The online racing simulator
Quote from ButterTyres :Same two camps as always in these dicussions - the ones who say there is a problem with the physics and the ones who dont.

I'm gonna sit in the middle just so that there are 3 camps

Your LFS alias gives this thread enough irony hahahaha.
#52 - Vain
It takes some days of training to control a RWD car under racing-conditions. That goes for real-life cars and LFS-cars. I had enough problems to get my 190 HP car go nicely along the nordschleife. So I had equal problems of getting my XRT nicely along Blackwood GP.
Oh, and on a side-note: Don't believe the default-setups are anywhere near "good". A nice setup (bob's easy race-setup for example) will make the car feel much better.

Vain
Quote from Delerue :I have one of these cars. But what you said it's different of what I said. I said 'until you reach 25 km/h', and not 'full throttle'.

BTW, of course my car (and any one, even 'baby cars'...) don't lose grip at 25 km/h.

Why LFS fans have this huge difficult to say that the game has wrong tires physics? I can't understand this behaviour.

i have a 900kg 75hp (almost half of gti) fwd car and even with centered wheel, i must calibrate throttle to avoid spinning, so dont mention when turning.
if you try corners IRL like lfs your car slides much more -> lfs is too grippy!
i try almost every car sim and i found lfs far more realistic than any other, lfs is the only one that behaves almost exacly RL cars...just my 2 cents...obviously u may not think the way i am, so i suggest you to search RSC for a thread where a PhD was trying to challenge the suspension and tyre phisics, with RL equations...if you can understand maths you would agree to the conclusion that lfs is damn close to RL!
Quote from Honey :i have a 900kg 75hp (almost half of gti) fwd car and even with centered wheel, i must calibrate throttle to avoid spinning, so dont mention when turning.
if you try corners IRL like lfs your car slides much more -> lfs is too grippy!
i try almost every car sim and i found lfs far more realistic than any other, lfs is the only one that behaves almost exacly RL cars...just my 2 cents...obviously u may not think the way i am, so i suggest you to search RSC for a thread where a PhD was trying to challenge the suspension and tyre phisics, with RL equations...if you can understand maths you would agree to the conclusion that lfs is damn close to RL!

Agreed.
i been playing lfs since beta and i do have to say the way the game feels has changed quiet a bit and the rwd's are alot easyer on limit driving then they used to be but their still is a small issue with low speed weights and such

i have a 240 hp RWD and i have to say it feels alot like the xrt for on limit driving but it comes alot down to sets for on limit driving most road cars are built to understeer rather then over steer

i still think real driving is easyer then LFS cause u can feel the g's gaining and droping due to loss of grip hence the reason lfs feels slippry u cant feel the g's only through a wheel

if anyone says i use a bad set or no wheel or what ever let me state this first

i use a DFP 720 deg mode act labs shifter act labs pedals no aid's and managed a 1:25:61 on black wood in the XRT

now their is still a few things that BMW M3 mod had over LFS but rember LFS isent about touchy race cars fully tuned for racing lfs has allways had a feeling of slowness to it even the GTR cars feel slow and sloppy but if u check ur g's and corner speed u will realize that u are going pritty quick and the response u get from the FFB is the best out of any sim

so theirs my 2 cents
I don't think the corner speeds or the G's the cars can pull is the problem, it is the grip regain, it's just aint that slow. Thats why Rwd's feel so slippery, if they just could get that one right i think i could enjoy lfs again. Every time i try lfs after a long pause, i enjoy it a lot for the first hour, then i get sick of the sliding and quit the game..

I've tried different setups, but it's just a way to fool yourself if the grip regain is wrong. Just like having rust on your car and instead of fixing it properly, you just hide it under the paint and say, see doesn't look that bad....
You mean how tyres, especially slicks, snap back into grip? Yes, that is the biggest flaw in LFS's tyre physics. The overall grip is about right, and the way it looses grip isn't bad at all either, but the change between no-grip and grip does need to happen a bit more suddenly. Otherwise you end up with very long slides that are almost impossible to regain control from.

