Performance Alignment

[Nliiitend1]

i would think it depends on the lateral loading, for how much negative camber is effective, in the regard to understeer to oversteer. i know that more neg makes the car harder to drive straight, from a little exp. regardless of toe set up. isnt the focus suspension similar to the Mazda3 design in the rear at least?

The Focus suspension is almost exactly like the MS3's.

The rear of these cars gains less positive camber (i.e., it loses less negative camber -in fact, the camber curve for the rear is probably such that it doesn't gain ANY camber under compression- ) than the front does under compression. This fact, coupled with the general rule of running less rear camber than front camber (which was bore out of the principle of the needing the tires that do the actual turning to have more grip than the tires that are sort of "along for the ride") means that you probably want to run less rear negative camber than front negative camber if you want to have less understeer-prone car.

Lateral loading is definitely part of the equation. As a general rule though (at least in my experience), on a car with a MacPherson strut suspension you want to maximize front negative camber (I use the term "maximize" because there's only so much negative camber available on a conventional MacPherson strut setup due to the nature of the design) and then go from there (if you want maximum turning grip).

 

[ericrapp]

okay. Can you tell me a liitle about rear toe for my goals. As i mentioned i will have to do the rear setup first. i realize the front and rear setup are affected by each other but this is where i am at till i solve the issues up front. we can discuss castor/caster later. As a reminder stability at speed is my goal. I am not too concerned about low speed numbness or chasing road irregularites at 55 mph. I have a fairly numb center now. But the feel picks up nicely above that. i do not have the specs but as i move towards my goals i will keep accurate accounting of where the geometry is at. Thanks for your Patience with someone new to this realm. If this should go to a pm thing thats cool.

 

[Nliiitend1]

I'd say you'd probably want to run a little bit of toe IN at the rear. Perhaps 1/16" or so. That should give you some more stability at speed (especially under braking at high speeds) than running zero. Do NOT run toe out in the rear.

 

[ericrapp]

Is the fractional sixteenth the smallest increment of adjustment? we have discussed rear camber. and not much is needed it seems. Ilike where they are at now and when i install the rear (coilovers, not exactly) i will try to replicate the settings i have now besides the rebound for the heavier springs. What can i do with castor/caster in the rear? That would help me. I believe the factory has supplied some adjustment there. I will purchase some adjustable camber arms for the rear. The sway bar links should be here soon. Also what else do i need to gain adjustability? it seems besides the specs i should have all the parts i need in hand or on my list for the rear end. your suggestions have been appreciated

 

[Nliiitend1]

Is the fractional sixteenth the smallest increment of adjustment? we have discussed rear camber. and not much is needed it seems. Ilike where they are at now and when i install the rear (coilovers, not exactly) i will try to replicate the settings i have now besides the rebound for the heavier springs. What can i do with castor/caster in the rear? That would help me. I believe the factory has supplied some adjustment there. I will purchase some adjustable camber arms for the rear. The sway bar links should be here soon. Also what else do i need to gain adjustability? it seems besides the specs i should have all the parts i need in hand or on my list for the rear end. your suggestions have been appreciated

The adjustment is actually continuous. There are no "clicks" or pre-defined fractions of adjustment.

There is really no rear caster to speak of, as it is something that is really only important in the front because of the fact that the front wheels turn. You don't need any in the rear (and there is no adjustment for it since there really isn't any need for it) because the rear wheels don't turn.

Adjustable upper "camber arms" are all you really need in the rear to have complete adjustability of everything that's important back there. There is more than enough toe adjustment afforded by the OEM rear eccentric toe bolts.