1.09 update physics changes....

[oppositelock]

Idk lol, common sense? put your toes in and bend upfront, then do the same with your toes out, what's more stable? toe-out obviously... why would toe-out in the front help with stability and toe-in in the rear too, makes no sense to me. Toe out on both does, no?

Er, I only understood about half of that, but that's a pretty terrible analogy. Instead, imagine being on roller skates while being towed behind a bicycle. With your toes pointed inward you'll still track directly behind the bike. With your toes pointed outward, your legs will wander all over the place and you'll zig zag down the street. That's more or less how toe works.

 

[Lionheart2113]

Try your toe theory wearing ski's. I understand your thinking and you are right to a degree but its about the direction of travel of each wheel rather than the vertical stability.
The intersecting lines of thrust mean that with toe in the rear of the car is opposing itself during rotation and forward motion.
With toe out you can get the same cancelling effect in a straight line but during rotation when the rear tyre is loaded it can cause instability due to the direction the wheel wants to travel.

I was always under the impression that toe out on the front is to help reduce understeer. It causes the inside tire to drag when unloaded and snaps the car around. Similar to hooking the inside tire on the line in NASCAR. Or is my thinking why I only keep getting 3rd place finishes in the FITT challenges??

 

[meek]

Well @GTP_CargoRatt, I'm not so sure anymore haha, maybe it works in GT6 the opposite of how it should, like ride height?

In real life:

The alignment of the wheels of a car can help to change the handling properties of the vehicle. A toe in alignment of the wheels can help to reduce over steer problems and can increase stability in vehicles that have front-wheel drives. Alternately, a toe out alignment can help to mitigate issues related to under steering and can improve the handling on a vehicle that has a rear-wheel drive. The actual amount of the angle that the toe is adjusted for each wheel is incredibly small and is sometimes measured in fractions of a single degree.

Interesting bolded part, and confirms my thoughts @oppositelock, +0.60° rear toe on almost every car is ludicrous! especially considering the following:

Interaction with Camber

When a wheel is set up to have some camber angle, the interaction between the tire and road surface causes the wheel to tend to want to roll in a curve, as if it were part of a conical surface (camber thrust). This tendency to turn increases the rolling resistance as well as increasing tire wear. A small degree of toe (toe-out for negative camber, toe-in for positive camber) will cancel this turning tendency, reducing wear and rolling resistance.

http://www.gilisautomotive.com/gilis-autoblog/wheel-alignment-toe-in-vs-toe-out.html
http://en.wikipedia.org/wiki/Toe_(automotive)
http://www.240edge.com/performance/tuning-toe.html

(Front) toe-in on FWD & RWD = more stable but understeering, can help correct some oversteering.

Toe-out helps with steering and tire wear at the cost of straight line stability. Works best with negative camber.

@DolHaus
I like your ski example, the rest is a bit too complicated to me, sorry.

Er, I only understood about half of that, but that's a pretty terrible analogy. Instead, imagine being on roller skates while being towed behind a bicycle. With your toes pointed inward you'll still track directly behind the bike. With your toes pointed outward, your legs will wander all over the place and you'll zig zag down the street. That's more or less how toe works.

that's an even worse analogy lol (wheels are stuck to a car and cannot separate or cross, you wouldn't zig-zag with toe-out behind a bicycle, you'd tear your groins, and with toe-in you'd fall), but I admit I'm seeing this wrong, between IRL and settings that worked in game for me (hence me asking if the in-game description was broken)

 

[Lambob]

Awwww my head hurts.

then take the camber off. works for my headache

 

[GTP_CargoRatt]

Well @GTP_CargoRatt, I'm not so sure anymore haha, maybe it works in GT6 the opposite of how it should, like ride height?

