How come my front coils look so over compressed

Anyone have any info on why my front shock looks so wound up? I can’t fit my fingers through them at all. And the ride was degraded after the install.

This is a 2021 kdss off road premium.

The Bilstein is set at .85

 

I don't have any personal experience with that setup, but I'm gonna go with "that's normal."

Any photos of the springs on the stock shocks?

The weight of the 4Runner is obviously on there so it's compressed a good bit. 4Runners (and maybe all IFS) are known for limited front travel.. you're seeing it first hand.

That's stock springs for you.. and that's exactly why I caution the use of large top-hat spacers, especially with softer stock springs. It doesn't look like it would take too much to fully compress that spring, does it? But honestly, I bet it would. I feel your concern though. Put a jack under the corner and make sure the bump stop engages before the spring fully compresses. If so, you should be fine.

 

Did you get 0.85” of lift in the front after install or are you sitting at the same height or lower than stock?

 

I’m noticing springs with 8 and 9, but mine has what looks like 10.

this is at .85. Second ring from bottom.

 

yes, I’m asking if it lifted your front end. If the coils are overly compressed, then your lift would be lower than 0.85”.

 

Sorry, the a quick answer is yes. I went from 19.25” to 20.

 

Have you added any additional weight to the vehicle......like a winch, skids, sliders, ect....?

Did you install the lift yourself or have a shop do it?

Are those the stock coils or an aftermarket coil?

 

I don't think it'll affect your spring spacing but I believe the shocks/springs are supposed to be installed so that the bottom "end" of the spring coil rearward.. yours are facing sort of forward.

 

Moving the spring perch up doesn’t compress the coil any more than normal. That’s how you get lift with these types of set-ups. If your truck still weighs the same, the coils will still sit the same.....just higher since the lower perch is higher.

However, adding weight to your truck will begin to compress the coils. So will some sort of binding issue or perhaps KDSS not adjusting to the lift quite yet??

 

IFS Spring Pre-load is confusing and I still don't understand it. I've searched and.. I don't think most understand it because all I can find is arguments with no scientific fact.

I used to fully think that pre-load couldn't occur until the shock could no longer extend. However, now I'm thinking that when you move the spring up (or down) via perches, collars, or spacers, you are of course extending the shock shaft some.. but I believe that some pre-load must be occurring as well, effectively stiffening the spring. At this point, I can only assume that this phenomenon is a result of the geometry of IFS suspensions. It might be related to the fact that when you extend your coilover by X, it actually lifts the vehicle by X times 1.7 or so. More "pre-load" resulting in a stiffer spring (effectively), or something about angles, must explain this.

Practice proves this because most that lift their trucks via the top perch say the ride gets super stiff.

 

The main takeaway that I have learned from all of the multiple threads on suspension upgrades is that I need to jack up one of the front LCA's to see if it hits the bump stop before fully compressing, especially since I have top spacers.

I believe the front Readylift spacers are only about an 1" tall, but because of the suspension geometry, it yields approximately 2-3" of lift.

Fortunately I don't drive like the Dukes of Hazzard.

I am a pretty conservative driver, especially off-road.

 

Adding preload shouldn't compress the spring any more or change it's compression characteristics... but I too have experienced poor ride quality when too much "preload" has been added.

My two plausible understandings of why this happens:
1. if you're lifting the front enough to where you are creating some rear low rake; you are also shifting some more of the weight distribution to the rear as well. Less weight on the springs means that they will no longer compress as easily which equates to potentially stiffer ride.

2. As the position of the spring is moved, you're also moving the default position of the shock. Too much preload could then significantly limit the shocks travel - you are going to lose down travel as the shock is now further extended at ride height, and you could limit up travel as the spring could now bottom out before the shock can fully travel (or something like that, made sense in my head as I was typing it anyways).

As for OP's question - those look normal to me. If the coils were touching or nearly touching then I would be concerned.

 

Found a new ORP at the dealer without kdss and here a few comps between that one and mine.

they are at 20.25” and mine is at 20”.
Mine are all on the right side.

 

Interesting. I did notice that your spring is clocked differently, and in one of your first pictures it almost looks like the shock might not be sitting centered in the spring, indicating the spring could be bowing slightly inward... but it only looks that way in the first picture; so could be just a wild theory. I'm curious what, if any, difference it might make if you rotated the spring... but that would be a lot of work to prove/disprove a hunch.

