[Chowbow]

I searched but did not find any relevant information about spring rates for all the different springs / coilovers out on the market right now. It's unfortunate that most manufacturers don't post these specifications as I think it's a good piece of information in the decision making process.

I could not find the spring rate information for the stock setups either.

Unfortunately, I'm starting this post without any relevant information either... I'm going to search around some more to see if I can find something and I'll update this post with information posted.

For progressive spring rates, see if you can find the range and post the range of the spring rate from the soft end to the stiff end.

Let's see if this goes anywhere...

[luckyD]

bump

[luckyD]

i found this

Praxis Spring Rates (lb/in)
Mode Touring SporT Track
Front 250 325 460
Rear 440 680 770

those were used for 2005 bmw 330i sedan weight of the car is 3285 lb ,E 90 weight is 3616 lb. THats only 331 lb difference so those rates could be used

[luckyD]

i would go with sport seting for everyday 350 front and 700 rear. Mybe someone with real expirience can chime in here

[mwahlert]

tein lists springs rates...they are one of few.

i have stumbled upon the following spring rates for eibach pro kit
148 lbs./in. in the front, and 456 lbs./in. in the rear

bilstein pss9 is rumored to be
400 Front
630 Rear

mr. 5 - from another thread you mentioned that orb mentioned stock spring rates of
Front springs--145 lb/in
Rear springs--460 lb/in

not sure if those are for e90/e92 or if regular or zsp rates....

[Mr. 5]

I would love to find the difference in spring rates between the ZSP springs and BMW Performance Springs.

I have a huge feeling that the spring rates are the same even though the springs lower the car a bit.

Maybe Orb will chime in with some information regarding this since he has done so much testing.
I'm not sure if he has actually tested the spring rates with each though.

[Chowbow]

If somebody had a bunch of the springs laying around I am close to some shops that can test them out...

[mwahlert]

the tein stech springs run a 191 up front and 593 out back..

the euro damper system is 280/392

the ss-p is 392/671

i had my eye on the euro damper but can't figure out why the rear springs would be so soft..

i have had kw v1's and now am running eibach pro kit/koni fsd... the kw's were a bit too stiff and the pro kit is too low and soft..... 3rd times a charm i hope..

[cn555ic]

I wonder how the Fk silverline plus spring rate compare to the KW2....are they equal???

[Orb]

The e9x rear suspension has a very high motion ratio so to make any scenes of the spring rate we have to do a few simple calculation so it is comparable. The end result of the calculation will give you the wheel spring rate and this is what your tires see and what you feel.

The motion ratio for the car:

• Front: 0.96^2
• Rear: 0.563^2

Calculation for wheel rates:

Coil spring rate * Motion ratio = Wheel spring rate

Stock 335i example.....

E.g. 145lb/in * 0.96^2 = 134 lb/in
E.g. 460 lb/in * 0.563^2 = 146 lb/in

Spring rates:

Stock 135i:

• Front: 120 lb/in
• Rear : 350 lb/in

Stock 335i e92:

• Front: 145 lb/in
• Rear: 460 lb/in

Stock M3 e92:

• Front: 160 lb/in
• Rear: 550 lb/in

335i KW v3:

• Front: 260 lb/in (progressive average)
• Rear: 570 lb/in

335i KW Clubsport:

• Front: 400 lb/in
• Rear: 570 lb/in

M3 KW v3:

• Front: 285 lb/in
• Rear: 630 lb/in

M3 KW Clubsport:

• Front: 508 lb/in
• Rear: 800 lb/in

335i Bilstein PSS10:

• Front: 385 lb/in
• Rear: 615 lb/in

Orb’s 335i:

• Front: 336 lb/in;
• Rear: 672 lb/in;

To scale the OEM suspension frequencies you can use this formula to get a rear spring rate.

(New front spring rate/OEM front spring rate) * OEM rear spring rate = new rear spring rate

E.g. (265 lb/in /145 lb/in) * 460 lb/in = 840 lb/in

If you do the calculation you will see the rear spring is really soft in these performance setups. Soft ass end means more understeer! Kind of makes one wonder if anyone is telling the truth that thier car is all that great!

Orb

[Orb]

Originally Posted by mwahlert

the tein stech springs run a 191 up front and 593 out back..

the euro damper system is 280/392

the ss-p is 392/671

i had my eye on the euro damper but can't figure out why the rear springs would be so soft..

i have had kw v1's and now am running eibach pro kit/koni fsd... the kw's were a bit too stiff and the pro kit is too low and soft..... 3rd times a charm i hope..

