Ground Control sleeves, spring rates?

[PencilShavings]

I have GC sleeves in my car, and Im trying to find out the spring rates.

the front is labeled:88823GC 180.64.44

rear:86544GC 125.64.75

anyone know the breakdown for that info? I emailed them but havent gotten a response yet

[PencilShavings]

after looking around for a bit, i found the first # is the spring length, second is the diameter, and 3rd is the spring rate..

GC180.64.44 is 180mm long, 64mm in dia and 44n/mm spring rate

now Im even more confused because my front springs are shorter then my rears, but according to the numbers my rears should be shorter then my front. also, why would my rear spring rates be more then my fronts? 44 vs 75? they seem completely backwards..

[naed240sx]

after looking around for a bit, i found the first # is the spring length, second is the diameter, and 3rd is the spring rate..

GC180.64.44 is 180mm long, 64mm in dia and 44n/mm spring rate

now Im even more confused because my front springs are shorter then my rears, but according to the numbers my rears should be shorter then my front. also, why would my rear spring rates be more then my fronts? 44 vs 75? they seem completely backwards..

Yeah that doesn't really make sense. As far the rates go, those are surprsingly stiff. 75 Newtons/mm equates to 7.6kg/mm, and 44 equates to 4.5 kg/mm. For reference, Stock rates are around 2kg/mm f/r, and most coilovers are 8/6 f/r.

Read my post in that other thread about you needing custom length dampers for those springs.

[nismofly]

a lot of people with ground control run "non-normal" rates, just because they can

but that would be a 425 front / 250 rear, not something ive ever heard anyone running on them

if those are indeed your rates that might be one reason it feels so weird

[PencilShavings]

but that would be a 425 front / 250 rear

it would be 250 front and 425 rear...even more akward.

[nismofly]

weird, i made a post where i had realized my mistake, and its gone

i wonder what thread i posted in...or where the post went

[nismofly]

oh, the stiffer are in the rear?

those rates swapped will *certainly* make it feel twitchy, thats definately your problem if those are your rates

EDIT: found it, stupid internet took a **** in the middle of posting, i just had to hit refresh

[McRussellPants]

180 and 125 should be the spring rates, IIRC thats about right for a little stiffer than stock.

It looks like the 64 is the Inside Diameter, thats about what it should be in MM.

and the last numbers are the length. but the numbers don't make sense unless the springs are retarded short.

[PencilShavings]

180 and 125 should be the spring rates, IIRC thats about right for a little stiffer than stock.

It looks like the 64 is the Inside Diameter, thats about what it should be in MM.

and the last numbers are the length. but the numbers don't make sense unless the springs are retarded short.

This is exactly what I thought when I got the numbers, then I searched them on google and found differently..

however, the 44 and 75 spring rates feel closer to how stiff the springs feel, and the 180 and 125 appear to be about the correct lengths, just the wrong springs..it's as if the front and rear spring labels are switched

anyway I'm still waiting on a response from ground control

[McRussellPants]

In mm 180 and 125 is still super short.

180 is about what? a 3kg? I cant rememember if the conversion is 63 or 49.

Thats about right for crappy springs.

[PencilShavings]

180 and 125mm is around 7 and 5 inches, and that is about the lengths of them.

the conversion from lbs/in to kg/mm is 56. however if 180 and 125 were spring rates, that means they put the spring rates in english and the measurements in metric, which doesnt make sense.

also I think they list the spring rates in n/mm, not kg/mm (though I could easily be wrong)

I actually havent driven a stock 240 to feel the stiffness for comparison, but my car really doesnt roll much. the pic in my sig was when the car thrown sideways at probably 30mph or more and it's still fairly flat

Im sure Ill have the same setup still at the glen meet, so you NY guys will have to take a look/ride/drive.

