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-   -   toe out setting for FB (https://www.rx7club.com/race-car-tech-103/toe-out-setting-fb-766557/)

notveryhappyjack 06-25-08 02:59 AM

toe out setting for FB
 
I'm in the middle of replacing tie rods on my FB. The car has a fair ammont of susp. work on it done, but still has the stock manual steering rack (17'' wheels, coils, sways, camber, tower braces, adj struts yada yada)

I would like the car to have a slight toe out setting because this would net me a sharper turn in and direction change. I don't track the car very often, actually never so this setting would be a fully street thing. Who has experience with toe in settings ? How much is too far for a street machine ?? Ballpark numbers >?

Thanks,

Rxxx-7_GSL-SE 06-25-08 03:37 AM

i think for camber and toe you wanna keep it within -3 to +3 degrees

Bruceman 06-25-08 10:29 AM

I used to run 3mm toe out per side to help with autocross turn-in

Kentetsu 06-25-08 11:05 AM

Starting with the standard alignment performed at Sears, I will turn the adjusters to make them shorter by one full turn per side for races. This seems to work very well, if not quite a scientific method. I have to return them to their standard setting before hitting the road though, otherwise she's quite a handful on the highway.

Hope this helps...

KhanArtisT 06-25-08 09:27 PM

I don't think the sharper turn in would be worth the extra tire wear. On the street unless you drive on twisty roads I doubt you'd feel the difference. It will also wander and weave on irregular road surfaces.

Kentetsu 06-25-08 10:46 PM

Damn, I misread this and assumed he was racing. Yeah, you don't want to play around with toe out on the street. You'll end up pointing the wrong direction at the worst possible time. Zero toe, maybe. But not toe out...

Hyper4mance2k 06-26-08 02:41 PM

Toe out on the street will make your car a headache to drive. You'll constantly be fighting rutts and dealing with a darty car at anything over 35mph. I run my car with 0 toe and it works perfect. Remember dure to g forces and stresses on the suspension and tires under braking you get about 1/8" of toe out from just breaking, so running 0 toe still gives you some toe out when you need it, under braking durring turn in. If we lived somewhere with decent roads then you could run 1/32"-1/16" (.75mm-1.5mm) total toe out, but our roads suck here, so I wouldn't try anything more than that.

notveryhappyjack 06-27-08 03:21 AM

good advice, zero sounds like it will work just fine for me.

bean13 06-28-08 11:05 PM

I never run zero toe, anywhere. It will dart all over the road, that has been my experience in every race car I have ever driven. You have to have some toe in one direction or the other. I don't even run toe out on the street, even though that is what I am used to. There is no real point.

If you are working on a street car, set it up how the manufacturer describes, usually 1/8" in. The whole deal with toe is to keep the front stable and from wandering. It becomes important in racing as and toe in either direction is scrubbing the tire as it rolls in a straight line, decreasing speed. Most race cars run toe out in the front (NEVER in the rear, always toe in) because it gives the car a slightly better turn-in. The inner tire has to turn more in relation to the outside tire to go around a corner, and if there is toe out, it aids in this. (The front tire is already pointed where it needs to go) If you run toe in, the outside tire is pointed inward more so than it needs to be.

I ran 0 toe once, and will NEVER do it again. We initially tired to get fancy at Road America with 3 long straights and were hoping that reducing the scrub would show an increase in terminal speed, well, it didn't (at least the lap times and data didn't show). But it did make for a real hairy ride, I would strongly recommend against this from my experience.

So, really, street car, scrub of 1/8" of toe is nothing in all respects.

My two cents, set it how the factory tells us to. Don't mean to come off as a jerk, just an opinion.

Oh yeah, as for camber, it depends solely on what tire you have. On the street, set it to the factory spec. If you run, lets say a Hoosier R6, and have 3* to 4* of neg camber, that is good....on the track. On the street, all you will get is a big tire bill every 5,000 miles.

peejay 06-29-08 12:16 PM


Originally Posted by Kentetsu (Post 8319274)
Damn, I misread this and assumed he was racing. Yeah, you don't want to play around with toe out on the street. You'll end up pointing the wrong direction at the worst possible time. Zero toe, maybe. But not toe out...

I run 1/4" toe out on the street, no problem.

I'm not running rubberbands on 17" wheels.

As a rule, the lower profile/wider the tire is, the less camber and toe you want. The tires don't deflect as much.

So for 13" wheels you can run something crazy like 2 degrees of camber and 1/2" toe-out and it will drive just fine. Low profile tires will absolutely hate it.

So, for 17" wheels, I guess the first thing would be to find a car that goes well with huge wheels and drive that instead...

j9fd3s 06-30-08 01:45 PM

this is a different chassis, but the rx8 actually feels more stable with zero toe in the front. i was the rx8 tester at the dealership too, so i got to compare several different cars.

i could see it being a problem at 150mph, but we're not going that fast

Kentetsu 07-01-08 06:41 PM


Originally Posted by peejay (Post 8329328)
I run 1/4" toe out on the street, no problem.

I'm not running rubberbands on 17" wheels.

As a rule, the lower profile/wider the tire is, the less camber and toe you want. The tires don't deflect as much.

So for 13" wheels you can run something crazy like 2 degrees of camber and 1/2" toe-out and it will drive just fine. Low profile tires will absolutely hate it.

So, for 17" wheels, I guess the first thing would be to find a car that goes well with huge wheels and drive that instead...



