Why preload?
01-03-2008, 12:19 AM
#51
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Re: (Tyson)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson »</TD></TR><TR><TD CLASS="quote">having not read any of the posts in this, or the other ksport thread (which went totally ignored by me previously), i think you guys are overlooking the fact that it would take an unreasonable amount of "preload" of the spring on a threaded body independent height adjustable coilover (aka "full coilover") to overcome the amount of static vehicle weight at the suspension.
preloading the spring any amount basically makes the suspension travel(verb) less from full droop (jacked up in the air) to resting on the ground (aka sag). until the preload overcomes that amount of "sag", at which point, the suspension doesnt even move when it comes down to the ground. which again, is simply an unreasonable situation.
the effect of a "little" preload or none is really insignificant (and certainly not worth all this discussion). because the car will have some amount of sag at rest. basically as the car leans in a turn, the inside wheel will EXTEND. as you add more preload, this extension travel is lessened. thats ALL it does ppl. (ok, perhaps its not ALL trivial, but i havent seen any obvious discussion in this thread headed towards this effect in handling yet.)
on a motorcycle sag and preload is much more important because the vehicle dynamics are dependent on only TWO wheels. and the sag on a motorcycle is dependent on the riders weight, which is NOT insignificant to the vehicles weight. thats why you ONLY hear about this stuff when it comes to motorcycles. for a car, the ratio to drivers weight and vehicles weight is not all that big a deal.
btw, if you are using GC or sleeve type spring kits on a typical shock, there is no such thing as preload unless you have some unreasonable situations which arent beneficial. </TD></TR></TABLE>
so spaketh the lord. lol
preloading the spring any amount basically makes the suspension travel(verb) less from full droop (jacked up in the air) to resting on the ground (aka sag). until the preload overcomes that amount of "sag", at which point, the suspension doesnt even move when it comes down to the ground. which again, is simply an unreasonable situation.
the effect of a "little" preload or none is really insignificant (and certainly not worth all this discussion). because the car will have some amount of sag at rest. basically as the car leans in a turn, the inside wheel will EXTEND. as you add more preload, this extension travel is lessened. thats ALL it does ppl. (ok, perhaps its not ALL trivial, but i havent seen any obvious discussion in this thread headed towards this effect in handling yet.)
on a motorcycle sag and preload is much more important because the vehicle dynamics are dependent on only TWO wheels. and the sag on a motorcycle is dependent on the riders weight, which is NOT insignificant to the vehicles weight. thats why you ONLY hear about this stuff when it comes to motorcycles. for a car, the ratio to drivers weight and vehicles weight is not all that big a deal.
btw, if you are using GC or sleeve type spring kits on a typical shock, there is no such thing as preload unless you have some unreasonable situations which arent beneficial. </TD></TR></TABLE>
so spaketh the lord. lol
01-03-2008, 01:02 AM
#52
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Re: (Mr.E.G.)
this was a good question....I am still a little fuzzy about why companies advertise it so much if I understood PIC and Patick94 right. Does preloading manly occur on firmer spring rates? (stupid question I know but I am a noob)
01-03-2008, 04:14 AM
#53
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Re: (JDM5075)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM5075 »</TD></TR><TR><TD CLASS="quote">this was a good question....I am still a little fuzzy about why companies advertise it so much if I understood PIC and Patick94 right. Does preloading manly occur on firmer spring rates? (stupid question I know but I am a noob)</TD></TR></TABLE>
It can occur on any spring at all if the spring is in a device that can exert a preloading force on it.
As Tyson said, there really isn't much need for preloading on a car. On a coilover assembly with independent height and preload adjustments, there really only needs to be a tiny hair of preload, i.e. just enough to keep the spring in place when the car is jacked up in the air.
It can occur on any spring at all if the spring is in a device that can exert a preloading force on it.
As Tyson said, there really isn't much need for preloading on a car. On a coilover assembly with independent height and preload adjustments, there really only needs to be a tiny hair of preload, i.e. just enough to keep the spring in place when the car is jacked up in the air.
