Split 1 - R5: Hockenheimring - 16th April 2018 (2 Viewers)

[miagi]

The thing this is trying to solve is those who were having enormous problems controlling the car. For some people their car was damn-near undriveable and I was one of them. The car was more like a hovercraft, with zero feeling of connection to the road underneath. When I drove it last night I struggled to keep the car under control, doing 1m55s laps (or more) almost as soon as the rain started falling consistently. Yes, the 1m44 was at the start of a session that was set as Light Rain, but after 15-20 minutes I was running consistent 1m50-1m51 laps on a dry-setup car (near-as-dammit the default 'loose' setup with 1 extra rear wing - 1F, 7R - and wet tyres) and in full control.

I haven't yet tried the transition from dry to wet, simply because the wet tyre was a disaster, so I was ready to pull out of the race entirely (I even tried just running the wet tyre on a dry track and I couldn't make it round a single lap). However, one of our staff tried it on the Ford GT and was able to run the dry tyre for a number of laps after the rain started, so that didn't seem to be a problem for him.

I did a test on a setup based on my old setup an well, I think I didn't had the problems you mentioned. I did a light could > light rain > hazy and a light could > light rain > clear test. When it starts raining hard tires cool down to too low temps and too low pressure, forcing the driver to pit while the track is still in transition state. Softs can go deeper into the transistion state. But the moment the track sounds wet, it's game over for the slicks. Change to wet tires made me think they are absolutly broken. But a few more laps into the wets, they started working. However when the track drys up 1:46 is the pace where the wets overheat badly. Becuase of the deep puddles that cover the entire track at a few places and some apexes, the slick is only slighly quicker with sliding off track, evading a few apexes and pure struggle for survival.

 

[Cluck]

I just ran a full simulation run and came in just as I saw spray emerging from cars in front. Changing to wet tyres at that point was fine, I had no problem with grip but of course saw a drop in pace. However, I was then able to run that same set of wet tyres right to the end of the race, on a Light Cloud -> Light Rain -> Hazy setup. The wet tyres only overheated when I made a mess of a corner, caught a kerb and spun myself round. However, just backing off the throttle slightly in the next couple of corners brought the rear tyres back into their normal operating temperature window. Laptimes in those latter stages, where the track was 'mostly' dry, were down to 1m45 without overheating. It might be a different story in the Ford, of course, but I'm obviously not going to spend what little time I have left before the race testing a car I'm not going to be driving!

That was all done in the Ferrari, starting from the baseline "loose" setup and barely adjusting anything (certainly nothing to do with springs, camber or dampers).

I can't explain what was going on before but the car was undrivable. I couldn't do a lap on wet tyres on a dry track without spinning out multiple times. What I do know is that I've gone from "wanting to pull out of the race" to "wanting Monday to come sooner".

 

[AndrexUK]

Not sure about setups, but having issues with a pit bug...
Tires are changed as requested, but the pressures do not match what was set.
(adding about 0.4 bar on each tire).
Then, when static in the pit lane (after the tires were just changed), the pressures will rise by a further 0.3 bar (even though they tires are cold, and cooling down - so the pressure increase is not due to temps.

 

[fab. ICEMAN]

Not sure about setups, but having issues with a pit bug...
Tires are changed as requested, but the pressures do not match what was set.
(adding about 0.4 bar on each tire).
Then, when static in the pit lane (after the tires were just changed), the pressures will rise by a further 0.3 bar (even though they tires are cold, and cooling down - so the pressure increase is not due to temps.

I don't think there's anything wrong in your video.

The tires come pre-heated onto your car, so that's not the cold pressure you see in the telemetry. But it's also not hot pressure as your tires and mostly the rims will heat further up.

And the pressure significantly rising when standing still is not a bug either, it's a complex situation that has been explained by Casey Ringley. Can't provide links atm as I'm on phone and I got it from a German speaking website, but I will post a few quotes as soon as I get home.

EDIT: This is what he wrote:

It's a complex system. There is much more to it than if the tread rubber is hot, most of which what the brakes are doing. They are really the primary heat source which drives change in tire pressures. I can't speak to many specifics of your situation except what happens when stopped or in the pits: if you have stopped the car with very hot brakes, being stopped means no airflow and that heat now radiates through to the rim and air inside the tire, increasing pressure. It can be a strong effect, but becomes clear why it is so strong if you think about a 6-8kg mass at 400°C being in close proximity to the metal rim, which can then conduct through to the inflation air quite rapidly.

I agree it is pretty damn cool

Looks like a small detail, but it is so cool that setting tire pressure for the track, weather, car setup, everything else is this deep now. It's a big job getting it right in real racing, and our 9-layer dip* of a heat model means it is just as significant a challenge in game. Was more than a little pleased after we got the calibrations right and it worked so that a single heat model gives accurate results for how temperature builds up through all the important layers over time on the IndyCar both at Long Beach and Indianapolis. There couldn't be more extreme ends of the spectrum on how heat flows through the wheel-brake-tire system and I think it adds a lot to the 'living tracks' experience.

You're right that it's totally against what we've learned from games for going on 25 years now where tire pressure is directly related to tire temperature. Yeah, they are connected but the whole system is much more involved than that.

