I've been playing the game for 3 months now, predominantly in the GTI, and whilst I find the game a lot of fun I'm begining to question the physics a bit.

Here's the rub:

The fastest GTI setups amost invariably use Hybrid tyres on the rear.


Now whilst this does alow for the rear to drift out, and therefore give more oversteer, (and a quicker turn in), I have to question any in game physics where this is the fastest driving technique when IRL if this was the case all FWD race cars would use hybrid rear tyres for the same reason, which patently they do not !!

In real driving, (all other things being equal), maximum pace around the track is achieved when the tyres have maximum grip, expecially under braking and around corners, (even to the extent of using tyre pressures that lead to straight line instability). It seems obvious to me that hybrid tyres are never going to give the same ultimate level of grip than a good "normal" tyre, even one of a road going variety. By definition they have less rubber/road contact area and therefore can never acheive the same levels of grip.

So my question is, how can we correlate this real world deficiency with the fact that in LFS, hybrid rear tyres mean faster laps??

Unless of course there is something off with the in game physics?


Thoughts?

Have you considered that the hybrids' compound might be softer than the Normal tires'?

well, IRL usually small GTI- type cars DONT have a rear antiroll bar, which causes the inner rear wheel to lift from the ground (going into tripod mode), which causes massive oversteer. me thinks that if you put a stiff front anti-roll bar, you can forego the rear hybird tyres.
BUT the main reason is that hybrid tyres give you MORE grip than normals. why? cause they heat up faster, and at the end of a short 5 lap sprint race, the normal rear tires are JUST coming up to temp, while the hybrids have been at optimum temp since lap2...

It's not really the tire choice that what you state is the problem, but more the driving technique used in LFS that is the fastest. It's only the tire choice that creates that technique in LFS. I agree, using hybrid tires on the track wouldn't be very realistic.

There's a saying with racing fans here in the US, "loose is fast." Tis very true. The fastest way around the track isn't maximum grip. Having oversteer gives you the ability to rotate the car around the corner rather than steer the car around the corner. But I think in real life, it isn't used to the extreme that LFS racers use it because it is too easy to lose the car and spin out. In real racing, that means much more than being disappointed that you have to spectate and wait 10 minutes for the next race. In real racing, that means loss of points in whatever series you are racing in if racing professionally. It means a crashed racecar and money to fix it. It means the very real possibility of injury or death.

In LFS, we don't have to worry about those things. We don't have to worry about injury, thus many use quite an unrealistic driving style. I can't and I don't drive like that, because it just means I'll be spectating quite a lot of my time on LFS. The extreme oversteery setups that I see others use just means I would spin out constantly. Though I understand what you are saying here, and agree with you, I don't necessarily think that the behavior of that driving style comes down to the physics being wrong. I just think the actual driving style of using extremely loose setups is unrealistic.

That's my take of it.

Good points. I had noticed that the hybrids warm up quicker and put it down to the assumption that the tread blocks move more than on the road tyres (which would be the case IRL). I must admit that I hadn't considered that they might be of a softer compound too.

To which I must ask the question, why? As in why aren't the road tyres softer compound too (and therefore more grippy). I'm sure if you were to try the experiment with real tyres available on the market a "normal" road tyre would give more grip than a "normal" hybrid. If the hybrid that's available in the game is of a particularly soft compound, then we should have the choice of a softer compound "normal" tyre surely??

Just a quick answer as I saw your question :

The road supers are supposed to be actual road legal tyres, like track day tyres, not full racing tyres.

The rallycross tyres are real racing tyres, so they do have some good grip on the road. Though they overheat too quickly to be used in most situations on most of the road cars.

Quote from mrodgers :

It's not really the tire choice that what you state is the problem, but more the driving technique used in LFS that is the fastest. It's only the tire choice that creates that technique in LFS. I agree, using hybrid tires on the track wouldn't be very realistic.

There's a saying with racing fans here in the US, "loose is fast." Tis very true. The fastest way around the track isn't maximum grip. Having oversteer gives you the ability to rotate the car around the corner rather than steer the car around the corner. But I think in real life, it isn't used to the extreme that LFS racers use it because it is too easy to lose the car and spin out. In real racing, that means much more than being disappointed that you have to spectate and wait 10 minutes for the next race. In real racing, that means loss of points in whatever series you are racing in if racing professionally. It means a crashed racecar and money to fix it. It means the very real possibility of injury or death.

