Toe, Camber And Tigt3wdkocc

TOE, CAMBER AND TIGT3WDKOCC


Camber and toe are wheel/tire geometry settings. That is, they affect the relationship between the wheel/tire combo and the rest of the car. These are tough settings to get right in real life because they are dynamic by nature. That is, they change naturally as the suspension moves up and down through its range of motion. So when you adjust a car's camber or toe, you do so in its static state, i.e., Sitting in your garage with your alignment gear around it. Out on the road (or on a track), it changes as soon as you take a corner or hit a bump.

In real life, different cars' suspensions have very different characteristics. Old British sports cars like with swing axles are well known for making positive camber on the inside rear wheels under cornering. BMWs and Porsches, with their front MacPherson struts are known for their limited ability to make negative camber under load. Live axle cars like Mustangs and Camaros are often ridiculed for virtually uncontrollable rear geometry because a single bump upsets both rear tires instead of just one.

In GT3, these suspension characteristics are abstracted and we have no control over them. I call this TIGT3WDKOCC. That is..

Things In GT3 We Don't Know Or Can't Control. The developers have taken suspension geometry completely out of our hands in GT3. This means we really have very little information to go on when we try to decide what the best camber and toe settings are. We can only experiment.

As a general rule, increase the amount of negative camber to increase grip in cornering. Adding too much can reduce grip. Too much negative camber can also increase braking distances (very bad) and make the car twitchy or jittery. In addition, you should avoid positive camber settings, which have almost no redeeming values to a race car.

As a general rule, FRONT toe IN increases stability at speed. FRONT toe OUT can help the car turn-in quicker. I find most cars work well with just a tick of front toe-out.

As a general rule, REAR toe IN can reduce oversteer. REAR toe OUT can increase oversteer. I find most cars work well with neutral rear toe(that is ZERO rear toe) or with a slight toe out.

Remember that each car will react to static camber and toe settings differently. For example, a Ruf 3400S (Boxster) or BMW 328 can benefit a great deal from 3.5, maybe even 5 degrees of negative camber. This setting may be overkill for a Corvette C5R or Toyota GT-One, which should have plenty of capability to make negative camber under load. Tune carefully.

Correct adjustment will improve steering traction into medium to high-speed turns at the front wheels. Correct adjustment at the rear will improve rear-drive traction during and exiting the same turns. A severe angle will not affect straight-line speed, but it can decrease grip levels under acceleration and braking forces. Setting-up is a trade off between steering grip and straight-line traction.

A NOTE ON TIGT3WDKOCC
Ever wonder why GT doesn't let you change simple and rudimentary things like .. oh... Tire Pressure?? Or tire width and height? GT3 models tire wear and heat to a basic level, but doesn't give you access to important information like pyrometer readings --something that would make suspension tuning significantly easier. Obviously, the developers decided to leave them out for game play reasons... which leaves car buffs like us wonder just how the physics modeling works and what it takes into account.

I've found that any toe adjustment, except 0.0, will reduce the straightline speed.
I just did some laps in a Boxster at Test Course and it's top speed was:

174mph with 2.0
174mph with 1.5
175mph with 1.0
176mph with 0.5
177mph with 0.0
Settings were at both ends, 306hp/all other settings were defaults.
Toe-out gave the same results


Camber had no effect on top speed. (Separate test)

how much camber did you put on ODP?

Minimum to maximum, front and rear.

Did you have a semi racing suspension or something? I can't imagine a camber angle of 13 doesn't slow the car down at all.

Suspension / Full Customize
A "knee jerk" selection.

Somebody wrote, in a tuning guide, that excessive camber would reduce straightline speed.
I've always questioned that.
To me, it just didn't seem intuitive.
It might slow the car if the camber made the tire poke out of the bodywork and cause an increase in aero drag, but with less contact patch there would be less frictional loss. Though in the real world that reduced contact patch could make a wheel-driven vehicle spin the drive wheels when the aero drag reached a certain level (assuming there's enough HP). One thing's for sure, they would get mighty hot!

Anyway, the tests I ran showed no straightline speed loss due to camber.
Toe yes, camber no.

