Hi

Here's the thing. I was on CLC server the other day, and at some point, I stopped on the side of the road. At this moment, some random guy comes on the side of my car and begins to poke it, then reverse about a meter, then poke my car again.

Anyway, I was on the handbrake because I didn't want to move, but I noticed that as he was poking my car, the tires were deforming side to side, which is normal, but it really seemed exagerated to me. I mean, if you take a car and poke it a bit with another car, the tires would not deform themselves so much, right?

I don't have a screenshot, but trust me, the tires were deforming alot as I was being poked by the other car, who was moving maybe 5 kph fast. I'd reckon it would be more the suspension's job to absorb that movement, not the tires themselves...?

And this applies to a bit anything in LFS, it's really great to see the tires deform, but sometimes it just seems a bit too much.

/discuss ^_^

hmmm i am not quite sure about this because suspension does not cope that much with sideways-movement. so if you poke a car from the side, the only thing that can move that much are the tires. but i really don't know how much and if it is apropriate in lfs.

i don't think the suspensions job is to deal with sideway movement of a car. it probably is fixed in that direction

Also if used typical race setup tire pressures would been quite low. Tires do flex quite some amount IRL too, text of my tires are scrubbed because of driving on track and that with 280kpa pressure.

Slick tires do not flex so much, at least IRL, but don't know about LFS.

Can't tell if effect is too much in LFS, if used normal tire pressures it is not so excessive after all.

i can see what you mean about the tyres deforming, but when you said if you do it to a real car, the tyres dont deform that much, that is most likely because....

1. your pushing the top of the car, which will obviously cause the car the suspension to take the force because your putting your energy to the top of the car or .....

2. a person can not really shift a car TOO much.

i think the reason the tyres moved so much is because the car that was "poking" you was taping your door in the centre, which is the obviously point of contact for a car as the front end meets up with the middle of the door, so thus, the energy of the car was pushing your car sideways, on which the suspension cannot absorb as the the suspension cannot go sideways, or not too much. also, dont forget that a car even travelling 5kph is still quite a strong force due to the weight, i think even the UF1000 weighs 600/700kg, which is still alot of force even if moving 5kph!

just my two cents, :twocents:


frenchy

3. A RL car would rather absorb the impact force than exagerate it (current collision detection)...

Forces would only be absorbed if there is deformation of the car, I'm not sure how much energy a thin metal body panel will absorb in a walking pace collision.

I wouldn't be surprised if any tyre model used in any racing sim ever will fall to pieces much below 10km/h, as it's designed to work at racing speeds. Also, many simulators have problems with 'stopped' cars, as can be shown by them 'floating' down hills with the brakes on, in neutral, pointing across the gradient.

However, a real car will have sidewall deformation too, but also suspension/bush deformation, body panel deformation etc etc, which LFS doesn't have (in quite the same way), so it's all in the tyres. I'm not surprised it's [the result I mean] magnified in LFS. If anything it's a bit strong at racing speeds, although not as strong as people seemed to think (until proven wrong with videos of real deformations).

Actually, in Don's tire deformation slowmo you can see it quite clearly. At least IMHO, it looks quite excessive.

This video shows tyre deformation of low profile performance tyre, I think most tires should deform more in LFS as profile is higher, but judge by yourselfs.

I've driven a 4x4 truck for the last 12 years or so, with 31 inch semi-offroad tires on it (BFG All-Terrains). I would run around 23 psi in the rear and 25 psi in the front. I was able to move my side mirror so that I could see the rear tire on my side. I can tell you, it takes very very little for the sidewall to deflect, with those tires and at that tire pressure. Just easing down the access road at work, which is quite smooth, I could see the tire deforming. When I hit a significant bump that allowed me to feel the suspension movement, it deflected a lot.

That's all with quite a large truck tire compared to a normal car tire....

