i've noticed that everyone on H-T is of the opinion that stiffer is always better. is there an actual mathematical formula to determine a starting point as far as spring rates are concerned? i was not involved in springing the car when i was a member of MU's FSAE team and i never bothered to ask why they picked the rates they did.

i've been thinking about this because of two recent events.
1) my friend finished his STS 92 Si...i had a chance to drive in (450/380) and was surprised at just how freakin' stiff that really is.
2) said friend has yet to run faster/beat me at an autoX yet....and his car is built to the limit of STS...including all the power mods

my car is set-up really soft, in fact it's only @20% stiffer than the stock rates. but i have also driven extremely stiffly sprung cars that didn't feel as rough as my friends civic....could it be because of a lack of proper dampening? very possible.

could #2 be because i'm just a better driver than him? doubt it...we've both been autoXin' for the same amount of time, and he has all of his experience in low hp fwd cars while almost all my experience (~50 events) has been in a ESP Cobra. i've had to learn how to drive all over again.

so now i have a couple questions....some of which you will roll your eyes at and say 'search' or 'rookie' but i'm gonna ask:

-the new suspension i'm building is based around OTS koni yellows (best bang for buck IMO) and currently i have 450/500 (don't really want input of 'you need to increase the rear rates, cause i have no problem rotating the car as is with 123lb rear springs ) it's been said that the max rates koni's can run is in the neighborhood of 500-600. i'm not concerned with the max, but rather what is the optimal range of spring rate that will allow the shock to provide ample and proper dampening? my logic here is what performance benefit will i see from maxing my shocks other than a bouncey ride and wearing them out faster?

-also, what kind of effect on the set-up does tire choice, sway bar choice, and wheel width have on set-up? for example I run the 205 azenis on a 6.5 rim (not ideal, but it's what i have) with 25mm/19mm sway bars.

am i beating a dead-horse? very possible.....but i would like to hear the opinions of my fellow autoXers. CivicSiRacer, if i recall correctly you run a pretty soft set-up, but you seem to do pretty well....what was your logic in setting the car up?

solo-x, what made you decide on those REALLY high rates?
Todd00 how did you arrive at your rear-biased set-up?

also has anyone thought about the fact the when you look at the motion ratio's of the DC2 if you run 500/500 (just an arbitrary example) you will have a higher rear wheel rate? ie the motion ratio in the rear is closer to one than in the front.

sorry for such a long winded post.....i'm going to a suspension seminar on the 29th and i guess i'm a bit anxious for knowledge

oh yeah, TIA in advance for you input

 

The answer to "why did xxx decide on xxx setup" is testing and driver preference and testing and tuning and so forth....

every driver given their style, chassis, swaybar setup, and so forth will generally never keep the same setup for a long period of time. They will modify the setup that works best for them and the type of autocross courses/tracks they run at.

There's absolutely no right or wrong setup. The right setup is the setup you can drive fast with.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">The answer to "why did xxx decide on xxx setup" is testing and driver preference and testing and tuning and so forth....

every driver given their style, chassis, swaybar setup, and so forth will generally never keep the same setup for a long period of time. They will modify the setup that works best for them and the type of autocross courses/tracks they run at.

There's absolutely no right or wrong setup. The right setup is the setup you can drive fast with.</TD></TR></TABLE>

i absolutely agree with you 100%

my problem is where do some of you get your #'s from? when people ask 'what spring rate blah blah blah' the answers vary sometimes by 500lbs/in

i'm just curious if there is a formula for base point, a place to start from and adjust according to driver taste, surface, etc etc.

and i wouldn't call the stock rates that my car came with a good starting point...

 

The starting point given is usually a happy medium for what works with some people thats going to be reasonably comfortable on the street and that OTS shocks will handle....

 

using some of the numbers that scott produced in his dissertation on suspension theory and rear stiff setups. i picked my front rates by figuring i wanted all the weight off the inside rear and that whatever else weight i transferred would come off the inside front and onto the outside front. i then measured my bump travel range from my working ride height and picked a spring that would keep me off the bump stop (1/2" bump travel in reserve). i then picked a rear spring rate that would give me enough rear stiffness to get all the weight off the inside rear.

your friends 92 si sounds like it's on stock length shocks. that means he's on the bumpstops, which will make a rather softly sprung car feel _very_ stiff. been there, done that. why do you think i have shortened shocks and double the spring rate?

nate

 

while it is on stock lenght shocks....he's running skunk2 upper control arms, so it's not dependant on ride height for camber....it's maybe an inch lower than it was in HS trim

 

I personally like a stiff car. I hate driving an autox car that has vertical horizons when I take a turn.

