Koni spring shock combo spring rate help needed

mx589 · Postby **mx589** » Sun Jun 11, 2017 8:08 pm

Hey guys i just bought some 2nd hand koni spring shock combo and the springs are blue ish kind of like the picture below.
Have koni written on them but no matter were i look on the internet i cant find spring rates for them.
Does anyone have any data ?
Thanks

93_Clubman · Postby **93_Clubman** » Mon Jun 12, 2017 11:04 am

Any alphanumeric printed on the outside of the springs?

mx589 · Postby **mx589** » Mon Jun 12, 2017 12:41 pm

koni 110 on the rear
and koni 109 on the front

wasp47 · Postby **wasp47** » Mon Jun 12, 2017 1:09 pm

Ring KINGS springs on the Gold Coast, usually very helpful and give them the numbers.
Cheers

mx589 · Postby **mx589** » Mon Jun 12, 2017 1:23 pm

There not king springs tho
kings are yellow
these have koni stamped on the springs

93_Clubman · Postby **93_Clubman** » Mon Jun 12, 2017 3:21 pm

How's your German - here's the Koni manual for them: <www.koni-rus.ru/manuals/koni_1110-7030-tuv.pdf>

mx589 · Postby **mx589** » Mon Jun 12, 2017 4:48 pm

trying to translate now wish me luck lol
thanks mate

wasp47 · Postby **wasp47** » Mon Jun 12, 2017 6:45 pm

mx589 wrote:There not king springs tho
kings are yellow
these have koni stamped on the springs

I fully realize that they are not KINGs springs however they could shed some light on the KONI numbers

RS2000 · Postby **RS2000** » Mon Jun 12, 2017 7:59 pm

If you can do basic maths, have vernier calipers & a calculator it's easy enough to work out:

k = (W^4 x G) / (8 x D^3 x N) or written out k = (W x W x W x W x G) divided by (8 x D x D x D x N)

k - spring rate (lb/in)
W - wire diameter (in)
G - 11,000,000 (psi) - close enough for spring steel modulus of rigidity
D - PCD of Coil (in) i.e. coil outside diameter minus wire diameter
N - number of active coils = 6.5 by your photos

The photo shows all springs have 7.5 total coils. The ends closest to camera are open, but the far ends look to be closed (hard to tell in photo)
If both ends are open N=7.5, but if one end is closed, N=6.5.

Sorry to work in lbs & inches, but I'm old school

mx589 · Postby **mx589** » Mon Jun 12, 2017 8:10 pm

ahhh wasp ic ic may call them this week then
rs2000 wow 2 many numbers im lost already
That german pdf i google translated some of it and not anything in there about spring rates that i could see

93_Clubman · Postby **93_Clubman** » Tue Jun 13, 2017 10:38 am

RS2000 wrote:The ends closest to camera are open, but the far ends look to be closed (hard to tell in photo). If both ends are open N=7.5, but if one end is closed, N=6.5.

Tops appear to be closed from following pic: http://contour.org/ceg-vb/forum/modific ... rings-info

mx589 · Postby **mx589** » Wed Jun 14, 2017 4:17 pm

Thanks for the link
they are the same springs as what i have

93_Clubman · Postby **93_Clubman** » Wed Jun 14, 2017 4:45 pm

Yeah, believe they're the Koni recommended springs for the MX5 NB.

mx589 · Postby **mx589** » Sat Jun 17, 2017 7:36 pm

Thanks for the info mate

CrazyRacer · Postby **CrazyRacer** » Sat Oct 14, 2017 9:06 pm

I was looking for the same information but unable to find it, so ended up measuring the set I had and thought I'd put the info here for anyone looking for it in the future...

Front - Koni 109
Wire diameter 0.465 inch (11.8mm)
Coil OD 4.135 inch (105mm)
Active Coils 5.75 (The top and bottom spring platforms "deactivate" about a full)

Rear - Koni 110
Wire diameter 0.425 inch (10.8mm)
Coil OD 4.135 inch (105mm)
Active Coils 6 (The top and bottom spring platforms "deactivate" about a full coil)

So using RS2000's formula we end up with
Front 226 lb/in (4.0 kg/mm)
Rear 146 lb/in (2.6 kg/mm)

which fits in nicely with the usual 3:2 ratio on the front to rear rates.