Dr. Zhivago

I think that the top coils touching is normal for a Progressive Spring. EVERY Progressive Spring I have ever seen has done this. Eibach springs do this as well many others. Normal, constant rate springs that have coils touching is a bad thing.

The Eibach Springs on my Supra looked like this from the day they were installed and I know for a fact that there was nothing wrong with them.

My .02
Dr. Z

WATRD

That totally defeats the purpose of having progressive rate springs. When the first stage is binding, you are not using it. You may as well weld the coils together for all the good they are doing you.

The idea behind progressive rate springs is that in normal cruising, the top or softer part is easier to compress, giving you a nice soft ride. When you require additional stiffness in the suspension, the firmer section then begins to compress.

When the top coils are binding at rest, you are not even getting the benefits of the progressive rate, as all of the compression is happening in the stiffer section of the coil. You would be better off going with a single rate coil of the same length in that case so that you at least got the travel, instead of having what is effectively a spacer sitting where your softer coils should be.

Ride around in a vehicle with progressive rate coils that are set up properly and you will immediately feel the difference.

Coil bind defeats the purpose of having springs, progressive or otherwise and is NOT normal. You may like yours just fine that way and that is fine with me, but it means that your suspension is not set up properly.

Progressive springs that bind are too soft for the application.

TDiddy

I was checking out OME stuff from Rocky Road Outfitters and while I was clicking around, I stumbled on this quote on their Order Page:

Buy now, ask for forgiveness later :^)

How true, how true...

Hokiez97

Hey guys,

Hey WATRD that is a good point on coil bind.

WATRD wrote.....
"The idea behind progressive rate springs is that in normal cruising, the top or softer part is easier to compress, giving you a nice soft ride. When you require additional stiffness in the suspension, the firmer section then begins to compress. "

I would like to ask where you are getting this top softer part?

On 2nd gen 4 runners with softest part is the part that mounts on the axle. The top part is positioned on the body. This would allow the axle to flex and take more of the bumps out of the road closer to the road surface, therefore minimizing the bump going into the body of the vehicle.

My P.P. springs are like what Dr. Zhivago talks about. Installed you do have the tougher top two coils touching..... I believe this performs a "base" to which the spring works. There are still all the other "hard" coils that are in the spring combined with the "soft" coils that do not come in contact with one another.

I am not saying anyone is wrong, but I would think that P.P.
(made in germany) would be engineered the correct way and that the liability involved would be too steep if they were not engineered correctly.

Everyone knows that germans tend to over-engineer things, especially when it comes to designing manufacturing plants.... Lots of redundant systems if one goes down... They incurr the extra cost so that the plant doesn't go down. Production = money.......

Just my opinion.

Mike

Ps. very good discussion!

TStango

I was worried that my PP springs would limit suspension flex off road because of the way the upper portion of the springs touch and basically act like a spacer. Also I worried that they were too stiff to reach full compression. After installing front swaybar disconnects last week, I flexed the suspension to it's limit by lifting the front driver side tire and the rear pass side tire with fork trucks. (Pictures on the way, I hope)
This showed that the progressive springs do allow the suspension components to touch the bumpstops and utilize it's full stroke of articulation.

Also, this weekend I took a road trip for the first time with this suspension under a mild load. I had three passengers and the back cargo area loaded with gear. The handling characteristics were still great, and the ride comfort was perfect. No butt sag in the suspension either.

As far as long term sag, it's too soon for me to say. I'll have to periodically take measurments. I sure hope everything stays as is.
Rear tire stuffed into the wheel well

WATRD

You make some excellent points.

First, let me state that I am by no means a 4Runner specific expert. Driving and working on mostly Tacoma's means that in general, when I am refering to the coils, I am talking about a front suspension as Tacoma's have leaves in the rear. I don't even pretend to be a pro in area of 4Runner rear coil springs.

However, after working on coil suspensions for years, from muscle cars to Heeps to Toyota's, I do have some pretty specific knowledge of coil suspensions in general. Generally, the softer portion of the spring is at the top, but I don't see any reason why that would HAVE TO be the case.

