[TampaF87]

Curious if anyone knows factory rates. I'm looking to run a spring with factory dampers, and prefer a linear setup and want a rate that's more aggressive than off the shelf H&R's or Eibachs. When looking for Swift's, I only came across M3/M4 specifics and their rates, which seem rather high, and I'm concerned about the valving on factory dampers at that rate.

My concern is twofold:

A ~15% in spring rate is negligible to me. I need something more than that.

A quality damper with proper valving for spring rate in my experience (including on an M2) in off the shelf coilover form is too expensive. Rode on a set of KW V3's and it was bouncy as hell. If I'm going to spend Ohlins or AST money, I better be tracking it everyday (which I'm not).

So I'm looking to try out a spring for factory dampers (they look beefy as hell, I'm just not sure of what rate they are valved for), and work on from there. If I need to upgrade damper afterward I will. If anyone can help, I would greatly appreciate it.

[Deutsches Blut]

I'm also interested.

[horsepower_and_hounds]

Same.....

[UltraMagneticAL]

there should be a sticky w/ all the known spring rates of all the known off-the-shelf suspensions available for this car

[Orange fever]

got Macht Schnell - Sport Competition Springs and love them

[TampaF87]

Originally Posted by UltraMagneticAL

there should be a sticky w/ all the known spring rates of all the known off-the-shelf suspensions available for this car

Definitely. There's so much info on the other areas of this forum, but because there are so few of our cars, and even fewer enthusiasts willing to contribute, its like pulling teeth to find any info.


I'm thinking about ordering a set of Swift Spec-R's for F80 M3 to see if I can make them work. Macht Schnell is using a progressive spring, with hardly any increase in rate over OEM. Same thing with Eibach and H&R. This is appealing for the mass market, but I like to be difficult Progressive is just too soft during most driving scenarios for me. Swift, as far as I have been able to discern, are the only linear rate spring available.

I will report back with my findings to see how they work on the M2. I'm sure the drop levels are going to different. I think the M4 (different part number) is too much of a drop in the rear for the aggressive offset BC Forged wheels I have going on.

[UltraMagneticAL]

Originally Posted by TampaF87

Definitely. There's so much info on the other areas of this forum, but because there are so few of our cars, and even fewer enthusiasts willing to contribute, its like pulling teeth to find any info.


I'm thinking about ordering a set of Swift Spec-R's for F80 M3 to see if I can make them work. Macht Schnell is using a progressive spring, with hardly any increase in rate over OEM. Same thing with Eibach and H&R. This is appealing for the mass market, but I like to be difficult Progressive is just too soft during most driving scenarios for me. Swift, as far as I have been able to discern, are the only linear rate spring available.

I will report back with my findings to see how they work on the M2. I'm sure the drop levels are going to different. I think the M4 (different part number) is too much of a drop in the rear for the aggressive offset BC Forged wheels I have going on.

why not get coilovers and replace the springs w/ a rate you want? that way you get the exact height you want plus the added benefit of adjustable dampers

[Saanen]

I'm running 80N/mm front and 160N/mm rear spring rates on the Ohlins R&T...when the dampers are wide open/ 20 clicks it is tiny bit firmer than stock; 10 clicks it is firmer than stock and 5 clicks is really not reasonable for the street..

I am really curious to find out what the OEM spring rates are!!!!????

[TampaF87]

Originally Posted by UltraMagneticAL

why not get coilovers and replace the springs w/ a rate you want? that way you get the exact height you want plus the added benefit of adjustable dampers

In my opinion and in my experience with a few different suspension options on this platform, where I find a properly valved damper on a coilover setup is stupid expensive for a daily driven car. The resident go-to KW V3's on this car are bouncy in my opinion, even after playing with settings a bit.

Also, a spring/strut combo is quite a bit cheaper than going full coilovers. The valving on factory dampers is pretty damn good, and the internals are beefy as hell, so I figured a higher rate spring would be a great starting place.

This isn't to say I'm trying to be cheap, I'm just trying not to throw away money when I don't see the value. TC Kline DA setup is probably my starting point if I were to be looking at coilovers, and that's 10x what a spring setup runs.

[horsepower_and_hounds]

I would like to know what the spring rate is stock and if they are liner or progressive then also of the H&R sport springs

[TampaF87]

Originally Posted by m2ruder

I would like to know what the spring rate is stock and if they are liner or progressive then also of the H&R sport springs

Unfortunately, H&R doesn't publish their springs rates. Some enterprising individual would have to take it upon themselves to contact H&R directly and inquire, or do the testing themselves. As far as I know, they haven't ever published their rates.

