This weekend i am setting aside to attempt to try different settings for my next autocross event at Fontana Speedway on 7/13.

One thing I have on my list is the swappage of the UCA's. I HAVE searched. So if this is dumb and obvious answer to you, forgive me, i overlooked it.

While searching both current and archived post dealing with caster, I'm pretty much sold on its pluses. One thing i came into confusion with was its effect on ride height. I am not sure whether more caster from the UCA swap adds more height or decreases it.

This is due to two threads:

https://honda-tech.com/zerothread?id=144111
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Warren: It's the front arms you want to swap. You will be marginally lower when you swap them. I doubt you will even notice the difference.</TD></TR></TABLE>

versus

https://honda-tech.com/zerothread?id=84781
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">KRSchultz: Something else that I thought was interesting. I seem to have picked up some negative camber. I've got 1.9 and 2.0 degrees now - but at a substantially higher ride height. Don't know if this is another benefit of the swap or not.

It didn't really raise the ride height - I turned the coilovers up a few turns. What I should have been more clear on is that even with the ride height raised probably 1/2 an inch, I still have 2 deg. static camber.

So bottom line, I can't authoritatively tell you that this change helped handling, since I changed some other things on the car. What I do know is that I've got the same camber, higher ride height, and better tire wear.</TD></TR></TABLE>

So can any of you suspension geometry experts help me out in determining whether it lowers or raises the ride height? I even looked in my "how to make your car handle" book and could not find a definitive answer. Thanks for any help.

edit: From my general thinking. Adding more caster/ moving the axis from its normal "upright" positing and making it tilted farther back would theoretically lower the car. But i may be wrong. I think of it as having an old bmx Bike. You ride hard some day and bend the front forks. The bend pushes the front wheel a little farther fordward*. That should lower the bike's ride height correct?

 

I think Schultz meant that swapping the UCA's added camber so that he could raise the car slightly and maintain -2*.

 

Our experience says that there is no direct relationship between the ride height and Caster. Caster is the forward/backward angle of the Knuckle not the In/Out position. It is true that certain suspension changes will directly affect Caster. Take a look at the articles on both the Ingalls and Specialty websites for more details.

 

Logic (and simple geometry) tells me that if the knuckle is pushed forwards or backwards, that the ride height will decrease. I 'm talking about the top of the knuckle where it connects to the UCAs. The knuckle will no longer be in the original straight up position, thus reducing the angle with the ground. Doesn't the caster that some seek move the top of the knuckle forward so that the wheel is pushed backwards to reduce the wheelbase? Smaller wheelbase supposedly translates to better handling.

 

The Caster of any car is not part of the wheelbase equation. It is the inclination of the knuckle only. The centerline of the spindle is not relocated. The fact is that the amount of potential ride height change is actually very small compared to the change in spring height or perch position used for lowering.

 

Read It!

http://www.ground-control.com/gctalk5.htm

 

jc836: what? when a car has a caster difference (like mine that runs into potholes) you can measure or even see it by eye that the whole spindle is moved backwards! One tire is behind the other, and this is what GC is also saying: the pivot point changes..