[GasBurnlife(landapanda)]

I have called couple of KW dealers to identify a set of stiffer linear springs that I can go to instead of the progressive slightly softer springs that come with the M performance suspension. Does anyone have the serial number or the identification number for that spring set? The one dealer that I called in Maryland wanted to this information so that they can figure out the stiffer spring set that I could use with the existing dampers.

Thanks!

[FaRKle!]

KW rear springs generally say what the rate and length is on them. Typically they have a number printed like "120-200" which is 120N/mm, 200mm length. The front spring PNs aren't descriptive and just a PN. For the specs you have to email KW for them.

For the M-Perf suspension the usual KW markings aren't there since they have BMW markings.

If your front/rear perches take 60 or 65mm springs (measure the ID of the spring in there now), you have LOTs of options to retrofit.

Here's an example where I changed the springs on a friend's B14 kit. Additionally on my own F31 suspension I'm doing something similar (using KW V3 F83 front spring on B14 based strut, and hyperco standard coilover spring in the rear).

Originally Posted by Index

0:00​ Intro and why we did this
2:04​ Front strut modifications to use 60mm coilover springs
4:45​ Rear spring pad modification
5:15​ Ride and handling impressions

[2020M2Competition]

Like FaRKle! said, the M Performance coilover springs do not bear the typical KW markings

Also, the springs are linear (not progressive)

This is stated in the TUV Certificate and also confirmed by jetbill

https://f87.bimmerpost.com/forums/sh....php?t=1590553

The front springs are/were marked 31 33 2 412 973

The rear springs are/were marked 33 53 2 412 975

However, it should be noted that realoem.com lists different part numbers for replacement springs

The front springs are listed as 31 30 2 448 588

The rear springs are listed as 31 30 2 488 590

[AWC-F87]

This is a great post and a problem I am currently trying to figure out.

I have kwv3. My understanding is that the springs that come with them are only a tad stiffer than stock.

On the track my car leans a lot.

I am going to install a front sway bar and end links and I am hoping to figure out what 60mm swift springs I can go with.

In the rear it's a straight forward 60mm spring 8" tall.

My problem is the front. Idk what length I need in the front. 8"? But maybe that's too long. Maybe a 6" with a 2" helper spring?

I'm trying to convert them to a linear spring and ditch the "comfortable" progressive springs.

In hindsight I wish I never bought the v3s. But the price was right. I'm just hoping I can convert the front to a linear swift spring and have a decent set up for now untill I by MCS.

Any help is appreciated

[FaRKle!]

Originally Posted by AWC-F87

I am going to install a front sway bar and end links and I am hoping to figure out what 60mm swift springs I can go with.

In the rear it's a straight forward 60mm spring 8" tall.

My problem is the front. Idk what length I need in the front. 8"? But maybe that's too long. Maybe a 6" with a 2" helper spring?

The spring length is going to be dictated by the rate.

One thing you need to be careful of is making sure the spring you're retrofitting has enough stroke for the load capacity. This typically isn't an issue for these cars when the springs are >350lbs/in. I'd go to 2.5" or 65mm springs since they have a bit more stroke than 60mm. That and the dust boots (like the ones Bilstein has on their C/O) fit better in them (still a bit scrunched).

For the range of springs the KW V3 are valved for, I can't see you running a high enough rate where a 6" long spring would make sense. You'll want to stick with 8".

You could step up to the KW V3 F83 front spring. It's 265lbs/in, 9" long, and maintains the OE top mount ID, 60mm bottom perch ID. PN is 60210190, and they're $80 each.

[M Fifty]

Unless you've changed the top mount, on the front you're going with whatever is available for the M2/M3/M4 (or 2-series).

[FaRKle!]

Originally Posted by M Fifty

Unless you've changed the top mount, on the front you're going with whatever is available for the M2/M3/M4 (or 2-series).

There are OE top mount ID to 60mm ID adapters. Millway sells some. I've used them.

He may also want to check how wide his bump stops are though and if they'll fit in a 60mm ID spring.

[ornicar]

Originally Posted by FaRKle!