OMG...someone got it right and the winner is.....the tein stech springs at 191 up front and 593 out back

Use the formula above in my other post and guess what scales within 10 lb/in.

Orb

[mwahlert]

orb - where did you get the spring rates for the KW's? any idea if the kw v1's run the same rate springs? i assume yes...

and what setup are you running?

i verified with eibach last night

e90 335i pro kit rates
148F/456R

multi-pro-r1
200F/500R

perhaps tein s-tech springs and bilstein dampers would make a good match? although they are pretty low... are bilstein "sport" - ie shortened stroke dampers - available for the 335i e90?

if i'm doing the math correctly...

• Front: 191 * 0.96^2 = 176 (31% stiffer than e92 zsp spring effective 134)
• Rear: 593 * 0.563^2 = 188 (29% stiffer than e92 zsp spring effective 146)

[mwahlert]

hks hipermax very aggressive spring rates up front - don't understand why

448F 504R

[Chowbow]

Great compilation of info from you guys here. Just to add a quick piece here, TCKline and Vorshlag both have a few spring rates that the user can choose from, and I know for sure Vorshlag can provide custom wound springs at any (reasonable) rate for no extra charge. I would assume TCK does something similar too.

[mwahlert]

Originally Posted by Chowbow

Great compilation of info from you guys here. Just to add a quick piece here, TCKline and Vorshlag both have a few spring rates that the user can choose from, and I know for sure Vorshlag can provide custom wound springs at any (reasonable) rate for no extra charge. I would assume TCK does something similar too.

the eibach multi-pro-r1 and multi-pro-r2 coilovers come with 200F/500R as mentioned above - but you can order additional springs of a wide range of choices..... they just can't be ordered w/ different springs from what i understand - they have to be ordered separately...

i should also mention that these coil overs are similar to the design of the FK's....they have a separate top spring hat - but still use the stock upper mount.

[Orb]

Originally Posted by Chowbow

Great compilation of info from you guys here. Just to add a quick piece here, TCKline and Vorshlag both have a few spring rates that the user can choose from, and I know for sure Vorshlag can provide custom wound springs at any (reasonable) rate for no extra charge. I would assume TCK does something similar too.

You don’t need custom spring as both vendors you listed just get it made or buy them from another vendor. The best spring and selection are listed below and they have a full range of rates and sizes. Swift springs are heads above everyone and Hyperco are very close in quality but fall a bit short on useable displacement. The rest of the vendors out there are not even in the same league.

http://www.swiftsprings.com/products...r_springs.html
http://www.hypercoils.com/

Orb

[Gen_E92]

Originally Posted by Orb

You don’t need custom spring as both vendors you listed just get it made or buy them from another vendor. The best spring and selection are listed below and they have a full range of rates and sizes. Swift springs are heads above everyone and Hyperco are very close in quality but fall a bit short on useable displacement. The rest of the vendors out there are not even in the same league.

http://www.swiftsprings.com/products...r_springs.html
http://www.hypercoils.com/

Orb

does Swift make stock style springs that can be used with my FSD?

[Orb]

Originally Posted by mwahlert

orb - where did you get the spring rates for the KW's? any idea if the kw v1's run the same rate springs? i assume yes...

and what setup are you running?

i verified with eibach last night

e90 335i pro kit rates
148F/456R

multi-pro-r1
200F/500R

perhaps tein s-tech springs and bilstein dampers would make a good match? although they are pretty low... are bilstein "sport" - ie shortened stroke dampers - available for the 335i e90?

if i'm doing the math correctly...

• Front: 191 * 0.96^2 = 176 (31% stiffer than e92 zsp spring effective 134)
• Rear: 593 * 0.563^2 = 188 (29% stiffer than e92 zsp spring effective 146)

All the spring rate info I have was either from load testing, hand calculated or got the information from the vendor. KW v1 thru v3 use the same spring. The newer e90 applications now use KW 2023 (285 lb/) and KW 2017 (630 lb/in).

Your math is correct.

Orb

[TSM330i]

I have the JIC-Magic Cross coil-overs. Here are the spring rates:

450 lbs/in Front
674 lbs/in Rear

[HP Autosport]

Originally Posted by Orb

Kind makes one wonder if anyone is telling the truth that thier car is all that great!

Orb

I know mine is!

[mwahlert]

Originally Posted by HP Autowerks

I know mine is!

what spring rates are you using on the TCK's?

[mwahlert]

i wish someone would make a spring that is about the same rate as the stock ZSP springs - but didn't lower the car so damn much....i basically like the ZSP stance but wish it had a slight forward rake - i hate how the car looks like its squatting when it is standing still