Exactly.
We all know how Scawen works, he has said it over and over again on the forums. He sets off with some goals in mind. But, sometimes he will find things during that process that just aren't right or up to his standards. He will then stop and fix those things and bring them up to standard. That is what I suspect is going on right now.
These test patches are minor tweaks that probably have absolutely nothing to do with the new work being done (from a code and programming perspective) for the next major release. It is stuff that he wants cleaned up and the only effective way of testing them and insuring quality, is to get them out there in test patches prior to the bigger release. That way, things are solid all around and we can enjoy the new features without a lot of minor issues that crop up with things like language packs, Linux shadows, etc. At least, that is my guess.
Keep it clean guys. This is just for fun. A little bit of wish listing and hoping is cool and fun.
I oversteer coming out of corners with iRacing too... mostly because of all the lock I have in trying to make the corner.
What i mean by required is that if I am slow enough to make my initial turn in point, mostly off throttle and my arc is good to hit the apex, if I want to stay on that path, I have to increase steering lock substantially with iRacing or my arc will wash out and I won't hit the apex. This is especially bad when I am using a touch of maintenance throttle to keep the back end pinned down. I found that I can't use maintenance throttle in the Solstice. However, with other cars I have to use it because of the throttle steering and then the steering lock goes way up.
But, seriously, the iRacing car will drift out nicely with a tad of throttle induced oversteer coming out of a corner. LFS does this as well.
LFS does throttle steering very well. It is the setups that generally wash all of it out.
Driving the spec racer Ford in iRacing and the Barber car is a bit nuts. The throttle steer in both of those is way happy. I swear I could make it around a lot of tracks without turning the wheel more than a degree. Throttle steer is good and it is realistic, I'm just saying that iRacing goes a bit too far with some of the cars. It's a car model thing though, not a tire physics thing I think.
Anyway, I am not sure if any of that is right or wrong, I am just saying that is how I see it.
Entry is bad, yes. Little to no throttle, possibly brakes, or just coming off brakes. I don't find it completely unrealistic, but it isn't exactly sharp either. When you are on throttle, its worse of course. Throttle steering also seems to be way too pronounced in most of the iRacing cars that I have tried.
Yes, steering more when understeering in real life can bring you out of understeer, but you come out because you are scrubbing the tires, using them as a brake which of course transfers some weight. It will destroy your tires in a short while. With iRacing, it seems to be pretty much required once the weight distribution evens out after braking.
I would agree with that. LFS is very hard to stop understeering once it starts and it does seem to be easier, in general, to catch oversteer. iRacing seems to be similar to other games in that oversteer can be extremely difficult to catch, even in mild situations where understeer is easier to recover from.
New physics could definitely change the balance on the cars but it isn't going to make the FXR more competitive in my opinion. It already can accelerate with full power pretty much no problem. It *may* help with turn-in on FW/AW drive cars but I would suspect that it would be pretty balanced in that way for all cars.
O/T
Interesting. I have found that the understeer in iRacing is very unmanageable. I think that iRacing regains grip after sliding better than LFS does, but initial turn-in seems worse to me. It also feels like the mid-corner understeer is greatly exaggerated in iRacing. You can overcome it by steering a lot more, which also seems odd. But, it's so darned hard to tell sometimes without exhaustive testing because of differences in the tracks, cars, and setups.
O/T
If Scawen is working on the tire physics, I will be very interested in seeing what he comes up with. I would love to see setups in LFS that are more aligned with reality than what we see now.
I think there are several aspects to the tire physics that might be under some consideration. I think the use of the term "understeer" in this context is a bit general. In other words, Scawen might be working on some tire physics changes that will have an affect on car understeer. I doubt he would fix the code to reduce understeer. What I suspect he would do (if he is in fact doing anything) would be to work on better overall tire physics that will address some of the odd behaviors that we see which includes some of the understeer, oversteer, lateral grip, etc. That's not a simple thing at all.