The spring length is going to be dictated by the rate.

One thing you need to be careful of is making sure the spring you're retrofitting has enough stroke for the load capacity. This typically isn't an issue for these cars when the springs are >350lbs/in. I'd go to 2.5" or 65mm springs since they have a bit more stroke than 60mm. That and the dust boots (like the ones Bilstein has on their C/O) fit better in them (still a bit scrunched).

For the range of springs the KW V3 are valved for, I can't see you running a high enough rate where a 6" long spring would make sense. You'll want to stick with 8".

You could step up to the KW V3 F83 front spring. It's 265lbs/in, 9" long, and maintains the OE top mount ID, 60mm bottom perch ID. PN is 60210190, and they're $80 each.

Hi FaRKle! thank you for all these informations and your videos, really appreciate it.

I would like a more flat ride style with my ohlins 1M set (60N/mm front ; 110N/mm rear) , sadly the conic spring is not Ø60mm but Ø65mm at the bottom. Do you know a company that sell a spring same as 60210190 ( aroud 45 or 50N/mm rate) but with a 65mm ID at the bottom? I would like to keep the conical shape for the maximum stroke.

Thanks

[FaRKle!]

Originally Posted by ornicar

Hi FaRKle! thank you for all these informations and your videos, really appreciate it.

I would like a more flat ride style with my ohlins 1M set (60N/mm front ; 110N/mm rear) , sadly the conic spring is not Ø60mm but Ø65mm at the bottom. Do you know a company that sell a spring same as 60210190 ( aroud 45 or 50N/mm rate) but with a 65mm ID at the bottom? I would like to keep the conical shape for the maximum stroke.

Thanks

What's the top ID of your spring? Googling that PN doesn't bring anything up.

[ornicar]

Originally Posted by FaRKle!

What's the top ID of your spring? Googling that PN doesn't bring anything up.

The top is the same as F20 F30 ... the issue is at the bottom. it is an Ohlins spring PN : 47040-06 the ID a the top is 97mm. It come from a 1M full Kit MI_BMZMN01 for information.

I think that i will lot have some issue with a KW 2025 and a 60mm ID at the bottom, by te way if i can find the same but with an65MM ID it would be better for the dust below clearance.

[FaRKle!]

Originally Posted by ornicar

The top is the same as F20 F30 ... the issue is at the bottom. it is an Ohlins spring PN : 47040-06 the ID a the top is 97mm. It come from a 1M full Kit MI_BMZMN01 for information.

I think that i will lot have some issue with a KW 2025 and a 60mm ID at the bottom, by te way if i can find the same but with an65MM ID it would be better for the dust below clearance.

I would see if there are any springs from a front "HAS" kit for the F8x dampers that use 65mm ID on the bottom. I know there are some that go from 96mm down to 70mm ID (like KW part 60210218 with 210lbs/in rate). Or see if there's a 65mm to 70mm spring perch adapter.

[ornicar]

Originally Posted by FaRKle!

I would see if there are any springs from a front "HAS" kit for the F8x dampers that use 65mm ID on the bottom. I know there are some that go from 96mm down to 70mm ID (like KW part 60210218 with 210lbs/in rate). Or see if there's a 65mm to 70mm spring perch adapter.

Thank you Farkle. I have search for HAS spring but without success. I just come to order the KW 2025. I hope i have done the good choice and that my drive will be a litlle more comfy.

[HP Autosport]

Originally Posted by ornicar

Hi FaRKle! thank you for all these informations and your videos, really appreciate it.

I would like a more flat ride style with my ohlins 1M set (60N/mm front ; 110N/mm rear) , sadly the conic spring is not Ø60mm but Ø65mm at the bottom. Do you know a company that sell a spring same as 60210190 ( aroud 45 or 50N/mm rate) but with a 65mm ID at the bottom? I would like to keep the conical shape for the maximum stroke.

Thanks

You could go with camber plates to make this a bit easier. Running an 8" spring will give you plenty of stroke.

The alternative is to use an adaptor between the top mount and spring.