01-03-2008, 06:45 AM
#55
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Re: (JDM5075)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM5075 »</TD></TR><TR><TD CLASS="quote">this was a good question....I am still a little fuzzy about why companies advertise it so much if I understood PIC and Patick94 right. Does preloading manly occur on firmer spring rates? (stupid question I know but I am a noob)</TD></TR></TABLE>
The only companies I hear mentioning preload are the ones who offer fixed-stroke coilovers (i.e. Omnipower, D2, K-Sport, Function & Form, etc.). These types of coilovers require the spring perch to be set in a narrow range of positions in order to work properly without sacrificing ride quality and handling due to topping out or bottoming out the damper. Realistically, with those you don't need to do anything other than snug up the spring between the perch and the upper mount, and then give it maybe another half to full turn. Any more or any less than that can cause problems with a fixed-stroke damper.
Coilover sleeves that use off-the-shelf type performance shocks don't really require this, because those types of dampers are made to work with a wider stroke range. There are benefits and limitations of both types of coilovers.
While I can't think of any brands right now for Honda cars, I've also seen some coilovers using progressive springs - in which case setting preload (moreso than just snugging up the spring) would increase the initial rate of the spring (the rear coilover assemblies on my CB750 are set up this way).
The only companies I hear mentioning preload are the ones who offer fixed-stroke coilovers (i.e. Omnipower, D2, K-Sport, Function & Form, etc.). These types of coilovers require the spring perch to be set in a narrow range of positions in order to work properly without sacrificing ride quality and handling due to topping out or bottoming out the damper. Realistically, with those you don't need to do anything other than snug up the spring between the perch and the upper mount, and then give it maybe another half to full turn. Any more or any less than that can cause problems with a fixed-stroke damper.
Coilover sleeves that use off-the-shelf type performance shocks don't really require this, because those types of dampers are made to work with a wider stroke range. There are benefits and limitations of both types of coilovers.
While I can't think of any brands right now for Honda cars, I've also seen some coilovers using progressive springs - in which case setting preload (moreso than just snugging up the spring) would increase the initial rate of the spring (the rear coilover assemblies on my CB750 are set up this way).
01-03-2008, 09:07 AM
#56
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Re: (JDM5075)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDM5075 »</TD></TR><TR><TD CLASS="quote">this was a good question....I am still a little fuzzy about why companies advertise it so much if I understood PIC and Patick94 right. Does preloading manly occur on firmer spring rates? (stupid question I know but I am a noob)</TD></TR></TABLE>
honestly, i think its only because they want to insure the spring stays put. without a touch of preload, or just snug, the spring can rattle out of place. the top hats arent designed in a way to capture the spring.
the other reason is that they dont want the user to lower the spring perch in order to lower the car more than the lower cup adjustment allows. that will increase the chances of bottoming out the piston internally and destroying the shock too.
honestly, i think its only because they want to insure the spring stays put. without a touch of preload, or just snug, the spring can rattle out of place. the top hats arent designed in a way to capture the spring.
the other reason is that they dont want the user to lower the spring perch in order to lower the car more than the lower cup adjustment allows. that will increase the chances of bottoming out the piston internally and destroying the shock too.
01-04-2008, 09:21 AM
#57
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Re: (PatrickGSR94)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 »</TD></TR><TR><TD CLASS="quote">
Also I just re-read this post:
*mike-y's post*
This is correct. However, what mike-y forgot to post is that the ride height of the car with the 1" preloaded spring will ride 1" higher, unless you have separate ride height and preload adjustments.
