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ianbellh0tguy
01-10-2017, 23:15
Just wrote a massive essay on tyre temps only for the forum to lose it.

To summarise;


In GT3 the tyre temp windows seem oversensitive
Grip performance from quali to race can lead to times being 3-4 seconds off (track temp changes and starting temp change)
Soft tyre has ridiculous amounts of grip straight out the box in quali, so much that I will deliberately drive super slow on outlap and start flying lap still cold for optimal performance
Soft tyre will overheat on track surface temps even as low at 10 degrees C (pressures have little effect on heat build up)


As a result I am finding the overall experience quite frustrating as the consistency from track to track and session to session can vary massively. I am spending more time on setup than enjoying my racing and I feel sorry for the users who don't go the extent of researching setups online to have a chance of being competitive. I appreciate it is a simulation and I should not expect a cookie cutter setup to work every time but I am convinced that there are issues with how the tyre model is working and its effect on grip. It is clear that some other areas of the game this is the case (read thread on ginettas in career mode).

Would appreciate some feedback

Jussi Karjalainen
01-10-2017, 23:30
In real life the vast majority of GT3 racing is done ONLY on the hard tyre compound, the series usually mandate the usage of it, or the tyres are only supplied via the official suppliers who will decide what compounds they send over (which pretty much always is the hard one).

If we didn't have the wide variety of operating conditions we do, we wouldn't have included the soft tyre at all. But we do have a huge variety of tracks and you can drive them in a huge variety of weather conditions and temperatures, so we had to include it as an option tyre for the coldest of weather conditions.

Indeed, for the vast majority of the time the GT3 soft is only useful for qualifying, since it works so well when it's cool/cold, but overheats very easily as well. Other series don't have quite as big of a gap between the soft and the hard, since they tend to use their softs more commonly.

Roger Prynne
01-10-2017, 23:32
The forum lost your thread/post, never had that happen before?
What was the title of it, where did you post it?

ianbellh0tguy
01-10-2017, 23:33
The forum lost your thread/post, never had that happen before?
What was the title of it, where did you post it?

It logged me out within 5 mins when I clicked submit, probably a cookie issue on my side tbh. doesnt matter

ianbellh0tguy
01-10-2017, 23:39
In real life the vast majority of GT3 racing is done ONLY on the hard tyre compound, the series usually mandate the usage of it, or the tyres are only supplied via the official suppliers who will decide what compounds they send over (which pretty much always is the hard one).

If we didn't have the wide variety of operating conditions we do, we wouldn't have included the soft tyre at all. But we do have a huge variety of tracks and you can drive them in a huge variety of weather conditions and temperatures, so we had to include it as an option tyre for the coldest of weather conditions.

Indeed, for the vast majority of the time the GT3 soft is only useful for qualifying, since it works so well when it's cool/cold, but overheats very easily as well. Other series don't have quite as big of a gap between the soft and the hard, since they tend to use their softs more commonly.

Thats fair enough, but even the hard can be a nightmare for grip. I saw you suggested 195F (90C) is around about where the hard works best, why do the cars start the race and time trial up at 100C in that case?

Zenzic
27-10-2017, 11:37
I saw you suggested 195F (90C) is around about where the hard works best, why do the cars start the race and time trial up at 100C in that case?

Interesting question. Too bad it hasn't been answered so far. I'll add to that: why are soft slicks still shown as green in telemetry at 95C when their working temperature is in the range of 75 to 90C?

rich1e I
27-10-2017, 11:58
I remember Jussi saying tyre temps don't matter, you need to find the right pressures, 1.80 bar or 26 psi hot for modern GTs. I'm wondering if the same pressures work for hard slicks.

Keena
27-10-2017, 12:07
I remember Jussi saying tyre temps don't matter, you need to find the right pressures, 1.80 bar or 26 psi hot for modern GTs. I'm wondering if the same pressures work for hard slicks.

You may well be right but I really really hope that's not the case.

honespc
27-10-2017, 12:19
Interesting question. Too bad it hasn't been answered so far. I'll add to that: why are soft slicks still shown as green in telemetry at 95C when their working temperature is in the range of 75 to 90C?This is something I've been asking for ages. The icon colours are completely deceiving since pc1 latest patch, and this made them jump in on to project cars 2.

Slicks should be already brown colour by around 100ºC, and completely red at 110-115.

