Ok I understand that a change in camber effects the toe as well. What I'd like to know is in which direction and how much? For examle changing my front camber from -2.5 degs back to zero how will it affect my front toe? Any input is appreciated. Thx.

 

Bump!

 

I would also like to know.

 

Ok, i'm going to try to explain this simply (there are a lot of things going on at once, so it's easily confused)

You gain negative camber when you lower your car due to the suspension's design to handle cornering (read my other post about it... https://honda-tech.com/zerothread?id=1533017)

Imagine you are looking at the front suspension from head on. When your suspension compresses, five things move vertically, as compared to the car.

1) the spindle (and all the wheel and brake stuff)
2) the bottom of the shock/strut assembly
3) the outer end of the upper control arm
4) the outer end of the lower control arm
5) the outer end of the tie rod

All of the these parts move in an arc. When the spindle goes up, the outer ends of all the atachments move up as well (as makes sense.....since they are bolted to the spindle).

assume, for visual sake, that the UCA, the LCA, and the tie rod are all horizontal when the car is at rest. The LCA is longer than the tie rod, and they are both longer than the UCA. As the spindle moves up, the horizontal length of each item gets shorter (obviously, the arm doesn't change length itself, the horizontal length gets shorter and the vertical height gets longer...OK you got that? it's important..re-read it, or play with a pencil on graph paper until you understand).

Now, in a perfect world, the tie rod would be a proportional length considering it's placement between the UCA and the LCA. As the wheel moves up, the camber changes, but the three points always remain in line and the toe (the difference between the ideal route of the tie rod end, and the actual route of the tie rod end) would never change.....but Mr. Akerman had to go and screw that up.

Akerman Geometry is what allows your short wheelbase cars to turn impressvely. Go out to the drive way, and crank the steering of your car all the way to one side. Notice that the inside wheel is turned sharper than the outside one is? This is intentional. Akerman discovered that when the front wheels turn exaclty the same (imagine the front end of a solid axle 4x4 truck), and the back wheels don't, the fronts fight each other. The inner is making a small circle, and the outer is making a large one. The actual path is the somewhere between the two, depending on instant traction...and you're scrubbing both tires the whole time. Akerman decided that if the inner wheel was turned sharper than the outer (based on wheelbase and track) the vehicle would corner more accurately. The car would stay on the same path, though the wheels were pointed in different directions.

So, how does that tanget relate to you toe issue? Well, to get the Akerman geometry to work, you have to locate the pivot points of the steering eccentrially (off center). This eccentric placement forces the tie rod arcs to be different than the control arm arcs. As the wheel goes up, and the arms get shorter, the tie rods get shorter too, but not as quickly.

On a rear steer car (as all FWD hondas are, thier steering gear is behind the center line between the upper and lower ball joints) as camber goes negative, toe gets negative as well. As the wheels go up in the car, they start pointing towards each other in the front. Likewise, as the tops of the spindles come out (fixing negative camber) the tie rods don't come out as far, so your toe will become postive (the fronts will point away from each other)

Luckily Honda's design is pretty good, and the toe change is not as massive as many cars, but it does change, and is something that has to be straightened out, else massive tire wear, and erractic steering is the result.


hope that helped.

 

my brain hurts now man

 

Very interesting. So, any general numbers regarding the ratio in which toe changes as the result of a change in camber?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JustinHoMi &raquo;</TD></TR><TR><TD CLASS="quote">Very interesting. So, any general numbers regarding the ratio in which toe changes as the result of a change in camber?</TD></TR></TABLE>

generally gaining camber increases toe in, "de-cambering" cause toe out.

at least this is my experance with hondas.

 

Oh, I think that's the opposite of what psychoboy said... ::confused::

 

Agreed for the front. However, I didn't see much (if any) change in the rear when adjusting camber.

 

what i said comes from experance on track.


on some honda's with stock suspension or soft(er) front springs, when braking the rear unloads alot, hence decambering and (toeing out) and the car becuase very skiddish

 

nope, he and i said the same thing

the problem lies with the nomenclature

"gaining camber" to him means cambering in a negative direction. (it's techinically losing camber, since it's increasing negatively)

as far as the spindle is concerned; as the tops go in, the backs come out. as the backs come out, the fronts go in.

negative camber = toe in (wheels point towards each other) on nearly all "rear steer" cars.

 

Thx for the very detailed answer! Although I would lie if I said I understood every bit out of it. But I have an excuse I'm not a native english speaker.

So to sum it up if I have a front suspension setup with -2.5deg camber and 3mm toe out for the track and then with my camber gauge I set the camber back to zero for the street (daily driver) my toe would go to toe-out even more. And now the situation became much worse since we all know improper toe causes more excessive tire wear than improper camber. Am I thinking right?

 

if you are current running toe-out (front of the tires further apart than the rears) and negative camber on the track, and you positively affect the camber, then yes, you will also increase the toe-out condition.

but i have to ask, why are you running toe out on the track? Thru my experience, running slightly toe in is a better option (well, running zero is my faovrite, but if i had to pick a side.....) when you stab the brakes and crank the wheel, you load the outer front wheel. with it toe'd in it's already turned in the direction of the corner. with it toe'd out it's pointed away from the corner.

If youhave a really good reason to run toe-out, I'd love to hear it. Hell, I might even learn something.

 

Well I have always thought that front toe-out helped the car turn into a corner that's why every race car is set up like that. Your opinion is interesting too but I think that's only useful in theory. To take a corner fast it's very important to have a good turn-in point that enables you to have a good apex. And that's where toe-out helps. When already in the corner and the outer front wheel is loaded maybe toe-in would be more desirable than toe-out but now the most important factor in cornering speed is a proper camber and not toe. At least that's what I think but since I'm not a suspension expert I could easily be wrong.