Nice work ODP. 👍

Thanks boom.
I was bored.
I have to work tomorrow and there's 4ft. of new.
I probably won't get to go 'til next week and it'll be ski'd out.
OMG it's almost 3am.

Toe is really the only thing left in gt3 that I am still sorta a newb to.

It seems like no matter who is describing what, there is never a simple definitive statement on toe.

If any one wants to give that statement, that would be great, otherwise it's gonna be back to the test track for me.

Anyway, try something like...

A negative Toe value will create _______, and a positive toe value will create ______.

Thanks a million.

btw, boom, I never really got to mention it, but the school here is great. Love the place and really think you have done an awesome job with it.

Catch you guys around.
Later.

Interesting; nice find Oliver.

So what does negative toe do?

Originally posted by 1989therat
So what does negative toe do?

Click to expand...

OK, I'll give it a quick shot.

Toe OUT is when the wheels of the car are pointing away from each other as they roll forward. This is NEGATIVE toe. The degrees referenced in GT3 indicate the total angle by which the wheels are not parallel. In other words, at zero toe, the centerlines of the wheels are exactly parallel with each other and the centerline of the car. At -0.5 degrees of toe, each wheel is pointed -0.25" (away) from the centerline of the car, for a total of 0.5 degrees.

Toe IN is, therefore, positive. The wheels are pointed slightly toward each other as the car rolls forward.

Now, to get a handle on what toe does, consider what happens as the car turns. As the car settles into a turn, obviously weight transfers to the outside wheels, as we all know. That means, since those tires are handling the brunt of the cornering duties, we want their alignment to best fit the desired path of the car. If the front wheels are toed OUT and the rear wheels are toed IN, the car looks like this: As you can see, either way the car turns, left or right, the outside wheels are going to be biased slightly against that turn. Now if you reverse that, and put positive toe IN at the front and negative toe OUT at the back, you get the configuration you're looking for: Too much toe, however, adds friction on the straights, because the tires are continually crabbing slightly. So you don't want to run more toe than necessary to get good handling in the turns. As I said, rear toe OUT is more effective than front toe IN due to locations of the forces involved. Consider this example: Push a grocery cart forward, with the steering casters at the front, and make a turn. Feels like a normal car, with the back end following the front around. Then, push the cart backwards and make a turn. The end you're pushing will oversteer like crazy, because the rear wheels are steering to the outside. It's not precisely the same effect as a car, but it illustrates the point. The effect of the cornering force acts through the center of the front wheels, so adjusting toe there has a smaller effect than it does at the rear, where the effect is amplified by the distance from the rear wheels to the front.

The Ackerman toe that I mentioned above applies only to the front wheels. Suspension geometry is designed so that toe out increases as steering input increases. In other words, the farther you turn the steering wheel, the more the front tires toe out. This designed in to accomodate the fact that the inside wheel must take a tighter-radius surve than the outer wheel. Without it, the inside tire would have to crab in order to accomodate the outside wheel following its true path. So if you set too much toe OUT statically (meaning when the car is at rest), then you get too much dynamic toe out when the car corners (due to motion of the suspension).

Any help?

And here's a little more info reposted:

Originally posted by munkeeeee
Fixed the Link..........

http://tuning.racing-line.org/gran_turismo/toe_alignment/toe_alignment.htm

Click to expand...

OK, I read through the information at this link, and I fired up my PS2 to check how the settings are handled in GT3. This guy, whoever wrote it, is all wet. Or at least partly wet.

First and foremost, in the game and in real life, toe in is POSITIVE and toe out is NEGATIVE, for both axles. The info at racing-line is incorrect on that score. In the little summary at the bottom, he's not only got the values reversed for his descriptions, but some of his advice is mediocre at best, even allowing for differences between the game and real life. For instance, he quotes front toe out as being the proper way to reduce excessively quick steering response on MR or RR cars... when it would be toe IN that does so. Unfortunately, he's not consistent in his reversal, so it's not a simple positive/negative misunderstanding to clear up. He's just not very clear in his conception. He also says this:

All cars with medium to high Down Force will benefit from zero to a slight toe-out alignment. This can induce the required optimum handling package of turn-in understeer and corner exit oversteer.

