Cut Tyres

[aral]

There is a good photo of Massas tyre after the explosion, on Planet f1 heading. No sign of yellow Kevlar, just light grey and dark grey.

[thisisatest]

has anyone mentioned the tire blowouts in the GP2 race? i didnt see the whole race, but around lap 8, one left rear blew like the others.

[Cam]

BRDC president, Derek Warwick, has dismissed claims that the kerbing at Silverstone was to blame for the numerous, spectacular tyres failures during yesterday's Grand Prix.

"These kerbs have been in since 2009," he told Sky Sports. "We've had thousands and thousands of cars go over these kerbs and they have been absolutely fine.

"We've had them checked by the FIA and they comply completely," he added, admitting that at one stage he feared for the future of the event.

"We need to make sure it's a good race here at Silverstone in order to bring the crowds back for next year so to say I was panicking would be an under-statement.

"I think Bernie, the FIA and Pirelli are bringing the sport into disrepute," he continued, "and they need to have a serious look at themselves and change these tyres and not expect all the teams to agree. Take it out of the teams' hands and put safe tyres on these cars."

via Pitpass

[Poncho]

My reading of Pirelli statements says that cuts were not the cause of the exploding tyres.

A couple of weeks ago, there was debate about the tyres being swapped side to side. A close up photo of Massa's tyre remains, shows that the barcode label, on the left rear, is clearly marked R. If the tyres are manufactured with a bias in one direction, and this is reversed, for whatever reason, could this be putting extra strain on the bonding of the tread to the belt?

It was reported that Rosbergs tyre was starting to delaminate, with NO cuts apparent.

I was thinking the same, and wasn't it supposed that for this years tyres, the walls were "made" with different configuration, maybe the inner part more strong, and the outside "softer" but with the swapping, for performance reasons, that was not useful anymore?

[CBeck113]

My reading of Pirelli statements says that cuts were not the cause of the exploding tyres.

A couple of weeks ago, there was debate about the tyres being swapped side to side. A close up photo of Massa's tyre remains, shows that the barcode label, on the left rear, is clearly marked R. If the tyres are manufactured with a bias in one direction, and this is reversed, for whatever reason, could this be putting extra strain on the bonding of the tread to the belt?

It was reported that Rosbergs tyre was starting to delaminate, with NO cuts apparent.

I was thinking the same, and wasn't it supposed that for this years tyres, the walls were "made" with different configuration, maybe the inner part more strong, and the outside "softer" but with the swapping, for performance reasons, that was not useful anymore?

If that were the case, then Pirelli would have immediately told the press that the teams were at fault for using their tires incorrectly. But since that didn't happen, you can be sure that the problem is in the tire construction itself, either a design or a manufacturing error. Interestingly, many teams were shown adding air pressure to the tires when the safety car came out. I believe that the area where the contact surface meets the sidewall is the source of the problem (the same as before). Adding the Kevlar ply did not change the temperature coeficient in the shoulder, so the delamination problem was not solved; instead the Kevlar caused damage to the shoulder area (where the tread was now ancored) through the higher than expected/calculated centrifical forces, and tore that sensitive out with it, leading to the "new" failure mode.

But at least Mercedes will now receive a proper punishment (in my opinion at least). Can the teams or the FiA take action against Pirelli?

[Poncho]

My reading of Pirelli statements says that cuts were not the cause of the exploding tyres.

A couple of weeks ago, there was debate about the tyres being swapped side to side. A close up photo of Massa's tyre remains, shows that the barcode label, on the left rear, is clearly marked R. If the tyres are manufactured with a bias in one direction, and this is reversed, for whatever reason, could this be putting extra strain on the bonding of the tread to the belt?

It was reported that Rosbergs tyre was starting to delaminate, with NO cuts apparent.

I was thinking the same, and wasn't it supposed that for this years tyres, the walls were "made" with different configuration, maybe the inner part more strong, and the outside "softer" but with the swapping, for performance reasons, that was not useful anymore?

If that were the case, then Pirelli would have immediately told the press that the teams were at fault for using their tires incorrectly. But since that didn't happen, you can be sure that the problem is in the tire construction itself, either a design or a manufacturing error. Interestingly, many teams were shown adding air pressure to the tires when the safety car came out. I believe that the area where the contact surface meets the sidewall is the source of the problem (the same as before). Adding the Kevlar ply did not change the temperature coeficient in the shoulder, so the delamination problem was not solved; instead the Kevlar caused damage to the shoulder area (where the tread was now ancored) through the higher than expected/calculated centrifical forces, and tore that sensitive out with it, leading to the "new" failure mode.