You make an interesting point about things being engineered properly, but I think it is overly vague. No aftermarket manufacturer could possibly engineer for all the possible variables that their products will encounter in the real world. Weight is one factor that they have no control over, etc. While these products were engineered to fit the application, anyone who has ever gotten deeply into modifying a vehicle has run into situations where the parts didn't quite fit/performed as you imagined. There is no such thing as one size fits all and if you browse even just the members photos here, you will see what I mean. There is an incredible variation in the way people have set up their rigs and with the +/- aspect of vehicle assembly, we get even more variation.

A manufacturers liability ends at their part failing under carefully specified conditions. If you were to insert one of your springs, into a city bus and it were to fail, do you think that would still be a concern of the part manufacturer? It's an exageration, but you get the idea... that use would be "unforseeable" by the manufacturer.

However, I refer back to the experts. I posted a Google search listing hundreds of pages discussing the problem of coil bind and how to fix it. I have yet to see a single page, credible or not, where they state that coil bind is desireable or even normal. I hang out on a number of boards similar to this one and have seen this discussion a number of times. Only here are there arguments that coil bind is "normal". I am assuming that is because this community is relatively young and the ratio of "gearheads' is still pretty low. It's easy for misinfomation to become gospel, if no one steps in with contrary evidence.

So, my suggestion is that you not take the opinion of any one person on mods. Read what is offered and do some research.

In the event that you find a manufacturers website or other credible source, where they specifically call out that their springs are designed to bind at rest, not only will I be surprised as all heck, but I will learn something.

TStango

Apparently there is a function for dead or inactive coils.

The following statement is quoted from the website linked below it.

"Another issue that adds to the debate between "Linear" and "Progressive" rate springs, is that when most spring manufacturers say that their springs are progressive they are not! Springs may be wound progressively, but that does not mean that they function progressively. Some suspension springs are wound progressively but function as a linear spring. These springs can be called "dual-stage" coils, but are generally referred to as springs with "dead" or "inactive" coils. Dead or inactive coils are coils that are in contact with adjacent coils at loaded height. Inactive coils do nothing but give the spring enough free-length to stay tight in the spring perches at full rebound (when the tires and wheels are hanging in the air like when the car is on a lift). A spring that is wound with inactive coils and no progressive coils that are active, is actually working as a linear-rate spring. This is why when you call a spring manufacturer for spring rates for your application you must ask, "What is the actual working spring rate?"

THe quote above is from the H&R Springs website.

Now I'm questioning if these so called progressive PP coils have "active" coils of varying spring rates.

Does this company make the progressive coils for PP? H&R sounds familiar.

ALBPM

Yes, H&R makes the Progressive coils for PP.

WATRD

This is great info and is consistant with my statement above about progressive coils with binding not being progressive.

Keep in mind that were you to replace those springs with binding, with springs that did not have the binding but were slightly longer, you would still not drop the coils out at full extension AND you get the added benefit of the increased travel.

BTW, good for you on doing some independant research instead of following along on the word of some "authority". I think you are asking the right questions to finally get to the bottom of this

ALBPM

So, since the top coils on PP's so called Progressive Rate coils are binding can PP really call them Progressive?????

The other question all this brings up is:
Does H&R really make these for the intended application (4-Runners) for Perfomance Products or are these Progressive Coils made for some other vehicle?????

H&R does not show any Part Numbers for 4-Runners. All they show are wheel spacers for 2001-2002 4-Runners.

TStango

EXACTLY.

I'm curious as to whether or not the binded coils become unbinded at full droop. When I jack up the front of my truck by the frame and that front tire leaves the ground, there better be some spacing between the binded coils. Otherwise I will be led to believe that these springs were in fact not designed for this specific application.

ALBPM

This is what my front looked like right after the weight of the vehicle was placed on the coil.

WATRD

Since those springs are "captured" or retained by the upper mount, lower mount and shock, the compressed coils do not serve the purpose in the quote above about keeping the springs retained. That assembly is just like the Tacoma front end and rides MUCH better with springs that are not bound up.

I have seen this same symptom when people, including me, have put winch bumpers on the stock TRD progressive coils. There is too much weight for the spring and it binds up, sacrificing the ride. When the springs are replaced with a stiffer coil that does not bind, the height and ride come back

The springs pictured are too soft for the weight that is on them and the ride would be improved by going with a slightly shorter, stiffer coil.