In real life:

The alignment of the wheels of a car can help to change the handling properties of the vehicle. A toe in alignment of the wheels can help to reduce over steer problems and can increase stability in vehicles that have front-wheel drives. Alternately, a toe out alignment can help to mitigate issues related to under steering and can improve the handling on a vehicle that has a rear-wheel drive. The actual amount of the angle that the toe is adjusted for each wheel is incredibly small and is sometimes measured in fractions of a single degree.

Interesting bolded part, and confirms my thoughts @oppositelock, +0.60° rear toe on almost every car is ludicrous! especially considering the following:

Interaction with Camber

When a wheel is set up to have some camber angle, the interaction between the tire and road surface causes the wheel to tend to want to roll in a curve, as if it were part of a conical surface (camber thrust). This tendency to turn increases the rolling resistance as well as increasing tire wear. A small degree of toe (toe-out for negative camber, toe-in for positive camber) will cancel this turning tendency, reducing wear and rolling resistance.

http://www.gilisautomotive.com/gilis-autoblog/wheel-alignment-toe-in-vs-toe-out.html
http://en.wikipedia.org/wiki/Toe_(automotive)
http://www.240edge.com/performance/tuning-toe.html

(Front) toe-in on FWD & RWD = more stable but understeering, can help correct some oversteering.

Toe-out helps with steering and tire wear at the cost of straight line stability. Works best with negative camber.

@DolHaus
I like your ski example, the rest is a bit too complicated to me, sorry.


that's an even worse analogy lol (wheels are stuck to a car and cannot separate or cross, you wouldn't zig-zag with toe-out behind a bicycle, you'd tear your groins, and with toe-in you'd fall), but I admit I'm seeing this wrong, between IRL and settings that worked in game for me (hence me asking if the in-game description was broken)

In all seriousness, I find that it just depends on the car and tuning style of the tuner. Some use toe-in with good results, some use toe-out. Just depends on how you have tuned the rest of the car.

 

[Ian_83]

It's also dependent upon the driving style too. I can deal with understeer far better than some, so a slightly understeer setup is something which I can still set reasonable lap times with...it's all about the corner entry.

One tune does not work for everyone.

A guy that I race with regularly doesn't always adopt the same tune as myself, we can be in the same car but arguing over which tune is better. The answer is quite simply 'the one which you can set the lowest most consistent lap times with'.

Comparing real life to Gran Tursimo 6 is like comparing ice cream and vinegar. They are two distinctly different things. GT tries to copy real life physics, but when has it ever been correct?

 

[Lionheart2113]

Comparing real life to Gran Tursimo 6 is like comparing ice cream and vinegar. They are two distinctly different things. GT tries to copy real life physics, but when has it ever been correct?

The wheels are round...for the most part! But you are right, that is one of the great things about racing, tunes, and setups, they can be different in their own right and still end up with fast drivers and cars.

 

[DolHaus]

I was always under the impression that toe out on the front is to help reduce understeer. It causes the inside tire to drag when unloaded and snaps the car around. Similar to hooking the inside tire on the line in NASCAR. Or is my thinking why I only keep getting 3rd place finishes in the FITT challenges??

Sorry, I was talking about rear toe in my example.

Front toe out will give you a more aggressive initial turn in but will cost you front end grip mid corner
Front toe in means that you will have a less aggressive turn in but increased front end grip during mid corner.

Rear toe in will stabilise the car in a straight line and cause understeer during cornering
Rear toe out will stabilise the car in a straight line and encourage rotation during cornering.


Both forms of toe have their different pros and cons at either end of the car and there is no right or wrong. Cars coming with toe in at the rear as standard is completely normal as it is the safer option. The amount of extra toe in this update has thrown on seems a bit extreme but I'm sure there is a reason.

 

[mustangxr]

Sorry, I was talking about rear toe in my example.

Front toe out will give you a more aggressive initial turn in but will cost you front end grip mid corner
Front toe in means that you will have a less aggressive turn in but increased front end grip during mid corner.

Rear toe in will stabilise the car in a straight line and cause understeer during cornering
Rear toe out will stabilise the car in a straight line and encourage rotation during cornering.