I think this would help with the dirt and heat modelling to. Right now, on hot rear tyres (130+) there is absolutely no grip, and I don't think it should be quite that bad. If the tyres regained grip a bit quicker then I reckon, based on my simple 'tests' that it would help.

Any thoughts on this Scawen, or are you going to keep us in suspence a bit longer?
Quote from tristancliffe :You mean how tyres, especially slicks, snap back into grip? Yes, that is the biggest flaw in LFS's tyre physics. The overall grip is about right, and the way it looses grip isn't bad at all either, but the change between no-grip and grip does need to happen a bit more suddenly. Otherwise you end up with very long slides that are almost impossible to regain control from.

That's exactly what i mean. The transistion from grip -> no grip is i quess ok, but other way around no grip -> grip is just too slow.

Just few points from my own experience. My friend owns an 84' corvette, not exactly a masterpiece, but can be slid around the bends. Now i tried to slide it and the way it grips back when you ease the throttle is just very quick. Same thing i've experienced with my 170hp bmw, actually when i got it and tried to slide it i almost crashed because of what i had learned in lfs. I just countersteered too much and didn't return the wheel to center when i let go of the throttle and almost ended on the opposite lane. Just because the regain of the grip was far quicker than i expected, almost same happened with my friends supra...but i ain't no expert and won't claim to be. Just what i've experienced.

Now i dunno why the same problem has existed from the day lfs saw the light, it's been few years now and i'm actually already a bit suprised that it hasn't been fixed yet. I'm not in a rush though, but i'd hope to see it in future patch. I think if scawen would spent a day or two on track, or even at some closed place, just to slide the car he might get more clearer view of what happens...

The fact anyway stands that scawen rides a bike and has if i remember right the only rwd he has driven is a kart. Things may have changed already, i dunno, haven't much been in touch with guys on "the inside".

Anyhow, i just hope it will get better in the future, maybe it would bring me and lots others that i race different sims with back to lfs, as they dislike it for the fact that your sliding a bit too much
i don't have any experience IRL with slicks, but with road tyres and fwd, yes: i learned that regaining grip from little slides is very quick (as in lfs), but recovering from a complete loss of grip requires many meters...and in that i found lfs again to feel like RL...but i have to say that even if i cannot compare rwd with RL experience, i admit that except for fox and mrt i find all other lfs rwds quite hard to recover from a slide, i often see some ferrari scaglietti (fz50 like) on the streets and they seem pretty stable...i guess that maybe the problem could be not in tyre model, but rather into engine model...let's dont forget that modern cars (rwd especially) have electronic stability control, antispin and whatever...obviously i think that a deeper look into each aspect of lfs phisics is always good, to help make it even more and more realistic
Quote from Honey :let's dont forget that modern cars (rwd especially) have electronic stability control, antispin and whatever...

For girls!!!!!

And to avoid lawsuits and injuries.

But if I want a powerful rwd car I don't want a spotty 17 year old computer programmer to stop the car giving me the power I paid for.

I better stop now, cos I usually rant on and on about this for ages, and offend people who need these computers on board.
Maybe it's all because Scawen gets soap through his plumbing?

Tristan: there's nothing wrong with spotty 17 year old programmers, don't mention them in such a negative manner. And besides, they free up more women for other people, such as lesser-spotted 20 year old programmers
Quote from Bob Smith :Tristan: there's nothing wrong with spotty 17 year old programmers, don't mention them in such a negative manner. And besides, they free up more women for other people, such as lesser-spotted 20 year old programmers

Fair Point, Well Made.

However, I still don't want the car manufacturer stopping me drom getting the power/torque/brake force that I paid for, and that I want. Thats why cars have pedals, so you can choose the amounts. Choose too much and thats your own stupid fault.
Quote from tristancliffe :For girls!!!!!

And to avoid lawsuits and injuries.

But if I want a powerful rwd car I don't want a spotty 17 year old computer programmer to stop the car giving me the power I paid for.

