Suspension Travel on front coilover

[digger]

What are people using as a setup free clearance for the front coilover bump stops, as in at ride height what travel before the bump stop makes initial contact? 1", 1.5", 2" ?

it is my understanding the micro-cellular polyurethane elastomer bump stops will compress about 50-60% of their free length so in the order of ~30 mm (1.25") before the rate get so high it is essentially "solid", and that this adds to the total travel. So a clearance of say 1.5" means total travel 2.75" (assuming spring doesn't get solid first).

I am using ground control shortened struts, koni shocks and the GC bump stop but not running super low (the tyre is roughly about 40 mm below front guard).
When I play around with settings of different length springs and adjuster positions it seems like the bump stop may need to be longer when the adjuster to nearer to the top to avoid the spring becoming solid before the bump stop fully engages.

A 6" 450 lb/in spring solid length is 2.39" 61mm
A 7" 375 lb/in spring solid length is 2.65" 67mm
A 8" 275 lb/in spring solid length is 2.72" 69mm

For example, if the lower spring perch at the top of the adjuster range see image I found in google showing adjuster at the top. By the time the bump stop compresses 50% the spring would have gone solid so the bumpstop is just a token

it looks like you need the spring to sit towards the bottom of the adjuster to give the spring somewhere to "hide' under maximum travel regardless of the length of the spring
Whereas this image shows the adjuster near bottom of the range

So it looks at least plausible that when the bumpstop is compressed there is a place for the spring to be out of the way

So me this leads me to that if you want to run with the height adjuster in the top region of the range with this type of setup and maintain the correct engagement sequence in the event of huge impact bump that you need to either:
• Use a longer bump stop and accept the reduction in free travel
• Use a longer spring to keep the adjuster at the bottom.

Of course, if you have a enough free travel then you are less likely to put enough energy in the get that much travel (especially with very stiff springs) to activate but the bump stop but the sequence in the extreme case should still be done correctly.

[Northern]

Nothing intelligent to add here... This 100% was not a consideration for my setup.
My two goals were to increase travel over the stock strut housing while not impacting wheel/tire clearance in hopes to run a 225 or 245 square tire setup (without flares)
As far as I can tell, you may lose tire clearance at the strut as soon as a 7" spring, but that depends on ride height and camber plate/top perch stack height.
I recognize that not everyone wants this.

Spitballing/obvious stuff:

You can run a longer spring for more spring/strut travel, but at some point you'll hit something else depending on the car/ride height/wheel/tire/clearancing efforts. I rub as-is in the rear over big bumps, but can't say how close I am to anything up front other than the forward edge of the fender liners.

Different springs will bind at different compressed heights - you could investigate switching to Hyperco or some spring which achieves the same rate with smaller wire diameter/fewer coils to gain some fraction of an inch of travel without running a longer spring, but likely not worth it.

Resolving it seems reasonably straightforward... Measuring the spring solid height, ensuring that the damper does not bottom out first, then spacing the bump stop to engage at some point ~40mm (assuming using the bump stops in your other post) before that point?

[digger]

i am trying to run a softer setup if possible or at least refine what i have to be a bit nicer on the really crap country roads in this country as i am not so young anymore.

I currently use 7" 375 lb/in (ride height 13.2" centre to wheel arch with tires 205/45/17 )

I removed the spring and reinstalled the strut into the car and checked / worked out the maximum travel before the tire hits the wheel well/guard which was only 65 mm travel (w.r.t. static height) and the bump stop would not have prevented the tire hitting the guard it was only partial compressed, so that's not good.

At static height the clearance to solid/blocked spring was 60 mm. So my bump stops are not doing anything meaningful as they are 50mm from touching at static height and at 10 mm compression there is negligible load (50lbs) in the bump stop. So i am i think the springs have been going solid over some of the really big bumps on rough roads and that what i was feeling as far as that goes.

I am going to add some bump stop length to prevent the wheel from theoretically hitting the guard and also ensure the spring isn't going solid. This will reduce bump travel depending on final ride height i set (i don't want the car low). To me the progressiveness will be much better as springs going solid means the only compliance is the tire (which isn't that great once it is loaded pretty hard) and i don't think a 37 yr old chassis will like that too often.

i have an 8" 275 lb/in and 9" 250 lb/in to try and on paper they can work but at a slight increase in ride height. this should get me more total travel (less before the bump stop comes into play) and much more progressive ramp up at the end of available travel as a softer spring will obviously tend to compress more for a given load