I was replacing a rear BC shock and noticed the old one had wear showing how it was bottoming out on the top mount. The shocks have only 4" of stroke from full extension to hitting the bump stop.

I want to make sure my suspension is matched to this 4" stroke and will not bottom out (which probably blew the shock). I noticed with my car's height even on both sides, the springs and shocks adjusted to the same length (with half inch preload), the right rear spindle droops right around 4" when car is jacked up. Then when the car is on the ground the spindle is pushed up the 4". Measured by the top of the tire to the wheel well in each position.

The left side only droops about 3 inches when adjusted the same as the right side.

Should I add about 1-1.5" of preload on the spring to push up the spindle and shorten the shock to basically as short as it can go? That would make

 

Are you set up as a true coilover or OEM style

 

good questions, forgot to add- OEM style with spring and shock separate in rear
BC BR type

 

First thing, remove the springs and disco the sway bar. Now set the length of the shock, do this by installing the wheel and jacking it up till it bottoms out on the bump stop. If you need more up travel, shorten the shock, if the tire it hitting something before the bump stock engages , lengthen the shock assemble. Once you do this, take the other side off and match the length, I use a micrometer for this, very simple.

Now reinstall the spring. The adjustment on the spring is preload, it is actually used to set the ride height. Both sides will not be the same , but they will be close ( usually within 1/4 inch )


If you do the first part I mention properly , you will have the max usable travel your damper allows. For a performance application, you want a good amount of up travel, but still have some droop from your ride height.

 

OK thanks for the help, I am little confused....but I think I get what you are saying. So jack up the spindle so the tire is in the wheel well where it would be if the car was on the ground and set the shock length? -Making sure there is enough stroke for the shock to compress when the car naturally lowers in dips and enough for the shock to expand when the rear hops up?

There is 4 inches to play with. It's going to be tough to get right I think because the shock can only be adjusted so much without compressing it.

When you say up travel is that the shock compressing up or the rear up the car bouncing up and expanding the shock?

How that all makes sense.

 

If I compress the shock so that it's right at 2 inches in the middle of the stroke and the length is adjusted to where the tires is supposed to sit in the wheel well I think would work.

I'm thinking right in the middle because I don't want it bottoming out on the up and down stroke.

And then hopefully that will work and it will easy to spin the spring to the right height, with still needing to push it up about half in for the preload.

 

Bottom out= shock fully compressed , bump stock engaged
Topped out= shock fully extended

Car sitting still on its tires (ride height) , it should have both up travel and down travel. Shock length is how travel is determined. A long shock will bottem out sooner than a short shock at the same ride height.

Give you a quick idea of how much up travel I have from my ride height. My rear tire will almost tuck to the wheel when fully compressed. I have about 20mm of gap from top of tire to wheel well at ride height.

 

OK so you are saying about 2 inch of travel UP and down would work well? I probably don't have rubber band tires like you do, so I am not tucking most of the tire. Thank you for the help it helped me picture the functionality and will readjust everything. I think my shocks are way too long...I will follow up later after after I look at it

 

My tires are far from rubber bands. This is getting close to bottomed out in a banked corner, but I still have more travel to take a bump while it's loaded like that.

 

Static ride height

 

Suspension fully extended

 

Thanks for the pictures, will let you know how it goes