quattro digest, Vol 1 #3412 - Coilover adjusting

[Larry C Leung]

Raising the lower spring seat (i.e. wrenching up) will bring the two
spring perches closer together, i.e. compressing the spring from
your point of view.

However, since the car does not weigh any more before the adjustment
than after, the load on the spring does not increase, therefore, by
Hooke's Law   x = F/k

where:         x = the length of the spring
                     F = the corner weight of the car (i.e. weight on
that corner of the car)
                     k = the spring constant of the spring i.e. 250
lbs/in

Since,

the weight (and therefore corner weight) doesn't change,

the spring constant (k) doesn't change (unless you change the spring!)

then, by the formula (and logic) the spring's length remains unchanged

Therefore, if you bring the two spring perches closer together, and allow
the spring
to naturally rebound, the car's ride height will raise. The opposite
would happen
if you separate (wrench down) the lower perch, i.e. lower perch, lower
car.

HTH,

LL - NY


> Reply-To: "ccohen5" <ccohen5 at compuserve.com>
> From: "ccohen5" <ccohen5 at compuserve.com>
> To: "Audi S Car List" <s-car-list at audifans.com>,
>         <urq-request at audifans.com>, "qlist" <quattro at audifans.com>
> Cc: "Robert Pastore" <rpastore at animalfeeds.com>
> Subject: How do coil overs adjust?
> Date: Sat, 11 May 2002 20:45:24 -0600
>
> I am about to alter my coil over adjustment nuts for the first time
> and was
> searching the web for the best tool, and any BTDTs.  One Miata site
> says
> that you wrench up the shaft to raise the height, and wrench down to
> lower.
>
> This is counter intuitive: if you raise the nut, you compress the
> spring,
> and the car should sit lower. Vice versa if you lower the nut.
>
> Where am I going wrong here?
>
> I have only seen an after market tool at one after market site.  It
> has a
> variable diameter that cannot be locked. So each time you engage the
> pawls
> of the adjustment nut, you have to reset the size of the wrench
> claw.
>
> Colin