Both forms of toe have their different pros and cons at either end of the car and there is no right or wrong. Cars coming with toe in at the rear as standard is completely normal as it is the safer option. The amount of extra toe in this update has thrown on seems a bit extreme but I'm sure there is a reason.

Well, I thank you for your cogent explanation Dolhaus,

I did some "trying out the new Physics racing " today and the results were very interesting. Somebody stop me if you find this boring!
I went back to the Suzuka 600pp "A Spec" race today with my trusty NSX-R LM prototype road car. First of all I ran it with what I thought it should have for Camber F 2.5 R 0.8. I won with some difficulty and ran all laps in about 10:42 with a few excursions (being pushed off the track by that damn SLR McLaren)

Then I loaded the new default suspension page and ran it as published with lots of rear camber and 0.60 positive rear toe.
I was very surprised to find this combo worked like a damn!! I had loaded the default LSD settings too. The end result was that I had better front grip with better turn-in and the rear rotated effortlessly. All my laps ran around 2:01 and my 5 lap total time was the lowest yet....10:34. So, I'm happy to report that the car was better than acceptable right out of the box. Oh, and I removed the front ballast also before my default runs to be totally fair to the published tune. (I was running an Arrakis tune.) I did run more downforce than stock,... 340 front and 545 rear.

Full of optimism about the new regime I went to the Rome circuit in "A Spec" with the Lotus 111R and ran the stock tune there again with no ballast from my Praiano Tune. With a quirky car like this I figured that it would be a good test.
Once again, the car performed quite well with a little soft pedalling in the corners. But that was true for all my Lotus tunes. I won handily and did it again to be sure I wasn't imagining things!

OK, so what next? Ahhh, the Lancia Stratos of course! Once again I loaded the stock default suspension stuff and LSD settings and off we charged. And spun, and spun, and spun, going into the first sweeper after the start straight. I abandoned this try and added the ballast back in and it was OK, but like walking a tightrope in the corners. I could feel the ass end in the wheel and it felt like a PORCHE!! This car will need some serious tweaking.

ANYWAY 2 OUT OF 3 M/R cars is pretty good and I now feel optimistic that we are going to be having some fun again with this game/simulation.
Cheers, Mustangxr

 

[FordMKIVJ5]

That's because you're running zero camber, which creates way more drag.

The only thing that is going to slow you down in your setup in a straightline more than aero is 0 camber and toe in/out.

Toe in/out - yes. 0 camber - no.

The static contact patch is the same with more negative camber. The part of the tyre that initially contacts the road is much smaller but still has the same weight pressing down on it giving a higher pressure. This causes more significant deformation, creating a longer and narrower contact patch, but the area is the same. If anything the camber thrust induced by running a camber angle will increase the rolling resistance (though this is probably not modeled in GT).

 

[feydrautha]

So I was messing with my Aventador tune last night. Once I got the camber figured out the (2.4/1.0) the car is pretty well planted, but it had some wonderful oversteer before when you used the e-brake. Now that playfulness at the rear is gone. Can anyone confirm if this is due to the new physics for mr/rr?

Also it seems like 4wd's push a little more than they used to. At first I thought it was the diffs that needed adjusting, but no matter what I do, that push is still there. Anyone else experienced this?

 

[332i]

Toe in/out - yes. 0 camber - no.

The static contact patch is the same with more negative camber. The part of the tyre that initially contacts the road is much smaller but still has the same weight pressing down on it giving a higher pressure. This causes more significant deformation, creating a longer and narrower contact patch, but the area is the same. If anything the camber thrust induced by running a camber angle will increase the rolling resistance (though this is probably not modeled in GT).