What Jussi means about preheating is that when we preheat tires, it's like done in ovens as you might see used in FIA WEC. The whole tire and wheel come out at maybe 90°C throughout, but that's not where it will be after running a few laps. Tread might be 90, carcass interior 105, rim heated to 140 by the brakes, surface layer changing rapidly above and below tread core, etc. All that can make the inflation pressure fluctuate in unexpected ways until you run long enough for the whole system to stabilize.

*The layers: Ambient<->Flash<->Surface Layer<->Tread<->Carcass<->Inflation Air<->Rim<->'Well' air between rim and brake, which also vents to ambient<->Brake rotor

 

[Cluck]

Fab.iceman is correct, the brake temperatures have an effect on tyre pressures and this will be quite pronounced when sat in the pits with hot brakes.

However, in testing this - to show that this is the case - it has highlighted an interesting bug. The brake temperatures appear to be being reset when you come into the pits and change tyres. I will get this reported to the devs now. Key thing is, don't hang around when you pit, get out of your pit box as soon as possible.

It might also be worth running slightly bigger brake ducts than usual.

EDIT : This problem with brake temperatures only appears to affect online lobbies. I've run 3 online sessions (with just myself in them) and got these abnormal brake temps in each. When running an offline session, I got normal brake temps at the start and immediately after the tyres were changed.

 

[AndrexUK]

Cool (well... hot..) thanks for the info.

But what about the pressures of the tires as they are put on the car though?
I ran 2 practice sessions before this race session, and in practice, they were put on with pressures matching my pit strategy. but on this race run, they started with more pressure than requested.

 

[Cluck]

You get pre-heated tyres in the race, that's why. For quali and practice you are always given cold tyres, so you will get the cold pressures. You can check for yourself with the on-screen telemetry

 

[Ashnoom]

However, in testing this - to show that this is the case - it has highlighted an interesting bug. The brake temperatures appear to be being reset when you come into the pits and change tyres. I will get this reported to the devs now. Key thing is, don't hang around when you pit, get out of your pit box as soon as possible.

It might also be worth running slightly bigger brake ducts than usual.

you don't happen to have "repair brake damage" turned on right? Because that has always reset my brake temperature in pcars1

 

[Cluck]

you don't happen to have "repair brake damage" turned on right? Because that has always reset my brake temperature in pcars1

That's the first thing somebody else asked . The pit strategy was set up to only replace the tyres, there was no damage repair enabled at all

 

[Hujkis]

What kind of pressures are we looking for in wet tyres?
Do we increase the pressure to "open up the tread" in order to get more water out, or reduce to get more contact?

 

[SillySausage]

What kind of pressures are we looking for in wet tyres?
Do we increase the pressure to "open up the tread" in order to get more water out, or reduce to get more contact?

Yes @Puffpirat, what wet pressures should we aim for? Tell us your tyre wizardry secrets

 

[Puffpirat]

I have zero clue in the rain xD I guess a bit lower than dry pressures, at least that’s what I’m aiming for.

Currently I’m only hoping I won’t puke in my rift tonight because I feel like shit

 

[Hujkis]

Currently I’m only hoping I won’t puke in my rift tonight because I feel like shit

Drink some Kräuterbitterschnaps before race. You'll feel better and I heard alcohol makes you faster behind the wheel

 

[SillySausage]

I have zero clue in the rain xD I guess a bit lower than dry pressures, at least that’s what I’m aiming for.

Currently I’m only hoping I won’t puke in my rift tonight because I feel like shit

I don't believe you but I will accept your reply

 

[Puffpirat]

I’ve heard some are taking a different route to low pressures so I might be wrong. It’s pretty hard to compare setups in the wet because you never really know which wetness level you get.

 

[Cluck]

I'm going to do what I always do. Drag some sliders around, at the last minute, and hope for the best. I'm all set for the dry stuff, I just genuinely don't have a clue about the wet part. Then, of course, we have the random wheel of weather spinning fortune delight to serve up the 3rd slot which, if it's not 'hazy' will throw my single full-length practice run plan out of the window. Oh yes, I did a full practice run, fear my l33t skillz

 

[Col_McCoy]

So I made a setup for my car in the light rain and thereafter just did some light cloud running..... guess I'm about a second off the pace in my BMW.. which might be the BMW as well besides my driving ;-).

Anyway, feeling confident for the wet part... at least I did not spin. But can't seem to get much power down and have a lot of understeer.. so really interested in everybody else their pace.

See you tonight

 

[AndrexUK]

I've done the same as you! Built a wet setup, and just deal with the dry session.
Suspect I'll be waaaaay off the pace in the dry, but hoping I can keep her pointing the right direction in the wet...
Couple of nasty puddles out there!, and in my 'random slot test', it changed to heavy fog!!! That was quite an experience!

Can't remember my lap times, but no where near the fast end of the scale I'm quite sure....

 

[Cluck]

For what it's worth, I found little difference in laptimes between various wing and suspension stiffness settings in the Ferrari in the dry, so I'll probably stick with my near-default setup if random throws up hazy, clear or light cloud. Anything else will see me probably leaning towards a more wet-focussed setup, depending on exactly what weather we get.

 

[AndrexUK]

How would you know before the race starts though?