The other thought, I know often times there are different OEM spring rates; which would have me wondering if you might just have a stiffer factory spring? Not sure if you by any chance have a picture of what yours looked like before, or if you can recollect that they for sure had larger gaps pre bilstein swap.

 

In an attempt to get .85 of an inch, mm’s make all the difference. Right?

 

Couple things..

First, just so you're aware.. the non-KDSS 4Runner has a different front left spring than KDSS models do. Non-KDSS spring is a little taller. I don't know why KDSS 4Runners don't use the taller spring there, but they don't.

The Toyota installation instructions are clear that the springs need to be clocked a certain way. Why does it matter? Without diving into it, I dunno.. but I'm sure they wouldn't bother saying it had to be a certain way if it didn't need to be. I don't know if it will affect anything regarding spacing or height.. but if you want to get to the bottom of this, you need to eliminate all variables possible.

Also, it looks like your shocks top nut might be threaded on too far. Might want to look into that.. but probably not a huge deal. Essentially that just means you're squeezing those shock shaft bushings more than they need to be.

I still think that the spring looks normal for a slightly "pre-loaded" stock spring.. but I could be wrong.

My pre-lift measurements were 19-7/8" FL and 20" FR.. but there are variances in how we all measure this.

 

The ride gets stiffer with perches, collars, or spacers because often times with these set-ups you’re extending your shock and causing it to ride in a stiffer valving zone.

There really can’t be any additional preload with a coil/strut set up unless you max out the shock travel and are pulling the coil down or are using a coil with a lower spring rate than stock. Another way is by cranking down an adjustable coilover set up.

 

I would have agreed but I think there is more to it.

I know it's a bit different, but IFS snowmobiles use coil-over adjustment to add pre-load so that they have more traction with the front skis. If pre-load wasn't a thing, all they'd really be doing is "lifting" their snowmobile.. however that is not the case. Perhaps some lift occurs, but additional traction via more "pressure on the ground," via a more "pre-loaded" coil-over spring, is why the adjustment is made. For us, the reason we adjust is lift, but pre-load (which, like the snow-mobile, does offer additional traction, albeit functionally indifferent) also occurs even though we don't necessarily want it. It is apparently proven and practiced that pre-load occurs from this adjustment.

No need to argue so if you just don't believe it's possible, OK. Just saying that's where I'm at, for those that may agree or wonder. More research needs to be done but currently I don't have the time to bust out my engineering math textbooks, and a quick internet search just showed me that most don't understand this principle despite how much they talk about it.

Curious, can anyone explain to me why the 4Runner's overall body height raises more than the amount of adjustment at the coil-over in the front?

Please explain what you are saying here. Are you saying that raising the vehicle by adjusting coil-overs adds pre-load to the springs? Because that's exactly what I'm saying. And that's the same thing as raising to a higher perch, or adding a coil spacer.

 

My understanding is if the 4R front axle was a solid axle, you'd have a 1:1 relationship of lift amount object to lift amount. Because of the IFS front end, however, the lift object is raising a point along the control arm, which extends inward and outward, creating more lift. It's like raising the fulcrum on a lever - the outward end of the lever (upper control arm) remains the same height on the wheel side. If you raise the fulcrum (lift spacer/spring etc.), the inward end of the lever (body attachment of the upper control arm) goes up higher than the height of the spacer/spring.

That's my take. It took me a while to understand what was going on, having come from the solid axle Jeep world.

 

In the snowmobile world, I thought that was more about getting the nose up and weight shifted to the rear so it would tend to climb up and float on snow as opposed to wanting to dive or dig? Which I guess in a way would lead to better handling; or perhaps also giving the track a better angle at which to bite.

As far as the lift height raising more than the adjustment of the coilover; it's because you are changing the inside angle of what is essentially a triangle. Small changes made near the inside angle, will affect both legs by (almost) just as much. I don't have the bandwidth nor motivation to draw it all out at the moment, but let's say at 1" gap near the inside angle nets a distance (lift) of 10" at the outer ends. Now you increase that gap by another 1" (2" total); that 1" will move each outer leg further apart by about say 7/8" from each other, so now the distance (lift) at the outer ends is 11 3/4". If you wanted to POC it, grab a couple sticks and try it out.

I did use some cheesy triangle maker online for these just as a visual (not necessarily a good representation of what I was trying to say though).

 

Simple question.

Does your example have the same number of coils as yours?

