How should the suspension react with no weight on it? Problem, or normal?

[ajcarson11]

All --

Have an interesting question -- not sure if this is normal or an issue:

Went to raise ride height on my tein flex Z coilovers (just to get the front end up 3/8" or so), and noticed that with the wheels off, car jacked up in the air, that there was 1/2" or more space between the top of the coil and the top hat... I could move the coil spring up and down easily with my hand.

I sat and thought about this -- Would the gap be closed up when I lowered the car back onto the ground, thus eliminating the negative preload I was seeing with the car in the air? I had the coilover preload set properly when I put the coilovers on originally, so perhaps there is just a gap when the car is in the air since the springs had time to settle?

Or should the spring NOT move at all (just a small amount of preload) with the wheels off and car jacked up?

Wondering if my preload adjustment rings worked themselves loose and provided me with a bunch of negative preload?

Thanks all!

[Twinz]

My STU-prepped 350Z had that kind of play on the front and it was not an issue. I used helper springs on the rears since I ran no sway bar in the back. The sway bar on the front kept the springs seated when turning, and I didn't lift the front end enough to unload them on a straight- line launch.

[whataboutbob]

I *think* it isn't an issue as long as your suspension doesn't become fully unloaded when driving which might cause the springs to become unseated from their perches. If this were to happen and then the car came back to rest on the suspension with the springs not properly seated I suspect it could cause problems. Helper springs might not be a bad idea though.

Both the RCE T2s I had, and the RS-R CRs I have now both have some very minimal preload on the springs such that even when I jack the car completely up there is no play in the springs.

[ryoma]

I might be overthinking this, but doesn't the word "preload" elude to the fact that you want the springs tight/loaded prior to the actual load being placed on them? I am no suspension guru, but I always regarded preload as loading up the springs prior to load being placed on them (the car being lowered onto the wheels). you also don't want to adjust your ride height with the spring perch, but rather the lower portion that connects to the hub (not exactly sure what it's called). if you only have a setup that allows adjustment with the spring perch though, then there's no way around that

[bfrank1972]

I had street flexes, but I'm pretty sure the Flex Z's also have a preload collar. You need to move it up so it's hand snug against the spring with the suspension unloaded. Then move up the locking collar and tighten with the wrench (note there's a little square hole in the wrench, that's for your ratchet/torque wrench to get leverage). You use the lower collar to set the ride height - you can do this on the car by loosening it, moving it to where you want, and turning the shock body so it snugs against the bottom (measure carefully of course). Under normal load situations having a loose spring shouldn't be a big deal, but if you completely unload the suspension (dukes of hazzard?) you might have problems, or at least noises.

[renfield90]

Originally Posted by whataboutbob

I *think* it isn't an issue as long as your suspension doesn't become fully unloaded when driving which might cause the springs to become unseated from their perches. If this were to happen and then the car came back to rest on the suspension with the springs not properly seated I suspect it could cause problems. Helper springs might not be a bad idea though.

This right here. Helper springs are a great idea IMO since they provide some peace of mind, especially for a street driven car. An autocross/track only car that is trailered or driven carefully to/from events will see less benefit from a helper spring.

One other option is to replace your main spring with a longer one such that it isn't fully extended at full droop (i.e. if you have a 1.5" gap with the car fully in the air, buy a spring 2" longer). The downside is helper springs compress easily by hand, whereas a longer spring is going to require a spring compressor to get the top hat back on.

Lastly, if you stiffen up rebound enough the spring is unlikely to unseat fast enough unless you get the car airborne for a considerable length of time, and then you likely have other problems...

[bfrank1972]

Originally Posted by renfield90

This right here. Helper springs are a great idea IMO since they provide some peace of mind, especially for a street driven car. An autocross/track only car that is trailered or driven carefully to/from events will see less benefit from a helper spring.

One other option is to replace your main spring with a longer one such that it isn't fully extended at full droop (i.e. if you have a 1.5" gap with the car fully in the air, buy a spring 2" longer). The downside is helper springs compress easily by hand, whereas a longer spring is going to require a spring compressor to get the top hat back on.

Lastly, if you stiffen up rebound enough the spring is unlikely to unseat fast enough unless you get the car airborne for a considerable length of time, and then you likely have other problems...

He doesn't need a helper spring or longer spring, they have adjustable spring collars, he just needs to learn how to set up his coilovers. You can even put preload on them, thought I don't think there's much room, you might get into coil bind with full compression with any significant preload.

Here's a picture of the upper collar/spring seat:



Basic instructions:
1) Untighten the "middle one" from the "top one"

2) Hand turn the "top one" until the spring is snug

3) Turn the "middle one" until it's snug against the "top one", then tighten it down with the wrench to lock them both in place

That should solve your problem. Then the "bottom" one is used to adjust height