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CSL-Drive
02-04-2018, 09:07
I noticed on Project Cars 2, you have tire flex, and I can drift above the limit with gt3 mclaren 650s.
Using the same car, I have the same ability for all games that has tire flex, like gt sport and rfactor 2.
Now, if i try assetto corsa and especially iracing, this same car on the same track and weather, nearly impossible to drift or drive over the limit in anyway. due to absolute 0 tire flex in this game. it feels so weird and fake. And noticing how big the difference is and how lacking iracing and assetto corsa are, now that I have been experimenting with what cars can do in project cars 2. I can never return to assetto corsa or iracing. racing is all about the limit and stretching it driving on it or / and sometimes over it. Now assetto corsa and iracing is like, no stop, not able to compute this reality. Project cars 2 on the other hand. Dude, what ever you do with the car, I will make it a reality for you. Tire flex is such a huge game changer. It's amazing to see.

MrTulip
02-04-2018, 09:43
It is really much more complicated than just tyre flex, although it has a lot to do with the complete equation.

All of the simulations you mentioned emphasize bit different things in their tyre simulation. All of them do an excellent job at simulating real life phenomenons (including tyre flex, even when not visually), but it is really difficult to get all parts falling in their places without getting really weird results at different places and conditions, so that you'd have to start using "magic constants" in places where you shouldn't.
For instance iRacing for a long time put their efforts at simulating heat but did not pay (enough) attention to grip characteristics of the tyre beyond slip curve, which lead to iceracing over some angles of travel. And Kaemmer (the developer of iRacing tyre simulation) admitted it very early on; it was simply not their focus as the types of racing simulated in iRacing did not have much use for this information (until Lotus 49 and Rallycross later), and that information was hard to get as it was not priority for the real tyre manufacturers either.

I agree that PCARS2 is very good at drifting and its model does not feel limited to one specific type of racing. It is just that with the top crop of the current sims the difference is much more in *what car with what type of tyre* you drive than just what sim you are playing.

All these developers are doing scientific research of physical real life phenomenons *and* they try to get their models to run at several hundreds times per second too. One ends up doing some compromises somewhere to get the model running fast enough on home computers and consoles.

Pekka Salminen
02-04-2018, 11:12
Tire flex is not the only factor determining the handling while slipping; the relation between static friction and slip friction is equally important.

iRacing most definitely does have tire flex simulation, it is not very good though (the whole tire model is IMO the weak point of the sim). This video from a real pro-driver puts it nicely; if something, there is too much side wall movement.
https://youtu.be/9-W6fA7bumQ?t=8m8s
Assetto Corsa, on the other hand, might be among the best what comes to tire model. Tire flex is most definitely modelled there as well, it just isn't visual.

My experiences in PCars 2 falls between two. The tire model itself feels good and pretty advanced, but the slip friction might be too high compared to static friction (at least with GT3/GTE slicks), making drifting and saving spinning car little too easy. Of course I'm not a pro-driver, so take this with a grain of salt :P

The above comment has very good points as well.

demand34
02-04-2018, 14:33
It's because pc2 is leaps and bounds above assetto and iracing in that regard.

If you say you can drift with safety on a gt3 car in pc2, then you should definitely try with the powerful road cars, road a for example, and drift hard with increased preload and an open decel diff until you burn the tyres. You just don't know what you 're missing about PC2 awesome tyre model until you try this.

Assetto Corsa Street Tyre model is so bad I won't even comment on it. It just can't compare to pc2 street tyre model whatsoever. Assetto Corsa feels good on GT cars only with slicks, but as you have also said, even PC2 wins in this department too.

Project Cars 2 is, without doubt the best sim currently available very close to rfactor2. Assetto Corsa feels like a bad joke now specially with road cars, and iRacing..., oh well.

CSL-Drive
02-04-2018, 21:05
It is really much more complicated than just tyre flex, although it has a lot to do with the complete equation.

All of the simulations you mentioned emphasize bit different things in their tyre simulation. All of them do an excellent job at simulating real life phenomenons (including tyre flex, even when not visually), but it is really difficult to get all parts falling in their places without getting really weird results at different places and conditions, so that you'd have to start using "magic constants" in places where you shouldn't.
For instance iRacing for a long time put their efforts at simulating heat but did not pay (enough) attention to grip characteristics of the tyre beyond slip curve, which lead to iceracing over some angles of travel. And Kaemmer (the developer of iRacing tyre simulation) admitted it very early on; it was simply not their focus as the types of racing simulated in iRacing did not have much use for this information (until Lotus 49 and Rallycross later), and that information was hard to get as it was not priority for the real tyre manufacturers either.

I agree that PCARS2 is very good at drifting and its model does not feel limited to one specific type of racing. It is just that with the top crop of the current sims the difference is much more in *what car with what type of tyre* you drive than just what sim you are playing.

All these developers are doing scientific research of physical real life phenomenons *and* they try to get their models to run at several hundreds times per second too. One ends up doing some compromises somewhere to get the model running fast enough on home computers and consoles.
wow tyvm, whoever does all this science and physics work I love all of it and appreciate it too, as I just read the crazy thought processes on rubber from iracingdeveloper, its funny as hell to read, when I am thinking, oh its just you have grip and then you lose it, lol. maybe he's overthinking it all, because even nickii thiim says iracing tires is not realistic at all, but ill have to wait and see untill the new tire models come and then see how they feel myself. Hope it will be good. If not, meh, I play pc2 and rfactor 2 the most anyway.

