrid construction from steel and Kevlar it could explain why we had different failure modes in Silverstone compared to prior delaminations. The resonance or standing wave frequencies would have been shifted by the different elastic and damping properties of the materials used. It could also explain why the use of Kevlar only in 2012 did not create any problems. Kevlar has superior damping and ductility properties compared to steel or hybrid.

[Pierce89]

I guess this is the wrong thread, but its pretty clear Merc made huge gains in their tire test.

[FW17]

Pirelli in May 2013


Pirelli June 2013


A definite change in thread construction

[WhiteBlue]

Pirelli in May 2013
https://imageshack.us/scaled/large/849/pirellir.jpg

Pirelli June 2013
http://sphotos-e.ak.fbcdn.net/hphotos-a ... 9570_n.jpg

A definite change in thread construction

Yep, completely different and also consistent with Marca's explanation.