With adjustable-height coilovers, what difference does it make having preload on the spring or not? When the car is on the ground the spring is going to be compressed the same amount, whether or not there is preload when the suspension hangs freely.

When I had GC's and my car was up in the air, I had probably 1" or more between the top of the spring and the top hat. But the weight of the car still compresses the spring the same amount regardless of preload.

Just a thought that popped into my head and I was wondering about it.

 

The term "pre-load" implies that there is a load already applied to the spring, prior to the weight of the car being applied onto the spring.

So, before (hence pre-) the car is on the ground (read: jacked up in the air), the springs have already been compressed a certain amount (load).

In any case, pre-load isn't a huge deal with cars. If you have the option to do so, you just want to make sure that you don't have a lot of up-down play in the spring at full droop.

 

in your case with GC's, preload will remain the same. it will be just the weight of the car as you pointed out.

if i can interpret your question as to whts the big deal about preload, well its not a big deal.

 

some companies are die hard when it comes to preloading but either way will still be putting the full car weight onto the springs i dont think it makes much difference at all.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson &raquo;</TD></TR><TR><TD CLASS="quote">in your case with GC's, preload will remain the same. it will be just the weight of the car as you pointed out.
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actually the weight of the car is the load. The preload is like PIC explained, load put on the spring (compressed slightly) with no load otherwise, like while the car is jacked up off the ground, with the suspension at full droop.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">
suspension at full droop.</TD></TR></TABLE>

full droop actually STOPS when the spring becomes unloaded.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">

full droop actually STOPS when the spring becomes unloaded.</TD></TR></TABLE>

huh? So what do you call it when the suspension continues to drop after the spring separates from the top hat?

From what I have always understood, full droop = shocks fully extended, or as far as the suspension bushings will allow.

 

Pre-load in my pants! Who cares...I've never had a problem with my skunk2's getting re-seated after full droop. I don't know why companies make such a big deal about it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">huh? So what do you call it when the suspension continues to drop after the spring separates from the top hat?

From what I have always understood, full droop = shocks fully extended, or as far as the suspension bushings will allow.</TD></TR></TABLE>

You will never have the suspension extend further than the spring an extend, if you have a swaybar on that end. The swaybar itself will prevent the shock from extending further than the spring, unless you have both tires off the pavement (jumping the car).

When I lift a rear tire off the pavement autocrossing, I still have several inches of shock travel left, but the swaybar is picking the tire up off the pavement and keeping the coil spring slightly compressed. Without some tension on the inside spring, how would the swaybar continue to function?

 

I was saying full droop, like when both tires on either front or rear or both are off the ground, like when you have jack stands under the front or rear of the car. When I had my GC's and the car was on jack stands, I had at least an inch of free space or more above the top of the springs.

 

That's the first thing I think of when I hear full droop as well, entire car (or one end) off the ground.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">I was saying full droop, like when both tires on either front or rear or both are off the ground, like when you have jack stands under the front or rear of the car. When I had my GC's and the car was on jack stands, I had at least an inch of free space or more above the top of the springs.</TD></TR></TABLE>

In that situation, I think the only benefit of preload is knowing that your springs will be correctly seated when you take it off the stands. Personally, I've never seen my GCs not come down on the perches correctly, even when I tried to get them to do so, but I've heard others have had different experiences.

I define "full droop" as the shocks extended as far as they are capable of doing so under driving conditions. Others could very well have a different interpretation of the term though, and I really don't know who is technically correct.

Though, the reason I instantly rule out jackstand conditions is because even up an jackstands I can't fully extend the rear shocks on my Spitfire, the rear spring prevents the shocks from ever fully extending (leaf spring, though enough weight/force on the rear tire should eventually extend the shock fully). How does one define "full droop" in such a case? What about bushing binding preventing full shock shaft extension, does such a suspension ever enter into full droop? What is the correct definition of "full droop"?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">

huh? So what do you call it when the suspension continues to drop after the spring separates from the top hat?

From what I have always understood, full droop = shocks fully extended, or as far as the suspension bushings will allow.</TD></TR></TABLE>

i don't remember what thread it was in, but in a rather long thread in the RR/AX forum the subject of droop came up and a few people came in the thread to properly define the term to clear some things up. They also gave the exact reasoning why, i have a fuzzy idea but can't remeber exactly so don't want to try and peace it together

 

what could be the possible problems of......to much pre-load

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by K20A_EH &raquo;</TD></TR><TR><TD CLASS="quote">what could be the possible problems of......to much pre-load</TD></TR></TABLE>

Topping out the shock.

Taken to an extreme, you could be at full droop at ride height, if you have more spring tension in preload than the weight of the car at that corner.

 

im waiting on a set of Koni 8041 race shocks... and they are pre-shortened.... they give about 1.5" less droop.... dos that mean they will only lower the car 1.5".... or will there be alittle extra drop when the weight of the car is on them
700/600 lb. spring rates

 

Don't they just shorten the shaft on those and not the shock body? If it's just the shaft, then it will not affect ride height at all.

 

body is shortened

 

That means that the shock's over all length is 1.5 inchs shorter. You probably couldn't get the car up to stock right height any longer, and you can get it lower with out bottoming out.

 

preload tends to be more of an issue on those shock body adjustable type coilovers like omni, megan, PIC, etc, where you have seperate adjustments for the spring height and the shock body height.

Typically, you would just want to raise the spring perch up to a point where the spring is secure against the top mount (preload it a very small amount, like .5" or something), and then use the shock body adjustment to set the ride height and corner balance of the car.

I suppose if you had softer, longer springs, you could preload them a bit more so that you wouldn't totally compress the shock when the car is settled, but that really doesn't happen on performance type suspensions.

dirt bikes use preload to a much greater degree, and there are some pretty good articles on the web about what it does in a moto-cross application.

 

The benefit of preloading for lowered cars, is moving where the shock travel is. The higher the spring perch/more preload, the further out the shock shaft will be. The result will be not bottoming the shaft as soon or more shok travel where you want it. You adjust height by shortening overall length of shock assembly, not moving spring perch.

An extended tophat works similiar, it is adding preload.

 

um. no.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by luciferi &raquo;</TD></TR><TR><TD CLASS="quote">The benefit of preloading for lowered cars, is moving where the shock travel is. The higher the spring perch/more preload, the further out the shock shaft will be. The result will be not bottoming the shaft as soon or more shok travel where you want it. You adjust height by shortening overall length of shock assembly, not moving spring perch.

An extended tophat works similiar, it is adding preload.


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say what? If the shock is already fully extended, then preload is not going to change anything relating to the length of the shock/spring assembly.

 

All I am trying to say is preload changes where the shock shaft is, not overall length. Preloading or compressing the spring by raising where the spring sits will extend the shaft outward and not let the shock shaft travel in as far when spring is fully compressed. This will allow the wheel to travel upward more and downward less. You should not adjust vehicle height by spring perch, use the lower collar that adjusts overalll length.

If you are not using a double adjustable coilover and are using just a sleeve, then what I said may not make any sense to you. On a sleeve like ground control, there are not seperates adjustments for preload and height. They use an extented tophat to increase preload. By extending the shaft, the gc tophat is really lowering the mount in relation to the spring and creates preload. The spring may still not be contacing the mount when extended on some setups.

Preloading for car balance and whatever for performance or racing purposes is not what I am talking about. I have no idea on that should be done. I was just giving a reason you should preload on a low daily driver.

 

youre confused. really.