Likely many in this subforum have seen details on my 2006 MCS specifically ordered and modded for tracking by the original owner when brand new. Outlined in that thread topic includes my plan to tame some of those aspects for more practical street and highway usage. Right now, I keep eyes on the pavement ahead for dips and potholes due to the especially harsh ride and minimal ground clearance. I believe the Eibach springs are primarily responsible for that with the polyurethane bushings, sway bars and super low aspect ratio tires all contributing to a lesser extent.

After doing online research, my plan has been to replace those Eibach springs with a full set of WMW's TSW linear rate springs, with claimed ride compliance closer to OEM MCS spec plus a mild drop. In any case, I'll continue using the Koni Yellow shocks also included as part of performance handling mods back then. My dilemma is, WMW has been out of stock on TSW springs for quite a while with no indication when they'll have them again. Some here might suggest Swift or H&R but I'm not interested in progressive rate or similar in the weeds ride height as my car has now. OK then, the subject JCW Sport springs which are still available but quite spendy compared to aftermarket brands. OTOH, I'd prefer to pay 2X once and be done with it to achieve my objectives. Any comments that might change my mind before ordering? http://motoringfile.com/files/JCWSUSPENSIONKIT.pdf

BTW, my mentioned thread topic stated just 4026 total verified miles at the time I bought it less than 2 months ago. Actually, that's not quite accurate. Tires installed within a few hundred miles from new were/are Toyo Proxes RA1 205/40R17 vs OEM spec 205/45R17. As I've determined by Garmin Nuvi GPS unit (installed on ProClip mount), the speedo is reading fast by prox 11% at 55 mph, thus the actual total miles was correspondingly less (~ 3650) as of that date. Those tires are 15+ yrs old yet look like new but I'll be replacing them to correct the speed/odo error after the suspension project and with full alignment at that time.

TIA...

 

Swift Spec R springs are not progressive, they're linear. JCW Red springs are progressive. I swapped them out on the GP for the Swift Spec R's using KONI Yellows. They're an improvement....Not dramatic but much more predictable for the track. The Spec R's will not dramatically lower the vehicle, only 25-30mm as I recall but your 40 aspect tires are responsible for some of your lowered aspect and more harsh ride. Suggest you go with 215/45x17 for a little more contact patch and minimal speedo error. The Spec R/KONI Yellow package is a good, all round Street/Track set-up. You can dial in soft or firm with the strut/shock adjustment.

 

Very interesting comments - much appreciated! Wasn't aware MINI used anything for OEM fitment other than linear rate.

These Swift Spec-R are not progressive rate? Googling spring types suggests stacked dual-rate type progressive vs linear.

 

One thing that might throw a monkey wrench into your speedo/odometer correction is MINI speedos read fast from the factory, but the odometers are supposed to accurate in spite of this. The fast speedo thing is a built in safety cushion due to German regulations. Apparently manufacturers can be fined for selling a car in Germany with low reading speedos so they read fast because of this. I don’t remember if it’s about 3 mph or 3%, but if you make your speedo match your GPS with bigger tires the odometer will start to record more miles than actually travelled. I think I’ve seen posts about programming the digital speedo in the small on-board computer display to read correctly, but I think they also said the main “analog” speedo isn’t affected by this setting.

 

Another informative reply appreciated! I'm aware correlation between speedo and odo errors often isn't a constant. I didn't know about that German speedo reading thing but a similar offset used to be considered normal with USA car mfrs. Aligned with NC Trackrat's suggestion for 215/45R17, I'm thinking replicating OEM spec 205/45R17 revs/mile but just a bit taller/wider tire to close the gap. For example using Toyo catalog specs for Proxes Sport A/S (brand/model not yet chosen), baseline for 205/45 would be 857 revs/mile whereas 205/40 @ 885 rpms (+3%) and 215/45 @ 843 rpms (-1.7%) seemingly reasonable compromise. Those differences don't equate to discrepancies shown on gps readings, so the remainder likely is intentional by design as you suggested.

Edit - aside from the instrument calibration issue, also meant to comment on tire aspect ratio being a major contributor to ride harshness, i.e, the less air volume present with such low aspect ratio, the less effective "air spring" is present which OEM spec size or a bit larger will improve at same or similar psi settings.

Still looking for feedback on the JCW red springs from owners that have them from new or switched to them and are satisfied for non-tracking utilization.

 

I believe that looks are deceiving. When installed, the closer coils of the Spec R's are fully compressed. They are only there to take up the necessary height. The wider coils are linear.

 

I am not sure why the MINI springs have been come to be known as progressive. The red JCW springs for a R56 look to be linear. I can check our R50, but I am pretty sure they look to be the same...
(Update: see post below for description of the springs for the R53... Not the same as that for the R56)


R56 JCW Sport springs

The little bit of turn-in at the bottom is just for the perch and has no affect on the spring rate once compressed...

 

Update: I got confirmation from my chosen BMW MINI dealer's online parts store this morning that (2) of the original (6) JCW "red" Sport Suspension coil springs are available to order with inventory on both front spring P/N 31-33-6-768-415 and rear spring P/N 33-53-6-768-417. I placed my order just now, subject to delivery in 3-5 weeks.

 

Eddie07S, you may well be correct but the R53 Red fronts look somewhat different. They're shorter in height and the coils are somewhat smaller in overall diameter at the top and bottom but "fatter" in the middle. One noticeable difference was that I was able to achieve about 1/2 degree more negative camber with the Swift Spec R's than the Red's because the spec R's are smaller in overall diameter than the Red's, thereby allowing me to go further inboard at the top without hitting the inner wheel well.