 

When you add pre-load to a coilover, it only affects the spring tension at full droop. Otherwise it would not lift the vehicle. The spring will be the same length under the vehicle's weight regardless of how much pre-load is added, unless you're riding around at full droop.

I realize I'm beating a dead horse here, but I think you're overthinking it.

The front strut/coilover attaches to the lower control arm about midway between the frame and the steering knuckle. So, there is actually less travel at the coilover than there is at the steering knuckle.

 

LOL, thanks. I couldn't resist. A couple hours later of thinking.. here we go!

Right.

So I bet on a solid axle, our version of pre-load doesn't occur, unless of course you are maxing out your shock travel.

OK.. so geometry is the reason that the lift isn't 1:1. We are extending our suspension by X, which is a sort-of-vertical distance somewhere within the triangle that represents the (a) fender height from LCA plane (wheel hub, basically), (b) LCA plane distance from below the edge of fender (wheel hub, basically) to the LCA-to-frame pivot point, and finally (c) the distance from the LCA-to-frame pivot point and the fender height/edge. As we change the suspension height by X, aka resting coil-over length with vehicle weight applied, the change that occurs at the fender, aka "lift," will be greater. This is because the fender height is located farther from the pivot point (LCA-to-frame connection) than the suspension is, along that top arm of the triangle.

Got it.

Now, here why pre-load occurs. I think.

Consider another triangle that represents the suspension coil-over length as one side (a), the LCA-to-frame connection, to lower coil-over bushing (b), and the LCA-to-frame connection, to upper coil-over hat connection (c). Unlike solid axle, our coil-over does not sit vertically, but rather at an angle. And because the lengths of sides (b) and (c) of the triangle are fixed, as we extend our coil-over length (a), the angle opposite the coil-over increases, which is the angle in between the (b) and (c) connection (which is the LCA-to-frame connection/pivot). As that angle increases, the angle of the coil-over, with relation to the ground and gravity, also changes. It get's less vertical.

Now let's consider the opposing forces. When you lift your IFS truck, you are opposing two things. Like with a solid axle, one of them is gravity. The weight of the vehicle is a result of a fixed mass and fixed gravity. This weight is against gravity, so in a vertical plane. But with IFS, you are not extending your suspension along a vertical plane alone, rather at an angle off of it. So not all of the force applied to the vehicle where the top-hat is located, via suspension, is applied vertically as lift.. with IFS, some of it is applied horizontally along the plane that represents the LCA.

As we extend the coil-over, the angle at the LCA-to-frame pivot increases, and the angle of the coil-over gets less vertical, as we established. So as we lift the vehicle and change it's suspension geometry, less and less of the force applied via the coil-over is translated to lift, and more and more of the force applied via the coil-over is eaten up as "pre-load," simply because, while (a) can lengthen, (b) cannot. The spring is pushing against an immovable object, or at least part of the springs force is. So there is where your pre-load comes from. Some pre-load is always present with IFS, as opposed to solid-axle. This is surely an engineering topic that is considered and applied when designing the vehicle. But more lift translates to different angles (assuming that OE suspension arms are used) which results in more applied pre-load due to decreased angle of the coil-over in relation to the vertical axis, which where lift occurs.

At a certain point, as that angle changes, and the coil-over gets closer and closer to level with the ground, applying force to extend the coil-over would not lift the vehicle at all, but rather just pre-load more and more. This point would depend on the spring rate, I imagine, because enough of the spring's force needs to be applied vertically to overcome gravity. The amount of force applied vertically would depend on angle and spring rate. The gravity to overcome is fixed.

Sorry, I'm not a science teacher, so my explanation may be difficult to follow. But this is where I'm at. Looking forward to discussion!

I realize that these angle changes are minor. But they are there. The pre-load applied is also probably minor, at least when done responsibly, which is why small lifts aren't considered a terrible thing. But it's there. And countless "experts" surely wouldn't refer to pre-load over and over again if it's effects weren't present, right? The snowmobiles increase pre-load for ski traction. I imagine there is a knowledgeable engineer somewhere at Polaris that knows what he's talking about.

So pre-load with solid axle is gravity based. Pre-load with IFS is based both on gravity as well as suspension geometry, specifically the angle of the coil-over with respect to the ground, which changes as lift occurs, all else constant. A more lifted vehicle with the same spring rate will have a more pre-loaded spring, because the angle is different.

 

I would say that all of that certainly sounds plausible, and could very well be a factor (or at least a contributing factor).