Camber, Graining and Tire Pressure

[vonk]

Really depends on what you mean by the 'dark area' I guess, and when you're looking at it.

I'd say it's true that the middle of the crown area is going to be very vertically compliant.. but that's kind of a separate issue.

It happens mostly in early Friday practice, and most cars show it distinctly. Then, after some quick pit stops, they loose it. The TV commentators called it graining. I got the impression that teams at first run a few aggressive laps at high tire pressure (high crowning) to check their camber settings for the “new” track that day. As you know, each track puts a car through a unique “roll program” with the attendant camber changes, also depending on ambient conditions. Once they’re happy, they reduce pressure again for best contact patch.

[marcush.]

Really depends on what you mean by the 'dark area' I guess, and when you're looking at it.

I'd say it's true that the middle of the crown area is going to be very vertically compliant.. but that's kind of a separate issue.

It happens mostly in early Friday practice, and most cars show it distinctly. Then, after some quick pit stops, they loose it. The TV commentators called it graining. I got the impression that teams at first run a few aggressive laps at high tire pressure (high crowning) to check their camber settings for the “new” track that day. As you know, each track puts a car through a unique “roll program” with the attendant camber changes, also depending on ambient conditions. Once they’re happy, they reduce pressure again for best contact patch.

?
camber settings are checked by temperature spread across the tread .High pressure will not do any good in determining what cambers are best..?
the fresh rubber will of course show a lot of pressure buildup ,but I doubt they force the tyre intentionally towards graining.

[Jersey Tom]

Really depends on what you mean by the 'dark area' I guess, and when you're looking at it.

I'd say it's true that the middle of the crown area is going to be very vertically compliant.. but that's kind of a separate issue.

It happens mostly in early Friday practice, and most cars show it distinctly. Then, after some quick pit stops, they loose it. The TV commentators called it graining. I got the impression that teams at first run a few aggressive laps at high tire pressure (high crowning) to check their camber settings for the “new” track that day. As you know, each track puts a car through a unique “roll program” with the attendant camber changes, also depending on ambient conditions. Once they’re happy, they reduce pressure again for best contact patch.

Eh.. not following you on this.

TV announcers generally don't know what they're on about.. sometimes the drivers don't either.. particularly when it comes to graining. I think Kubica even had been talking about "graining" a tire and then having to "clean it off." I've never seen a truly grained race tire that you could get back to normal by just driving on it. Once it's torn up, it's torn up. Worms are a different story.

[vonk]

?
camber settings are checked by temperature spread across the tread.

That's the way I used to do it. But by the time you drive over different pavement to your pit, temps are somewhat after the fact. So, what are they doing then? Maybe, it’s the beer.

[vonk]

Eh.. not following you on this.

TV announcers generally don't know what they're on about.. sometimes the drivers don't either.. particularly when it comes to graining. I think Kubica even had been talking about "graining" a tire and then having to "clean it off." I've never seen a truly grained race tire that you could get back to normal by just driving on it. Once it's torn up, it's torn up. Worms are a different story.

It's really not important whether it is graining or not. That's why I called it "dark bands" earlier. It's just a phenomenon that they also observed. What do you think it means? As I said to marcush, it must be the beer.

[marcush.]

Really depends on what you mean by the 'dark area' I guess, and when you're looking at it.

I'd say it's true that the middle of the crown area is going to be very vertically compliant.. but that's kind of a separate issue.

It happens mostly in early Friday practice, and most cars show it distinctly. Then, after some quick pit stops, they loose it. The TV commentators called it graining. I got the impression that teams at first run a few aggressive laps at high tire pressure (high crowning) to check their camber settings for the “new” track that day. As you know, each track puts a car through a unique “roll program” with the attendant camber changes, also depending on ambient conditions. Once they’re happy, they reduce pressure again for best contact patch.

Eh.. not following you on this.

TV announcers generally don't know what they're on about.. sometimes the drivers don't either.. particularly when it comes to graining. I think Kubica even had been talking about "graining" a tire and then having to "clean it off." I've never seen a truly grained race tire that you could get back to normal by just driving on it. Once it's torn up, it's torn up. Worms are a different story.

+1 that is my undertstanding of graining and pickup

that is also the reason why testing alone on a track can be very misleading..you just don´t have those masses of rubber lyingaround waiting to stick to your nice fresh rubber..with semi professional drivers you would not believe just how much a tyre can grow over a stint..
graining is a form of excessive wear and it does not really heal even when conditions improve.

ref tyre temps ..i don´t get the point there..where do you drive? of course you are not interested in measuring up the pickup ...but as long as your driver is
diving into the pits bringing with him a band of debris ,I don´t think he has understood that he needs to push before it even makes sense to take a reading of tire temps.. I´d just wave him out again and tell him to try harder.

[vonk]

+1 that is my undertstanding of graining and pickup

that is also the reason why testing alone on a track can be very misleading..you just don´t have those masses of rubber lyingaround waiting to stick to your nice fresh rubber..with semi professional drivers you would not believe just how much a tyre can grow over a stint..
graining is a form of excessive wear and it does not really heal even when conditions improve.

ref tyre temps ..i don´t get the point there..where do you drive? of course you are not interested in measuring up the pickup ...but as long as your driver is
diving into the pits bringing with him a band of debris ,I don´t think he has understood that he needs to push before it even makes sense to take a reading of tire temps.. I´d just wave him out again and tell him to try harder.

I have never seen rubber slag accumulate on an F1 tire, even when coming in to the pits. That’s because slag lies outside the line that everyone uses. If the car is driven on edge, accidental pickup is scrubbed off very quickly.

[marcush.]

+1 that is my undertstanding of graining and pickup

that is also the reason why testing alone on a track can be very misleading..you just don´t have those masses of rubber lyingaround waiting to stick to your nice fresh rubber..with semi professional drivers you would not believe just how much a tyre can grow over a stint..
graining is a form of excessive wear and it does not really heal even when conditions improve.

ref tyre temps ..i don´t get the point there..where do you drive? of course you are not interested in measuring up the pickup ...but as long as your driver is
diving into the pits bringing with him a band of debris ,I don´t think he has understood that he needs to push before it even makes sense to take a reading of tire temps.. I´d just wave him out again and tell him to try harder.

I have never seen rubber slag accumulate on an F1 tire, even when coming in to the pits. That’s because slag lies outside the line that everyone uses. If the car is driven on edge, accidental pickup is scrubbed off very quickly.

in fact all cars in parcferme look like they where in bosnia on their cool down lap..
we have ssen a lot of that on pics posted here. ..

not 2010,but as a reference..
http://images.google.de/imgres?imgurl=h ... s%3Disch:1

http://images.google.de/imgres?imgurl=h ... s%3Disch:1

[vonk]

I have never seen rubber slag accumulate on an F1 tire, even when coming in to the pits. That’s because slag lies outside the line that everyone uses. If the car is driven on edge, accidental pickup is scrubbed off very quickly.

in fact all cars in parcferme look like they where in bosnia on their cool down lap..

Yes, because on their cool down lap they drive slowly all over the track.