Spring Rate Chart for Evo X

[Hiboost]

I think it's time to start a sticky on all the different Springs as well as Coilovers out there for the Evo X. If you have any additions or corrections with a link to the stats, please post here and I or a moderator will update the list.

Springs .................... Front Rate ........ Rear Rate ...... Front/Rear Drop

Stock GSR .................... 3.5 kg ........... 2.8 - 3.7 kg .......... 0.0" / 0.0"
Stock MR ...................... 3.5 kg**........ 2.9 - 3.8 kg .......... 0.0" / 0.0"
Cobb ........................... 3.8 kg*........... 3.1 - 4.1 kg*......... 1.3" / 1.4"
Eibach Pro ................ 2.6 - 4.9 kg ...... 1.8 - 4.8 kg .......... 1.2" / 1.0"
Swift Sport Mach ...... 2.7 - 4.3 kg ...... 2.3 - 4.4 kg .......... 1.0" / 0.6"
Tanabe GF210 ............. 4.5 kg ............... 3.5 kg ............... 0.7" / 1.1"
Tanabe DF210 ............. 4.5 kg ............... 3.3 kg ............... 1.1" / 1.4"
Tein S-Tech .................. 4.2 kg ............... 3.8 kg ............... 1.4" / 1.0"
Works .5" .................... 3.8 kg*........... 3.2 - 4.3 kg*......... 0.5" / 0.5"
Works .9" .................... 3.8 kg*........... 3.2 - 4.3 kg*......... 0.9" / 0.9"

* Cobb spring rates estimated based on +10% front/+10% rear and Works based on +10% front/+15% rear
** Estimated based on rears being very close to the GSR

Shocks .......................... Damping

Stock KYB (GSR) ............... Preset
Stock Bilstein (MR) ........... Preset

Single (rebond only)
Single Dual (compression and rebound adjusted together with one knob)
Dual (compression and rebound adjusted independently)
Triple (compression high/low and rebound)

Coilovers ........................ Front Rate ...... Rear Rate ....... Damping .............. Front/Rear Drop

AMR ................................... 12.0 kg* ......... 14.0 kg* .......... 8-way ........................Adjustable
BC ...................................... 8.0 kg* ........... 6.0 kg* ........... 32-way........................Adjustable
Eibach Multi-Pro R1 ............ 8.0 kg* ........... 6.0 kg* ... Multi-way / Single dual ... 0.8"-> 2.5" / 0.8"-> 2.5"
Eibach Pro-Street ............... 8.0 kg* ........... 6.0 kg* ........... Preset .......... 0.8"-> 3.0" / 0.8"-> 3.0"
HKS Hipermax III ................ 7.0 kg ............. 5.0 kg ... 30-way / Single dual .................Adjustable
HKS Hipermax III Sport ..... 12.0 kg ............ 10.0 kg ... 30-way / Single dual .......... Adjustable
JIC FLT-TAR ....................... 10.0 kg ............ 8.0 kg ............. 15-way .....................Adjustable
K-Sport Kontrol Pro ............. 9.0 kg ............. 7.0kg ..............36-way .....................Adjustable
KW Variant 3 ....................... 8.0 kg* ........... 7.0 kg* .......... 14-way ......... 0.4"-> 2.0" / 0.8"-> 2.2"
Megan Street ...................... 8.0 kg ............. 6.0 kg ............ 32-way .....................Adjustable
Megan Track ...................... 12.0 kg ............ 10.0 kg ........... 32-way .....................Adjustable
Ohlins Stage III DFV .......... 10.0 kg* .......... 7.0 kg* ........... 25-way .....................Adjustable
Stance GR+ ........................ 10.0 kg ............ 9.0 kg ............ 15-way .....................Adjustable
Stance GR+ Pro .................. 14.0 kg ........... 14.0 kg ........... 15-way .....................Adjustable
Tein Monoflex ..................... 14.0 kg ........... 10.0 kg ............16-way .....................Adjustable
Zeal Function Xs ................ 10.0 kg* .......... 10.0 kg* .......... 6-way .....................Adjustable
Zeal Function X .................. 12.0 kg* .......... 12.0 kg* .......... 6-way .....................Adjustable
Zeal Super Function ........... 14.0 kg* .......... 14.0 kg* .......... 6-way .....................Adjustable

* Custom spring rates may be available

Spring rate conversions kg/mm to lbs/in (originally posted by Vankuen in the Evo 1-9 forums)

1lb = 0.45359237kg
1in = 25.4mm

.45359237 / 25.4 = .017857967322834645669291338582677

So now we know that 1lb/in = .017857967322834645669291338582677.

So if we want a spring that's roughly 560lbs; we'd multiply both sides by 560, and come up with roughly a 10k spring rate. Alternatively if you already know the kg/mm rate and want to find out what the lbs/in is, just divide the spring rate by that reaaally long factoral above (the .0178...).

But just in case you all didn't want to go through all that, here's a chart:

kg/mm to lbs/in
-----------------------------
16 = 896
15 = 840
14 = 784
13 = 728
12 = 672
11 = 616
10 = 560
9.0 = 504
8.5 = 476
8.0 = 448
7.5 = 420
7.0 = 392
6.5 = 364
6.0 = 336
5.5 = 308
5.0 = 280
4.5 = 252
4.0 = 224
3.0 = 168
2.0 = 112

[goofygrin]

Coil overs:

BC: 8/6 but can be revalved at time of purchase (free?)
Stance GR+ 10/10
Stance GR+ Pro 14/14

KSport: 9/7
Megan: Street series 8kg/6kg, Track series 12kg/10kg

[Hiboost]

Originally Posted by goofygrin

Coil overs:

BC: 8/6 but can be revalved at time of purchase (free?)
Stance GR+ 10/10
Stance GR+ Pro 14/14

KSport: 9/7
Megan: Street series 8kg/6kg, Track series 12kg/10kg

Thanks for the updated info, I'll be sure to check here every few days to get the stats entered in.