Click to expand...

This is actually the worst possible handling condition, at least in my experience. The optimum, late-apex racing line for most simple corners calls for a tighter turn at the beginning of the corner, followed by a shallower path at corner exit. This allows the earliest possible acceleration and thus higher exit speeds for the following straight.

So why on earth would you want to set up the car for understeer at turn-in - when you want rotation - and oversteer at exit, when you want to be able to stand on the gas and let the car track out?

That's exactly opposite of what should yield fastest times: mild entry oversteer, to get the car rotated early, followed by mild exit understeer, allowing the car to four-wheel-drift past the apex and through trackout under hard acceleration. Note that I'm using four-wheel-drift with its real meaning, "cornering with all four wheels at the limit of adhesion", not with the modern made-in-Japan terminology.

thanks a lot for that neon_duke that helped me deciffer toe

Great School sub forum Boom, most enlightening and some great contributions by all.

This don't really help anyone, but just an observation I made a whiles ago. I think the game (or at least Sim mode) uses Toe at times to emulate extreme tyre wear. I remember doing one of the long in-game series (might have been the Formula GT) I'm sure you've all seen it, the long one at the Test Course always burns the brains out of the right rear tyre (or might be front right) and you have to correct the steering even on the straights. I just went to the end without pitting. I checked the settings in the next race's menu before hitting start, and the toe (which I left at 0.0) had changed. I presume when you hit start for the next race it resets the value.
Niether here nor there I know, but thought I'd share it

boombexus

TOE, CAMBER AND TIGT3WDKOCC

In GT3, these suspension characteristics are abstracted and we have no control over them. I call this TIGT3WDKOCC. That is..

Things In GT3 We Don't Know Or Can't Control. The developers have taken suspension geometry completely out of our hands in GT3. This means we really have very little information to go on when we try to decide what the best camber and toe settings are. We can only experiment.

Click to expand...

Boom,
Thankyou for your post. Congratulations for being the only person on the internet to realise that GT uses a physics MODEL, so no matter how much you know about vehicle dynamics, it doesn't mean a thing. All that matters is what the designers of GT know!!!
In my searches for tips about camber and toe settings, the internet is awash with either "use 3.486 degrees coz that's what I use and my car handles sik" or "well grasshopper, the camber angle of the car is affected by roll centre migration leading to a contact patch movement and/or size...<continues for 8 pages>...". Anyway, thanks for your tips, they will be helpful as I try to work out the best suspension tuning strategy.

I did a bit of motorsports in my engineering degree, so I'm pretty familiar with the concept of tuning a car. My current GT3 tuning basically involves adjusting springs/dampers/sway bars to get the front/rear grip balance I want from the car without excessive body roll. Then, if the car still doesn't feel nice, I blindly fumble around with camber + toe to try and fix it. But I've been wondering "sure, the car feels balanced, but maybe there's more overall grip to be had in the camber + toe settings".



Here are the other things I'm gonna test, if anyone has thoughts on how these things work in GT3, I'd be really grateful if you could share them. Thanks!

-I have read of some people using the Car Selection graphs in Arcade mode to work out the best settings (ie adjust and see if handling is increased or decreased) so this is something I'll be checking out.
- does more camber = more grip, up until the point where tyre wear becomes excessive? if so, what is that point? Is there a trade off between acceleration/braking and cornering like in real life? Also, I have read that less front camber = more turn-in in GT3, but less mid-corner grip?
- another theory is that the most grip is gained using the stiffest spring, damper + sway bar settings possible, but the stiffer everything is the more grip you lose when you hit a bump? If this is right, I'll just set everything to max and stay away from the kerbs!!
- should the spring, damper and roll bar rates be kept in proportion (this is what I currently do)? or is it better to run soft dampers and stiff springs etc? (this is gonna be hard to test)
- should toe be set neutral to avoid losing power? or can you get more grip with some toe and not lose too much straight-line speed?
- Ride Height? I have no idea, aside from lowering it when I start feeling seasick!

(sorry if most of this post is just thinking aloud, but I'm hoping other people have tested these things and can give me a headstart...)