Progressive VS Linear Rate Springs, ed ju cate me.... Options

[Mueller]

QUOTE (Aaron Cox @ Feb 8 2005, 11:16 PM)

QUOTE (MattR @ Feb 8 2005, 11:15 PM) you have a sway bar, right?  a big ass tarret one.  That is most definatly not a linear progression. its a torsion bar..... thats all it is.... effective spring rate doesnt change.... and i have no body roll (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

the swaybar does act as a spring and it does affect the ride of the vehicle....unless you drive on perfectly smooth roads so that both sides of the bar travel up and down at the same time....being in the real world, that is not the case (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)


the rate of the swaybar does change corner to corner and changes with the differential of wheel movement from side to side....a bar set on firm is going to have a worse ride than a bar set on soft........

[bondo]

QUOTE (Mueller @ Feb 8 2005, 11:39 PM)

QUOTE (Aaron Cox @ Feb 8 2005, 11:16 PM) QUOTE (MattR @ Feb 8 2005, 11:15 PM) you have a sway bar, right?  a big ass tarret one.  That is most definatly not a linear progression. its a torsion bar..... thats all it is.... effective spring rate doesnt change.... and i have no body roll (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) the swaybar does act as a spring and it does affect the ride of the vehicle....unless you drive on perfectly smooth roads so that both sides of the bar travel up and down at the same time....being in the real world, that is not the case (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) the rate of the swaybar does change corner to corner and changes with the differential of wheel movement from side to side....a bar set on firm is going to have a worse ride than a bar set on soft........

The rate also changes based on how far the sway bar "arm" is from horizontal. If you're twisting the bar such that it's 45 degrees from horizontal (I know, it'd never be that much, this is just an extreme example) then it'll be at a different rate than when the arms are horizontal.

[Trekkor]

QUOTE

a bar set on firm is going to have a worse ride than a bar set on soft........

Or in my case, a better handling car which allows me to drive faster than most...Muhahahahahaaaa.

KT

[nebreitling]

QUOTE (trekkor @ Feb 8 2005, 10:49 PM)

QUOTE a bar set on firm is going to have a worse ride than a bar set on soft........ Or in my case, a better handling car which allows me to drive just barely faster than most horse-and-carriages, but not nearly as fast as nathan. he's really fast....Muhahahahahaaaa. KT

thanks trekkor! (IMG:http://www.914world.com/bbs2/html/emoticons/cool.gif)

[Trekkor]

O.K., This is really wierd (IMG:http://www.914world.com/bbs2/html/emoticons/unsure.gif)

[SirAndy]

QUOTE (Aaron Cox @ Feb 8 2005, 10:07 PM)

unpredictable handling

that's what i heard too.
unfortunately for you, i'm running 180 *progressive* springs and i very much like the way the car handles.

contrary to popular belief, i'm having *no* problems predicting the cars handling ...
(IMG:http://www.914world.com/bbs2/html/emoticons/aktion035.gif) Andy

[redshift]

I must have installed my progressive springs upside-down, they get stiffer when the car is going straight, then the get lax in the turns, when my car rolls over, and begs you to rub it's belly.


M

[Marv's3.6six]

One of the more recent trends in damper technology is to run linear springs with "position sensitive" dampers. These dampers are very tuneable. You are able to tune the absorbtion rate at various positions of the damper stroke.
At the minimum these dampers have adjustments for initial or beginning rate and ending rate. The ending rate is used to slow the stroke of the damper as it nears "bottom out" in effect making the damper "progressive" in action. (IMG:http://www.914world.com/bbs2/html/emoticons/wacko.gif)

[ArtechnikA]

QUOTE (MattR @ Feb 9 2005, 01:21 AM)

If your car is sprung too tightly it will literally bounce under acceleration...

you mean -- if your car is underdamped ...

more spring means you need more damping; they go in pairs.

[Trekkor]

QUOTE

and i have no body roll

(IMG:http://www.914world.com/bbs2/uploads/post-2-1099340737.jpg)

me neither... (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

KT

[Trekkor]

REALLY flat... (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

(IMG:http://www.914world.com/bbs2/html/emoticons/chairfall.gif)

[TimT]

QUOTE

look at generic race springs: all linear.

actually some ground effect cars used progressive springs, the 956, and 962 come to mind (IMG:http://www.914world.com/bbs2/html/emoticons/beer.gif)

[Mueller]

Hey Tim,

are cars with tender springs considered progressive or linear?

[Aaron Cox]

since i have dialed in more swaybar trekkor (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[slivel]

QUOTE (Mueller @ Feb 9 2005, 08:08 AM)

Hey Tim, are cars with tender springs considered progressive or linear?

The answer depends on whether or not the tenders are in coil bind with the car in a static condition weight on wheels condition. Some people call this arrangement "keepers" and "tenders" are springs that actively work dynamically. In my case I just went to progressive rate spings on the racecar after 5 years of linear rate. I have only one test day for data but the car felt a little better to me in the high speed sweepers at Willow Spriings. My front set up is progressive rate 161-450. I achieve this by stacking a linear rate 450 and a progressive rate tender of 250-625. I also have the stacked set-up on the rears - currently 125-250 progressive. Most modern Porsches with triple adjustable shocks at the track seem to be using tenders. I don't know how many are just "keepers" to prevent spring droop when the car is jacked up or if they are active working springs when the suspension is working. On my set-up the tenders go into coil bind and the rate becomes linear after about 2 inches of shock travel. Next race is at Phoenix on the weekend of 19 Feb so I'll have more experience with progressive rate spings and be able to give you guys some more feedback.

Steve

[TimT]

QUOTE

are cars with tender springs considered progressive or linear?

2 linear spring equals a linear progression.

Those little tender springa are pretty insigificant anyway. They collapse with such little pressure. They are mainly to hold the spring in line with the perches

Eibach is making spring sets with what looks like a tender spring, but is really a short progressive spring. You can get multiple progressive, progressive linear sets etc. Get the Truechoice paper catalog, they have a pretty large selection of springs and some explanations

[groot]

I believe many racers use linear rates springs because they are cheaper and it's easier to buy several sets of them (me included). I use my jounce bumpers to add some progressiveness to the setup. Also, a compliant ride (a primary benefit of the progressive spring) is not critical to a race car. Everything's a compromise.

You want the rate to go up towards the end of your travel to prevent bottoming out. If a vehicle bottoms out, the loads are simply astounding. Using jounce bumpers means you can run a reasonable rate spring that allows some suspension travel and then count on your jounce bumpers to dissipate the energy, in case you excede the energy your spring can sbsorb.

There's a reason many (maybe all) production cars use progressive springs. It's much easier to get a compliant ride and attempt to control the energy with the limited travel available in today's vehicles with a progressive spring. OEMs also spend a lot of time and energy developing/tuning jounce bumpers because they cannot get enough energy dissipation from the spring alone.