I'm still working on the OEM rates, but I think they are somewhere in the 200in/lbs F and 580in/lbs R. That's just my estimate.

[Saanen]

that's pretty low estimates for the OEM spring rates given that the Ohlins run 515 lb/in front and approximately 1000 lb/in rear...so with the OEM setup the damper is doing a lot of the work managing the kinetic energy whereas the aftermarket setups rely more on the springs....I wish I paid more attention in my physics classes....


200m 65mm 70 N/mm // 400 lbs/in // 7.1 kg/mm
48010-23 200mm 65mm 80 N/mm // 458 lbs/in // 8.2 kg/mm
48010-27 200mm 65mm 90 N/mm // 515 lbs/in // 9.2 kg/mm
48010-31 200mm 65mm 100 N/mm // 572 lbs/in // 10.2 kg/mm
48010-35 200mm 65mm 110 N/mm // 630 lbs/in // 11.2 kg/mm
48010-39 200mm 65mm 120 N/mm // 687 lbs/in // 12.2 kg/mm
48010-43 200mm 65mm 130 N/mm // 744 lbs/in // 13.3 kg/mm
48010-47 200mm 65mm 140 N/mm // 801 lbs/in // 14.3 kg/mm
48010-55 200mm 65mm 160 N/mm // 915 lbs/in // 16.3 kg/mm
48010-63 200mm 65mm 180 N/mm // 1030 lbs/in // 18.4 kg/mm
48010-71 200mm 65mm 200 N/mm // 1144 lbs/in // 20.4 kg/mm

[TampaF87]

Originally Posted by Saanen

that's pretty low estimates for the OEM spring rates given that the Ohlins run 515 lb/in front and approximately 1000 lb/in rear...so with the OEM setup the damper is doing a lot of the work managing the kinetic energy whereas the aftermarket setups rely more on the springs....I wish I paid more attention in my physics classes....


200m 65mm 70 N/mm // 400 lbs/in // 7.1 kg/mm
48010-23 200mm 65mm 80 N/mm // 458 lbs/in // 8.2 kg/mm
48010-27 200mm 65mm 90 N/mm // 515 lbs/in // 9.2 kg/mm
48010-31 200mm 65mm 100 N/mm // 572 lbs/in // 10.2 kg/mm
48010-35 200mm 65mm 110 N/mm // 630 lbs/in // 11.2 kg/mm
48010-39 200mm 65mm 120 N/mm // 687 lbs/in // 12.2 kg/mm
48010-43 200mm 65mm 130 N/mm // 744 lbs/in // 13.3 kg/mm
48010-47 200mm 65mm 140 N/mm // 801 lbs/in // 14.3 kg/mm
48010-55 200mm 65mm 160 N/mm // 915 lbs/in // 16.3 kg/mm
48010-63 200mm 65mm 180 N/mm // 1030 lbs/in // 18.4 kg/mm
48010-71 200mm 65mm 200 N/mm // 1144 lbs/in // 20.4 kg/mm

My estimation is based on what the "upper limit" of the factory dampers are on the M3/M4 from various spring manufacturers. BMW has confirmed that while our suspensions are largely similar, they are setup different for weight differences. Those being heavier, I cannot imagine that they set up the M2 more aggressively.

185 lb/in Stock M3/4 Front Springs
575 lb/in Stock M3/4 Rear Springs

268 lb/in M3 Swift Spec-R Front Springs
715 lb/in M3 Swift Spec-R Rear Springs

279 lb/in M4 Swift Spec-R Front Springs
726 lb/in M4 Swift Spec-R Rear Springs

These are obviously from a different car, but it's a good reference point. If anything, my estimates are high lol

[dvas]

Not sure about OEM, but for comparison with the Bilstein PSS10 progressive spring rates:

F: 514lbs
R: 800lbs

[ZM2]

Originally Posted by TampaF87

Curious if anyone knows factory rates. I'm looking to run a spring with factory dampers, and prefer a linear setup and want a rate that's more aggressive than off the shelf H&R's or Eibachs. When looking for Swift's, I only came across M3/M4 specifics and their rates, which seem rather high, and I'm concerned about the valving on factory dampers at that rate.

My concern is twofold:

A ~15% in spring rate is negligible to me. I need something more than that.