It isn't like LFS uses look-up tables to figure out the tire physics. So you can't go in and find the "understeer" parameter and tweak it down a few notches. LFS doesn't work like that. LFS is more like working with the Unified Theory of Everything combining quantum physics and general relativity than it is working a Sudoku game.
Quoted for reinforcement!
Don't read anything more into it that what is there.
Don't read anything more into it that what is there.
Wow, that is more like the original "heal toe" where they did brake with their heal. I can see that he is using the ball of his foot and pivoting to blip the throttle though so he isn't really using his heal. Cool shot. I'm going to have to give it a try that way since I always run into trouble with my heal hitting the floor when I try to blip the throttle with my heal.
I also had never seen somebody switch the foot they are braking with mid-corner like that. I can understand though, using the throttle to balance the car along with the brake would be advantageous in that car.
I think he means the number of degrees the actual tire and wheel turn not how many degrees of rotation that the steering wheel turns. He said the wheel turn being like 450°.
All of what you say there is true and LFS physics support it all. What does happen though is that there are things you can do with the nearly infinite setup possibilities in LFS to counteract a lot of those things. Yes, it is still a compromise, but these hot lappers make everything extreme. They have to in order to make the times that they do.
Not to mention a lot of the hot lap guys can do things with those cars that look impossible. If you try it, you won't make it work, trust me. So a lot of what you are seeing is down to the driver.
You are better off getting some replays from somebody who is practicing for a race and doing tire tests or something. Then you can see a more reasonable setup and more normal driving.
I trail brake, but i have to carefully modulate the brake in order to do so. You will turn the car around if you are too aggressive with it. You'll find that with a reasonable setup, LFS will feel very realistic and predictable, if not exactly like ISI based sims.
I think that the heat changing the chemical composition will have a big effect on the mechanical keying of the tire. This also has an effect on the adhesive properties because the tire can't conform as well to the surface it is on and therefore less surface area will be in contact. Basically, the tire gets harder through heat cycles eventually. There is a point where the tire gets soft enough that it keys better, but once it is past that point, it does lose a lot of material and the keying won't work as well because the material does not "snap back" into its original shape. It will never work as well again after that.
Big chunks falling out of the tire will obviously have disastrous effects on grip. But that is a pretty extreme result
Speaky English??
Yes, but the chemical structure change is 99% due to heat. I think that it the degree that the chemical structure changes is going to be related to just how much heat was applied.
Mechanical should not go off over a 20 minute session, at least not enough to notice. The only way mechanical is going to go off over that short of a session is if you have really bad quality tires, are outrageously abusing them (eg catching the inside of curbs, off roading, under pressured, etc), or you are over heating them.
Any professional driver, as claimed were driving these cars, should be able to keep their lap times within a couple of 10ths on a track that short. Looking at it from that standpoint, that's a huge degradation of the times.
There's a lot we don't know about that test. Thanks for pointing that out to all of us. But you make the assumption that the degradation happened prior to the last lap and that the degradation wasn't a result of cooking the tires (which it probably was).
I've seen that kind of degradation on tires. It usually happens after multiple track days and most often to front wheel drive cars. If you look at the pictures, it sure looks to me like the tire was rolling very far onto the sidewall indicating it had the pressure set too low for what they were doing. That will also cause degradation of the tire pretty quickly. But again, that's just a guess given the pictures and data that we have.
I would say that there is pretty severe degradation in those tires. It's only a 1:07 lap time. 1.2 second degradation over 20 minutes is quite a bit.
I would also guess that these guys were pushing very hard. I run 20 minute stints on performance street tires 4x a day (in about the same temps as that test), and I have no trouble with chunking like that. Maybe my tire is better, I don't know, but that's pretty extreme either way. I ran 7 track days on those same tires and drove them on the street every day. They lasted for 18k miles. The last track day on them was marginal. They had lost a lot of grip and I was down a couple of seconds over my normal times.
At the end of the 20 minutes, you can feel the tires getting greasy. You had to back off a bit or you would risk sliding off. But by the next session the tires were OK again. These guys must have just kept pushing hard the whole time with no regard to working with the tire.