I better stop now, cos I usually rant on and on about this for ages, and offend people who need these computers on board.

maybe i wasn't explaining very good what i meant -> i don't want anti spin into lfs!!!

i meant that RL rwd cars may recover from a slide easier than lfs, because of that...and enforcing my idea that lfs does not comes with "soap included" but rather that RL commercial rwd are for "noobs" and not for racers

i like lfs and i like it realistic/difficult as it is...
Great
#65 - Vain
I drive a 193 hp '85 RWD car without the electronic assistances (not even ABS), so I have a slight understanding of the real life behaviour of RWD cars (talking about LFS' street cars). When the car oversteers and I catch the back the car will, once I reached the right steering and gas, immediately regain grip and sometimes turn the tail for 15° or more within a moment. That is the moment where I have to beware of counter-sliding. Such an effect seems to completely miss in LFS. This is propably bound to the slow regaining of grip in LFS.

Vain
Let me first state that I bought LFS S1 and S2, and plan to buy S3, but I think there are some issues with LFS:

The cars in LFS over react when the tires are pushed just a bit past the limits.

S2 is a big improvement over S1 in this aspect of the tire model, but it still isn't quite right yet. I don't know how LFS does it's tire physics, but in real life, there is no sudden transition from static (not slipping) to dynamic (slipping) friction. There is almost alway some amount of slippage at the perimeter of the contact patch of a tire. In addition, there is an inwards squirm effect due to the force from a tires sidewalls.

As longitudinal acceleration (or braking) increase, the amount of area at the leading and trailing edges of the contact patch that are slipping increase, until you reach the point where all of the contact patch is slipping. The amount of loss in grip when all of the contact patch is slipping depends on the tire compound and construction. Wrinkle wall drag racing slicks are sticky, but lose a lot of grip if they spin. Performance street tires don't lose quite as much grip, and because many street cars have clutches that don't grip well when there's a big difference between driving and driven rpms at the clutch plate, most auto magazine testers simply drop the clutch at a medium low rpm and let the tires spin to get the best and most consistent launches when doing drag testing.

A similar thing happens with lateral acceleration (cornering). Slip angle is the difference between the direction the tire is actually moving, and the direction the tire is pointed. As slip angle increases, the sideways force increases, and the amount of area that is slipping at the perimeter of the contact patch increases, until it reaches a critical angle of peak sideways force. Increasing the angle further results in less sideways force, but how much less depends on tire design. With an ideal tire, there would be a large range of slip angle past the peak where the sideways force would remain about the same. Most drivers will give up .1g of lateral accerleration if this resulted in a tire that closely approximates an "ideal" tire, which would be more forgiving and allow them to drive at the limits. Some of you will be "tired" of hearing about this, but do a web search for bias bly racing tires, and you'll find that most non-downforce racing cars use bias ply racing tires (DOT or slicks). This is because these tires behave very closely to an "ideal" tire, losing very little grip even when pushed past their limits. Even road racing radial tires are designed to have similar properties.

tires take too long to regain grip after going off track

In real life, race cars often go off track, and back on track, and it doesn't take as long for grip to return as it does in LFS. If a race car travels over a wet patch (grass for example), the tires lose little heat, and dry up very quickly once back on the road, and at most tracks, they don't water the grass just before a race. Gravel traps use fairly large pebbles to prevent them from getting stuck into the tires and later flung off at other drivers.

The tires in LFS heat up much too quickly when sliding

Not much to explain here, the model just seems to be wrong. The hot spots seem to develop almost instantly, and yet take a long time to dissapate.

Segemented tire model

Again I don't know how this is implemented, but a contact patch varies in size depending the forces acting on it (downforce and accelerations), and the circumference of a tire flows continously through the contact patch, not in segments. If you lock up the tires under braking, even for a fairly short period, then look at tire temps while moving slowly, you can see a very small hot spot "segment". This isn't realistic.
I agree with you only on the not regaining grip quickly enough. The rest, whilst correct, is what LFS tries to acheive.

