Quote from Ball Bearing Turbo :

You and RIP appear to be saying different things, though correct me if I am in error about that.

Sorry I meant forgiving in terms of getting good starts. AND locking wheels, cornering stability etc... which is what the post starting this thread said...

@Ball Bearing Turbo :

I don't understand of what evidence you talk? As I said above there is really no single "evidence" for anything here ... just contrary information. I showed a video from the real world and there are some graphs which are quite different.

But just lets take some "evidence" of the other side :

http://www.performancesimulations.com/files/longslip.JPG

This graph posted by jtw (Todd?).

Now look at the difference there from 0.2/0.3 to 0.8. Tyre loses about 10% force from slip ratio 0.2 to 0.8 or lets say 1.0 to make it easy.

Slip ratio is defined as wheelSpinVelocity/groundVelocity-1. So that means if tyre goes twice as fast as car it has a slip ratio of 1.0 (100% spin you could say)

Now lets take a start with the XF GTI. Reving up at the limiter, which is about 50 to 60 kph. Lets say 50 kph at limiter.
Then get off the clutch. You'll notice, that there is no blue clutch sign left. So clutch is fully engaged.

Tyres are now spinning at 50 kph, while car starts from 0. Lets say car is now at the beginning moving with 5 kph.

That means, tyres are spinning 10 times as fast as car is moving. This means 10/1-1 = 9.0

Now watch the graph. It seems that it will decent even faster. But lets say it is linear. This means the loss of force is about 9 times as big as from 0.2 to 1.0.
This would mean only 10% force left, which is a bit off. But 60% force left or so seem to be quite realistic with your "own" evidence.

But I'd say those graphs say nothing. Every one is different. No real knowledge in there. I'd go for real experiences and ask drag people or watch my video ...
There is a very significant difference with street tyres. And it should be easy to start faster than someone going full throttle as IRL too ...

btw. everyone can post just some graphs from the internet. Watch this one :

http://www.racer.nl/images/pac_f12002.jpg

See how much force drops even to SR 2.0?
Empirical data. You all have to believe me now.

No no. I do that kind of things all day, because I study at a technical university. And I know how to prove something with real evidence. You need SERIOUS sources which back up each other and have to explain and understand it all. Not just posting some graphs, which show infact different things and pick up the one, which you like most.
In a LFS forum most people tend to take the graphs which show how infinite great LFS is and how perfect physics are already. No more changes ... its all great

Generally we may agree that LFS is one of the best simulations out there right now. But it still has flaws. And not just one.

@jwt : Plz don't misunderstand me. I think we can talk very productive and I know you have a lot of knowledge. But some people seem to be to much impressed by just some graphs which can be interpreted this or that way, because you don't know if the tyres are from a space shuttle landing, a formula 1 car or a old beetle road car.

*claps*
nice post Rip. Be a dull forum if we just accepted the words of one so called expert with one random graph up his sleeve Nothing at all against Todd - I'm eager to be convinced, but there is not enough factual data posted imho.

:

Hmph.

I guess you're probably right.

I gave it the good go.

** wavers between sides in the debate **

Edit: I'm still satisfied with the lateral grip behaviour though, but I'm questioning the longitudinal. I still maintain that there is no (real) problem with lateral grip since the patch.

Maybe Todd will come back and rip it up (no pun intended), and I wouldn't call him a "so-called" expert, that's a bit cocky since he'd bury 99.9% of us in this field.

Maybe he would be so kind as to post one of his videos of his own sim with a massive wheelspin launch? 50km/h wheels really are not turning that fast RIP2004.

Wasn't trying to insult him, just trying to make the point that I only know him through his posts on this forum. Might have come across a bit rough.

50km/h spinning wheels off the line have a far bigger slip ratio than the sole graph posted...

Quote from AndroidXP :

I made a custom layout where I just tested the accelleration in first gear.
With TC at 8% my fastest time was something like 2.85, without I never got below 2.93, IIRC.

I think the difference is far too small to warrant not going pedal-to-the-metal in cars where the stability isn't an issue to begin with.

I'd say that it's about 2.15m difference at 40m for a time differece like the one you measured.
Not a small difference actually...
That's only from the tyres.
IRL you'll have a reaction time to account for...
In LFS the start is "automatic" and all the pilots start with the same reaction time (when "flooring" is 0 actually), whereas IRL there can be differences in the order of 0.05-0.1sec between two pilots. (another 2-3 meters?)
Then you have to consider the even bigger differences in tyre type/condition, transmission, gear ratio, engine etc...
In LFS all the cars are identical and "perfect"
All this toghether will make a much bigger difference at start (car lenghts maybe?) IRL than you can see in LFS.

All IMHO

Very good point actually. Everyone starting at the same 100th of a second must have a pretty reasonable effect on starts. Yet another reason to rid us of the unsightly starting method in LFS.

Really great to see that everyone here is discussing properly I also gave up point 3 of my list (FZ50s strange slide behaviour because of weight transfer) because it really was just a setup thing with the differentials.

I fully agree that reaction time is a big factor for good starts. And it is something completly missing in LFS.

But wheelspin is another noticable factor.
Some quotes from real life racing drivers I found in the internet :

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"Stefan Everts (Yamaha L&M Motocross Team) DNF-first
“I had a bad start in the first race with a lot of wheelspin, to start on concrete is hard if you are not used to it!"

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David Coulthard: I moved a little bit just before the start and had to stop the car. And then that's when the lights changed so I then got too much wheelspin. And to be honest I thought I was going to be swamped at the start, but I presume Mika must have made a bad start as well
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“I got a very bad start with too much wheelspin but I still overtook two or three cars at the first corner." (Formula Audi, Deman)
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Now to roadcars:

Drag Racing:

"Oh and for the people saying that the drag skills are good launches, smooth gear changes and no wheelspin, isn't that really a skill for all motorsport, a bad start can **** any race."
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"Get a good launch to start with, too much wheelspin & apart from killing your tyres, you'll not go far. Also, don't burn your clutch sitting on the line, it'll affect your gearchanges later up the strip and if it's slipping you aren't getting drive to the ground.

Keep driving tyres about 5-10psi lower than normal, depending on conditions (remember you have to be able to brake effectively after the finish line :blink: )

(Seat Ibiza car ... so no racing car)

...
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You can propably find much more on the internet about that. But bad starts are nearly ALWAYS mentioned in connection with wheelspin. In race cars and in street cars. Tips for 1/4 mile races are always to avoid to much wheelspin. The only point where it is wished is when heating up your tyres at the beginning.
Also see my M3 vs RS4 video. It is obvious how much the M3 gets backwards at the start in the end because of wheelspin. And that even though the driver immediately goes off the throttle and corrects that mistake and doesn't stay full throttle. And both react pretty good to the signal.