Aftermarket suspension: springs / coilovers

Carsten Haase

Carsten Haase

Well-Known Member
I'm looking at getting coilovers soon (although for some atypical reasons) and am curious what others have done about the different weight distribution vs the ICE F56 the suspensions were designed for.

I can't find a reliable source for the actual weight distribution of either the SE or the ICE cars:
  • For the SE I've seen both 58/42 and 54/46
  • For the Cooper S I've seen both 63/37 and 68/32
From those numbers, the SE should have a 30% to 65% stiffer rear spring (a huge range) and a 8% softer to 6% stiffer front spring (probably negligible).

To anyone who's upgraded their suspension, what spring rates did you get? How did it change the balance of your car?

Theoretically, using ICE F56 suspension should cause more understeer with the softer rear which is definitely not something I want.
 
Is there even a choice of spring rates among the available springs or coil-over kits? I think moving the handling needle from negative to neutral will require a stiffer rear ARB and playing with corner weights.
 
SameGuy said:
Is there even a choice of spring rates among the available springs or coil-over kits? I think moving the handling needle from negative to neutral will require a stiffer rear ARB and playing with corner weights.
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Buying springs separately isn't too bad especially for coilovers that use a standard size.

A stiffer rear ARB is essentially just a stiffer spring that is only active during cornering and one sided bumps. Stiffer springs aren't used to tune balance for a number of reasons like making the ride harsh but a softer spring would need a stiffer ARB to keep the handling the same.

I'm actually looking for a slight lift and longer suspension travel in addition to improved handling balance. Contradicting goals, but I had that setup on my Miata and it was pretty great for having fun driving to the typically dirt trailheads.

I've already been a tripod a couple of times getting to trailheads and a stiffer ARB definitely wouldn't help that...
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I have ST coilovers for the SE and went with the standard spring rates that comes with the kit. They don't publish the actual spring rates either.

If you do compare the S with the SE spring sizes from KW and ST, then you will see that the front springs are in fact softer and the rear are stiffer. By how much is hard to say. They use progressive springs too.
 
JonR said:
I have ST coilovers for the SE and went with the standard spring rates that comes with the kit. They don't publish the actual spring rates either.

If you do compare the S with the SE spring sizes from KW and ST, then you will see that the front springs are in fact softer and the rear are stiffer. By how much is hard to say. They use progressive springs too.
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Thanks! Good to know I'm mostly on the right track with S vs SE rates. I've definitely noticed a lack of info on many aftermarket suspension, how are you supposed to compare stiffness without some sort of spring rate or curve?

One of the things I miss about my Miata is the level of information available both from the community and aftermarket vendors... Not only did they publish spring rate but also damping/rebound curves and even a recommended alignment.
 
I believe that the stock front springs are close to F55, the rears close to F54. A vanilla F56 coilover set is very likely to disappoint. There are some companies offering SE specific sets. Buy one of those, preferably a high quality one.
I'd love to know what the actual SE spring rates are.
 
  • KW/ST is the only company that sell coilovers specifically for the SE. Both brands use the same KW springs.
  • H&R springs sells a set but they are the same as the F57 convertible. The front springs are the same as the S and the rear springs have a higher spring rate.
  • Eibach sells a set which use the front springs from the S and the rear springs from the F54 Clubman.
I've also tried the Eibach springs with stock dampers and the rear was too bouncy for me. Eibach uses progressive and really long springs in the rear which was a little better for handling rough roads but it was too bouncy for me over large bumps and dips in the road.

The dampers from an S should work just fine in the front of an SE and you could probably use the rear dampers from a Clubman in the back. I don't think anyone sells just dampers for the SE.
 
JonR said:
  • KW/ST is the only company that sell coilovers specifically for the SE. Both brands use the same KW springs.
  • H&R springs sells a set but they are the same as the F57 convertible. The front springs are the same as the S and the rear springs have a higher spring rate.
  • Eibach sells a set which use the front springs from the S and the rear springs from the F54 Clubman.
I've also tried the Eibach springs with stock dampers and the rear was too bouncy for me. Eibach uses progressive and really long springs in the rear which was a little better for handling rough roads but it was too bouncy for me over large bumps and dips in the road.

The dampers from an S should work just fine in the front of an SE and you could probably use the rear dampers from a Clubman in the back. I don't think anyone sells just dampers for the SE.
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Clubman dampers are way too long for an SE. Unless you are lifting one?
Clubman 625/408mm
F56 563/373mm
The SE dampers are slightly longer than vanilla F56s. Lower an SE, and the vanilla F56 dampers are ideal length. Rear damping, not so much. Adjustables should be OK, though. Just add an extra click or two.
Eventually, we'll get a wider choice of SE tailored stuff.

Bilstein has SE B4s, which are their OEM replacement.
I wouldn't be at all surprised if they came off the same production line...
 
pictsidhe said:
Unless you are lifting one?
Click to expand...

I am in fact planning on a slight lift out of necessity. Currently looking at these which have rebound adjustments and independent ride height and spring preload adjustment. They do say elsewhere that they can ship whatever springs you want but I have to confirm what they have available for the MINI.

pictsidhe said:
Clubman 625/408mm
F56 563/373mm
Click to expand...

Where did you get these dimensions? I'm looking for the SE's shock travel but can't find that info anywhere
 
Carsten Haase said:
I am in fact planning on a slight lift out of necessity. Currently looking at these which have rebound adjustments and independent ride height and spring preload adjustment. They do say elsewhere that they can ship whatever springs you want but I have to confirm what they have available for the MINI.



Where did you get these dimensions? I'm looking for the SE's shock travel but can't find that info anywhere
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The f54 is from a Monroe spec sheet, the f56 from a Koni spec sheet. I've also seen a Bilstein f56 spec, which I'm sure was the same as Koni. I haven't found measurements for the SE yet. But my ruler says they are slightly longer. About 10-15mm I haven't measured them accurately, yet. Somebody is going to have to take one off and measure it properly...

Easy way to lift the front it spacers on tope of the struts. Rear you could space the shocks, then either find longer springs, or make some spacers for those, too. I wouldn't go too far. An inch of suspension lift will let you run bigger diameter tyres.
 
JonR said:
In response, I'm going to buy a Jeep Wrangler and slam it as low as it will go. Or maybe a Toyota Land Cruiser. I wonder how much negative camber and how much tire stretch I can have. :D
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There is a very quick Cherokee in my autocross club.
 
I am ordering the H&R springs, hopefully the ride quality won't change too much. My daily commute has some stretches of relatively bumpy freeway and the car is already slightly bouncy.
 
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