View Full Version : Coilovers... setting Preload
Yeah, I know how I've always done it, but recently my car seems to be handling kinda janky and I wanna make sure I've done it correctly. I don't want the opinions of backyard mechanics, I want the opinion of the guys who competitively track their cars or professionally set up performance suspension systems. Weekend warriors need not apply.
BTW, this isn't necessarily for an S chassis, so if that changes things let me know please.
norbac
07-03-2008, 11:55 AM
id like to know too... going to be in the market for a coilover someday, and this would be helpful...
SR20d2fourT
07-03-2008, 11:59 AM
id like to know too... going to be in the market for a coilover someday, and this would be helpful...
So then start your own thread when you get them.
Don't waste his space.
Btw, I can't help you on this Dook.
Nice wallet.
norbac
07-03-2008, 12:41 PM
um okay, so there are more than one person interested in the same info?
blueshark123
07-03-2008, 01:04 PM
So then start your own thread when you get them.
Don't waste his space.
Btw, I can't help you on this Dook.
Nice wallet.
Wow what a dick head next time just help the op or stfu.
WQhat i do is lower the shock into the mount. You have to set the preload with the spring and LEAVE IT!! Basically the spring should not move up and down but you should be able to spin it between the top and the bottom mounts (while jacked that is). Do not adjust the height by the spring!!
IM NO PROFESSIONAL so take it or leave it for what it is
g6civcx
07-03-2008, 01:06 PM
Yeah, I know how I've always done it, but recently my car seems to be handling kinda janky and I wanna make sure I've done it correctly.
What are you asking?
I don't want the opinions of backyard mechanics, I want the opinion of the guys who competitively track their cars or professionally set up performance suspension systems. Weekend warriors need not apply.
What do you mean by "competitively"? Points racing? Have sponsors? Win/place requirements? Open practise? Racing license?
What are you asking?
What do you mean by "competitively"? Points racing? Have sponsors? Win/place requirements? Open practise? Racing license?
your opinion would be one I would value... Russ would be another... I wasn't looking for the opinion of every fanboy with coilovers on a 20 year old rust bucket who likes to think they are a drifter cause they slide around empty parking lots at their local grocery store. I want the opinion of people who have knowledge, not those who THINK they do. That is all.
Currently, my preload range is set like so: I tightened the top collar to snug the coil, at that point I tightened about another 1/4 inch or so. Obviously, I then used the bottom mount to adjust ride height. I am wondering if the additional tightening I did was adverse to my car's handling.
punxva
07-03-2008, 02:09 PM
your opinion would be one I would value... Russ would be another... I wasn't looking for the opinion of every fanboy with coilovers on a 20 year old rust bucket who likes to think they are a drifter cause they slide around empty parking lots at their local grocery store. I want the opinion of people who have knowledge, not those who THINK they do. That is all.
Currently, my preload range is set like so: I tightened the top collar to snug the coil, at that point I tightened about another 1/4 inch or so. Obviously, I then used the bottom mount to adjust ride height. I am wondering if the additional tightening I did was adverse to my car's handling.
the way you did it, is the way i've always set mine up, basically too much preload will make the car feel bouncy, since it is really only using the spring to dampen. Could you go a bit more indepth on how it is feeling? like is it bouncy or what? atm i've got mine drooped a bit so i dont lift my tires when making sideways entrances into my drive way, only about a 1/4 inch while raising it the same so i didn't lower the car.
sure... around town it seems to do fine, over big bumps, it seems to be bouncing excessively regardless of the setting I have the dampening set at. For what it matters, the other day I hauled about 300 pounds or so of mulch in the back and it seem to ride a WHOLE lot better, though I can't for the life of me figure out why.
az_240
07-03-2008, 02:37 PM
struts are being over powered by the preloaded springs causing it to bounce.
with the heavy mulch in the back it was forcing the car to the ground creating less suspension travel and less bounce.
Get better struts or coilovers...
also check all your suspension links and make sure the bushings arent worn out.
They are Tein Flex... bushings are all fine... I'm thinking along the same lines that you mentioned except for maybe I'm running too much preload causing the issue, not poor quality parts.
az_240
07-03-2008, 03:23 PM
ahhh preloading flexes? but they ride so smooth without preload...
Id suggest selling those and getting some more aggressive coilovers if you want a stiffer ride.....
burnsauto
07-03-2008, 03:29 PM
I'm having a very similar problem with my car. the springs are overpowering the dampening, no matter what setting i have them on (JIC's).
Hopefully the car will back together and drivable soon so I can start messing around with the preload, if i find any difference, I'll be sure to post up what I had to do.
S14DB
07-03-2008, 03:41 PM
What are the shocks set up?