Very cool data though. I think it shows us some more interesting tidbits about how tires work.
I would also guess that these guys were pushing very hard. I run 20 minute stints on performance street tires 4x a day (in about the same temps as that test), and I have no trouble with chunking like that. Maybe my tire is better, I don't know, but that's pretty extreme either way. I ran 7 track days on those same tires and drove them on the street every day. They lasted for 18k miles. The last track day on them was marginal. They had lost a lot of grip and I was down a couple of seconds over my normal times.
At the end of the 20 minutes, you can feel the tires getting greasy. You had to back off a bit or you would risk sliding off. But by the next session the tires were OK again. These guys must have just kept pushing hard the whole time with no regard to working with the tire.
Very cool data though. I think it shows us some more interesting tidbits about how tires work.
Bob makes a good point here. None of us can really say with precision what the effects of tire temperature are exactly. First, even if you drive real race cars or spend a lot of time at the track, you don't push nearly as hard as you do in LFS. You are driving 11/10ths all the time in LFS.
Secondly, the conditions do make a huge difference. Each track has its own characteristics for both grip and how abrasive the surface is. It's extremely difficult to compare.
I think these things makes Scawen's job even more difficult. Getting valid test data to compare against is virtually impossible. And even if he did have that data, it's probably only for one tire type on one surface.
So, there are things that we are going to see in LFS that may be 100% accurate as compared to the real world, but it is so outside any of our experiences, that it seems wrong.
As far as the heat loss goes, I don't know for sure, but it seems that the cooling would not be a linear processes. It would cool more rapidly down from higher temps, but then slow down considerably as the temperature of the tire dropped. This is just intuition, but real physics have shown millions of times that intuition is patently wrong. eg, which weighs more, a pound of lead or a pound of feathers?
Yes, of course race tires last longer. They are designed to take more heat and don't have groved tread that wiggles more causing more heat. I am just surprised that specialized drift tires haven't been produced.
I think you are slightly missing the point about the grip and heat. As I suggested earlier, it probably has more to do with the grip model, and more specifically, with the way grip is regained once it is lost.
We think we know two things about the LFS grip model, one mostly imperical and one mostly a qualitative estimate. First, we are pretty sure that the longitudinal grip is not right. You can spin the tires like mad on acceleration, yet you still are able to accellerate out at as good, or better speed than a car that does not spin the tires. If you think about that for a minute, it might imply that even though the tires are spinning, they are still generating a lot of grip. This to me might imply that you are going to generate more heat than you realistically should.
Second, when a tire loses grip, it seems to regain it in a nice, linear manner makes things like the snap-back spin problem and other recoveries from slides a bit easier than it should be in some situations. This to me implies that once the tires break loose, it is easier than it should be to keep them broke loose. Therefore, you get the effect of a low power car being able to keep the tires spinning during drifting when you shouldn't be able to. I suspect it has more to do with the grip model than it does with the heat model, although the heat obviously does play a roll too. It is completely counter to the idea that spinning tires on start still allows you to accellerate quickly, so there is a lot going on here that we can't possibly know about (just like the real world, eh?)
So, yes, the heat modle needs some work, but it is pretty close as is. The grip model also needs work, but it is also very close, and dare I say still the most responsive and "realistic" out there right now. When you combine the two together while drifting, you do see some of the flaws a bit more dramatically.
(BBT, good to see you post again. I like you, don't post a lot anymore, but I can't resist a good discussion on tire physics.)
OK, good to know. I just assumed that nobody would be stupid enough to go out and burn up perfectly good, new, race tires for drifting. What a waste. A good set of used up R888's maybe, but it would seemingly be better to just grab any old discount tire that's harder than a rock. But, obviously I know nothing about the fine display that drifting is.
I would bet that they heat cycle the R888 before they use them though. If you burn the snot out of a tire, it will be nasty hard and lose a lot of grip.