Actually, when you zero camber, the pressure points are far less acute on the tire, but it is distributed relatively evenly now. Rather than having a portion of the tire receiving acute pressure and the rest receiving much less - the pressure is relatively balanced off with zero camber and there are no points receiving less than others, which means more of the tire is creating friction across the board. There are no hot spots on the tire, because the entire contact surface is hot. When you reduce the pressure on a majority of the contact patch, you can only create so much friction. It is hard to explain and easier to draw, which sounds silly, I know.

I suppose the easiest way to explain it is that, instead of creating a lot of friction with a narrow pressure point, you're creating a little less, but with a far wider pressure point and nowhere for the heat to disperse to, other than ambient air. There is nowhere for the heat to disperse right or left into the rest of the tire either with zero camber.

The static contact patch is not the same with more negative camber. I have an e36 track car on the driveway that begs to differ. It is clear between the front and rear and that the inner last inch if the tire has more mating surface to the groud than the outer inch. Haven't measured by how much, but enough to see it with the human eye.

 

[meek]

@332i
you're confusing friction and traction. The more the tire is in contact with the track, the better the traction, there's a reason Formula 1's don't use camber on their rear, driving wheels. Zero camber certainly doesn't add friction in straights.

 

[332i]

@332i
you're confusing friction and traction. The more the tire is in contact with the track, the better the traction, there's a reason Formula 1's don't use camber on their rear, driving wheels. Zero camber certainly doesn't add friction in straights.

Not going to have a dispute, but f1 cars do use a little camber in the rear. I am an avid raikkonen fan.

What you quoted was my response to drag, not traction.

Friction is resistance between two surfaces. Broader pressure point across a surface patch (tire) = more friction.

For reference, toe creates horizontal, aka lateral friction. Camber or lack there of affects longitudinal friction. Speaking on both in terms of going in a straight line.

 

[FordMKIVJ5]

Actually, when you zero camber, the pressure points are far less acute on the tire, but it is distributed relatively evenly now. Rather than having a portion of the tire receiving acute pressure and the rest receiving much less - the pressure is relatively balanced off with zero camber and there are no points receiving less than others, which means more of the tire is creating friction across the board. There are no hot spots on the tire, because the entire contact surface is hot. When you reduce the pressure on a majority of the contact patch, you can only create so much friction. It is hard to explain and easier to draw, which sounds silly, I know.

I suppose the easiest way to explain it is that, instead of creating a lot of friction with a narrow pressure point, you're creating a little less, but with a far wider pressure point and nowhere for the heat to disperse to, other than ambient air. There is nowhere for the heat to disperse right or left into the rest of the tire either with zero camber.

The static contact patch is not the same with more negative camber. I have an e36 track car on the driveway that begs to differ. It is clear between the front and rear and that the inner last inch if the tire has more mating surface to the groud than the outer inch. Haven't measured by how much, but enough to see it with the human eye.

The bold bit doesn't relate at all to what I said.

In a straight line though the heat dissipation won't affect the top speed. In fact, if negative camber gives a greater cooling effect as you say then that would surely give lower tyre pressures, which again create more rolling resistance.

And presumably your front tyre pressures are higher than your rear ones? Therefore they would deform less.

 

[332i]

The bold bit doesn't relate at all to what I said.

In a straight line though the heat dissipation won't affect the top speed. In fact, if negative camber gives a greater cooling effect as you say then that would surely give lower tyre pressures, which again create more rolling resistance.

And presumably your front tyre pressures are higher than your rear ones? Therefore they would deform less.

Front tire pressures higher than the rear??? Umm... I'm not even going to get into the bolded part not applying either...but, since we're talking things that don't even appy to GT yet...anyone with half a brain on a real circuit in a real car is adjusting their pressures with expansion and contraction in mind. Example - the higher tiers you go up the ladder in racing, the finer the tire pressure adjustments. The 2013 and 2014 F1 teams are adjusting by quarters of a lb for example, because the air inside expands outrageously. Pirelli put insane amounts of money into researching this stuff beyond anyone else. Watch some thermal imaging footage from recently that FOM has been putting on the cars. Heat dissipation will certainly affect top speeds. A tire set to the correct pressure, will undoubtedly produce a higher top speed in the same situation as one that is either building heat or not dumping it. A hotter tire is softer. Assuming the tire is not overheating, merely hot which renders it softer than when it is of lower temps = less drag, because a hotter, softer tire is stickier than a cold, hard tire.

