[LM24 Race] Tyres stints

[Adam43]

Watching the laps being put in and it is dificult to gauge how the tyres are holding up. The Audi never did a single stint on tyres last year. IIRC they double stinted the tyres even when the drivers did longer stints. McNish is on a stint now and RLM are trying to gauge if the lap times are holding up - it is hard to tell because of traffic.

RLM also hypothesised that a loss of a couple of seconds per lap is about the level where it is better to change tyres than push on on old tyres.

How will the tyres hold out? Audi traditionally has been easy on the tyres. Is the new R15. How will the Pugs and the petrol cars do? What have we learnt from the previous races?

Are there any suprises on this topic in other classes?

[Adam43]

TK has just done a 3m32 on the 8th lap in this practice run. Still too early in a tyre's life to tell...

[Adam43]

A 3m30s on the last lap before TK came in (a 10 lap stint?). A good practice pit stop too, while Peugeot celebrated the pole.

[AndrewF31]

wonder if he was pushing hard because 3:30 is 7 seconds off pole. Race pace will be in the 20s I'd think.

[Adam43]

I think there will be high 3m20s in the race, but I suspect a good normal race pace is low 3m30s. 7s off pole seems about right to me.

[skeeskirrt]

Anyone know how many stints Audi #1 did on one set of tires in the second session? Or whether they were hard or soft?

There was some speculation on RLM that they were trying out the hards in the first session. (Although I'd bet they slapped on a new set of softs for McNish's hot laps at the end.)

I think I heard Peugeot #8 was on softs when Sarrazin grabbed the pole in the second session. It will be interesting to see how the tire strategies play out.

Anyone with more accurate info please fill me in!

[davehenrie]

The only real data we have is probably already outdated, but at Sebring, the Audi's were not able to double stint while the Pugs did manage a few double stints. (Rocky, I think it was he, tried with miserable results for the R15 team)

[cmk]

Sarrazin was on softs as they were assessing their wear level for running at night during the race (or so Pug claim!). Would be interesting to know how that jibed with heading out and setting that lap with only 15 minutes to spare though! How can you check wear on a stint that short? You can tell if they really suck, but that's about it...

[Holt]

If you look at Lemans 2007, Peugeot's first year, you will see their tires fell off alot in the race. They were able to match the R10s pace over a couple of laps that year but that was it. Audi could run around their qualifying speed in 2007 for entire stints, while the Peugeot was 4-6 seconds off it's qualifying speed during the race.

For 2008 Peugeot improved and they were able to match their qualifying speed in the race.

Peugeot double stinted their tires at Sebring until they switched to the softs in the evening. Audi never double stinted the tires at Sebring except once with poor results.

While Peugeot may not be able to triple stint the tires, they should be able to double stint soft tires in the night without too much fall off

Judging from last year we know Peugeot can run their qualifying pace in the race.

The question is, can the R15?

[Holt]

I can't edit my previous post after finding some new info, so here it is

After looking over the timing and coring again, I found times for full stints

#1 Audi in the First Practice session, 12 laps

3'31
3'31
3'33
3'30
3'27
3'29
3'27
3'26
3'27
3'25
3'34

#1 Audi in the Second Practice session, 12 laps

334
3'39
3'34
3'31
3'35
3'31
3'36
3'31
3'38
3'34
3'29
3'37

The #2 Audi never did more then 3 laps in a row without pitting

#3 Audi did many 6 lap runs in the first session, but never did a full fuel run until the second session.

3'35
3'34
3'35
3'34
3'35
3'32
3'31
3'30
3'30
3'34
3'45

#7 Peugeot 11 lap stint to start the first Qualifying session

3'30
3'34
3'28
3'30
3'31
3'29
3'27
3'30
3'27
3'28
3'38

Again, in practice session 1 the #7 Peugeot ran another 11 lap stint

3'33
3'32
3'32
3'30
3'30
3'28
3'27
3'28
3'34
3'26
3'40

The #8 Peugeot never really had any real long runs over 6 laps

David Brabham was behind the wheel of the #9 Peugeot for the start of the first session. His times were pedestrian, but what is key is that he was able to run 12 full laps on his first stint. So we have seen the Audi run 12 laps and a Pescarolo run 12 laps. But its still up for grabs who has the fuel economy as I doubt the teams pushed the cars' fuel mileage.

Brabham came in after his first 12 lap stint, then went back out and ran these laps

3'29
3'28
3'29
3'28
3'54 - most likely the turn 1 spin lap
3'32
3'27
3'38
3'29
3'27
3'37

The #9 Peugeot never ran more then 3 laps straight in the second qualifying session.

The #17 Peugeot never ran more then 4 or 5 laps straight.

This is what I gather from this information.

The #1 Audi and #8 Peugeot will race off into the distance at the start followed by the #7 Peugeot or even perhaps the #17 Peugeot.

The drivers of the #2 Audi never seemed to be happy with the car so I think they will struggle in the race.

The #3 Audi appears to to be just off the pace.

I see a nice 3 way battle between Audis #2, #3, and the #9 Peugeot. Perhaps even the #17 Peugeot would make it a 4 way battle.

I don't think any of those cars have the outright speed to keep up with the #7, #8 Peugeots and the #1 Audis, and they will have to rely on one of the fast 3 cars breaking down to get a podium

[gwyllion]

According to the Audi press release about qualifying, the #1 car did a quadruple stint on a single set of Michelin tires. That is impressive.

[MGDavid]

Originally Posted by gwyllion

According to the Audi press release about qualifying, the #1 car did a quadruple stint on a single set of Michelin tires. That is impressive.

if a stint is 13 laps at 3m30secs then a quad stint is 3 hrs running; qually was 4 hrs yet ISTR we saw the #1 car change tyres several times reasonably regularly. So did they just practice the stops by removing the tyres and fitting the same ones again? (or has my memory failed again)

[gwyllion]

Originally Posted by MGDavid

if a stint is 13 laps at 3m30secs then a quad stint is 3 hrs running; qually was 4 hrs yet ISTR we saw the #1 car change tyres several times reasonably regularly. So did they just practice the stops by removing the tyres and fitting the same ones again? (or has my memory failed again)

They could have fitted tyres than were used during free practice.

[Holt]

Originally Posted by gwyllion

According to the Audi press release about qualifying, the #1 car did a quadruple stint on a single set of Michelin tires. That is impressive.

A break down of the #1's stints

Start of First Session
1 Lap
Pit
7 laps
Pit
4 Laps
Pit
12 laps
Pit
12 laps
End of First Session

Start of Second Session
12 laps
Pit
8 Laps
End of Second Session

The quadruple stint must have been from the first session, and as you can see 2 of the 4 claimed quadruple stints were 7 or less laps. 7+4+1 = 12, so the car has only gone at most the full distance of a triple stint, that is if they never changed tires for the entire first qualifying session.

Perhaps they used the same tires for the three 12 lap stints and the 8 lap stint? I dont know

[cmk]

One thing is almost for certain, I believe, and that is that the R15 will be kinder on its tyres than it was at Sebring. Coming to a track like that, with a relatively abrasive surface, virtually without dry testing beforehand, problems with suboptimal tyre wear were almost inevitable. They hadn't had any chance to work on the setup themselves in advance, and Michelin hadn't really had a chance to get plugged into what the R15 liked. With a spring's development behind it, surely both parties will have raised the game with respect to tyre wear @ LM.