The fact remains that tires get more slippery when over heated than they are when at the optimal temperature. LFS may have the curve wrong, I said that before, but it isn't as bad as you are wanting to make it out to be, I think. Plus, if you are running your tires in the red, you ARE DOING IT WRONG in the first place.
Plus, I think you are experiencing some of the other grip bugs that exist in that once you lose grip, it is overly difficult to get it back again in some situations.
I'm sorry, but comparing drifto tires to race tires is two completely different things. Drift tires are made to be slick (soapy if you will), and make lots of smoke. In real terms, they are crap tires. They are made to withstand the heat by letting it escape as smoke and massive quantities of rubber. It makes for a better show.
LFS does not model tires perfectly, but from my own personal track experience with performance street tires, when they get hot, they get slippery. Just like DragonCommando said. LFS does a pretty good job of this. The curve might be too steep where the tires get red hot too easily, or they might not shed high heat quickly enough, I don't know for sure. But what you guys are saying about red hot tires being to slippery is just crap. It sounds to me like you are just begging for a set of drift tires to use in this racing simulator.
Basically correct. However, BMW does now have speed sensitive steering. The steering ratio increases as the vehicle slows down. This enables you to negotiate the sharpest corners without ever having to take a and off the wheel. You just turn the wheel with both hands to about 160° or something like that and you will be at full lock as long as you are going slow enough. At higher speeds, the steering ration goes back down to a more normal value. I don't know how it would react to a situation like described above though.
I hadn't thought about this before, but lets say you wanted to drive an exact radius corner as you were slowing down. You put in the exactly correct steering input at 100mph and then start slowing. Would you then have to keep taking steering input out as the car slowed? Weird for sure.
Very good. Well, except for the fact that phrases such as "4 wheel drift" used to describe a particular type of sliding of the car has been in use for years in racing.
So, just come up with a different name for your sport, and we will all be happy. How about Makingmoneyfortirecompanies, or Gnicar or Smorking, or Lapsus (latin for slide), or Lapsusbalartro (for the driver), or something like that.
Although your explanation above is all over the place and kinda random, you make one critical error.
You try to make the distinction that Gripping is a form of motor sport. It isn't. It doesn't exist.
There is motor sport. This is a broad category that includes everything from F1 to track days and everything in between. There are multiple subcategories within motor sports. Unfortunately, drifting is one of them (I would rank drifting slightly below lawn mower racing). However, there is no subcategory called "gripping" or "grip-racing". There is just racing. Racing does break down into hundreds of subcategories too including ralley and club racing. To say there is such a thing as "gripping" basically implies that drifting is akin to and associated with racing. It is not. There is racing and there is drifting. They are two completely different subcategories of motor sport.
Drifting is synchronized swimming. Or, to look at it another way, it is "sports entertainment". It takes the guise of a sport in order to provide entertainment for viewers. It is much like the US professional wrestling, AKA WWF, in that regard.
Sam's explanation is good. But I doubt you'll get it.
I'll just say this and hope you understand. Speed has everything to do with locking up tires with brake systems that we have on cars today.
Speed = energy. In order to slow down, you have to get rid of that energy. Brakes do that. So, the faster you go, the more energy there is to dissipate.
I suspect you are under the impression that a good brake system should be strong enough to lock the wheels at any speed.
First, that would be stupid. Locked wheels don't slow down as quickly as threshold braking. Secondly, the brake system would be big and heavy. Not worth it. Third, it's very dangerous to lock up at high speeds. Could you imagine how quickly you would flat spot a tire at 150mph if you locked a tire?
And last, you only need enough brake on the car to take your tire up to the optimum slip angle for threshold braking. Any more than that, the tire just locks up and you don't slow down.
You do lock tires, because the brakes are set to threshold brake around the top speed of the car. As you slow down, there will be enough friction in the brakes to lock the wheel. That is why you see lockups. And yes, that is when the driver or the ABS must modulate the brakes to make sure that you don't lock up a tire.