If anyone can get the Stock MR Spring Rates as well as the Eibach Pro that would be awesome:

Stock MR ....................... ?? kg ............... ?? kg ................ 0.0" / 0.0"

Eibach Pro ................. ?? - ?? kg ......... ?? - ?? kg ............ 1.2" / 1.0"

[goofygrin]

I'd like to know the spring rates on the KW Variant 3. Their website is a hodge podge of 1993 and 2007 technologies and it's obvious that they don't really want to publish any real info...

[MrBonus]

Thank you for putting in the time to do this.

[PurgeIt]

Zeal Function Xs / Xs-Aluminum / X / X-Aluminum / T / A: Custom spring rate w/ matched valving can be specified at time of order (no extra charge)

Zeal Super Function: 14/14 spec; Custom spring rate w/ matched valving can be specified at time of order (not sure about extra charge)

[goofygrin]

Maybe we should put MSRP/Street prices on there as well? Just so that you know how much each of them costs without having to PM/email a bunch of vendors (who will not get back to you ;-)

[GTWORX.com]

Originally Posted by goofygrin

Maybe we should put MSRP/Street prices on there as well? Just so that you know how much each of them costs without having to PM/email a bunch of vendors (who will not get back to you ;-)

Tricky thing there is that MSRP can change quite a bit, especially recently. Prices are all over the place.

Good work on the chart!

- Andrew

[Hiboost]

Thank you for putting in the time to do this.

Not a problem, will be fun to see what is out there for our X's this way and have it in a central place.

Originally Posted by goofygrin

Maybe we should put MSRP/Street prices on there as well? Just so that you know how much each of them costs without having to PM/email a bunch of vendors (who will not get back to you ;-)

It may be a rough guide as to what to expect but I'm on the fence about how easy it will be to keep updated. Plus different vendors will be discounting them at all kinds of percentages making the retail prices hard to compare.


I was also thinking for the Coilovers we could possibly post an adjustable range of ride height like:

+1.0" to -2.3" / +1.2" to -2.1"

Obviously the optimal settings are not going to be the maximum slam but some want the range for car shows and then return them to realistic ride heights for driving. I would imagine that rally drivers may actually raise the ride height as well. Trouble is getting that kind of info for all the coilovers and still be somewhat accurate. I guess I could leave that column listed as "adjustable" unless we get the numbers for that coilover.

[Hiboost]

I did some searching on Eibach Pro spring rates and found the numbers above quoted. They seem in line with being about +30% stiffer than stock, but progressive for front as well as the rear.

[Gators2001]

HKS Figs?
KW Figs?

[Hiboost]

I haven't seen HKS springs or coilovers available for the Evo X yet. If you or anyone else finds some stats and where to buy I'll update the chart.

I put in the Robispec KW Streets, no idea on the stats though.

[Hiboost]

Added Damping column to Coilovers.

Corrected some specs for Tanabe GF210 Springs and Zeal Coilovers.

Added in Tein Springs and Coilovers to the list.

Still could use the stock spring rates for the Evo X MR.

[Tractionlimit]

This may be a dumb question, but why is every coilover at least twice the stock spring rate? Are we comparing apples to apples when looking at the spring rate of a traditional spring kit vs. coilover? Do coilovers ride that much more harshly, and would something like Eibach be a realistic option for the track?

Thanks.

[Hiboost]

Originally Posted by Tractionlimit

This may be a dumb question, but why is every coilover at least twice the stock spring rate? Are we comparing apples to apples when looking at the spring rate of a traditional spring kit vs. coilover? Do coilovers ride that much more harshly, and would something like Eibach be a realistic option for the track?

Thanks.

The spring rates are measured the same way on Lowering Springs as well as Coilovers. The biggest difference is that Lowering Springs are limited by what spring rates they can use if they are going to be used properly with the stock OEM shocks. Typically you will only see 10-30% increased spring rates and often progressive rate springs will minimize the impact on how much of that you feel in daily driving. If the spring rates are too high they will wear out the shock faster and could actually hurt the handling of the car if the shocks can't control them properly.

Coilovers can get away with higher spring rates because they also include upgraded adjustable dampers that allow you to tune them to the spring rates depending on what kind of ride you want. Most will adjust for compression and rebound where a softer setting will be a bit easier on the street to a point and stiffer settings are more for smooth race tracks. Going too far in either direction of adjustment in relation to the spring rate will make the car ride as if it's out of balance. If the settings from front to rear are not tuned to each other properly you can also get that porpoise effect where the whole car oscilates out of balance front to rear.

A well setup coilover combo doesn't always have to be harsher on the street, but if the roads are really rough you would definitely feel the increased spring rates and firmer ride. Where Coilovers really shine is on a relatively smooth race track where weight transfer on a good setup is precise and predictable when compared to the OEM springs and shock combo that often lets the car roll too far for crisp handling.

I'm no suspension guru by any means and this is just what I've read over the years. Perhaps we can get someone with first hand knowledge to add to that as I didn't really find any good links that talk about the differences when I did a quick google search.