Stock sways?
Stock Sway Endlinks?
Flex are currently set at midrange dampening... stock sways and endlinks. Stock sways are 20mm front and 18mm rear on the wagons. stock endlinks are still fine, not maxed out.
ahhh preloading flexes? but they ride so smooth without preload...
Id suggest selling those and getting some more aggressive coilovers if you want a stiffer ride.....
I don't want a stiffer ride, i want to get rid of the bounce... I think my problem may be the preload, I'm going to try backing them down and see what my results are.
S14DB
07-03-2008, 04:26 PM
Flex are currently set at midrange dampening... stock sways and endlinks. Stock sways are 20mm front and 18mm rear on the wagons. stock endlinks are still fine, not maxed out.
Stock end links are plastic and twist like a bitch. I would at least replace them.
Try dropping the damping to 2 or 3.
nismo tuned s14
07-03-2008, 04:28 PM
yay for a fellow tein flex owner. i have no preload on mine and they ride like a dream. my friend had flex's on his s14 with lots of preload and it rode like ebay coilovers.
my dampening is set at 14 f, 12 r
well that confirms it... I'll take all preload out and see how it goes...
as for the sways and endlinks, I should be ordering my Rallitek setup in the next month or so 22mm front and 19mm rear with endlinks.
aznpoopy
07-03-2008, 04:35 PM
i also have flexes and they are similarly installed
i have them set to roughly 6 clicks (very soft) and they only bounce driving slowly over what i can only describe as smoothly uneven road... like concrete in a parking deck with no big bumps but a imperfect surface.
imo problem is simply the shock characteristics at that general piston velocity. not enough rebound to bring the spring back to rest without a few oscillations. try upping shock stiffness.
naturally the trade off is the shock might be alot stiffer at a higher piston velocity and knock you out of your seat. that's why shape of the curve and how it changes at each click is nice to know. too bad we're pretty much in the dark when it comes to that information. luckily the flex's ride pretty awesome on most of the settings i've tried so far.
well we'll see what happens when I take the preload out of my setup... if that doesn't cure things, I'll pull them off and put the stock suspension back on and do one of two things... sell them or send them back to Tein and have them revalve them for me and run a softer spring rate spring from swift or something.
S14DB
07-03-2008, 04:45 PM
Try playing with your damper settings more. it took me a while to find 2 settings I like. One for DD/Dates and one for track. I am still tempted to get the EDFC.
haha... funny you mention that... I've had EDFC on my watched list on ebay for about 6 months now, I've got to the screen where it says to confirm ordering about 6 times... I just can't justify doing it to myself right now since the car doesn't and probably won't EVER see any track time. Unless I win the lottery and have ECS swap it for shits and giggles. I may order the damn thing just for ease of changing the settings until I find what I like.
nismo tuned s14
07-03-2008, 04:52 PM
lol ive been thinking about buy the edfc for a while too, but it just seems like a waste of money since it only takes like 30 seconds to change the settings with your hand.
S14DB
07-03-2008, 04:54 PM
I dunno even for the ability to trim on the fly it helps. People look at you like you are nuts when you pop the hood to turn 2 knobs. Also I like it super stiff on the HW so when I am going on a trip I'll crank it up. Then grin and bear it on city streets getting on and off the HW.
nismo tuned s14
07-03-2008, 04:58 PM
dont get me wrong. the ability to adjust on the fly is amazing, i just cant justify spending $300-$400 on something id (1) rarely use and (2) its simple to change without it.
another thing about EDFC is... I hate having to count clicks everytime I wanna change it and even then, you really don't know 100% where you're at to have front to rear and left to rear matching however you want them to be... I think EDFC is in my near future... wiring the shit up will be the bitch part, having to take all the panels and shit off.... ughhhh
S14DB
07-03-2008, 05:19 PM
I got so pissed when my friend was looking at my car and she started twisting the knob. I got so pissed, she looked like a lil kid with her hand in the cookie jar still holding on the knob.
yeah, I had a buddy who did that... I hit him and thought I stopped his heart... he was ok though. God damn honda guys.
I don't want a stiffer ride, i want to get rid of the bounce... I think my problem may be the preload, I'm going to try backing them down and see what my results are.
ZERO preload is ideal. Fasten the spring just enough so you can turn it. The bounce is most likely because you're shocks are blown, or you need to increase your dampening.
They are Tein Flex... bushings are all fine... I'm thinking along the same lines that you mentioned except for maybe I'm running too much preload causing the issue, not poor quality parts.
There's your prob right there. Tein Flex are garbage.
