Roll Center Adjuster,what length for AE-85/6?

[ezy10s]

buying locally is just easier if you either dont have a credit card or need it asap- i know eugene had most t3 item in stock so turn round time was about 2 days if i was lazy or 30minutes if i wanted to drive across town to pick them up.
As far a increased cost- how is someone supposed to put food on the table if theyarent allowed to put a margin on items that they are selling?

[rwd_mayhem]

i know i brought up an old topic with some obviously strong opinions involved but could it be possible to even try answer my question please?

[d1 mule]

are ae70 struts the same as ae85?? are they interchangeable?? if so then yeah bolt on

[frost]

it wont be as easy as saying "ok i dropped the car 30mm so i need 30mm RCA" you need to get the arms back to the angle they where intended to sit factory, things like wheel size tyre size spring height car weight will affect the total size you need, like for my AE85 i had dropped the car about 3inch but was running 15" wheels with 55 profile rubber. i didnt really get any dump steer from this set up but when i went for a midnight driving session i felt uneasy with the car and the next day ordered some 35mm RCA's and the car was feeling great. i also feel the harder the springs the less bump steer but thant is prob wrong. its just what has happened with my car and friends cars.

on my cousins ae85 it had really bad pump steer and it felt scarry seeing the car jerk for no reason. he had really soft springs,

i maybe talking out my arse....

[slonlo]

wheel / tyre size will not change suspension angles
if you put on a bigger tyre the whole car will be lifted , the suspension geomitry will not change
any change would be due to less side wall flex on lower profile tyres

[RomanV]

yes, and if an arm is horizontal, any further suspension compression will cause camber to increase, to the point where you may end up with positive camber on the outer wheels going around a corner at speed - which would not be at all good

Not true. it makes no difference to the camber change, if the arm is pointing 'down' or 'horizontal'.

Here's an exaggerated wire frame suspension drawing to show that it's true:



both wheels go over the same sized 'bump' and the camber change relative to horizontal is identical.

Regarding what causes bump steer, and why RCAs fix it, here are my thoughts. (I am possibly wrong)
The steering arms (as shown below in yellow) are on a longer (or shorter?) radius than the lower suspension arms. (shown in red) When the bottom arm moves up and down, the steering arm is moving through a different radius. The two radii of the suspension arm and steerin arm would be designed to intersect near the point of standard height/travel. When you lower it, you're moving the suspension travel to a point where the difference in length of the two radii is more pronounced. So when you go over a bump, the steering arm moves further towards the outside of the car than the lower suspension arm. Obviously if the steering arm and lower suspension arm arent parallel, then the wheel is going to be on an angle, turning the car. EDIT: Or thinking about it more, the radius of the steering arm and the suspension arm are more than likely the same on any half decent suspension setup. Perhaps its the difference in height/angle of the steering arm relative to the lower suspension arm that makes it travel through a different radius? Assuming that it does. I'm probably wrong, and would be happy to be corrected!
Maybe I should take some proper measurements of my suspension etc and model it to scale to see.

[Zak]

Your drawings are a bit off, (good atempt at it though ) you need to fix the angle to the strut not the lower arm. then you'll see it all when it goes over a bump.

[KinLoud]

RCA - Roll Centre Adjusters
I don't think they are designed to affect roll steer or bump steer at all!
They are called roll centre adjusters because they affect the roll centre!

read my rants in this thread
viewtopic.php?t=56020&highlight=roll

Yes there is an effect on the camber curve (or what part of the curve the suspension sits at) if you use RCA's.

Bumpsteer is often caused by people mucking around with their suspension without knowledge, and it isn't fixed by using a magic wand!

End of (minor) rant

Ken
Ham
021 408 863