[gowest]

I was shoping for some lowering springs yesterday about this time and called Helix, none in stock but had a good conversation and before getting off the phone ended up ordering a set of the KW version 1 generation 2 coilovers. These are the non rebounded adj. ones, the rebound adj. version is not expected for another month or so. To my surprise I look out the front door about an hour ago and their on my front porch. Great service from Helix and UPS. These will be on the car as soon as my co-driver gets the time to put them on, probably in the next week, but I thought I'd post some tech info on them.

The front main springs are marked 50-170, 170 mm being the lenght with an inside dia. of 60 mm. This is a linear rate spring with a rate of 50 newtons. If I understand this, 10 newtons = 1 kg. or 55.88 lbs., so they are 279 lb. sprrings. The struts come assembled and the front has a tender / hepler spring on top the main spring, this is marked 10-60-80. 80 mm being the length.

The rear spring is marked 40-200, with a 200 mm lenght and spring rate of 40 newtons or 223 lbs. and no tender spring.

New bump stops are included and the shocks are a non painted gold / brass color, sorry no camera, the springs are yellow and the top and bottom spring perchs are purple, very nice. A spanner wrench to adj. ride ht. is included also.

Parts curently in my house waiting to be put on, 15x7.5 SSR comps, Quaife and the above coilovers. On order adj. rear bar and control arms. Haven't decided on any specific power mods yet.

Edit, Took a few more measurements of the KW's.
Fronts weigh 8-8.5 lbs. complete and are just over 2" in diameter, probably 52 mm, in the critical will the tire rub the strut area but max lowering will put the spring perch and maybe the spring into that area as well so wheel spacers or wheels with less than 48 mm offset may be needed to clear everything if you want to slam the car. I'll post again once they are on the car and I have more measurements. Stock fronts weigh 12 lbs.

Rears weigh 7-7.5 lbs.
Stock rears weigh 6-7 lbs.

Edit to Diameter from under 2" to over.
added Stock coilover weights
ride comments and clearance issues
spring rate and camber plate info added

OK, I've had these on the car for a few days now and I must say I'm very impressed with the ride. The car is lowered 1.375" in front and 1.5" in rear. I've had 2 different sets of coilovers on my Subaru and driven several other cars with coilovers, the KW's on my MCS ride better than all of them and WAY better than most. I haven't been able to push it much to check the handling yet as we ended up rushing through the end of the install and alignment and ended up with my corner weights way off. Left front needs to come down 1/8" and left rear needs to go up 1/8" so the corner weights kind of took a double hit ASSUMEING they were close from the factory. They are made to lower an MC 30-60 mm or an MCS 20-50 mm but there needs to be some kind of a foot note on this as without spacers on the front I was only ably to lower it about 3/4" with the OEM 16's but I had some 3 mm spacers with me and with them I could probably go down another 1/8" to -1.5" total, if I wanted but I wanted to leave room for a proper corner weighting later. Get some 5 mm H&R spacers or some wheels with less than +45 mm offset if you want to go lower than this.

Just found out KW has camber plates to fit all versions of their MINI coilovers; V1, V2 still in production, V3 and their 2 way race coilovers. These last two are bump and rebound adj. but the V3 is a more streetable version. Other spring rates are available also, in 10 newton increments.

[gowest]

My question is; for someone that does just street driving but wants to improve the handling of the car wouldn't a progressive rate spring be better?

I guess the simple answer is yes. Better because; they cost less, possible strut clearance isn't a problem, you won't have to worry about corner weighting or adj. the rake or ride height of the car because you can't, yes.

What it will also do is ride better than if you put a linear rate spring, of the the avg. rate of the progressive spring, on the STOCK STRUT but then it probably wouldn't handle better than that but still better than stock/stock.

I hope this helps sometimes I come off a little rough.

[CurtP]

Edit: I had just written a pretty long spiel about progressive-rate springs on the street and during my re-read, realized it was another one of my trademark harsh statements which would probably **** some people off. So I decided to delete it and try to be nicer. In the end, I can't, so I'll try to keep it short and simple.

• Progressive rate springs are horrible for handling -- too unpredictable.
• Tender springs are not to make a linear rate spring progressive or to help the ride, it's to fine tune the suspension.
• Manufacturers of progressive rate lowering springs are catering to a particular crowd who want a low stance but don't know anything about handling.
• Most people who lower their car don't understand what they're doing, but "like the look" and think it's helped the car handle better.
• A car improperly lowered prevents the suspension from doing it's job -- absorbing an impact and allowing the wheel to roll over it, not bounce over it.
• Stock and many aftermarket shocks cannot properly dampen higher rate and progressive rate springs.
• 99% of the time, it's not an issue with the suspension, it's a shortcoming of the driver's ability. Instead of upgrading the suspension, a far better use of the money would be driver's school.

That's about as nice as I can say it.