Cooked/heated tyres continue to not be properly shown in pc2 through the colour of the icons. You begin to notice that your grip is already going while at the same time still see those those tyre icons on the green.

I just don't understand why they still haven't changed this since pc1 latest patch. Have been asking for this since then. Why can't we have proper temp/overheating icon colour representation like we had until pc1 patch 6?

Same on road car tyres. You know the tyres are very hot already even before reaching 90ºc (you notice you have to slow down immediately because the drifting fun is over until they cool down), but still you see the icons green, and also green in the telemetry.

Please fix this once and for all so we can know quickly when we have to begin to nurse the tyres instead of having to spin or lose a lot of grip = accident in order to acknowledge the overheat.

Marlborofranz
27-10-2017, 13:24
You may well be right but I really really hope that's not the case.

I Think this Thread was in the setup section, was originally about temperatures. Afaik the pressure changes the shape of the tyre and such the maximum available contact patch. Too much pressure = middle temperatures in your hud are higher than inside and outside temperature. Lower pressure = middle temperature is lower. But this also changes rolling resistance, more inflation = smaller patch since tyres are getting round = more top speed, but less grip and not so perfect wear rate.

But the contact patch doesn't matter if the temperature is not right so the tyres don't grip. Sometimes you have to trade off a perfect contact patch in order to get your tyres warm, e.g. by less pressure or setup changes... so both matters. Ideally they have the right operating pressure and temperature, means you have just soft enough rubber that grips the track perfectly AND a contact patch as big as possible, so the most of the rubber has contact. But this depends on track temps, driving style and even tracks have different grip levels... I don't remember the track names but at some of the tracks I wear soft tyres within a few laps, feeling them having less and less grip, while on other tracks they seem to last forever

Keena
27-10-2017, 13:42
I Think this Thread was in the setup section, was originally about temperatures. Afaik the pressure changes the shape of the tyre and such the maximum available contact patch. Too much pressure = middle temperatures in your hud are higher than inside and outside temperature. Lower pressure = middle temperature is lower. But this also changes rolling resistance, more inflation = smaller patch since tyres are getting round = more top speed, but less grip and not so perfect wear rate.

But the contact patch doesn't matter if the temperature is not right so the tyres don't grip. Sometimes you have to trade off a perfect contact patch in order to get your tyres warm, e.g. by less pressure or setup changes... so both matters. Ideally they have the right operating pressure and temperature, means you have just soft enough rubber that grips the track perfectly AND a contact patch as big as possible, so the most of the rubber has contact. But this depends on track temps, driving style and even tracks have different grip levels... I don't remember the track names but at some of the tracks I wear soft tyres within a few laps, feeling them having less and less grip, while on other tracks they seem to last forever

Thanks. I understand the physics behind it all. My main concern is that according to the previous post I replied to, none of the physics matter aside from pressure..

Marlborofranz
27-10-2017, 15:47
Thanks. I understand the physics behind it all. My main concern is that according to the previous post I replied to, none of the physics matter aside from pressure..

Wasn't meant to be a smart ass, though. :P

I did some testing with the Corvette GT3 on the Nürburgring GP course.
Cold tyres, default preassure: 21 front/20 rear --> Less grip, sensitive to throttle oversteer and brake lockup
Once warmed up: 26 front/25 rear --> Good grip, way less sensitive to spin at turn exit and lock under threshold braking

Cold pressure set to: 26/25 --> OK grip when cold, better than with 21/20. Still sensitive to throttle oversteer and brake lockup. Bit better than the old temps, but still noticable
Once warmed up: Grip seems ok, don't notice a lot of difference (driving inconsistant lap times), but less throttle oversteer and brake locku

So I guess both the pressure and temperature have effect on the tyres...

beetes_juice
27-10-2017, 15:52
Don't forget your brake ducts

LockeChris
27-10-2017, 17:26
What I don't understand is why there is no official guide to the in-game tire model. There's so many questions about how temps and pressures and grip levels work and wrong or right colors and telemetry data and whatnot, which all depend on the tire AND the car.
How is the average sim racer supposed to just know all about that? You can't just experiment with 180 cars and I don't know how many tires and tracks and conditions...:confused:

Maybe an idea for this insider YouTube series that was posted somewhere else in the forum? Anyway it would be nice to not just be at the mercy of coincidence!