I want a car that will transition ultra-quick and has firm feedback and quick turn-in response. It's just my driving style.

Also, I don't want to sacrafice rear tire pressures/grip to get the car to rotate. Sure, I can make my R spin on a dime if I play with rear pressures, but is that really optimal for overall grip? My theory is that if you set a car up correctly, you don't have to band-aid with tire pressures or wacked out shock settings (like you do in a stock class). And since ST and up is pretty open for suspension, might as well do it correctly.

I know most autox courses aren't go-cart tracks, but with good shocks and a proper setup a stiff car will, IMO, work better than a softly sprung car. Of course, there is such thing as too stiff, but I don't think any of us are close to that yet.

 

More important than being stiff is properly damped for whatever spring rates you choose....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">More important than being stiff is properly damped for whatever spring rates you choose....</TD></TR></TABLE>

Yes, that should be implied in my above comments.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">More important than being stiff is properly damped for whatever spring rates you choose....</TD></TR></TABLE>

I can't agree with this enough.

To try and answer some of your questions tho... Most of us that are running heavy springs, rear biased, or heavy front biased have grown into these from trial and error. I'm sure you remember the thread from about 6 months ago where I switched cars with RacerMike( https://honda-tech.com/zero...age=1 ). Both are cars were prepared to the same level EXCEPT for the springs selection. I was 500F/400R and he was 600F/700R. We each drove both cars. His car was easier to drive fast, and just seemed to be a better setup. Niether of us in my car could catch the times we ran in his car.

Just some thoughts...

 

Oh, one other thing...why hasn't anyone taken this thread title into the gutter yet?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Todd00 &raquo;</TD></TR><TR><TD CLASS="quote">Oh, one other thing...why hasn't anyone taken this thread title into the gutter yet?</TD></TR></TABLE>

Obviously because we the most mature forum ever...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Todd00 &raquo;</TD></TR><TR><TD CLASS="quote">Oh, one other thing...why hasn't anyone taken this thread title into the gutter yet?</TD></TR></TABLE>

We're too busy with hamburgers and street-racin civic-drivin e-thugs.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">More important than being stiff is properly damped for whatever spring rates you choose....</TD></TR></TABLE>

this is what i'm stressing!!!

maybe CRX_Lee can chime in hear.....does anyone KNOW what rate will allow proper dampening and still afford the full amount of rebound adjustment?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Todd00 &raquo;</TD></TR><TR><TD CLASS="quote">Oh, one other thing...why hasn't anyone taken this thread title into the gutter yet?</TD></TR></TABLE>

opps guess i didn't think about the pun there

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">There's absolutely no right or wrong setup. The right setup is the setup you can drive fast {edit by BOOBIES}and SAFE{/edit} with.</TD></TR></TABLE>

 

i would say... the general rule of thumb is as stiff as possible while keeping the tires on the ground. this is obviously track condition dependent. so think about what tracks the autox will take place and setup the best compromise. most ppl can't afford to change springs for each site. and most don't anyway, as auto results is so heavily dictated by driver's skill/experience.

also, after sampling the full range of ITR's @ the expo. i would say above 600 lbs/" spring rates, a good roll cage will make a huge different in terms of how the suspension feels. below that, you won't feel as much of a different with/without a cage.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B( * Y * )BIES &raquo;</TD></TR><TR><TD CLASS="quote">

</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GhettoRacer &raquo;</TD></TR><TR><TD CLASS="quote">also, after sampling the full range of ITR's @ the expo. i would say above 600 lbs/" spring rates, a good roll cage will make a huge different in terms of how the suspension feels. below that, you won't feel as much of a different with/without a cage.

</TD></TR></TABLE>


In the name TOTAL balance, a car's chassis should not be over-burdened by stiff spring rates. Higher spring rates mean there is less compliance/movement in the suspension and if you dont have the chassis to cope with the added stress, ur chassis itself becomes a peice of the suspension.
I believe spring rates should be chosen based on how much weight transfer ur car produces (based on weight of the car, CG, track width, roll centers, etc) Once finding a spring rate, most importantly, as others have mentioned, it should be mated with a damper that can effectively control the suspension movements smoothly for both low speed and high speed dampening.

 

well, i guess i'll be searching for RR98ITR's post and doing some heavy reading.

or maybe i'll just stop OVER-anaylzing this subject, put the new suspension on and drive

 

yes. many drivers OVER analyze, and OVER criticize themselves when they drive. it is OK to make mistakes, as long as you learn from it. just drive. seat time is what counts! and for most beginnier/intermediate drivers, consistancy is what you're looking for. not speed. that will come naturally with seat time.