Try it yourself with your ABS in your car (someplace safe, it would be best to do it on a track). Go as fast as you safely can, slam on the brakes as hard as you can. If you have decent tires on a decent surface, you will NOT lock up until you slow down a lot. You can confirm this by feeling the ABS kicking the brake pedal.
Interesting. Of course it is impossible to tell from the CST website. They say "pressure sensitive", but so is a spring. They do mention load cell somewhere, but they don't show how it works. It is cool if they do actually support pressure. The ECCI system uses a cam system to basically increase the amount of Pot movement as the pedal gets closer to full deflection. So as you press the pedal, the amount of Pot movement increases as you approach full travel. It's a lot better than standard pedals, but still leaves a lot to be desired.
That's not what I am saying at all. I am saying that brake calibration/settings are not setup in a way that enables you to configure your controls so they are usable. You can train yourself to overcome the problems, sure, but why should you have to? It's a problem. It should be fixed.
Hmmm, really? So you want the possibility of a lockup at 150mph?
How many times have you seen an F1 car lock the tires at the end of a long straight just when they hit the brake point? I never have. I think that implies that you can't lock the brakes at speed because if you could, you would certainly see it happen, and you don't.
Plus, I would think that brakes that are capable of locking up the car at speed would be so grabby and twitchy that you would lose most of the feel.
In a real car with a decent set of brakes, for example, my 87 BMW 325is, you can definitely go full pressure on the brake from 120mph down to about 40ish mph before you will lock a tire (assuming straight line braking). This of course depends on the type of tire you are using. The stickier the tire, the less the chance you have of locking up. And it depends on the amount of friction the brakes can apply overall (put on a 16 puck BBK and you will lock up easier). This is the part where I have trouble with iRacing. I can't even go full pressure in the Pontiac for a second and I am locked up. In my car, I can go full pressure for several seconds or however long it takes to go from 120 to 40 (it's about 400 feet of travel to do that).
It is more difficult in downforce cars because as you slow, you lose downforce. Since lift is proportional to velocity squared, you lose lift very quickly as you lose speed. This will allow you to lock the brakes much earlier because your brakes will be setup to allow you to brake at the limit from top speed. So, in this case, you are full on the brake for a second, maybe less, and then you have to start easing up on the brake pedal or you will lock up. The closer to the corner you are, the less brake you should have in (which seems counter intuitive since you still feel like you are going too fast, but if you press more, you will keep going too fast).
So, the reason this can happen is that the brakes don't have enough friction to overcome the friction that the tire has with the road. That's why on the same car with the same brakes, harder less sticky tires are easier to lock up than gumball tires. The hard tire has less grip to use, so the brake friction can overcome the tire friction with the road more easily.
The reason you see F1 guys locking up so often is that their brakes have huge friction and the outrageous amount of downforce those cars have. Well, and they are always trail braking going into a corner so it is very easy to lock up the unloaded front tire. But I guarantee you that they do use full pressure on the brake when they initiate braking from high speeds.
If it was a design decision, then it was a bad one. There are NO sim pedals out there that do a really good job of simulating pressure modulation. It is all travel modulation even if the pot travel gets progressively larger as you get closer to full pedal deflection (use of a cam system like on my ECCI pedals). For the game to arbitrarily decide where the full deflection point is, is ridiculous and speaks of a fundamental lack of understanding on how sims work. iRacing, in this one area, is certainly needing a lot of work. I cannot drive iRacing without having completely random lockups. Same brake point, same pressure works OK one time, but causes unexplainable lockups other times. I can only use about 3/4 deflection on my pedals before I can lock up any car. More than that and I can lock up from top speed.
LFS allows you to set brake friction so that modulation becomes more reasonable and to a point where it is comfortable for most drivers. Yes, it also lets you set it so low that you will never lock up a tire, but you will be giving up seconds a lap if you do this.
And I think this is very important, LFS lets you set brake friction... in other words, changing parts on the car. Then it just respects your calibration settings and lets you, the driver, evaluate how well it works. Yes, the settings are probably too flexible, but that's a small point. Anything too far outside a normal range won't work well anyway.
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