If that is the case, then to maintain the same ride height, you would adjust the lower part of the shock body 1" lower to compensate for the 1" of preload. What that is actually doing is moving the whole threaded shock body 1" farther down into the outer tube (if there is enough room to do that). That's where the extra inch of piston travel comes from in mike-y's example.</TD></TR></TABLE>
Thank you! I was having a hard time explaining this clearly. The only reason I have come to understand it, is because I had to do this on a car to make up for some poorly designed coilovers with soft-ish springs that were buttoming out the shock under hard cornering. after 1.5" of preload, the shocks did not bottom out.
but on any coilover with a decent spring rate, as said above, you really shouldn't need to preload the spring, other than keeping it snug against the top hat.
Also I just re-read this post:
*mike-y's post*
This is correct. However, what mike-y forgot to post is that the ride height of the car with the 1" preloaded spring will ride 1" higher, unless you have separate ride height and preload adjustments.
If that is the case, then to maintain the same ride height, you would adjust the lower part of the shock body 1" lower to compensate for the 1" of preload. What that is actually doing is moving the whole threaded shock body 1" farther down into the outer tube (if there is enough room to do that). That's where the extra inch of piston travel comes from in mike-y's example.</TD></TR></TABLE>
Thank you! I was having a hard time explaining this clearly. The only reason I have come to understand it, is because I had to do this on a car to make up for some poorly designed coilovers with soft-ish springs that were buttoming out the shock under hard cornering. after 1.5" of preload, the shocks did not bottom out.
but on any coilover with a decent spring rate, as said above, you really shouldn't need to preload the spring, other than keeping it snug against the top hat.
01-05-2008, 10:54 PM
#58
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Re: (PatrickGSR94)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 »</TD></TR><TR><TD CLASS="quote">...the ride height of the car with the 1" preloaded spring will ride 1" higher...
</TD></TR></TABLE>
this is NOT TRUE. 
this brings up a point i didnt bring up in my post above.
the ride height will NOT change by the amount of distance the spring is preloaded. and im NOT simply talking about the factor of wheel rates either.
the ride height changes by adjusting preload depending on the SPRING RATE. specifically the total preload force (spring rate x distance) minus the load of the vehicle's weight at that corner (after factoring in wheel rate), divided by the spring rate. the amount of preload force will be different for 1" of compressed distance of a 100lb/inch spring and 900lb/inch spring. so it will hold up the car's weight at that corner very differently.
so it is simply NOT true 1" of preload = 1" higher ride height.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 »</TD></TR><TR><TD CLASS="quote">... unless you have separate ride height and preload adjustments.
</TD></TR></TABLE>
this again makes no sense. you really shouldnt even be in a situation where you have any preload on a typical adjustable sleeve spring kit anyway. there should always be some gap from the top of the spring to the top shock mount when fully extended, or full droop, whatever. (unless you have a zero rate helper spring). it is true then, that for every 1" of spring perch adjustment is directly proportional to the amount of ride height adjustment (factoring in wheel rate). but once you raise the spring perch high enough the spring is now preloaded, the spring rate must then be a factor in determining ride height.
</TD></TR></TABLE>
this is NOT TRUE. this brings up a point i didnt bring up in my post above.
the ride height will NOT change by the amount of distance the spring is preloaded. and im NOT simply talking about the factor of wheel rates either.
the ride height changes by adjusting preload depending on the SPRING RATE. specifically the total preload force (spring rate x distance) minus the load of the vehicle's weight at that corner (after factoring in wheel rate), divided by the spring rate. the amount of preload force will be different for 1" of compressed distance of a 100lb/inch spring and 900lb/inch spring. so it will hold up the car's weight at that corner very differently.
so it is simply NOT true 1" of preload = 1" higher ride height.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 »</TD></TR><TR><TD CLASS="quote">... unless you have separate ride height and preload adjustments.
</TD></TR></TABLE>
this again makes no sense. you really shouldnt even be in a situation where you have any preload on a typical adjustable sleeve spring kit anyway. there should always be some gap from the top of the spring to the top shock mount when fully extended, or full droop, whatever. (unless you have a zero rate helper spring). it is true then, that for every 1" of spring perch adjustment is directly proportional to the amount of ride height adjustment (factoring in wheel rate). but once you raise the spring perch high enough the spring is now preloaded, the spring rate must then be a factor in determining ride height.