Either way, I've done a little racing in my life and know a thing or two about physics. You don't have to agree with me.

 

[FordMKIVJ5]

Front tire pressures higher than the rear??? Umm... I'm not even going to get into the bolded part not applying either...but, since we're talking things that don't even appy to GT yet...anyone with half a brain on a real circuit in a real car is adjusting their pressures with expansion and contraction in mind. Example - the higher tiers you go up the ladder in racing, the finer the tire pressure adjustments. The 2013 and 2014 F1 teams are adjusting by quarters of a lb for example, because the air inside expands outrageously. Pirelli put insane amounts of money into researching this stuff beyond anyone else. Watch some thermal imaging footage from recently that FOM has been putting on the cars. Heat dissipation will certainly affect top speeds. A tire set to the correct pressure, will undoubtedly produce a higher top speed in the same situation as one that is either building heat or not dumping it. A hotter tire is softer. Assuming the tire is not overheating, merely hot which renders it softer than when it is of lower temps = less drag, because a hotter, softer tire is stickier than a cold, hard tire.

Either way, I've done a little racing in my life and know a thing or two about physics. You don't have to agree with me.

It was a question. A lot of people run higher front pressures in the pursuit of better rotation.

It doesn't really apply, all you said is that the zero camber tyre has a lower pressure acting on it which spreads the weight more evenly over the tyre and gives a more even distribution of friction. Yes. But that is the same as what I said. The contact patch is more or less the same and the friction is more or less the same. So the rolling resistance is unaffected.

Yes of course tyre pressures and their expansion and contraction are important on the track. I don't see where I said anything to contradict that? And with regards to top speed the expansion of the circumference of the tyre under heat would affect it somewhat.

Why would a softer stickier tyre give less drag?

 

[332i]

That was a typo. More heat = more drag. You're making assumptions when it comes to heat, friction and drag and I do not know what you're basing these on. I don't have the energy for this. No matter what, 0 camber will result in higher tire temps in a straight line (and even worse heat absorbtion within turns because the entire tire is heating and rapidly), which makes them softer, which produces more drag. As I said, you're welcome to disagree and this is becoming rhetorical.
It is tough to describe these things without writing pages.
As I said, watch some thermal cams of a lap around a track. Part of the comparison problem you will find is almost no one runs zero camber on race cars anymore with aero advancements that we been given. So, you're probably not going to find many thermals of a 0 camber tire.

This stuff gets complicated and unless you have a decent understanding of physics pertaining to friction and fluid dynamics, this is not worth discussing here. Ask yourself why drag cars nearly use rubber bands for tires up front.

If you run 0 camber, your sway bars have to be as stiff as a board and you need a ridiculously soft suspension to allow the suspension geometry to compress and create any sort of negative camber as the wheel retracts up into the tire well. I don't know if that is even modelled into gt6 yet.

 

[Lionheart2113]

Rear toe out will stabilise the car in a straight line and encourage rotation during cornering.

I try staying away from rear toe out unless in an FF, and even that is a last ditch effort to reduce the understeer, but only if my fail safe transmission setup doesn't do it. Too much rotation on a RD, but it helps with my drift setups!

 

[DolHaus]

I try staying away from rear toe out unless in an FF, and even that is a last ditch effort to reduce the understeer, but only if my fail safe transmission setup doesn't do it. Too much rotation on a RD, but it helps with my drift setups!

