Blackwood GTI World record unrealistic

[DEVIL 007]

Hi all,

I just come back after a few weeks back to LFS and looked at fmy favourite combination of BL + GTI.I downloaded top time and tried the car and then realize that:eek: .

How can car makes faster times on hybrid tyres then on road normal???!!!
With higher and more complicated pattern you couldnt achive in real life faster times.For me it seems like a huge bug in physical model.I am getting a bit confused from that as it really shoot to my eyes :-(

I dont want to start flame about this as I know Scawen made till now great work but this is really odd.Hope some serious dïscussion will show below.

[[RCG]Boosted]

there r few threads bout that already, use search function first next time ;)
to topic, like in other threads said its realistic. hybrids are softer = more grip = faster turns.

[csimpok]

Some serious discussions were made below.

http://www.lfsforum.net/showthread.php?t=2830
http://www.lfsforum.net/showthread.php?t=2500

[DEVIL 007]

Boosted']there r few threads bout that already, use search function first next time ;)
to topic, like in other threads said its realistic. hybrids are softer = more grip = faster turns.

Its not only about softness but about the pattern on the tyre.You have on hybrid tyre less touching area with road so less grip then with road normal.THATS realistic.

Hybrid have more grip on dirty track due to pattern.So how they can do better on normal track then road normal tyres.

Sorry for not using search function.I just cam back after a weeks to LFS...still not having much time so I just tried as described above.

[bLaCk VaMpIrE]

i dont know if you had physics already at school, because you would have learnt, that the size of the touching area is more or less not important to the grip. rather the weight on one tyre and how good the material fixes to the ground.
if you would also compare the 2 profiles of the tyre, you would see, that there are no big diffrences.
in a whole that means:
you know already that hybrid-tires are softer and weight and profile of the tyres are almost the same. that all leads to more grip.

[keiran]

Also with the tyre pattern it will move around more generating more heat quicker.

Keiran

[mrbogeyman]

so they are better to a point, but i think it has been pointed out already that they are unlikely to last anywhere near as long as road super tyres.

[Bob Smith]

In my tests ages ago I found Hybrid tyres to pull the same G forces as Road Normal tyres. It is entirely possible they are actually slightly stickier. But as was mentioned before they will only last a couple of laps so nobody uses them for racing on the front. On the rears however is supposed to be good...

I think it's also important to remember that I don't think a single WR set will last for many laps anyway since they are all so aggresively set up for performance at all cost (even driveability).

[AndroidXP]

Yeah, Bob's right, WR laps are all nice and dandy, but they don't mean a damn thing to real racing. The only place where they could be useful is qualifying, but even then these setups are too extreme, IMO.

And as I said in some other thread, why should the hybrids have less grip on tarmac? They are the same as normals but with softer rubber and a different tread. They don't have the magic rallyx ingredient that makes them super good on mud and sucky on tarmac. Also many people seem to forget that road normals aren't designed to give extremely good grip but rather to last long. See: winter (hybrid) and summer (normal) tyres. Former grip better but aren't as lasting.

[--==Gogo==--]

So what are your best times with a race-setup that lasts at least for 30 laps ob Blackwood in the GTI?

I managed a 1:32.98x once.

[[RCG]Boosted]

my best time(s) with 4 normal are 1:32.60-70.
with hybrids in back i get about 1:32.40's
and my normal tire set allows me at least 25 rounds. with hybrids u wont drive that distance.

[csimpok]

1:31:65 is possible (from my best splits) with a normal front-hybrid back set too which should be good for 30 laps. Normal-normal pb is 31:88.

[Theafro]

There is one thing i do like about Hybrid rears is the even buildup of heat across all four tyres, it means you can really plan to use the rear of the car for weight transfer early on and consistantly throughout the distance but under race conditions mine only really go 17-18 laps:D

[axus]

Are world records with the gti on other tracks done with hybrid tyres too?

[ajp71]

Might be useful to point out to the doubters that single seaters that are mainly used for racing will occasionally be hillclimbed with wets, they give more grip and save the expense of hillclimb tires for occasional use.

[Whisper]

i dont know if you had physics already at school, because you would have learnt, that the size of the touching area is more or less not important to the grip. rather the weight on one tyre and how good the material fixes to the ground.


But doesn't bigger contact patch offer more grip? I thought that's why they used slicks for high-end racing. You know, the bigger the sticky area, the more it sticks. And the weight on the tire is the same, because you're racing the same car. The grooves on the tire surfaces are meant to maximize grip off road and help water escape from under the tire in the rain, if it weren't for that, all cars would have slicks, because more contact patch = more grip.

Hybrids would have to be a lot stickier than road supers to compensate for the holes between teeth. I guess they are, if they wear so fast.

[ajp71]

They will be even stickier than racing wets, which will be quicker than normal slicks over short distances.

[jtw62074]

i dont know if you had physics already at school, because you would have learnt, that the size of the touching area is more or less not important to the grip. rather the weight on one tyre and how good the material fixes to the ground.

That's essentially true for two hard materials pressed together, but rubber works quite differently. Rubber grip is highly dependent on contact pressure and contact area.

[Scirocco]

But doesn't bigger contact patch offer more grip? I thought that's why they used slicks for high-end racing.
Yes, but the hybrid tires and slicks are made out of different compounds with different grip characteristics.

The grooves on the tire surfaces are meant to maximize grip off road and help water escape from under the tire in the rain, if it weren't for that, all cars would have slicks, because more contact patch = more grip.
Not exactly. Don't you think that your traction would be compromised whenever you went over other items such as sand and dirt?