About the hotspots. When you lock a tyre in real life, only a little part of it (the bit on the ground) gets heated. Lets call this bit a 'segment'. Now, LFS is designed so that the tyre temps work in segments (see where I'm going), so a lock up with heat the segment that is considered on the ground at that point. What is wrong there? Nothing! For grip, slip angles, sidewall deformation I believe that LFS calculates them continuously (at 4kHz I think, even though the rest of the physics engine runs at 100Hz).

Your real life points are all correct, as always JeffR. But, like many of your previous posts, you have missed the point about LFS. It isn't real life. The tyre model is as close enough as we need. I doubt you'd tell the difference if the temp segment modelling was increased for 16 to 32 segments. LFS loses grip gradually. I can feel the tyres beginning to lose grip in 'stages' if you like, it's not a defined 'Grip' or 'Slip' condition.

You always state you don't know how LFS does the tyre model. Well, in future, perhaps you should find out before moaning about tyres for the millionth time.
#68 - Vain
The propblem is that for example loosing grip will always feel unreal because you can't rely on your bottom to detect small slipping - the usual way to determin sliding in real life. Only your eyes, ears and eventually your hands (FF) can get feedback from the game.
When the loss of grip is watched closely in replays using the force-view you can see that it seems very correct, nevertheless it feels strange. I don't think there is much LFS can do better to simulate this.
Though of course I agree, that the regaining of grip doesn't seem to follow a realistic model.

Vain
Yeah I don't understand your point about segmented tyres either JeffR. What should get hot during a lock up, the whole damn tyre? I think not.

I've no idea about tyres heating, since I don't have any real life knowledge on the subject. However tyres are a bitch to cool down, I played GTR around a friends house the other day and the difference is huge. Not saying GTR is perfectly real, but we all know they fudge the physics so that everything appears correct. Why would they intentionally speed things up? I'm sure that the devs would have found a reasonable number for the specific heat capacity for the rubber/metal mix that forms a tyre, so I'm guessing maybe the fast flow of air doesn't cool as much as it should do. I suppose engine and brake temps would be another way to check on this.

On the dirt side of things, the system has only just been introduced and known to be basic, give them a chance.
Quote :You always state you don't know how LFS does the tyre model. Well, in future, perhaps you should find out before moaning about tyres for the millionth time.

I would assume this is like a trade secret, no one but the developers are going to know, or are they explaining how they model the tires?

Quote from tristancliffe :About the hotspots. When you lock a tyre in real life, only a little part of it (the bit on the ground) gets heated.

The issue seems to be that there is no conduction of the heat away from hot spots. It's as if the tire surface is a perfect heat insulator. In the FO8, with 1.00 degrees of negative camber in the front tires, while going 50mph, tires at 60 degrees (Farenheight), I locked up the brakes to a complete stop (takes just under 2 seconds), track must have been cool, because most of the tire dropped from 60 degrees to 59 degrees during the 2 seconds, while two inside hot spots appeared, over 120 degrees. Three minutes later, the hot spots were still over 100 degrees, and the immediately surrounding areas hadn't heated up at all

I would have expected the heat to be conducted both deeper into the tread and outwardly away from the hot spot, but LFS isn't doing this . In addition, the hot spot appears to be much smaller than the actual size of the contact patch of a tire, because it's very difficult to move the car slowly and stop the car with the hot spots showing on the live tire temp HUD. The hot spots are extremely small, and dissipate heat extremely slowly.

Quote from Vain :The propblem is that for example loosing grip will always feel unreal because you can't rely on your bottom to detect small slipping
- the usual way to determin sliding in real life. Only your eyes, ears and eventually your hands (FF) can get feedback from the game.

Sounds offer good feedback as to what's going on. Tire scrub / squeal sounds are good for braking and cornering. Engine sounds are good for applying throttle, as long as the differential doesn't have too much locking factor. If engine rpms are increasing faster than they should, it's an indication that one of the driven tires is spinning.

Assuming that LFS S2's limited slip differential is modeled well, engine sound feedback should work well for throttle application, even on straights. A car can remain stable and in control with one driven tire spinning if the locking factor is low. Since this is player adjustable, the amount of sensitivity is adjustable.

