How do these spring rates translate to real world driving.

[danielo]

Hi,
Here are 3 examples of coilovers for the R56. They are all rebuildable.

They each have their own spring rates. How do these spring rates translate to the real world?

How do they compare to the S/S on the R56?

Thanks.

1) HKS Hipermax III. The adjustment knobs are located on the top at the front and on the bottom for the rears.

Front: 4.98kg
Rear: 4.98kg




2) Bilstein PSS10. Adjustment knobs are located like the the HKS units.

Front: 5.59kg
Rear: 4.07kg




3) TEIN Euro Damper. These have both the front and rear adjuster knobs located on the top, so rear adjustment can be a PITA.

Front: 4kg
Rear: 5kg

[txwerks]

Depends on the valving in the struts and shocks... If they're well matched to the spring rates, like ours, the ride will be as good or better than OEM even though the spring rates are higher...

For a quick and dirty calc, you can multiply by 5.7 to convert to lb/in:

E.g. Bilsteins

Front: 5.59kg/cm or 55.9 kg/mm * 5.7 = roughly 320 lb/in
Rear: 4.07kg or 40.7 kg/mm * 5.7 = roughly 232 lb/in

FWIW, we normally spec similar rates in the front and the rear (e.g. like the HKS specs) and slightly firmer rates than any of those you listed for most dual-purpose street/track applications (6 kg/mm = roughly 342 lb/in for our KW V2s and 7 kg/mm = roughly 400 lb/in for our KW V3's).

[danielo]

I picked those 3 as they are available in my country (Malaysia). Of those 3, the Bilstein and Teins are rebuildable locally. The HKS either to Hong Kong or Singapore.

I will probably not go with the Teins as i do not favor the USD coil on the rear because its harder to access the adjustment knob.

So that leaves the HKS and the Bilsteins.

I think i might consider the KW, but i can't work out which of the 3 versions i should get. Do bear in mind my R56 is a daily driver but gets driven quite aggressively. Do you have any clue what the spring rates that come with the KW's?

[txwerks]

Originally Posted by danielo

I picked those 3 as they are available in my country (Malaysia). Of those 3, the Bilstein and Teins are rebuildable locally. The HKS either to Hong Kong or Singapore.

I will probably not go with the Teins as i do not favor the USD coil on the rear because its harder to access the adjustment knob.

So that leaves the HKS and the Bilsteins.

I think i might consider the KW, but i can't work out which of the 3 versions i should get. Do bear in mind my R56 is a daily driver but gets driven quite aggressively. Do you have any clue what the spring rates that come with the KW's?

The off-the-shelf KW's re-use the stock upper spring perch in the front and have a 'trapezoidal' shaped spring - we didn't test those, as we knew about what we wanted to start with (i.e. 60mm ID springs, our spec). We got our setups fine tuned at the track with the help of KW's engineers and trackside support.

The Variant 1 is ride height adjustable only. The Variant 2's offer damping adjustment (aka single adjustables) and ride height adjustment... The Variant 3's have independent damping and rebound adjustment (aka double adjustables) and ride height adjustment. I believe that the off-the-shelf units have fairly soft springs right out of the box... For most agressive street applications, I would recommend the Variant 2's - the Variant 3's really are overkill.

If local rebuilds are a priority, I would say that narrows your choices somewhat. I can check with KW and see if they have services available in your locale or near it if you would like...

[danielo]

Its ok dude. Appreciate it.

I'll be going for the HKS units.... just found out the PSS10's will cost an additional 20% over the HKS ones.

Will post up pictures when i get them. Will take about a month as they will have to be ordered in.

[danielo]

Found the damping rates.

F: Rebound/Bump 756/296

R: Rebound/Bump 730/380


Mated with 5kg springs.

Good?

[Ottoman_FD3S]

5kg isn't that stiff..

my RX7 with Aragosta (ohlins) coilovers is running F10.3/ R7.8

but u do feel like u've been punched in the kidnies when they're set on full stiffness.. lol

depends what u want them for really

[andyroo]

Spring rates are only part of the story. Valving is huge, as is travel.

I've been on 7k/5k coilovers that rode like poop, and 12k/10k coilovers that rode really well (on a Subaru).

A shock dyno plot will tell you a lot if you know what you're looking for.

- andrew