Yeah FFs and maybe 4WDs are the only cars that I'd ever really use rear toe out, RWD has easier and safer ways of aiding rotation. I tend to stay around 0.16 with drift setups, I find it strikes a nice balance between rotation and over rotation so you can just hold the throttle and concentrate on steering.
You should give my '88 Supra a spin, pretty happy with how that thing drives. Its my first drift tune since the update so its nice to play with working camber again, really helps with balancing the car
https://www.gtplanet.net/forum/thre...accepting-requests.301978/page-6#post-9795995

 

[Lionheart2113]

Yeah FFs and maybe 4WDs are the only cars that I'd ever really use rear toe out, RWD has easier and safer ways of aiding rotation. I tend to stay around 0.16 with drift setups, I find it strikes a nice balance between rotation and over rotation so you can just hold the throttle and concentrate on steering.
You should give my '88 Supra a spin, pretty happy with how that thing drives. Its my first drift tune since the update so its nice to play with working camber again, really helps with balancing the car
https://www.gtplanet.net/forum/thre...accepting-requests.301978/page-6#post-9795995

499pp on Comfort/Hard? I don't go that far down the tire selection unless it's 375pp or lower! You are insane, can't wait to try it!

 

[DolHaus]

499pp on Comfort/Hard? I don't go that far down the tire selection unless it's 375pp or lower! You are insane, can't wait to try it!

Comfort Hards are my standard drift tyre, I don't tend to use anything softer unless the car has a lot of weight and/or power (600+). If you've not got much grip to begin with then you need less power to break traction, if you've got less power then things happen more gently and you have more time to adjust. I like my cars like I like my women... Easy lol

 

[FordMKIVJ5]

That was a typo. More heat = more drag. You're making assumptions when it comes to heat, friction and drag and I do not know what you're basing these on. I don't have the energy for this. No matter what, 0 camber will result in higher tire temps in a straight line (and even worse heat absorbtion within turns because the entire tire is heating and rapidly), which makes them softer, which produces more drag. As I said, you're welcome to disagree and this is becoming rhetorical.
It is tough to describe these things without writing pages.
As I said, watch some thermal cams of a lap around a track. Part of the comparison problem you will find is almost no one runs zero camber on race cars anymore with aero advancements that we been given. So, you're probably not going to find many thermals of a 0 camber tire.

This stuff gets complicated and unless you have a decent understanding of physics pertaining to friction and fluid dynamics, this is not worth discussing here. Ask yourself why drag cars nearly use rubber bands for tires up front.

If you run 0 camber, your sway bars have to be as stiff as a board and you need a ridiculously soft suspension to allow the suspension geometry to compress and create any sort of negative camber as the wheel retracts up into the tire well. I don't know if that is even modelled into gt6 yet.

Ok, what assumptions am I making? I don't think I've made any assumptions.

I fail to see how when a car is reaching its top speed having 0 camber will give significantly higher tyre temperatures than with an amount of camber. Sure I can see that having camber will allow the tyre to absorb and lose heat quicker, but reaching top speed the tyres (with and without camber) will be 'cold' and any temp. difference negligible.

Drag cars run skinny tyres up front because they are light and lower the rotating mass. Not because they have lower rolling resistance.


And please don't patronise me. You still haven't given me clear answer as to why camber increases top speed, other than that 0 camber decreases cooling efficiency, which as I say, in the time taken to reach V-max,is practically irrelevant.

 

[Motor City Hami]

@GTP_CargoRatt what car are we playing with first?

@DolHaus do you want in on some of this joint action?

 

[DolHaus]

@GTP_CargoRatt what car are we playing with first?

@DolHaus do you want in on some of this joint action?

Always keen 👍

 

[GTP_CargoRatt]

@GTP_CargoRatt what car are we playing with first?

@DolHaus do you want in on some of this joint action?

Hey Keith, I've got a massive headache right now so I'm getting ready to lay down for an hour or so, but the car I was going to start with is the '69 Camaro SS tuned to 500pp on stock tires unless you have a better idea, doesn't matter to me. Let me know and I'll meet up with you guys in an hour or so. Peace.