CSL-Drive
02-04-2018, 21:12
Tire flex is not the only factor determining the handling while slipping; the relation between static friction and slip friction is equally important.

iRacing most definitely does have tire flex simulation, it is not very good though (the whole tire model is IMO the weak point of the sim). This video from a real pro-driver puts it nicely; if something, there is too much side wall movement.
https://youtu.be/9-W6fA7bumQ?t=8m8s
Assetto Corsa, on the other hand, might be among the best what comes to tire model. Tire flex is most definitely modelled there as well, it just isn't visual.

My experiences in PCars 2 falls between two. The tire model itself feels good and pretty advanced, but the slip friction might be too high compared to static friction (at least with GT3/GTE slicks), making drifting and saving spinning car little too easy. Of course I'm not a pro-driver, so take this with a grain of salt :P

The above comment has very good points as well.
See I see massive drifting 100% of the time in the last f1 2018 race. I mean if those cars can drift all of the time, then I assume project cars 2, gt sport and rfactor 2 has all got it all right. We are suppose to be able to drift.
Anyway the sims nickii thiim tested drive nothing like project cars 2. he praises ac which can drift more like pc2 but still far from enough. And I know Max Verstappen plays rfactor 2 to practice formula 1 and also for fun, and rfactor 2 u can drift allot like in project cars 2. More more flexible tires when over the limit. same for gt sport. can drift gt3 without losing control completely at the slightest of wheel spin on the rears, unlike in iracing. which again, nicki thiim pretty much says iracing is like driving on overheating wets, which is not even close to a compliment of any kind, as that sim doesnt even have wet tires nor rain xD

CSL-Drive
02-04-2018, 21:24
It's because pc2 is leaps and bounds above assetto and iracing in that regard.

If you say you can drift with safety on a gt3 car in pc2, then you should definitely try with the powerful road cars, road a for example, and drift hard with increased preload and an open decel diff until you burn the tyres. You just don't know what you 're missing about PC2 awesome tyre model until you try this.

Assetto Corsa Street Tyre model is so bad I won't even comment on it. It just can't compare to pc2 street tyre model whatsoever. Assetto Corsa feels good on GT cars only with slicks, but as you have also said, even PC2 wins in this department too.

Project Cars 2 is, without doubt the best sim currently available very close to rfactor2. Assetto Corsa feels like a bad joke now specially with road cars, and iRacing..., oh well.
I like pc2 the most aswell, my playtime doesn't lie. but i have no idea about realism, just noticed ac and iracing is no drift. and nickii thiim praises tire model of ac which is slightly more driftable than iracing and nicki thiim bashes iracing which is 0 drift, and max verstappen practices on rfactor 2 which is full drift and sim racing girl says red bull simulator feels allot like rfactor 2. so adding it all up, 1+1=2 and project cars 2 is more realistic. it feels very similar to rfactor 2 or gt sport over the edge driving, tho gt sport ffb is an oddity, cant comment on that. and iracing is just the competitive scene is all.

David Slute
03-04-2018, 01:07
Im no physics or tire model expert lol

My favorite part of the pc2 tire model inregards to tire flex is the feeling and ability of being able to lean on the outside tire and power out of corners.

Many of performance driving books/video ive watched....alot of the pro drivers mention that when the car is in perfect balance the car should feel like its smoothly drifting through corners.

Which I find the description to be similar to what I feel ingame when I get the car setup properly and get into the zone.

In regards to iracing.....i recently renewed for a month just to test the rally X content which imo wasn't that great compared to pc2 when it came to the physics/ffb....once on dirt it just became light and numb with very little into what the tires were doing and found myself using visual and audio cues to get around on the dirt rather than using the details coming from the wheel.

For the longest time (iracing member since 2012) I could never put my fingure on what was wrong with there tire model until I heard Nicki Thiims description lol which I thought was perfectly described.

Lord of the Racing
03-04-2018, 05:52
I do not know from which experience comes yours statements. PC2 is for me a great simulation and currently it is my favourite but just with regard to drifting IMO it is still possible for improvement. In my experience in AC I can take almost any car of the list, switch off the stability control and abs and I am able to drift any single meter of all the 20 km of nordschleife and frequently on the online lobby you can race with other people drifting all time very very realistic. I ever try to be neutral, equilibrated and fair with my comments and definitively I can say that AC have a great drifting simulation meanwhile the limits are others but considering the full package, for me, PC2 is superior. Career, cars variety, numers of tracks and meteo makes for me difference.

demand34
03-04-2018, 07:25
@CSL: Basically, this is imo best sims from best to worse:

1) rfactor2
2) Project Cars 2
3) Raceroom
4) Assetto Corsa
5) IceRacing

ShimonART
03-04-2018, 07:45
assetto corsa has tire flex but its not visually animated(ACC will have visual tire flex), AC is very easy to drift even with stock cars and stock setups, so i dont know whats your issue, just practice.