In LFS, we don't have to worry about those things. We don't have to worry about injury, thus many use quite an unrealistic driving style. I can't and I don't drive like that, because it just means I'll be spectating quite a lot of my time on LFS. The extreme oversteery setups that I see others use just means I would spin out constantly. Though I understand what you are saying here, and agree with you, I don't necessarily think that the behavior of that driving style comes down to the physics being wrong. I just think the actual driving style of using extremely loose setups is unrealistic.

That's my take of it.

All of which count against the argument that the game is a realistic driving simulations surely?

The "squaring off" of corners that you refer to, is only the quickest way around a track if the vehicle has fast straight line acceleration. The GTI doesn't, (it's the car equivilent of the 125 class in motorcycle club racing), for this level of straight line acceleration it's all about corner speed and for that you need maximum grip.

And just to add : the tyre heating and temperature vs grip characteristics on the tyres is not finalised. Those characteristics are too rough an approximation at the moment.

Quote from Scawen :

Just a quick answer as I saw your question :

The road supers are supposed to be actual road legal tyres, like track day tyres, not full racing tyres.

The rallycross tyres are real racing tyres, so they do have some good grip on the road. Though they overheat too quickly to be used in most situations on most of the road cars.

Scawen,

Thanks for taking the time to answer. That of course explains everything given the length of the races and the car concerned.

Gez

Quote from gezmoor :

for this level of straight line acceleration it's all about corner speed and for that you need maximum grip.

...which you get more from warm hyrbids than cold road tyres.

Quote from gezmoor :

Now whilst this does alow for the rear to drift out, and therefore give more oversteer, (and a quicker turn in), I have to question any in game physics where this is the fastest driving technique when IRL if this was the case all FWD race cars would use hybrid rear tyres for the same reason, which patently they do not !!

iirc the hybrids peak at a higher slip angle causing the "oversteer"

The hybrids provide more traction than the road_normals would, and heat up quicker, there fore you can have perfectly green hybrids or cold road_normals at the rear... But this more traction isn't really the root cause of the oversteer, you're most likely driving with a locked diff...
(Bear with me when I mix the terms up) By applying the same (engine) torque to both driven wheels, this diff basically applies torque at the yaw axis, causing the car to straighten out in the direction the driven tires are pointing and thus you're able to apply full throttle sooner...

Quote from bbman :

(Bear with me when I mix the terms up) By applying the same (engine) torque to both driven wheels, this diff basically applies torque at the yaw axis, causing the car to straighten out in the direction the driven tires are pointing and thus you're able to apply full throttle sooner...

This is theory. in LFS reality, locked diffs work like this:
No throttle to neutral throttle: (car is decelerating) --> MAJOR understeer.
More than neutral throttle: (Car is accelerating) --> High Oversteer.
(on both FWD and RWD cars)
This is cause the outside wheel starts slipping, while the inside one is gripping. The slipping outside wheel tries to make the axis rotate on itself, towards the inside. Thus the outside wheel is burning rubber to help you turn.

It ISNT supposed to work like this - I've driven a car with a broken diff (dont ask me how, but the driver managed to make the diff become a solid ball of metal), and it was completely locked. Besides making slow-speed manouvering (like parking) a nightmare of stalling the car, the car just wouldnt turn at all if I took any bend at a more brisk pace. Even with full throttle down. Full throttle just made the outside wheel start slipping, and slipping and slipping loosing all grip and the car would just slide forwards. For some reason (dunno why), the steering was also quite heavier.
Scawen, pls pls PLS correct the locked diff in lfs,

I thought the locked diff works correctly in LFS but the tyres themselves are too forgiving. Thus you get less - and not so pronounced - negative attributes from a locked diff than you'd get in real life.

Also I recall real life racers noting that locked diffs have been used in many racing series throughout the years.

Ive been racking my brains to wonder why oversteer in lfs is relativly easy to use (as a style), and then something occured to me the other day, i have never been off the track backwards due to oversteer, only sideways even locking the rears in a hairpin, due to my outstanding superhuman control?, i doubt it

In summary in think understeer in lfs feels natural but oversteer does not, therefore wierd rear end setups become faster than they should be.