01-06-2008, 04:49 AM
#59
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yes I did overlook wheel rate.
So you're saying that if you could somehow move the spring perch higher on a loaded spring, such that the spring would be preloaded when the load is removed, that the car would not ride higher? Maybe it's not exactly 1" higher ride height for 1" movement of the spring perch, but it's still going to ride higher.
Putting cars aside for a minute, let's just think of a bench-top contraption like I was talking about on the last page where we can hold a spring captive in it, and apply pre-load from the bottom and set actual loads on top of it.
It doesn't matter what the pre-loads and loads are, but just say you apply a pre-load from the bottom of the spring, and then an actual load on top that compresses the spring more. Now push the pre-load adjuster up higher, and the load itself on top is going to move higher. When you remove the load from above, the spring will end up with more pre-load than it had before.
Modified by PatrickGSR94 at 8:01 AM 1/6/2008
So you're saying that if you could somehow move the spring perch higher on a loaded spring, such that the spring would be preloaded when the load is removed, that the car would not ride higher? Maybe it's not exactly 1" higher ride height for 1" movement of the spring perch, but it's still going to ride higher.
Putting cars aside for a minute, let's just think of a bench-top contraption like I was talking about on the last page where we can hold a spring captive in it, and apply pre-load from the bottom and set actual loads on top of it.
It doesn't matter what the pre-loads and loads are, but just say you apply a pre-load from the bottom of the spring, and then an actual load on top that compresses the spring more. Now push the pre-load adjuster up higher, and the load itself on top is going to move higher. When you remove the load from above, the spring will end up with more pre-load than it had before.
Modified by PatrickGSR94 at 8:01 AM 1/6/2008
01-06-2008, 08:33 AM
#60
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Re: (PatrickGSR94)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 »</TD></TR><TR><TD CLASS="quote">So you're saying that if you could somehow move the spring perch higher on a loaded spring, such that the spring would be preloaded when the load is removed, that the car would not ride higher? </TD></TR></TABLE>
where did i say that?
it will ride higher dependent on the spring rate. which previously it didnt factor in.
saying "the ride height of the car with the 1" preloaded spring will ride 1" higher" is false and omits more than just wheel rate.
where did i say that?
it will ride higher dependent on the spring rate. which previously it didnt factor in.
saying "the ride height of the car with the 1" preloaded spring will ride 1" higher" is false and omits more than just wheel rate.
01-08-2008, 07:41 PM
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pre-load
The only good reason i've ever heard to pre-load suspension is in the case of a race car that is heavily aero dependent up front. Basically zero droop is called for because the car will not handle correctly if the splitter gets too high from the ground. The spring rates, anti roll bars, tire pressure and shock settings all match the aero package.
The Radical SR3 we race at Funktion uses the body work from the SR8 (think v8 with hyabusa geometry) and calls for ZERO droop from the factory.
Pre-loading the springs isnt really for adjusting corner weights. It might work, but any coilover that allows pre-loading has a seperate ride height adjustment, and that will work for corner balance w/o pre-loading springs unevenly and creating uneven droop.
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The Radical SR3 we race at Funktion uses the body work from the SR8 (think v8 with hyabusa geometry) and calls for ZERO droop from the factory.
Pre-loading the springs isnt really for adjusting corner weights. It might work, but any coilover that allows pre-loading has a seperate ride height adjustment, and that will work for corner balance w/o pre-loading springs unevenly and creating uneven droop.