Dynomight Motorsports
27-10-2017, 20:33
Interesting question. Too bad it hasn't been answered so far. I'll add to that: why are soft slicks still shown as green in telemetry at 95C when their working temperature is in the range of 75 to 90C?

Well remember the debacle that came about when they adjusted PC1, and everyone was seeing red with their tires?

LockeChris
27-10-2017, 21:39
Another thing I wonder is why I always have to start my online races on overheated tires. I kept thinking I'm just a bad driver doing a good qualy and then throwing it away in the first lap of the race, but it's just the car not having any grip at all anymore because the tires are always too hot :(

nhitrac
27-10-2017, 23:34
I'm finding that the soft heats up way too much as others have already mentioned, however I can't get the hard tyres to heat up at all and will drop to 50s and 60s by a few laps after racing.

The other question is, do AI race on the hard slicks for most of the races if conditions aren't wet etc?

whip
28-10-2017, 05:23
what i find puzzling is the softs last for a couple of laps then you feel them go to crap, yet all the telemetry is telling you that wear and temp wise they are fine

rich1e I
28-10-2017, 07:57
Now from what I've experienced so far I can say in a 15-20 minutes race soft tyres are fine. If I'd go for hard tyres, what pressures are we aiming for here in modern GTs? Is it also 1.80 bar/26 psi?

hkraft300
28-10-2017, 10:45
Now from what I've experienced so far I can say in a 15-20 minutes race soft tyres are fine. If I'd go for hard tyres, what pressures are we aiming for here in modern GTs? Is it also 1.80 bar/26 psi?
Yes. Soft/hard, GT+ prototype tires you want about ~1.8 bar/26psi. Soft tires are good up to ~100℃ but hard tires can handle a little more.
However I haven't done tire wear testing at that high temps. Also hot tires will cause high hot pressures but you can somewhat control that with brake ducts and cold pressures.


what i find puzzling is the softs last for a couple of laps then you feel them go to crap, yet all the telemetry is telling you that wear and temp wise they are fine

What is "fine"? What temp and pressure? What track/ track temp?

3800racingfool
28-10-2017, 14:15
what i find puzzling is the softs last for a couple of laps then you feel them go to crap, yet all the telemetry is telling you that wear and temp wise they are fine

If they're anything above 120º F (~49º C) then they're definitely not fine and them going away is perfectly normal. They'll be fast for a couple of laps just because they're cold but once they start overheating (regardless of what the hud color is), they have absolutely no grip.

It's important to note that the softs also naturally gain and then lose maximum grip rather quickly compared to the hard tires. While you usually won't hit the absolute max laptimes on a hard tire that you can hit on a soft, you'll find that, over the course of a fuel stint, the hard tires are actually faster overall than the softs because once they (hard tires) get up to temp/pressure they stay consistent vs. the softs which will net you about 5 decent laps before they start falling off (and after 15-20 laps they really start falling off a cliff). The one caveat to this is during very cold races (think middle of winter... at night) when tires just won't come up to temp. This is what the soft tires were designed for and where they really shine so you'll notice they stay fast throughout the course of a stint there. Otherwise though, the only things softs might be used for is for super short races (~5-10 laps) or a couple of quick qually laps. Easy rule of thumb is: Softs = hotlapping, Hards = racing.

Marlborofranz
28-10-2017, 16:06
I'm finding that the soft heats up way too much as others have already mentioned, however I can't get the hard tyres to heat up at all and will drop to 50s and 60s by a few laps after racing.

The other question is, do AI race on the hard slicks for most of the races if conditions aren't wet etc?

I can imagine... I just drovea full Indy 500 race and swapped with ai because i got an headache. One thing I noticed is that when the AI drives, my tyres wore twice as much because of the way the AI steers the car. However the AI will the drive the tyres I selected for the pit stop. I assume that they will use hard tyres on gt cars and hards in road cars whenever there is no rain. The AI is not having the same physics as the player because of the nature AI is steering the car around the track. (Many small inputs and sometimes fluently).

Also it looks like the telemetry hud shows how "drivable" your tyres are rather than how worn they're in total. On the telemetry software I had 10 percent wear while in the game I had around 20-25 by the looks. Seems like when in the game you hit the bottom of the indicator the grip is gone while in order to destroy them you have to use them way longer...