[GTR_Yuni]

Not exactly. Don't you think that your traction would be compromised whenever you went over other items such as sand and dirt?
I think he was assuming the surface being driven at hand was tarmac.

[Scirocco]

I think he was assuming the surface being driven at hand was tarmac.
:scratchch So was I. You must live somewhere where all the roads are constantly swept clean of any dirt, sand and any other types of debris.

[joshdifabio]

They will be even stickier than racing wets, which will be quicker than normal slicks over short distances.

Hmm if wets are quicker over short distances how come people never use them irl for qualifying? Or do they..?

[joshdifabio]

I think it's also important to remember that I don't think a single WR set will last for many laps anyway since they are all so aggresively set up for performance at all cost (even driveability).

In the Vixen Challenge (formula XR league) a lot of us are using hotlapping sets in races. At ky national i used the wr set for 20 laps (100% fuel) and in a practice run, got all my laps bar 3 or 4 under 1 second off the wr (1:40.xx) which is quick there. In the formula xr it is certainly feasable at many circuits to use hotlapping sets over race distances.

[Whisper]

:scratchch So was I. You must live somewhere where all the roads are constantly swept clean of any dirt, sand and any other types of debris.

I don't see your point, but our roads are pretty clean.

[joshdifabio]

I don't see your point, but our roads are pretty clean.

Slicks lose most of their grip if they get a bit dirty.

[operator0]

Alright, I've seen a number postings about this. Most of what's been said in those posts is bunk. Some of it it is correct.

The point is we do not know what kind of compound the devs are trying to simulate. i doubt they even know. they have probably plugged in some numbers that appear to be proper, and they work for the game. In reality, the tire tire such as the hybrids probably only exists in the world of high dollar racing. Something like F1 and pro rallying. that being said, it is completely plausible to create a tire that shreds itself in a few laps but provides a huge amount of grip.



Real Life Evidence:

The only tire I know of that comes close to this is the Hoosier Dirt Stockers. These tires were originaly created to be used on dirt oval tracks. Their compound is very soft. Some bright guy decided to try them out on his BMW in a club race in 1999. It was raining very heavily. He lapped the entire feild and the tires managed to stay intact for the whole race. ever since then, these tires have been the prefered wet track tire in America. But, when these tires are used on damp tracks, they do not last more than 2 or 3 laps. They do provide more grip, even with their tread, on semi dry tracks, they just wont last. No one has ever tried to race them on a completely dry track. That being said, the time difference on semi dry tracks compared to those with both rain intermediates and slicks with treads hand cut into them is such that on a dry track the Dirt Stockers will still have more grip than even a full race slick that's been shaved. I have serious doubts abotu whether they could be used on the rear end of a FWD car and stay together for five laps. I don't think that's possible.

Again, going off of the above evidence, it is certainly possible for a tire manufacture to create a tire with a compound that's soft enough to provide that kind of grip and still last in a low load situation like being on the rear end of a FWD car.

[ajp71]

Hmm if wets are quicker over short distances how come people never use them irl for qualifying? Or do they..?

By short distances I mean 30 seconds, they'd simply overheat by the time you'd completed an outlap as well. Wet tires can only be used on a very wet track.

The reason wets can be so much quicker in hillclimbing than standard slicks is because they are normally free, whereas slicks are controlled in most race series, as there are basically no regulations governing hillclimb cars it's far cheaper to risk a set of wets for the odd hillclimb than it is to buy a set of super soft hillclimb tires that you can't use for racing.

[Whisper]

Slicks lose most of their grip if they get a bit dirty.

Isn't that mostly due to the compound and the dirt/sand sticking to it? If slicks were made out of the same compound that the regular street tires are, they'd probably lose no more grip on dirty tarmac as regular street tires do.

[Theafro]

wet's are used in hillclimbing over slicks, due to one fact, you get no real time to warm you're tyres up. maybe a quick burnout (and i mean quick, no drag style burns) and you're off, 'cause of the treads on wet tyres, they heat up very quickly in the dry an the soft compound will start to work almost immediately.

Hybrid tyres are for me, just a plain ol' cut-slick (as used in rallycross for decades) of a faily soft compound and arn't something to be afraid of. hybrid rears can last for 20-25 laps dependind on brake bias. that seems about right to me.

colway make some similar tyres on remoulds, and from personal experience i can say WOW, they don't half stick, BUT they only lasted 600 miles of abuse on the front and about 2000miles on the rear (pug205) try 'em for yourself (there still just about legal in the uk.:thumb:)

[ajp71]

wet's are used in hillclimbing over slicks, due to one fact, you get no real time to warm you're tyres up. maybe a quick burnout (and i mean quick, no drag style burns) and you're off, 'cause of the treads on wet tyres, they heat up very quickly in the dry an the soft compound will start to work almost immediately.


They won't ever be as fast as hillclimb tires, which are a similar ridiculously soft compound on a full slick, but hillclimb tires aren't cheap for the odd run and are no use in the wet.

[skiingman]

i dont know if you had physics already at school, because you would have learnt, that the size of the touching area is more or less not important to the grip. rather the weight on one tyre and how good the material fixes to the ground.
.

This is the danger of taking what your physics prof says about a CONCEPT and applying it to the real world.

In real life, it doesn't work the way you just assumed it does. More area will always be better because the forces involved aren't as simple as ideal friction.

[Theafro]

yeah, more variables than you'd ever think possible

the tyre model is (many will disagree) pretty damn solid, and each of the tyres have they're own merits, you just gotta pick the right one for the job.