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01-10-2008, 12:04 PM
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Re: pre-load (EG8steve)
oh wow. steve got his Login back.
what about a car with no front sway bar?
wouldn't it be somewhat benefical to have the springs preloaded in the front. when the weight transfers to the outside wheel, the inside corner suspension could droop enough to unseat the spring. Then basically only the weight of the suspension would be pushing down the tire to the ground, and you probably wouldn't get traction on it since only the damper force itself + weight of the suspension/wheel/tire is acting on it and keeping it on the ground.
now if the spring was preloaded, you would not be able to unseat the spring from the top mount. And you have some force of the spring acting on the damper. so even at full droop in a corner, youshould have more force acting on the tire to keep it on the pavement which would help improve inside wheel traction?
does that sound correct at all or completely stupid?
of course with most track/autox spring rates, i can't see any corner causing full droop of the inside front wheel, as travel is going to be limited due to the high spring rates.
maybe it would be something more usable on say, a Civic rally car, which should be setup with alot more travel and some softer spring rates?
what about a car with no front sway bar?
wouldn't it be somewhat benefical to have the springs preloaded in the front. when the weight transfers to the outside wheel, the inside corner suspension could droop enough to unseat the spring. Then basically only the weight of the suspension would be pushing down the tire to the ground, and you probably wouldn't get traction on it since only the damper force itself + weight of the suspension/wheel/tire is acting on it and keeping it on the ground.
now if the spring was preloaded, you would not be able to unseat the spring from the top mount. And you have some force of the spring acting on the damper. so even at full droop in a corner, youshould have more force acting on the tire to keep it on the pavement which would help improve inside wheel traction?
does that sound correct at all or completely stupid?
of course with most track/autox spring rates, i can't see any corner causing full droop of the inside front wheel, as travel is going to be limited due to the high spring rates.
maybe it would be something more usable on say, a Civic rally car, which should be setup with alot more travel and some softer spring rates?
01-10-2008, 07:34 PM
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Re: pre-load (hybridmoments)
I see what youre saying, I have to think about that some more. The sports racers and formula cars use no droop/preload to keep the front end of the car from getting very far above the ground, so that might work out side to side as well, either that or your on 2 wheels! One other effect of pre loading may counteract- thats the fact that when you preload the spring you loose droop travel. I guess it all depends on how much travel there is.
On my 240, i first set the front with some preload in order to gain some bump travel, only because i felt there wasnt enough travel overall. The result was lifting the front inside tire too early and quirky handling. That situation also involves rear roll stiffness too, but I currently have no adjustment there. I later reduced the pre-load/ increased droop in the front and the car seems to lift the front inside only at maximum cornering loads/body roll which is fine.
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On my 240, i first set the front with some preload in order to gain some bump travel, only because i felt there wasnt enough travel overall. The result was lifting the front inside tire too early and quirky handling. That situation also involves rear roll stiffness too, but I currently have no adjustment there. I later reduced the pre-load/ increased droop in the front and the car seems to lift the front inside only at maximum cornering loads/body roll which is fine.
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05-09-2009, 05:34 AM
#64
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Re: Why preload?
im going to have to bump this tread back up caz i have a question about how i set up my suspension. i have function and form coil overs on my eg, mainly use it for dd and sunday track events. but this year i think i messed up on the preload because the suspension feels much softer than it did last year before the winter. this year when i was lowering it back to the ride hight i like. i took the coilovers out of the car and lowered it by hand on the work bench. i think i messed up when i compressed the spring by turning the sleeve upwards, thinking that a compressed spring would mean a stiffer ride. but it only got softer can u tell me what im doing wrong. and how to preload the suspension again. i dont kno if this will help but i still 3wheel in the rear
05-09-2009, 01:09 PM
#65
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Re: Why preload?
im no suspension guru, but i was always under the impression that if the spring has "play" in it when you jack the car up, then its not as good for the shock when theres NO play in the spring...
im thinking this because the shock has to compress a certain amount until the spring starts compressing...
im thinking this because the shock has to compress a certain amount until the spring starts compressing...
05-09-2009, 01:18 PM
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Re: Why preload?
im no suspension guru, but i was always under the impression that if the spring has "play" in it when you jack the car up, then its not as good for the shock when theres NO play in the spring...
im thinking this because the shock has to compress a certain amount until the spring starts compressing...
im thinking this because the shock has to compress a certain amount until the spring starts compressing...
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