BTW ive got an imaginary degree in physics and i had a dream i won a grand prix therfore im fully qualified to make these statements

Simon

Quote from FlintFredstone :

BTW ive got an imaginary degree in physics and i had a dream i won a grand prix therfore im fully qualified to make these statements

LOL I think that would fit quite a few folks around here including myself

Quote from FlintFredstone :

i have never been off the track backwards due to oversteer, only sideways even locking the rears in a hairpin

Although you meant it as a tongue-in-cheek comment: The thing that always confused me initially when having oversteer was, due to lack of feeling the weight transfer (by means of forces on the steering column or visual cues) on stiff ARB setups, predicting the snap when grip returned for an instant and then the slip angle was exceeded in the opposite direction. It made sense though when viewing it in a replay from an external cam - just lack of sensation when in-car.

most front wheel drive racing cars, use a smaller rim on the rear to help stabilize the car, thats what this does, becasue u cant change rim/ tyre width, you have to use a different compund tire to suit ur style

Quote from Stigpt :

well, IRL usually small GTI- type cars DONT have a rear antiroll bar

From Renault brochure about Clio mk2:

Antiroll bar (mm)spaceFrontspaceRear

1.2 8vspa60bhpspacesp22spacesnone

1.2 16vsp75bhpspacesp22spacesnone

1.4 16vsp98bhpspacesp24spaces19,3

2.0 16vs172bhpspacesp25spaces22

1.5 dCi 65/80bhpspaces24spaces19,3

Refering to this XFG can have both antiroll bars for sure.
UF1 seems to be ok too, comparing to Fiat Uno which has none atiroll bars with nearly same weight, power and engine capacity. It had front a.roll only with 1.4, diesel or turbo versions.

If you ask me, I don't feel good (rather scaried!)when dynamic driving with winter tires on a dry tarmac. And winter tires has also soft compound and deep tread for loose surfaces, just like hybrids.

Maybe hybrid tires are good for mechanical-flying-smooth-hotlapping, but not for racing battle. And LFS physics should wreck (on that tree, cutted from Blackwood chicane) those cheaters!
FIA should take care about lfs servers and do somthing with this.

Another note. You'll find different tire widths used in real life as well, wider in front for fwd cases. Changing tire/wheel sizes is not something currently implemented in LFS as a normal feature. Changing to different tires can provide different grip characteristics. Similar goes for camber as a person can run excessive camber angles to limit or maximize the contact patch. Air pressures too influence tire and car behavior.

The physics of LFS is quite good, more so than you initially realize. However, like Scawen said, it is generalized. There's only a certain level of detail that can be implemented with so much work. I'd personally love to see an expansion of surface types as well as tire compound and tread choices more akin to what is experienced and is available in real life, but I wouldn't expect such a level within LFS at this time in development.

Quote from Stigpt :

For some reason (dunno why), the steering was also quite heavier.

What happens to the front wheels when you turn the steering wheel? Do a little dry steering and you will note this:

If you turn the wheel left, the left tire wants to roll backwards a bit whilst the right tire wants to roll fowards a bit (of course, this is dependant on suspension geometry). The opposite is of course true when you turn the wheel to the right. So, quite simply the tires want to do different things when you turn the steering wheel and the locked diff does not permit that.

When the car is actually in motion, this still holds true but at that point there's also the fact that since the tires want to travel different distances around the corner, you're fighting the diff on that as well.

Quote from FlintFredstone :

Ive been racking my brains to wonder why oversteer in lfs is relativly easy to use (as a style), and then something occured to me the other day, i have never been off the track backwards due to oversteer, only sideways even locking the rears in a hairpin, due to my outstanding superhuman control?, i doubt it

I've been autoxing for a couple of years and done a couple of hundred runs at least in RWD cars, and had plenty of oversteer but I've never spun a car in autox in real life (including a 911 GT3 on slicks in the rain ). As long as you have a feel for correcting oversteer you should be able to avoid spinning. You may lose a lot of time by sliding sideways but hopefully you can avoid spinning.

so it is the case of maximum lock?

the physics are good, afterall this is a sim where even 'tank slap' of petrol sloshing about is moddled (although race cars usually have baffles in the tank but no matter...).

However there are some short comings, firstly tyre temperature should fluctuate far more than it does now, which currently seems to be a gradual rise. This may represent the average temperaure of the tyre, but in my experience tyre have a much greater fluctuation in temperature than LFS models.

Also atmospherics are a huge factor in racing. Racing the same car and class most drivers will be constantly adjusting their setups to allow for changing track temperature through the day. Track surface has more effect on grip than any other single factor in motorsports, and currently all sims treat the conditions pretty much as static.

My car/track setup from my last visit to a track would last as long as it took to unpack everything, followed by adjustments made by observation and guessing, then the initiation run... If I get the setup good after that run I can have a productive day, otherwise I'm chasing setup half the day. Even if I raced there 20 times before.

Yet unmoddled...

Quote from Becky Rose :

My car/track setup from my last visit to a track would last as long as it took to unpack everything,

What cars did you used to race? You've said before that you did a few seasons in karts - did you race cars too?