 

[Zenmervolt]

I can't claim to be a great tuner (or even a good one), but from just generally playing around with the GT300 BRZ it really seems as though the adjustments are working much more as I would expect them to. In the older physics I'd had it set up with 0.20 degrees of rear toe out because it just wasn't rotating for me no matter what I did to the front. Now with 2.5/0.8 camber and -0.20/0.0 toe it rotates wonderfully for me.

Hardly scientific, but right now I'm incredibly happy with the changes. It actually feels like the alignment settings react similarly to the way I expect them to based on my autocross and track experience in real life. I'm still rubbish with spring rates, ride heights, shock tuning and ARB tuning, but at least alignment finally seems to be doing what I expect it to do.

 

[mustangxr]

Good evening guys and gals,

I did some more testing today and the first car I chose was the 86GT Toyota, a very benign handling car to start with and a very balanced car.

I loaded the default settings for suspension and LSD then went to Rome at 500PP in the A Spec online series. I won every race for about 3 races running 1:18 laps.

I bumped up the power to 533 PP which was all I could get with the lightened car and ran it at Willow, A Spec I waxed them all at Willow running 1:20 there.

I tried it at Suzuka in the 650 PP class A Spec, but could only catch the Stradale . Too much power differential.

I abandoned that race but took the 86 to the Nordschliefe in a 650 PP National A race, a 3 lapper, and worked my way through the pack and was running second in the second lap. The lead car, the Fina McLaren let me catch up in the 3rd lap so I could draft it down the straight and the politely moved aside for me to pass just before the last turn over the bridge.
Anyway, I have to say the car was impressive running sport hard, sport soft, and race hard. I never changed anything except power, and final gear for all 4 race tracks. The transmission was already tightened up.
My Nordschliefe time was 7:11 with Race hard and one roll-over LOL

So, I have to say that the default settings are pretty good on F/R too.

I raced the Mazda 787B on the 24H Nurb for 24 minutes and won easily of course while chatting with a visiting friend. My times were not that impressive, over 8 minutes, but I wasn't focused.

I raced Le Mans with the Peugeot 905B and won that quite easily running race soft and 3:25 laps

All of the afore mentioned cars were run with the 1.09 default suspension and LSD settings with tweaked power, transmission, and aero settings. In the case of the race cars, 3.5 rear camber and 0.60 toe-out?!?!
For your information.

Cheers, Mustangxr

 

[332i]

Ok, what assumptions am I making? I don't think I've made any assumptions.

I fail to see how when a car is reaching its top speed having 0 camber will give significantly higher tyre temperatures than with an amount of camber. Sure I can see that having camber will allow the tyre to absorb and lose heat quicker, but reaching top speed the tyres (with and without camber) will be 'cold' and any temp. difference negligible.

Drag cars run skinny tyres up front because they are light and lower the rotating mass. Not because they have lower rolling resistance.


And please don't patronise me. You still haven't given me clear answer as to why camber increases top speed, other than that 0 camber decreases cooling efficiency, which as I say, in the time taken to reach V-max,is practically irrelevant.

No, my point has been friction and drag related to camber and how they impact drag. And how does higher pressure fronts over rears induce rotation?? I don't feel like sifting through your posts ITT, but I'll take an assumption from the post I've quoted: "cooling efficiency, as I say, in the time taken to reach V-max,is practically irrelevant". One, if you think it is 'practically' irrelevant, yet you think 0 camber does not increase overall tire temps. Do you think they would be the same?? But, back to the higher front tire pressures for a second (because the temperature stuff is clearly a dead end with you)...that would do the opposite of any sort of rotation, unless you're driving in reverse lol. That's a recipe for understeer. You could have all the front grip in the world and too much tire pressure could totally negate that. It won't induce throttle lift oversteer, it won't induce rotation on entry, exit and so on.