Force feedback can help with steering inputs, depending on how the game models the force feedback. I noticed that with LFS S1, just enabling force feedback improved stability, even though my steering inputs were the same. The game was adjusting my inputs with the force feedback, so in essence, it was an stability assist. I don't know how much of this applies to LFS S2.

Quote :When the loss of grip is watched closely in replays using the force-view you can see that it seems very correct, nevertheless it feels strange. I don't think there is much LFS can do better to simulate this. Though of course I agree, that the regaining of grip doesn't seem to follow a realistic model.

One fix is pretty simple, adjust the tire model; specifically the sideways force versus slip angle curve so that it's more horizontal once past the peak force. This is one of the goals of the manufacturers of real racing tires, both DOT and slicks, to make them more forgiving.

Quote :recovery from off track incidents

There also seems to be some sort of recovery fudge factor that I can't figure out. The car seems to remain unstable for quite a while after going off track. I'm not sure what is trying to be simulated here. I can understand that it would be difficult to drive a high powered car on wet grass, but once it's back on the pavement, the tires quickly dry out.
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(thisnameistaken) DELETED by thisnameistaken
Quote from Bob Smith :Yeah I don't understand your point about segmented tyres either JeffR. What should get hot during a lock up, the whole damn tyre? I think not.

No, but that wasn't my point. Although over a long period of time, the whole tire should heat up a little.

Two issues here, in LFS the hot spots are extremely small, and extremely insulated. Looking at the HUD temperatures, there can be a huge differernce in temperatures between the inside, middle, and outside of a tire, as well as from segment to segment, and can remain that way for quite a while. As mentioned before, even after 3 minutes, none of the surrounding cooler areas got any hotter.
Actually, the heat emitting to bordering segments seams a good ida to me. I can't imagine that won't happen IRL.

But if it is realisic, not only the heat should not only spread, but also decrease in the hotter areas as it spreads, because it is basically a transfer of energy. The one degree you need to heat up the neighbouring part is lost on the originating part. And this keeps going as long, as all the temps are equaled out...

EDIT: I know I said "lost" in one sentence with "energy", so all you scientists out there, don't throw stones at me. I just couldn't think of any other term which is as easy to understand.

EDIT 2: horrible typing.
Quote from ColeusRattus :the heat should not only spread, but also decrease in the hoter areas as it spreads, because it is basically a transfer of energy.

Exactly my point. Especially when these hot spots are so extremely small and surrounded by realtivly large low temperature areas.
How long have we had tyre temps? Is S2 Final? How long have we had dirt? Is S2 Final?

Think before you moan about the new features of LFS. Just because you own a caterham replica doesn't make a driving god, doesn't make you understand the technical side of things. You have not really ever impressed me with your technical knowledge, but you seem to be good at 'bs'ing your way through a conversation about tyres.

The devs know it's not perfect. They will be coming up with improvements over the coming months. IF your posts were constructive rather than 'LFS is rubbish' then it'd be much easier - in this thread it took about 8 posts to work out what you meant about the segment heating alone...

P.S. I may not have impressed you with MY technical knowledge either, but I'm not the one with two hundred 'LFS can't model tyres' posts, so don't try to be clever.
Be careful with that handbag Tristan

I think it's clear that Jeff knows LFS is not finished, or else he wouldn't be posting here, in the "Improvement Suggestions" section.

I reallly don't like people using the "it's not finished yet" argument. Whether the criticism is justified or not, using this argument isn't a good defense. Obviously it concedes that LFS is wrong, but it also suggests that it isn't even worth judging yet on its own merit. Which it is, I think. It's not perfect, but then neither are any of the "complete" titles out there.
LFS is a fine product already, I don't think we have to suggest to people that they should wait until it's "finished" before they buy and enjoy it, which is, in effect, what is being suggested with these constant "don't judge it, it's not finished yet" arguments.

My two pence.

FGED GREDG RDFGDR GSFDG