But at least Mercedes will now receive a proper punishment (in my opinion at least). Can the teams or the FiA take action against Pirelli?

Yes, pirelli would have say that.

And now following your explanation with the increased forces, also the tyres increased the temperature, thus the radio from Jenson calling overheating in all tyres?

[aral]

Pirelli subsequently ruled out cuts, stating that the failure was a mystery. Yes, Vettels tyre did have what appeared to be a cut, but as he had run over tyre debris, that was said to be the reason.

[nacho]

I heard a couple of races ago that the teams are swapping tires between qualifying and race, left side tires go to right side and vice versa to get a bit of extra endurance on the more heavily loaded side of the car.

[strad]

SO it once again proves my point that the drivers should be required to drive ON the track...If they cut a tire becuase they want to straightline a corner..too bad..
That said,,,I would have sworn I saw Massa run over somethuing just prior to his tire letting go.

They do drive on the track. The track is defined as all area in which you can have some part of tyre touching the white line.

Sorry...You're wrong..The track as defined by the FIA is between the white lines.

[Jersey Tom]

SO it once again proves my point that the drivers should be required to drive ON the track...If they cut a tire becuase they want to straightline a corner..too bad..

So after however many decades of drivers happily and safely clipping kerbs in every open wheel and sportscar racing series (including years of F1 with more engine power and/or more open aero rues)... it's now that we should throw up our hands and say that riding the kerbs is too much?

Absurd.

[WhiteBlue]

In one way Strad is right that the culture of cutting the curbs is not in line with the traditional ethos of the racing driver. Tyre technology wasn't advanced enough to allow such things if you go back 30 or 40 years.

On the other hand Tom has a point with the fact that riding the cubs is perfectly normal particularly since we had a bunch of chicanes introduced in 1994. So it becomes a point of your perspective that you take on motor racing. If you are the average 21st century driver it is normal that just trade a bit of reliability for performance if you ride the curbs relatively hard. You expect the tyre supplier to protect you even when you do some abuse to their products.

If we go back to the current troubles we should simply acknowledge that tyres must be designed with a certain amount of abuse in mind from riding the curbs. If they aren't they do not provide safety for the vast majority of racing series and existing tracks today. So there is really no practical alternative to designing a tyre with a proper resistance against the destructive use modes that are out there.

That clearly includes resistance against cuts that are always going to be happening either by hitting debris or by sharp objects included in track design. It is simply unavoidable to have such things happening.

The underlying question in my view is whether Pirelli did enough in 2013 to stop superficial damages to propagate and cause further destruction to deeper elements of the carcass. The answer is most likely negative. They have replaced the Kevlar reinforcement with steel elements that negatively impact on the ability of the tyre construction to sustain thermal loads and they reduced the ductility. Hence you have to assume they opened the chance for dynamic and thermal driven loads to crack the carcass at the weakest point. And that is most likely what has happened in Silverstone.

[tf1250]

Hi guys,

First time post.

Could weather have played a part in causing the tire cuts? GB has had a very wet spring and water can cause settling. Wondering if differential settling between the curbs and 'green' concrete could be relatively recent?

[beelsebob]

Hi guys,

First time post.

Could weather have played a part in causing the tire cuts? GB has had a very wet spring and water can cause settling. Wondering if differential settling between the curbs and 'green' concrete could be relatively recent?

The bigger problem tends to be freeze and thaw, but no... Since we have these problems, we tend to design our roads (or circuits) to be able to cope with it. Plus, the curbs there look pretty much exactly what F1 curbs are meant to look like. I would be surprised if you found any circuit (bar street circuits off) that didn't have a "sharp" edge behind the curbs.

[gixxer_drew]

The cover story made me laugh. What a political mess. When they said the teams were increasing the pressure to "make them more resistant to being cut" I made popcorn.

[strad]

So after however many decades of drivers happily and safely clipping kerbs in every open wheel and sportscar racing series (including years of F1 with more engine power and/or more open aero rues)... it's now that we should throw up our hands and say that riding the kerbs is too much?

You know that's not true. For many decades they had kurbs you dared not cut across...and then as with all things the car owners and designers pushed for lower kurbs and the drivers exploited it.
Hell it was a big deal when Black Jack would drop a wheel off the edge at the apex. Silverstone was clearly defined by the hay bales.