[nismofly]

ill have to take a look at them then

unfortunately its looking like its going to be the second weekend of june before i install my coils, so im going to be rolling 4x4 still at that point

[PencilShavings]

thats not what it looks like in your sig

[nismofly]

i dont have the 18" volks and the stoptechs off the jic magic rx8 in real life either, sorry

dean (naed) was practicing his PS skills, look at his sig too

[PencilShavings]

haha I know I can see its photoshopped

I noticed a few pop up after axel did his DIY photshop deal

[PencilShavings]

alright, well I called GC, and the guy told me my springs were mixed up, the rears are in the front and fronts in the rear..

so when I get home from school next, Ill have to jack the car up and pull things apart. the wierd part is that the rear springs look longer then the front while theyre in the car (the correct way), and on top of that I would think my ride height would look akward if they were backwards.

he also confirmed the #'sits length . diameter . spring rate in n/mm

[nismofly]

i *think* that comes out to 7.6 kg/mm front, and 4.5 kg/mm rear, after switching them obviously

thats waaayy too much for gr2's, so you need something else damper wise

[PencilShavings]

i *think* that comes out to 7.6 kg/mm front, and 4.5 kg/mm rear, after switching them obviously

thats waaayy too much for gr2's, so you need something else damper wise

haha, yes. is that too much for yellows too?

[nismofly]

no, theyll easily hold those rates

yellows can take up to 12.5 kg/mm

[gepeto]

With the stock valving ?

I would think it is border line, but should work for a while...then get them revalved..

That stiffness is closer to coilover land man, isn't it a bit too stiff for grip? You must jump every small crack in the road!

[naed240sx]

With the stock valving ?

I would think it is border line, but should work for a while...then get them revalved..

That stiffness is closer to coilover land man, isn't it a bit too stiff for grip? You must jump every small crack in the road!

7/4.5 is not that stiff. Im on 8/6 kts and loving it. As opposed to stock, the only time that I have less grip is on really bumpy stuff.

[nismofly]

theyll hold, but you could get them custom valved to exactly match those rates

[PencilShavings]

That stiffness is closer to coilover land man, isn't it a bit too stiff for grip? You must jump every small crack in the road!

lol, I do! thats what I was saying in the other thread, its bad.

also, if I were to get yellows I dont even know if my GC sleeves would fit them (if you look at the GC site you choose what shock you have when you order)

would agx's hold up? theyre a bit cheaper cost wise, but tell me if the konis are worth it, I'd just save for them..

guess Ill have to look into this whole revalving deal and see how much it would run for future reference

[naed240sx]

You need more than revalving. You need custom length shocks to match those springs, unless you want severly compromised travel. In the end, I really don't think it's worth it, but that's just my opinion.

[PencilShavings]

You need more than revalving. You need custom length shocks to match those springs, unless you want severly compromised travel. In the end, I really don't think it's worth it, but that's just my opinion.

I guess I don't understand why I would need custom lenths. the GC sleeve overs say they drop the car from 0-2 inches. it looks like other springs used usually drop about 1.5 inches..

[naed240sx]

I guess I don't understand why I would need custom lenths. the GC sleeve overs say they drop the car from 0-2 inches. it looks like other springs used usually drop about 1.5 inches..

Well that would be fine, as long as you aren't going any lower. From the few ground control setups I have seen, it looks like there is quite a bit of spring sagging going on, but they might have had a more custom setup.

[hannibal]

This explains a lot about the problems you mentioned earlier. I followed along with the rate conversions and it seems right to me.

Dean scared me with his last posts talking about custom length shocks. Thats only if youre doing super low ride height, right?

THe AGX's are stiffer at the higher settings than GR2's, but I dont know if theyre stiff enough for the GC coils.

The best price Ive seen for Koni Sports is $590 from Tire Rack, but Ive havent searched that much...

[naed240sx]

This explains a lot about the problems you mentioned earlier. I followed along with the rate conversions and it seems right to me.

Dean scared me with his last posts talking about custom length shocks. Thats only if youre doing super low ride height, right?.

Pretty much. With any aftermarket replacement shocks, the shock length is usually the same as stock. So... If you lower your car 1 in, you lose 1 in of compression travel with the shock. If you go too low, you won't have enough travel, and will be constantly hitting the bumpstops unless you have a custom length damper. It's also bad when you have a non captive spring at full droop (The spring is not in contact with both perches when the wheel is off the ground). This means that for the last amount of rebound travel, the spring is having no effect on the assembly at all.

[Dori Dori]

yellows can take up to 12.5 kg/mm

Not out of the box. Unless they are valved accordingly anything over 300lbs/in would be pushing it.

[nismofly]

thats what i meant, the custom valved yellows cant go higher than 700 lbs...guess i shouldve clarified