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ChriSOL

coilover preload

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i have some time to work on my car this weekend. one of the things I wanted to do was address the issues i've been having with my coilovers. 99% of the knowledge i had when i purchased and installed them was based on internet hearsay, and that led me to put them in with 0 preload. in other words, bottom seat snug against the spring but not compressing it. a couple things i have read more recently say that 1) BC recommends you set a 5mm preload on certain models of their coilovers and 2) zero preload can contribute to a bouncy - not stiff like its supposed to be - ride.

 

so i was going to see if doing that helped any. i thought most of you also installed your shit with 0 preload but i thought i'd ask anyway before i start looking at a new set with different spring rates and valving.

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What type of coilovers do you have and how old are they.

 

My last set of coilovers, BC's, had no preload. They were fine for the first season and a half then got bouncy. The dampers were done after a season and a half.

 

The set of coils I had before that, k sport. I preloaded them a little. They blew up.

 

The set of coils I had before that. Low end JIC's. Pre loaded them a little, then a little more. They blew up.

 

The set of Tein Circuit master I had, didn't blow up.

 

There's a trend here. Cheap shit fails. The one nice suspension setup I had, didn't. You can try preloading your springs a bit to see if it helps, though if your getting some bounce it's the dampers releasing their grip on life. All you may do is delay the inevitable.

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Im running a touch of preload up front and none in the back. They don't bounce at all, dampening is full stiff up front and 3/4 soft in the rear. I get good grip/squat with this setup.

 

They are ~3 year old S9's

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my old teins don't have preload adjustment. it's a single perch, so even at the lowest setting, the helper spring is always pushing against the main spring.

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a little confusion going on in this thread. firstly, no preload won't cause bounciness unless its excessive, and it makes it feel like theres blown coils, because the shock is operating outside of its efficiency range. too much preload causes a different kind of bouncyness that makes the car feel jittery. this is because the spring isn't able to compress properly and as a result it starts flexing the chassis/suspension and causing the tire to lose grip. when i set preload i go until the perch stops against the spring, then depending on spring rate, i reduce the coil spacing by 10-25% AKA, if the distance between each coil is 1 inch, then i take it down to 7/8-3/4 of an inch. more for softer rates/heavier car. its not exact science, its all in the feel. secondly, bc's have plenty good product, improper settings will cause poor results.some times what feels great is fucking awful for the damper. its a trade off like anything else. don't sag the spring, and then just try different stuff to test your results.

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Guest 403is300

I run about 2" to 2.5" of preload on my HSD coilovers.

 

My roomate's IS350 runs about the same on his ZEALS.

 

Proper coils can take that kinda preload.. BC/Megan/K-Sport... its all the same china shit, they go low, but they do it at the cost of a properly built shock and they use low KG spring rates to make it feel like a more comfy coilover.

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Two inches? Why dont you just get stiffer spring rates with valving to match? All your doing is ruining your ride and slowly ending your springs/dampers/balljoints/bushings life. I realize your IS is pretty panned out, as is your buddy's car (saw them both when you were down for street wheelers). But I dont think that much is entirely necessary.

 

To add to my drugged up rabble, Austin has a fairly good way of going about it though I wouldn't go much above 10% preload myself.

 

IF your going to add preload, do it after the springs have settled. Take out the slop in the spring first, may take 5-10mm or adjustment on the collar, then add a touch more to firm it up. Beyond that and your ruining your suspensions ability to properly function.

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Guest swim

^ what huckersideways said.

 

12k/10k fortunes. I spin the collar up until the slack is gone, then do 3 to 5 more turns and lock it in place. feels good man. no preload = cut spring effect, too much preload and you're just limiting your travel for no reason.

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Guest 403is300

Two inches? Why dont you just get stiffer spring rates with valving to match? All your doing is ruining your ride and slowly ending your springs/dampers/balljoints/bushings life. I realize your IS is pretty panned out, as is your buddy's car (saw them both when you were down for street wheelers). But I dont think that much is entirely necessary.

 

To add to my drugged up rabble, Austin has a fairly good way of going about it though I wouldn't go much above 10% preload myself.

 

IF your going to add preload, do it after the springs have settled. Take out the slop in the spring first, may take 5-10mm or adjustment on the collar, then add a touch more to firm it up. Beyond that and your ruining your suspensions ability to properly function.

 

When you saw my car (slammed on stock 17's) ... I was running about 0.5" of preload, settling my new HSD's. My roomate was running about 1.5-2" of preload. The valving and spring rates are all custom and perfectly matched for the cars and the preload wont blow the coils, its there to protect them in this case. My car now that its fitted on the new S1R's, im running about 2" of preload to keep my fenders from kissing the new lip. Preload may be adjusted as i go along, working on dialing in dampening first.

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so you're doing exactly what we said. compensating for shitty spring rates by jacking you preload through the roof so you don't rub. grow a dick dude. get the fuck off this site of your worried about being all stanced out on cocaine.

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Guest 403is300

so you're doing exactly what we said. compensating for shitty spring rates by jacking you preload through the roof so you don't rub. grow a dick dude. get the fuck off this site of your worried about being all stanced out on cocaine.

 

You mad at proper fitting wheels with full functionality? lolz

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Stop quoting the post above you.

 

I've had many a car with 'proper' fitting wheels. None have had excessive preload. I can also assure you I drive and have driven them all harder than you drive yours with no issue.

 

So. Back to basics. If you have to run huge preload, your doing it wrong. You need more aggressive spring rates and valving. The end.

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Guest 403is300

Its not "huge preload", its preload, its there for a reason. Why even have adjustable preload if you just set the spring in and turn it 3 turns... shits pointless.

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I sure didn't listen to what other people said when I was 19. Maybe you'll learn yourself. Maybe you won't.

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Guest 403is300

This is coming from just two days ago, when I was getting my wheels on, and asking Jimmy for some help dialing in the suspension, (not like he knows what he's talking about or anything) and he told me "jack up the pre-load till it gets really hard to turn, we'll start there"

 

Thats called listening right?

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I don't know why jimmy sets up his suspension like that. I'll have to talk with him to see if there's logic behind it the next time I see him.

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Guest 403is300

I'll admit, my HSD's arnt exactly Zeals like my roomates, so they can use the extra preload to make up for their slack in the initial bounce area.. but i definitely prefer the ride with more preload, car feels more solid, less front end dragging. Jimmy custom valved both mine and my roomates coilovers, so maybe he worked into the valving a little bit of freedom in the shock to accept such preload.

 

Not sure, im sure he'll chime in at some point.

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I did my preload the same as Austin. My car rides nice and firm like it should.

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