Lowering Springs - North American Motoring

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Lowering Springs

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Old 03-09-2018, 12:47 PM
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Lowering Springs

Many of us with R52s are aware that when it comes to lowering springs, what works on a R53 will not work on the R52 when talking rear shocks/struts due to the weight. Even the older coilovers suffer from this issue. I just ordered a set of AST lowering springs and unlike some of the other makes out there, they have a specific set for the R52 that has lighter rates in the front and heavier rates in the back when compared to the R53.

I was hesitant at first but had a very good conversation with Sean Myers the NA Rep. He even noted that they block test their products and guarantee the lowering values to within 1 to 2 mm.

Will make another post after I have them installed.
 
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Old 03-09-2018, 02:18 PM
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Whatever happen to your Koni coilovers? Were you not able to dial them in to have the right rake? There is more to the spring rates for a car. I am amazed that I cannot find any thread here discussing the suspension geometries of the front and the rear. Spring rate means squat without taking into consideration of the suspension geometry. I suspect that a lot of aftermarket performance lower springs had done squat engineering work, except to shorten WRT the stock and stiffen the rate.


 
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Old 03-09-2018, 03:47 PM
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I don't know all the proper terms but in simple talk there are a couple basic types of coilovers; threaded perches to adjust the tension on the spring, and threaded perches to adjust the tension plus an adjustable shock body. Not going to get into rebound adjustment. The Koni's I have are the first type and unless the spring is designed to accept the additional weight that is associated with the R52 rear end, adjustable spring perches will not raise the car up enough merely by placing more tension.

When I started running spring calculations it became all apparent that the springs that came with the Koni's for the rears just were not thick/stout enough. I have another thread about calculating and what I found the JCW rates were. The rear JCW R52 springs are approximately 12 mm and that is thick.

Unlike struts, I can get a little adjustment and the main purpose of this thread is to let other R52 folks know that there appears to be options out there other than coilovers. Way Motors knows allot of suspensions as he bought TSW. His springs will lower the car about 3/4" that IMO is better for somebody that is concerned with the lowering impact on the axles, but he does not recommend them for the R52 as the car will settle more in the back.

From what I get from Sean at AST, it appears they have addressed the matter so a Koni Yellow or a Bilstein Strut will work.
 
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Old 03-12-2018, 09:34 AM
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Have you consider changing the rear springs? Cheaper than started from scratch. Swift makes all sorts of springs for COs. I think there are two standard diameters for COs. You would have to know what you have now as a baseline to select the optimum one. I was going to write more about my thoughts on R52s but never got around to.
 
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Old 03-12-2018, 12:07 PM
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The Koni coilovers use the stock spring design so you reuse the existing upper spring plates. I am trying to find something that may end up helping the next Vert guy in the future as I can do a set up as if I had Koni Yellows.
 
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Old 03-16-2018, 08:15 AM
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Very interested in this. Looking at doing springs on my R52. Found the AST and liked their 20mm/25mm drop. Have you installed them yet?
 
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Old 03-16-2018, 03:05 PM
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Waiting for them to arrive from Europe. Hopefully by the end of the month I will have them installed and a mountain run under the belt.
 
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Old 03-17-2018, 04:27 AM
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Sounds like a plan
 
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Old 03-30-2018, 02:54 PM
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My AST lowering springs came in today and I installed them. They are thicker than the Eibachs that came with the Koni coilovers (for the R50/R53). They appear to be as thick as the JCW springs. Took it out for a drive and it is stiffer than the JCWs were but then the Konis are set stiffer than the factory struts.

Now will see how they settle in.
 
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Old 03-30-2018, 03:43 PM
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Originally Posted by Whine not Walnuts View Post
My AST lowering springs came in today and I installed them. They are thicker than the Eibachs that came with the Koni coilovers (for the R50/R53). They appear to be as thick as the JCW springs. Took it out for a drive and it is stiffer than the JCWs were but then the Konis are set stiffer than the factory struts.

Now will see how they settle in.
No photos, didn't happen.

Sound encouraging. We need to see a side view to show the proper rake.

One cannot judge a spring by the diameter of the coil. My Swift springs were skinny compared to MINI issued S springs, but considerably stiffer once in stalled and sits at ride height. Must be the Japanese samurai sword steel.
 

Last edited by pnwR53S; 03-30-2018 at 03:53 PM.
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Old 03-30-2018, 04:02 PM
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No smart phone so no pictures. There is a basic formula for calculating the rate of a spring. It gets more tricky when you have progressive winds but the thickness of the wire, the number of coils and the mean diameter all factor in.
 
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Old 04-14-2018, 03:16 PM
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As advertised, got a 3/4" drop out the AST rear springs. The Koni/Eibachs that came with the kit dropped 2" and would hit the bump stop a whole lot (they were designed for the R50/R53). The ASTs are firm but no bump stops yet. IMO they would work fine on some Koni Yellows as the Coilovers I have are basically a Yellow with an adjustable perch.

Yes stiffer than the factory sport suspension, I have both front and back set at 50% stiff, but not bone jarring. I am hitting some mountain twisties next week and will stiffen the fronts up to 75%.
 
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Old 06-22-2018, 06:53 AM
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Whine could you measure your fender height front and rear and post it up here? I'm trying to fix my wife's R52 that we just bought. Someone put the Bilstein B12 Pro suspension kit on it which was for a coupe. The rear is sitting lower than the front which is all wrong. She also doesn't want a drastic drop and it looks like these springs would do the trick.
 
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Old 06-22-2018, 11:10 AM
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I have had my car up on jacks as I have a Brembo Brake thread going and have been measuring and mocking thing up.

From memory, the rears started out from the ground to the bottom of the 25 1/4" and with the ASTs it was at 24 1/2" . I did crank the perches up 3/16" on the driver side as between my butt and anything I put in the boot, that side was rubbing on the fender liner at 24 1/2". The verts appear to have a metal formation whereas there is a tab/fin about 1/2" long that is parallel with the tire and will slice the tire unless it is bent over. You cannot see this tab/fin unless you remove the fender liner.

The fronts are at 24 1/4"
 
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Old 06-22-2018, 11:14 AM
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Thanks that is about what I expected. My rear right now is at 24" and the front is at 24 1/4". I expect the fronts won't change much but the AST should give the back end a half inch lift at least if not 3/4". I've watched your Brembo thread. I went with the JCW upgrade kit. Expensive but looks and stops great.
 
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