Dragsters don't use skinny/small tires up front, for less rotating mass. That's a biproduct. A happy accident. You're assuming the rotating mass is unsprung. It is purely to save mass in general. It is sprung mass, because they're connected to a suspensionless chassis. Not unsprung mass like on a road car or 99.99% of other race cars. If it was unsprung mass, then that would be a reason to reduce wheel weight just due to rotating mass. It is not because it is rotating mass. When it comes to sprung mass, wheel weight just increases pressure at the contact surfaces, which creates friction. Being sprung mass, that is the sole reason you want to reduce the wheel's weight - because of pressure on the ground. More weight, more pressure obviously. Nothing to do with it rotating, though...being sprung and not a drive wheel. The exact reasons are to reduce rolling resistance and reduce weight (not rotating mass - net weight). The rotating mass does not matter, because it is sprung, unlike an unsprung wheel attached to a suspension, which is attached to the body; the sprung mass. Rotating mass that is sprung is fine on wheel meant for steering (friction is friction/drag is drag/etc. They just need to yield as least drag as possible, both through aero resistances (yes, aero drag as well) and ground frictions. Of course the less the better for drive wheels. Do some reading before saying this stuff. A quick Google search will probably net you some feedback from drag racers.

Rolling resistance is the direct result of friction...you're walking yourself into punches. And my whole argument has been based around friction regarding camber levels and drag, not cooling efficiency (not sure what you've been reading if you think that has been my point all this time) although that has been discussed somewhat. Idk what you have been reading, but this is a joke. Anything I am saying can be looked up with ease, because it is simple physics and common knowledge in the racing/performance engineering world. Merely in the racing world itself. Doesn't take engineering and physics-geared minds to understand this these things. Not going to repeat myself anymore.

I will say it again and one last time: running camber over 0 camber will increase TOP speed results. Running camber begins to reduce contact patch slightly and it is also putting more pressure on a narrower part of the tire, because much of the tire has much lower pressure on the rest of it and the pressure has to shift somewhere. Less contact patch = less drag. Higher pressure on said patch = less drag. Less drag is a result of reduced friction. When you reduce friction, you reduce heat generation (just to include that minor point that you thought was my entire argument). I think we've covered all the bases, no? Do you still feel 0 camber creates less friction or however you think it won't affect top speed or do you need further explanation from Google or other sources of remedial information? You don't have to answer that.

If we're going to post information, let's do it accurately. We're not the only ones reading and learning.

 

[oppositelock]

But, back to the higher front tire pressures...that would do the opposite of any sort of rotation, unless you're driving in reverse lol. That's a recipe for understeer. You could have all the front grip in the world and too much tire pressure could totally negate that. It won't induce throttle lift oversteer, it won't induce rotation on entry, exit and so on.

This is false, in my personal experience, but the whole truth is that it really depends on the car along with other factors. In my autocross Focus I'm currently running 51 psi in front and 34 in the rear. This is mainly because of A) roughly 60/40 weight distribution combined with B) having MacPherson struts in front with Ford's "control blade" semi-trailing suspension in the rear. When the car leans, the rear gains camber while the front does not, and the outside front tire takes the brunt of the weight transfer. The end result that at the factory recommended pressure (32 psi) the front tire physically rolls over onto the sidewall while the rear tire stays planted, and you get grinding understeer. Increasing the front pressure prevents this, increases front grip, and allows increased rotation. However, a car with 50/50 weight distribution and double wishbones on each end could be a totally different story, so there is no hard and fast rule here.

Another thing to remember is that the relationship between cornering grip and tire pressure is a bell curve. For any given corner, there is one optimum tire pressure for each axle. Either increasing or decreasing the pressure from optimum will result in a loss of grip. If both tires are below optimum, increasing pressure on either axle will increase grip on that axle. Likewise, if both tires are over optimum then decreasing pressure has the same effect. But since most production cars leave the factory with pressures below optimum for reasons of ride comfort and safety, the former situation is far more common.

But I have no idea why I'm talking about tire pressure since it's not in GT anyway...