[Grinder]

That wasn't too bad...

Here's a quote from a book I got for X-mas (I knew/know NOTHING about suspension):

Stiffer Suspension Springs:
Improves - Lower ride height for better handling and looks, reduced body roll for improved tire traction, quicker response to driver steering inputs, improved handling balance if well engineered.
Problems - Harsher ride, handling balance too extreme if poorly engineered, cut or poorly engineered springs can allow suspension or chassis to bottom out leading to potential damage or crashes.

No mention of progressive rate springs (yet).

[Grinder]

Obehave...You're the one who got me started!!! Remember back when you posted about that suspension book you were reading...well....

P.S. I'm on chapter 3 now and *still* no mention of progressive rate springs...

[DaveNagy]

I heard that the stock (factory) springs on the MINI are, in fact, progressive. Not true?

-Dave

[CurtP]

Quote:

Originally posted by obehave
Well you mean old man!!!

Actually I think you're getting a little soft there fella.
Good info as usual.
The one thing that always strikes me is the assumption that you will be lowering your vehicle. I'd eventually like to firm it up but don't really care that much about lowering and yes I do realize the advantages lowering would give me.

Classes. I found out a little late this year that the local SCCA club does some auto-x classes. Next year I'm going.
I'd love to have the time/money for a Bob Bondurant week but that will never happen.

Grinder; heh heh heh Knowledge is power.

Well, don't get used to me being nicer, I'm sure it's just a passing phase I'm going through

Well, the assumption is there because it's all but impossible to find a higher or lower-rate aftermarket springs that don't lower the car. That's why I really like aftermarket adjustable coil-overs that use standard springs coil-over springs -- the springs are cheap, usually fairly easy to replace, and you don't need a spring compressor (since you can just lower the spring seat until the spring is loose). And there's nothing wrong with lowering a car, provided it's done correctly and still allows the suspension to do it's job.

And I agree, knowledge is power -- but verify your sources
Don't just stop at the one suspension book, read several from different authors. You'll usually find conflicting theories as to what works between authors, and alot of it will make sense. Usually, there are two schools of thought when it comes to suspension:

• Stiffer springs, softer anti-sway bars.
• Softer springs, stiffer anti-sway bars.

Can't tell you which one is right for you, since needs vary. I have ran it both ways on my Formula, and personally, I like stiffer springs with slightly stiffer anti-sway bars (then again, the Formula is a big, heavy car and needs both to make it handle better, IMO).


Dave -- I'm not sure if the stock springs on the MINI are progressive or not. I haven't even bothered to look at anything on the suspension since this is my daily driver (and am trying to resist the urge to modify it at all, since I have the "other" car). I do think the MINI could use some upgrades though, as I think it has too much body roll going into hard corners.

[jlm]

re progressive springs:

coil springs are really just torsion bars; compressing the spring is resisted by the torsional strength of the wire which depends entirely on the wire material and wire diameter (not the coil diameter) The spring rate is the force required to compress the spring a certain distance and is constant for a standard spring untill the coils bottom out.

Coil springs are either constant rate (same pitch and radius of winding for full length) or not.

if not, they can be dual rate -like the picture in
davebret's "bushings" post, where you can see the windings get closer together at the top-or progressive rate, where the pitch varies continuously over the length of the spring.

The way they work is that the spring rate depends on the length of the wire that is capable of deflecting (it tewists), determined by the coil diameter and number of coils. In a dual rate spring, the rate is constant until the spring compresses enough to bring the close coils in contact...the remaining shorter length then abrubtly applies the new spring rate. A true progressive spring would change the rate progressively as each coil bottoms out, the idea being that you need more spring rate when the suspension is more compressed and can gradually increase the rate as coils gradually bottom out.

[gowest]

Maybe of interest, maybe not. In a dual rate spring, like the Front of the KW coilovers, if the spring rate of the shorter tender / helper spring is 200 lb. and the spring rate of the main spring is 200 lb. then the spring rate of the two springs assembled together is (AxB)/(A+B) or 100 lb. until the tender spring is full compressed and then the rate is that of the main spring, 200 lb.

In fact the rate of most tender springs in a dual spring setup is usually less than 120 lb. and their lenght is usually about 2" to 4", so they compress fully very quickly, as will be the case with the KW's where the tender spring will be fully compresed just by the car sitting on the ground.

Just some food for thought.

[CurtP]

Actually, the progressive would probably be better on a daily driver (no racing) -- I'm looking at it from more of a competition level. If this is a dual purpose car (race & street), then I would probably go with linear. If you're looking for the best handling, then linear would be the only choice. I would only consider progressive-rate springs on a non-competion car that I wanted to keep some comfort in the ride, and I wasn't too concerned about handling.

Since you've been talking about changing bushings on the anti-sway bars, you may want to try that first before spring replacement.

[gowest]

Bump, edit added in first post.