 

Can’t say I am surprised about the R53 springs being different from the R56. A lot of suspension parts are interchangeable between the two models, but apparently that doesn’t mean they are the same... Hence my confusion...

MINI does have “fat” springs up front. I have a set of K-Mac camberplates for my R56 and they have an off center upper spring perch that moves the spring outboard a bit. I haven’t installed them yet, so not sure how that works out...

 

Although I didn't buy my JCW springs from ECS Tuning (too expensive!), I'll link to their product pages with images of each spring:

JCW R53 "red" front spring


JCW R53 "red" rear spring

 

Same. I also paired them up with new Koni yellows and like the setup.

 

I'm also running Koni Yellows with Swift Spec-Rs and Vorshlag camber plates on my R50. I've been very happy with them.

 

Thanks for comments on what you're running, however it would be helpful to me (plus others likewise interested) why you chose specific springs relative to desired objectives and why you're satisfied. For me, not for tracking or autocross but instead, practical ground clearance and ride compliance on paved streets and highways while working well with the other suspension mods on my car done by the original owner when new. Seems to me Swift Spec-R springs wouldn't be an improvement vs the low ride height and relatively stiff (unknown spring rate) of the Eibachs installed with the other components in early 2006. I could have ordered OEM springs correct for my VIN but decided the JCW reds should work well with the Koni Yellows while being just 10mm drop as claimed in the Nov 2004 press release (linked in first post). I update the topic on my car with edits and new posts as I learn aspects in lieu of build history docs not found by the original owner when I bought it from him 2 months ago at just 4026 verified miles. Take a look at that if curious. BTW, that PO owned a new 2002 MCS, followed by a new 2004 MCS MC40 before ordering this 2006 MCS and then modding it (so-stated) to easily exceed factory JCW engine, brake and suspension specs. Whether or not that was achieved would simply be conjecture.

 

I think the Swift Spec-Rs have been pretty well covered in various threads, but I guess I can repeat a bit. They only drop the car 0.7" in front and 0.5" in the rear, unlike most other lowering springs on the market, which usually lower the car more. They ride decently well for what they are, and the rates and drop feel very well-suited to the first gen cars. I wanted a linear spring, and I didn't want the excess rear drop of the TSWs. I also wanted a straight-wound spring in the front, which the JCWs aren't. And last but not least, the right JCW springs for my car were NLA anyway (not that the Swifts were designed for my car either, but whatever).

 

I don't have any empirical data, just "seat-of-the-pants" impression. I had the Swift Spec R's with Koni Yellows on my '05 MCs for a few years and really liked them. After selling the car, I began by tracking the GP with it's stock set-up and it was "o.k." but, for lack of a better term, "uninspiring". The car seemed rather numb. I swapped out for the Swift Spec R's and Koni Yellows and am pleased. Perhaps it's just because I feel more "at one" with the car.

 

^^^ Thank you both for those clarification responses. Yes, I did use forum's advanced search with keywords on noted spring types. NC T's "tracking" his GP confirms for me Spec-R is ideally tuned and suited for that whereas MINI stated JCW Reds were not designed for that, hence my choice given currently available alternatives for non-tracking utilization. My own tracking history was a long time ago with '74 Alfa GTV (purchased new, owned 25 years) modded for club time trail events at Riverside International Raceway. I'm an old guy now who lives in a small town 100+ miles away from pretty much any larger population centers. My R53 is just for fun driving in the local mountains or simply as Garage Art. I'll update my primary thread topic after those "reds" are installed along with 4-wheel alignment and replacement taller profile tires.

 

I hope you'll be pleased with the "reds" but, just for clarification, the Swift Spec R's are designed for street/track, not just a track only scenario. They're sufficiently compliant to be comfortable in town or on the highway (as long as you don't hit a stretch with expansion joints)....and, as for being "old", I'm just 81 and still enjoy my time working in the garage, on track or sitting in the right seat instructing at HPDE's.

 

81? Schweeeet! I am seriously considering the Swift Spec R's thanks to your and others feedback. For the r56 it lowers a little more than an 1" which would put me where I want to be.

 

JCW springs obviously are linear. The only progressive component is the bump stop.
.

 

^^^ Agreed from what I've read on BMW (and similar car mfrs) typical design preference for linear rate springs. Curious though on what basis you say that, since there have been contrary perspectives stated here. Mine ordered from Germany via USA-based authorized dealer arrived a few weeks ago, however no time to install until hopefully next week when I'm back home again. When I do that, I'll measure and post findings on free length and wire diameter of the Eibach springs installed early 2006 vs these JCW "reds". Not a direct spring rate comparo, however should provide relative data WRT projected ride height and road compliance vs felt harshness.

 

You will also need to measure the overall diameter of the coils and the number of full coils in addition to wire diameter..

 

^^^ Thanks, knew that. Coil springs essentially being a straight rod of given diameter and tensile strength before wound. The shorter the overall rod length, the stiffer it'll be...

 

Rather than replicate updates just posted on my R53 thread topic, I'll link to that here

 

I don't get on this forum much any more but noticed this thread. I've had multiple suspensions on my car, including coilovers and the Spec R's, and the JCW's are the sweet spot for "me". No, they aren't as sharp as the Swifts, but I think for daily driving they offer a better ride with more than street capable handling. They also ride better than the factory optional sport plus springs. I think you should be quite happy with them. Also, as others have noted, I highly recommend going to a 215/45/17 tire. Not only do you get a bit more cross section, but more sidewall and it corrects the speedometer error according to my GPS.