Peejay, you're straight up insane man. :)

I'll push the limits as much as any other guy, but even I know better than to try driving a street car with 1/2 inch of toe out. With even a slight amount of toe out, you're just begging for a spin on a rainy day.

Who let you out of your straight jacket again!!! lol.

Mazdanowski 07-14-08 11:31 PM

If you have adjustable caster/camber plates crank in as much caster as you can get. As you turn into the corner you will gain negative camber. That will allow you to start with less static negative camber. The extra caster will also help the car to track a little straighter if you chose to try a LITTLE toe out. Remember if you have any play in your steering box, if any of your bushing/tie rod ends/ball joints have play and your tires have stiff sidewalls your going to get a little wandering. When you are stringing the car (aligning it) don't forget to check the toe on the rear housings. I had two with 3/16 toe out that caused all kinds of problems.

KhanArtisT 07-15-08 02:25 AM

Ehhh I'd say do some research on caster...more - caster is known to cause more weight transfer to the outside wheel and it surely makes the steering response slower (think pulling an object vs. pushing). Its something you'd have to test and tune.

buldozr 07-16-08 08:20 AM

so... what would be a basic setting for autox, road course, street performance driving?

Mazdanowski 07-16-08 10:57 AM


Originally Posted by KhanArtisT (Post 8376713)
Ehhh I'd say do some research on caster...more - caster is known to cause more weight transfer to the outside wheel and it surely makes the steering response slower (think pulling an object vs. pushing). Its something you'd have to test and tune.



This stuff may be in previous comments. I did not do a search for you.

Caster can NOT cause weight transfer. Only the size of the radius of the turn and the speed at which you take that turn dicates the amount of weight that is transfered. That is simple physics. If an image helps understand picture this guy putting in a ton of caster and then going around a corner at 1 mph. Is there an weight transfer in the chassis? Effectively none. Now picture him going around that same corner at 60mph. Did a fair amount of weight transfer in the chassis? Yes. The speed at which he took the given corner dictated weight transfer. NO suspension item on the car dictates the total amount of weight transfer.


Roll stiffness dictates which end of the car feels the greatest weight transfer. That is dependent on items like spring stiffness, the angle of the spring, swaybar thickness and leverage, etc. Ever see a front wheel drive car on a track with a big rear sway bar lift the rear inside tire?

The pros on more caster is it causes a return to center of the steering wheel which would be helpful if this guy runs toe out on the street. Caster also helps add negative camber while the wheel is turned. This also allows the tire to stay flatter on the ground so you can go faster. The downside of extra caster is that it makes it harder to turn the steering wheel in a non-power steering car. If the lady test driving the car has to fight the steering wheel to park it in the dealer parking lot she is not going to buy that car.

sctty 07-16-08 11:20 AM

Positive caster causes the steered wheels to drop (inside wheel) or rise (outside wheel) relative to chassis. This will cause a change in corner weight.

KhanArtisT 07-16-08 07:46 PM


Originally Posted by buldozr (Post 8380779)
so... what would be a basic setting for autox, road course, street performance driving?

To give you a short answer there really is none, suspension tuning is full of compromise, you really need to be the judge on how aggressive you want the alignment to be. But if you give us the type of roads you'd be driving the car on (bumpy, straight, twisty, rain, etc.) I'm sure we can give you suggestions. If you plan to track the car I recommend you buy a book on it, like "How to Make Your Car Handle" by Fred Puhn, or "Tune to Win", just go to amazon and search.


Originally Posted by Mazdanowski (Post 8381222)
This stuff may be in previous comments. I did not do a search for you.

Caster can NOT cause weight transfer. Only the size of the radius of the turn and the speed at which you take that turn dicates the amount of weight that is transfered. That is simple physics. If an image helps understand picture this guy putting in a ton of caster and then going around a corner at 1 mph. Is there an weight transfer in the chassis? Effectively none. Now picture him going around that same corner at 60mph. Did a fair amount of weight transfer in the chassis? Yes. The speed at which he took the given corner dictated weight transfer. NO suspension item on the car dictates the total amount of weight transfer.


Roll stiffness dictates which end of the car feels the greatest weight transfer. That is dependent on items like spring stiffness, the angle of the spring, swaybar thickness and leverage, etc. Ever see a front wheel drive car on a track with a big rear sway bar lift the rear inside tire?

I understand that at different speeds there will be different amounts of weight transfer caused by the centrifugal force acting on the car (which is determined by speed and other factors). I think it was in Howard Coleman's thread that I read that caster can increase weight transfer to the outside wheel, with the example being turning the wheel lock to lock on a typical FWD car stopped with the engine running and observing the front end move towards the outside wheel.

peejay 07-25-08 09:04 PM


Originally Posted by Kentetsu (Post 8337247)
Peejay, you're straight up insane man. :)

I'll push the limits as much as any other guy, but even I know better than to try driving a street car with 1/2 inch of toe out. With even a slight amount of toe out, you're just begging for a spin on a rainy day.

Who let you out of your straight jacket again!!! lol.

Actually zero toe makes it darty as hell. The further you stray from zero, the more "numb" the steering gets.

I have zero toe right now, trying to eke out the best fuel economy despite 225/50-15 gumballs. No problem staying awake!

SCCAIT7 07-27-08 08:57 PM

1 degree. When you start racing it go to 2 1/4. I like a car that is not over reactive. These settings usually give the best results.


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