I've always been of the impression that it isn't just tyre flex modeled in the tyre model in LFS. I could easily be wrong, but I've always thought that the tyre model actually is also a holding place for other flexes in LFS, while they're being developed in their own right - drivetrain and body flex for example. That's always been, to me, the reason the tyre flex was just a very tiny bit more than it might be.

Of course, I could have dreamed all this up, but that's always been my impression since April.

Here's another video of the tyre deformation of race-tyres.
http://www.youtube.com/watch?v ... ;mode=related&search=

Quote from JTbo :

Slick tires do not flex so much, at least IRL, but don't know about LFS.

Dunno if you've seen this, but they do, and quite a bit.

http://www.youtube.com/watch?v=ozdejs5GOxA

Quote from farcar :

Dunno if you've seen this, but they do, and quite a bit.

http://www.youtube.com/watch?v=ozdejs5GOxA

Yes they do flex, but not so much as street tires, which can be quite extreme because of softer sidewalls.

Quote from tristancliffe :

I wouldn't be surprised if any tyre model used in any racing sim ever will fall to pieces much below 10km/h, as it's designed to work at racing speeds. Also, many simulators have problems with 'stopped' cars, as can be shown by them 'floating' down hills with the brakes on, in neutral, pointing across the gradient.

thats something different though and i dont really see why a model wouldnt work correctly as long as the car is in motion

Quote from JTbo :

Yes they do flex, but not so much as street tires, which can be quite extreme because of softer sidewalls.

I thought it's the street tires that have reinforced sidewalls, whereas slicks just use thicker rubber...

I bought a set of new tyres recently for my 6cyl family car I checked out a few different brands and I can tell you the difference between the side wall softness of different brand tyres and price range is huge. it was one of the main determining factors in my purchase decision So are we comparing apples with apples or is it apples with peaches?

From what I've seen of RL footage of tyre deflection under race conditions and LFS tyre deflection under race conditions it looks pretty similar. If it appears to be at all excessive it's most likely due to the ability to run lower pressures in LFS than you would think of using in RL.

Quote from Glenn67 :

From what I've seen of RL footage of tyre deflection under race conditions and LFS tyre deflection under race conditions it looks pretty similar. If it appears to be at all excessive it's most likely due to the ability to run lower pressures in LFS than you would think of using in RL.

This is what I believe too

There certainly is also lot of difference in tires sidewall flexing between different tire brands and even tire versions. Also there is different types of slicks for different purpose. We have all seen slowmotions of F1 tires, very flexible

My question is why would anyone in thier Left mind race or do a track day with tires that are prone to excessive sidewall flex.

The cars in LFS may have accurate sidewall flex but they are the wrong dam tires for the application they are being used for.

Try having a look at some of last years bathurst videos. Under Craig lowndes's car they had a camera mounted under the suspension tower just so the viewers could see how much a tyre does actually move when put under the G forces of taking a corner at speed.

You'd acually be really suprised at how accurate LFS is with tyre deformation in cornering. Low speed not so much.

Find that footage!!

Quote from Unforgiven :

Try having a look at some of last years bathurst videos. Under Craig lowndes's car they had a camera mounted under the suspension tower just so the viewers could see how much a tyre does actually move when put under the G forces of taking a corner at speed.

Right here: http://www.youtube.com/watch?v=ozdejs5GOxA

Quote from Gimpster :

My question is why would anyone in thier Left mind race or do a track day with tires that are prone to excessive sidewall flex.

The cars in LFS may have accurate sidewall flex but they are the wrong dam tires for the application they are being used for.

Specifically?

Quote from Breizh :

Specifically?

He means get some better tires =P in RL the tires would not flex this easy if they were performance tires. I don't know honestly. I think they flex about right, it's the problem that everyone runs such low tire pressures bcause the sidewalls don't damage themselves. In RL you would be using street tires at almost 50PSI not 20-25 for sprint sets used in LFS

http://www.visionresearch.com/ ... =htm/app&page=gallery

Take a look at the Porsche at the bottom of the page

I think the drag link above it is also a good example. I was waiting on the damn thing shredding itself