Especially when you're talking about 'real racers' and all that. I'm pretty sure they don't run marshmallow spec coilovers.
yokotas13
07-04-2008, 12:37 AM
just put enough preload on it to keep the spring from moving
I personally put 1cm preload on my springs
from the point where it doesnt spin on the perch, then i preload 10mm
dont know why i do it, but i do, and its never had bad results
and note i told that fucker that tein were soft when he bought em from me
iwishiwas-all*
07-04-2008, 12:40 AM
They are Tein Flex... bushings are all fine... I'm thinking along the same lines that you mentioned except for maybe I'm running too much preload causing the issue, not poor quality parts.
my tein flex is madd bouncy... the front is okay but i get alot of squat, and i have decent preload too cause my car is low...
maybe a tein thing?
yokotas13
07-04-2008, 12:44 AM
maybe a blown tein thing?
flex arent normally bouncy, just soft.
There's your prob right there. Tein Flex are garbage.
Especially when you're talking about 'real racers' and all that. I'm pretty sure they don't run marshmallow spec coilovers.
if I tracked my car I wouldn't have bought Flex... it's a daily driver. I just want experienced opinions on preload.
My bros R32 had Flex. They rode like shit brand new out of the box. So bouncy.
Replaced with Section RMA8 or whatever and all is well now. Even my old Megan streets rode better than Flex. My GR-6 are 10x smoother riding too.
aznpoopy
07-04-2008, 08:23 AM
i had the exact oppositte experience
silkroads were bouncy out of the box on anything but 5/8 clicks or higher. absolutely hated them. on top of that they developed shaft play after 2 years and maybe 9000 miles tops. goddamn waste of money.
switched to flex and all is well
yah know I appreciate everyone's opinions, but this isn't the place for it. I don't care at this moment and time whether or not you think the coilover is blown or junk, i simply want to know about setting preload. At this point, I think that is probably my problem. If it ends up not fixing my problem, I may be looking for further opinions on a new set of coils. Until then, please limit responses to your experience with setting preload. Thanks.
g6civcx
07-04-2008, 07:44 PM
sure... around town it seems to do fine, over big bumps, it seems to be bouncing excessively regardless of the setting I have the dampening set at. For what it matters, the other day I hauled about 300 pounds or so of mulch in the back and it seem to ride a WHOLE lot better, though I can't for the life of me figure out why.
There are several things at work here. Let's see if we can sort them out.
First, let's look at the coil spring by itself. When you have a spring by itself with no load, the spring has a length called its free length.
The purpose of the spring is to absorb energy and store that energy in its coils while the spring is compressed by a force. When the force is taken away, the spring will release and fluctuate about its natural/free length at its natural frequency until all of the energy is lost through spring motion.
The distance the spring compresses depends on the spring rate and the force being applied to the spring. Let's say a force of X pounds is required to compressed a linear rate spring 1".
When you preload the spring 1", it means that you compress the spring between its mounts so that the spring is 1" shorter than its free length. Here's what preload does.
With a normal spring, you apply 0 to X pounds, the spring moves 0 to 1" based on how much force is being applied. When you preload the spring 1", applying 0-X pounds results in 0 spring movement. You have to apply more than X pounds to start seeing spring movement.
What this means is if your spring is stiff enough, and if you run enough preload, you in effect eliminate the spring. What you basically have left is a solid suspension with no spring.
So you would want to run preload when you want minor suspension forces not to move the spring at all, i.e. think of how a Cadillac/Oldsmobile bounce up and down over small bumps. Running a little preload eliminates this effect because minor suspension forces will not result in spring movement.
Pretend that you have springs only, no strut. When you hit a bump, the car would bounce up and down at the spring's natural frequency as affected by sprung weight and unsprung weight. The more sprung weight and the less unsprung weight, the more comfortable the ride because the Cadillac effect will be less because the spring has to move a heavier sprung weight and lighter unsprung weight = fewer oscillations.
The purpose of the strut is to absorb energy when the spring compresses and expands (jounce and rebound) so you don't get the Cadillac effect. A good strut should only allow 2 oscillations of the spring. The rest of the energy should be dissipated by the strut.
When you check suspension on an old car, bounce the car with your hand and see how many times the car goes up and down. If it's any more than twice, the struts are blown.
Ideally you can adjust jounce/compression and rebound dampening individually, but most cheap coilovers won't let you do this independently. So for most folks, stiffer/more dampening = fewer oscillations.
Cliff's notes: These things wil reduce suspension oscillation: heavier spring rate, more preload, more sprung weight, less unsprung weight, more strut dampening.
You have to be careful with preload though. If you run too much preload, the suspension doesn't move at all so the strut doesn't even come into play. This means that all of the energy is transferred to the frame and could possibly result in a loss of traction.
