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Another spring question


jon L

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I am trying all ways of lowering the rear that I can think of before spending about $600.00 on the custom coilovers,

plus my expense of machining the parts to convert the suspension.

So, I would like to know if anyone knows if the rear spring is extended when it is compressed.

I mean when it flexes under normal driving. I don't think it does, because it is mounted on both ends and not in the middle.

Normally a spring mounted in the middle would get longer when it is compressed.

Thanks everyone. Jon.

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Jon, I can't answer your questing about the spring.  I don't enough about how it works.

 

Before spending that kind of money you should explore the possibility of making (or having a machine shop make) some dropped spindles, or in the case of the Reatta some dropped knuckles.  I believe it would be easier than dealing with the spring and the shocks and all the other suspension problems you might encounter with the coilovers.  With dropped spindles you don't have to do anything to the suspension other than modifying the knuckle to raise up the spindle a couple of inches higher which will drop down the rear of the car.  I've had dropped spindles on the front of my S10 Blazer for over 15 years and they are trouble free. I was able to buy them from Belltech for the Blazer but you would have to make them for the Reatta. This video will explain what I'm talking about.

 

 

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I think we have had similar discussions here or on the other forum but the abs pickup was an issue for moving the hub area. I know at the time I advocated raising the knuckle assembly, #6, by adding a lower mounting point for the cross bolt at the bottom. I don't have a car at home, but I wonder if the pad the spring end bears against could be cut out and lowered, part #14 in the diagram. Even better would be some form of shim system to allow tailoring the ride height. It wouldn't need to be lowered the full amount due to the location closer to the pivot relative to the wheel mount. 

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2seater, you are correct. That's the problem. I already checked into it and with alot more money it could be done.

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I don't know why the sensor would be a problem.  I got to thinking about this and looking at some photos of the rear hub and knuckle. Below is a photo of the knuckle with the sensor in it. I took that photo and made a simulation of how I envision the knuckle being cut to move the spindle up.  I don't know what metal the knuckle is made of or how well a steel plate could be welded to it.  I believe a 3/8" steel plates with gussets welded in would be strong enough to support the weight of the rear of the Reatta. Perhaps a 1/4" plate would be enough. I would probably get the advice of an engineer before trying this.

 

I'm not recommending doing this.  This is just my thoughts on how I might do it.

 

Before:

rear sensor.jpg

 

After:

rear sensor2.jpg

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Looks simple, But in reality it's a very complicated process.

doing it this way you are changing the whole geometry of the suspension.

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Physically a whole new knuckle would work, or just cutting it and rewelding as depicted would also work. I believe the sensor issue came up where we were discussing just locating the bolted on hub higher. Relocating the bottom mount would do the same except it would also move the lower strut mount higher, reducing potential travel. Of course all lowering strategies will reduce potential travel except the cut and offset as depicted above. At some point the tire/wheel clearance in the wheelwell comes into play.

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Jon,  I don't see anything with dropping the spindle by cutting the knuckle that would screw up the geometry of the suspension. You may have dug into this deeper and see something that I'm missing.  When done correctly you just move the spindle straight up which wouldn't change the camber or caster any.  I've seen lots of people make dropped spindles for their cars.  That was back before you could buy them from companies like Belltech where I got my dropped spindles. All I had to do after installing my dropped spindles, and all I remember anyone else doing, was get a front end alignment done.   As I said before, I'm not pushing for anyone to do this. I was just giving my opinion on how I would go about lowering the rear. You should continue on your path of removing the stock spring and installing coil over shocks if that is what you feel most comfortable doing. ?

 

 

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Ronnie, I understand what your saying, but have you looked under the car and seen how close the bottom shock is to the ground?

If you moved the wheel up 2" you would be almost on the ground and if you hit something you would wipe out the shock and  whatever.

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You make a good point. I haven't looked at it from that point of view. You are probably right. I didn't know the bottom of the shock hung down so far.

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I wish I had mine home to look at but I can imagine . The one saving grace, if there is one, is the bottom of the strut travels with the tire, so while there is exposure, it is in a small area only. Is there any other similar chassis that perhaps has a different wheel mounting position? I have often wondered, if the Riviera has a similar suspension, and the ride height is lower, is there a different part available? I know the ride height specification for the front is definitely lower for the Riviera, not sure about the rear. I think the Olds Trofeo is somewhat related under the skin too. It would probably need to be a model with rear disc brakes and antilock standard.

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25 minutes ago, 2seater said:

I wish I had mine home to look at but I can imagine . The one saving grace, if there is one, is the bottom of the strut travels with the tire, so while there is exposure, it is in a small area only. Is there any other similar chassis that perhaps has a different wheel mounting position? I have often wondered, if the Riviera has a similar suspension, and the ride height is lower, is there a different part available? I know the ride height specification for the front is definitely lower for the Riviera, not sure about the rear. I think the Olds Trofeo is somewhat related under the skin too. It would probably need to be a model with rear disc brakes and antilock standard.

Maybe a hike out to Gibson's when it gets closer to spring? As you know all 3 [Riv, Reatta, Trofero] are out there.

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Ok, So far I have achieved a drop of two (2") in the rear.

From 27" at the top of the fender well, to 25" . It looks a little better.

No pics yet it's cold , snow and ice. And it's in the garage.

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Great! I look forward to seeing pictures of how you did it and how the car looks.  I think that is a first!!  Be careful and do a lot of testing before hitting the road.

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No hybrid parts, all stock. In Fact it was old school tech that got me the two inches.

 

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22 minutes ago, jon L said:

old school tech that got me the two inches

Nothing wrong with that.  I can remember in my early days it was becoming popular to lower the front of your car.  I didn't have any money to spend on any parts so me and a friend put a large flat rock in the front of my Corvair to lower it.  Surprisingly the extra weight in the front made the damn thing handle better.  LOL

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Here's the old school tech.  First I got another spring from Jim Finn. I cleaned it up and put it my vise.

wIth a gasket scraper I removed the end pads. Took them to my bandsaw and cut them in half so 

that they were half as thick. Then I took the (new) spring to my table router and removed 3/16" of 

material in the areas that you can see in the pictures. Then, with my bandsaw I removed 3/16",

material from both ends of the spring. then glued the modified pads back on the ends of the spring.

By the way, It is very easy to remove the old spring as long as you soak all bolts for a few days.

The actual removal of the spring took about one hour and less to put the modified one  back.

The only thing I regret is not taking more off the ends, as that seems to be the way to lower it more.

20200124_150144.thumb.jpg.5732bea194dfd06b5b270f51dc35ea2b.jpg

20200124_150139.jpg

Edited by jon L
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By giving the spring, more spring, it flexes more and when it flexes it becomes longer, so I would guess

you could take 1/2" to 3/4"  off the ends and get a lot more drop.

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29 minutes ago, jon L said:

By giving the spring, more spring, it flexes more and when it flexes it becomes longer, so I would guess

you could take 1/2" to 3/4"  off the ends and get a lot more drop.

How thick is the pad on the end to start with and does it show any significant wear? Maybe that rock in the trunk to complete the adjustment of the look? Are you going to need to adjust the camber when complete? Looking forward to pics of the finished product.

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