5th Coil Preload

[7uptruckracer]

Running a 5th Coil. Builder put a helper spring on top of it so it doesn't come unseated during heavy decel etc. Said to preload it 1/4" all Normal stuff. So we thought. The helper doesn't smash all the way shut. You can screw the collar down and load the 5th without it smashing the helper shut so there is no real way to know when you are at "Zero" any ideas?

[rick james]

Measure the length of the spring then compress it 1/4 inch

[7uptruckracer]

Well that made me have a duh moment. If this is a 6” 25lb helper spring would that change the thinking?


Measure the length of the spring then compress it 1/4 inch

[TheJet-09]

Assuming you have a slider between the helper spring and coil spring, is it by chance bottoming out on the nut before the helper spring is fully compressed? I experienced the same thing you are and found that to be the issue. I just went to a slider that is very short on the top.

I use the free height vs. compressed height to measure pre-load as well, most certainly on the 6th coil.

[7uptruckracer]

What do you mean by bottoming out on the nut? I can run it down to the bottom of the threads and it still wont collapse the helper?

Assuming you have a slider between the helper spring and coil spring, is it by chance bottoming out on the nut before the helper spring is fully compressed? I experienced the same thing you are and found that to be the issue. I just went to a slider that is very short on the top.

I use the free height vs. compressed height to measure pre-load as well, most certainly on the 6th coil.

[billetbirdcage]

If you have a 25# 6" helper spring on top, basically you have a stacked spring set up. So lets say the lower spring is a typical 300# spring, then unless you preload everything enough to coil bind the upper helper spring you're on that combined rate until it binds.

If they are just wanting to keep the adjuster from moving then it should have something more like a 15# helper that is way shorter (like 2 or 3" tall max) so once you put that 1/4" preload (1/4" on 300# spring = 75#) that it would bind the helper spring.

[TheJet-09]

@7uptruckracer, without drawing it I might have a hard time explaining, but in exaggerated numbers:

Say with no springs on the shock at all, run the slider up until it touches (bottoms out per se) on the coilover nut, then measure the distance between the flat surfaces (where the springs sit/make contact) of the coilover nut and slider. Merely for example, if that is 1", but the collapsed height of the helper spring is only 3/4", you'll never collapse the helper spring completely before the slider hits the coilover nut and begins compressing the primary spring (solely).

I only bring it up because I experienced that, and know there are many different sliders out there with variations on how tall the "lip" is that centers the spring on the slider. In my case, I had to go to a slider that has a very low lip on the helper spring side.

[Drake Racing]

Might sound stupid, but is the slider in upside down? I did that once on the LR, and couldnt figure out
why the helper wouldn't compress all the way....slider was flipped and nut hit it before it collapsed.

Curt Drake
Late Model #55x