Is there a guideline for how high up the strut to weld on the threaded sleeves?

I've been thinking about this a bit too since ordering a pair.

The way I have calculated it is:

You need the corner weight of the car (roughly), you then need to measure from the centre of your tyre to the lower control arm bush in the engine crossmember and also measure from the bottom of the strut to the same bush. Do a sum of moments about the bush in the crossmember to find the load on the strut.
Divide that load by your spring rate to find spring deflection.

Once you have the spring deflection it's just a matter of taking that off the unloaded spring length and doing some measuring of the total strut lenght etc to work out how high it will sit at rest. You would presumably try to make it so the desired point is in the middle of the threaded sleeve allowing for adjustment to either side of it.

You could work backwards as well by deciding how high you want it to be and choosing a spring rate that won't allow the suspension to bottom out.


The problem with the stanza struts I'm finding is that to go nice and low, you don't get much suspension travel which means you need to run a really heavy spring rate!

as to where the coil section is welded on will primarily be decided by the size of tyre wheel combo you run, on mine - the middle pic - the threaded section is welded up under the weld line you can see in the pic. this sets the spring seat at the lowest part of the thread without hitting the tyre. spring lengths generally come in 25mm incriments starting at 200mm upto 300mm by some makers. you can help set the height of the car with the length of the spring and use a tender spring to keep the main spring captive when on full droop.
sssute's running 175lb springs with a CA from memory the standard spring is around 115lb in a stanza setup. spring weight, number of coils, progressive or lineal wind also make a big difference to travel.
from what i've found from talking to different suspension people often it's a bit of trial and error to get it exactly how you want at the height you want ...

Also on the r31 struts the thread has to be welded flush with the top of the strut, even with the adjustment you can only wind the spring seat down to the point just above the tyre. Some people think that your hight is fully adjustable. Spring length and pressure is the main factor.