Ideally, if you could get your damper checked out on a dyno that would be best, but in reality, probably the best you could do is start with zero preload and play with the full range of damper setting more towards the stiff side. This should get rid of most of your low speed bouncing.
What you're describing sounds like high speed dampening adjustment is needed, but unfortunately most budget coilovers won't offer this adjustment. Your only option left would be to increase sprung weight and decrease unsprung weight.
You could also experiment with spring preload and see if it helps.
I'm sorry if that's not satisfactory. It's the best I have for you. Suspension is really hard to dial in and it really depends on the individual car.
great explanation of which I appreciate greatly. I will start with zero preload and work my way through the dampening adjustments to see if I like what I feel... Should that not be satisfactory I will take it from there. Thank you again.
your opinion would be one I would value... Russ would be another... I wasn't looking for the opinion of every fanboy with coilovers on a 20 year old rust bucket who likes to think they are a drifter cause they slide around empty parking lots at their local grocery store. I want the opinion of people who have knowledge, not those who THINK they do. That is all.
Currently, my preload range is set like so: I tightened the top collar to snug the coil, at that point I tightened about another 1/4 inch or so. Obviously, I then used the bottom mount to adjust ride height. I am wondering if the additional tightening I did was adverse to my car's handling.
On "real" coilovers you usually can't set the preload.
On "real" coilovers you usually can't set the preload.
great.... well I'm asking about setting preload on my "pretend" coilovers then.
I never suggested I have top of the line coilovers or that my car does anything besides street driving, so commenting on my cheap or junky or fake or whatever coilovers you feel, is inappropriate for this thread. Frankly, I don't give a fuck about anyone's opinion on the quality of the Tein Flex that currently reside on my car, I am however interested in what the appropriate method of setting preload is.
g6civcx
07-05-2008, 11:37 AM
On "real" coilovers you usually can't set the preload.
Maybe so, but you can preload any coil spring with spring compressors.
singlecamslam
07-05-2008, 11:47 AM
i have stance and it says to tighten the spring with your hand till you cant turn it anymore, than take the wrench and give it two more turns. Did that and it rides awesome in the streets.
alkemyst
07-08-2008, 06:54 PM
just put enough preload on it to keep the spring from moving
I personally put 1cm preload on my springs
from the point where it doesnt spin on the perch, then i preload 10mm
dont know why i do it, but i do, and its never had bad results
and note i told that fucker that tein were soft when he bought em from me
SPL recommended about 10mm of preload on my KTS...ride is not bad and the car does not bounce.
Preload takes care of a couple things. One is spring noise and the second is based on preload your car doesn't react as much to bumps. Too much and you get jolted, not enough and you can have too much bouncing.
Once you set your preload up, you adjust from bottom of most coilovers for height..
great.... well I'm asking about setting preload on my "pretend" coilovers then.
I never suggested I have top of the line coilovers or that my car does anything besides street driving, so commenting on my cheap or junky or fake or whatever coilovers you feel, is inappropriate for this thread. Frankly, I don't give a fuck about anyone's opinion on the quality of the Tein Flex that currently reside on my car, I am however interested in what the appropriate method of setting preload is.
Just jocking you a bit because of your short list of people you'll take advice from...
As for preload, there is going to be zero difference from a handling perspective on the street between zero and "moderate" amounts of preload. The spring rate is unaffected, and the only issue is that excessive amounts of preload will take away droop travel(i.e. you hit a bump and your suspension only has a little bit to "go down" before it extends out all the way vs. no preload).
I've changed it around and never noticed a difference, and I'm normally pretty decent at feeling changes with my car(few pounds of air pressure change etc.).
So you would want to run preload when you want minor suspension forces not to move the spring at all, i.e. think of how a Cadillac/Oldsmobile bounce up and down over small bumps. Running a little preload eliminates this effect because minor suspension forces will not result in spring movement.
You have the basic physics right, but this conclusion is not accurate... usually the preload is alot less than the weight of the car in that corner. Therefore the weight of the car alone is enough to overcome the preload. In that case, it does not matter if the spring is preloaded, the spring will be compressed to the same length.
For example, for a certain spring, say the spring without load measures 8" long. If you apply the weight of that corner of the car on that spring, it will compress to 6" long. If you preload the spring to 7", when the weight of the car is exerted on the spring, it will still compress to 6". Any small fluctuations in load, say +/- 1", the spring will behave exactly the same, whether or not it was preloaded.
Preload basically lets you set the droop limiter. In the above example, you are limiting droop to 1", vs. 2" if there was no preload.
As for ride characteristics due to changes in preload, that probably has to do with the shock absorber having uneven performance when the piston is at different positions within the shock body.
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