A quality damper with proper valving for spring rate in my experience (including on an M2) in off the shelf coilover form is too expensive. Rode on a set of KW V3's and it was bouncy as hell. If I'm going to spend Ohlins or AST money, I better be tracking it everyday (which I'm not).

So I'm looking to try out a spring for factory dampers (they look beefy as hell, I'm just not sure of what rate they are valved for), and work on from there. If I need to upgrade damper afterward I will. If anyone can help, I would greatly appreciate it.

Why not go with Dinan’s setup?

Springs are linear, slightly stiffer than stock, reuse factory dampers, and can adjust ride height and corner balance.

There’s a lot less roll & pitch, it remove the bounciness from the factory progressive setup, while being more comfortable over small/medium bumps, and a little harsher over big bumps.

[TampaF87]

Originally Posted by ZM2

Why not go with Dinan’s setup?

Springs are linear, slightly stiffer than stock, reuse factory dampers, and can adjust ride height and corner balance.

There’s a lot less roll & pitch, it remove the bounciness from the factory progressive setup, while being more comfortable over small/medium bumps, and a little harsher over big bumps.

The price point of coilover conversion kits like the Dinan, KW HAS, and Ground Control kits remove them from the budget category. The value/performance from those aren't justifiable to me personally, so I would just put that money toward a proper coilover kit.

I ordered a set of H&R's for the time being. I contacted Swift and inquired about the possibility of using either the M3 or M4 spring and they couldn't definitively tell me which spring would physically fit the car, as they haven't ever seen an M2 suspension setup yet. The H&R's were the last resort to hold me over until I can figure something else out while I get everything fitted to the car. From there I will assess where I feel it needs to be, assuming I can get my wheel/tires setup on the car. I will update this post once I figure out what the final solution is. I may very well go with a custom rate AST 5200 or TC Kline DA setup. The purpose of this thread was to try to figure out a non-of-the-shelf- option ( because I have to be difficult ), but I may have to suck it up and bite the bullet.

[horsepower_and_hounds]

I have liked the H&R's so far.... The fronts went right down to the advertised .8/.85 but the rear only went down to .6 so I didn't quite get the .8 at all 4 corners. So the car has a slight rake to it now

[Benzima]

Originally Posted by m2ruder

I have liked the H&R's so far.... The fronts went right down to the advertised .8/.85 but the rear only went down to .6 so I didn't quite get the .8 at all 4 corners. So the car has a slight rake to it now

I got a perfect .75 drop all around. Maybe you should check again once they settled more.

I will do also once my car is out of storage.

[horsepower_and_hounds]

Yea maybe a little more time but they had 2k miles on them when I got them and I have put another 600 so they should be weight relieved. Also the car has 2100 overall miles on it so everything should be good and run in. I will see how it sits after the alignment. I sure hope the rear drops a little bit more in the rear.

[Who?]

Hey guys,

I'm looking at a spring setup with the following spring rates for about a 20mm drop
front: 50N/mm
rear: 120N/mm

The OEM being
front: 36N/mm
rear: 100N/mm

how soft/harsh do you think the ride will be?

[alscks0414]

Originally Posted by Who?

Hey guys,

I'm looking at a spring setup with the following spring rates for about a 20mm drop
front: 50N/mm
rear: 120N/mm

The OEM being
front: 36N/mm
rear: 100N/mm

how soft/harsh do you think the ride will be?

higher rate means basically the amount of force to compress such spring in given distance (ie. 36N/ mm means that you need 36 Newtons of force to compress 1 mm of spring).

Higher the rate harder the ride.
Since you are basically going higher rates all around, they will give you harder ride compared to OEM.
BTW, where did you get OE spring rates? I wanted to find it but never had any source.

Are you just changing the springs or dampers also?

[Who?]

Originally Posted by alscks0414

higher rate means basically the amount of force to compress such spring in given distance (ie. 36N/ mm means that you need 36 Newtons of force to compress 1 mm of spring).

Higher the rate harder the ride.
Since you are basically going higher rates all around, they will give you harder ride compared to OEM.
BTW, where did you get OE spring rates? I wanted to find it but never had any source.

Are you just changing the springs or dampers also?

I asked the guys at st suspension about these rates, so take that as you will

I know eibach aims to be within 80% stiffness with their dpring rates, so these seem abit stiffer.. not sure if the stock shocks will be able to take them over the long term. Im just changing springs