Springs: Linear vs. Progressive
10-01-2010, 02:13 AM
#1
Springs: Linear vs. Progressive Hey everyone, I tried do search here and on Goog but didn't quite comprehend the pros & cons of Linear vs. Progressive springs.
Can someone explain to me the difference?
I'm running Konis SA with Hotchkis (progressive) springs, and love the ride quality (from stock) but recently I was told that with linear springs I would love it even more ... Any inputs?
Thanks.
Can someone explain to me the difference?
I'm running Konis SA with Hotchkis (progressive) springs, and love the ride quality (from stock) but recently I was told that with linear springs I would love it even more ... Any inputs?
Thanks.
10-01-2010, 03:07 AM
#2
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^ your guess is as good as mine lol but anyone else out there id like to know as well cause that may be a good reason (or excuse to the fiancee lol) to buy something new for my car
10-01-2010, 12:00 PM
#5
Let me start by saying if you are truly 100% happy, then I'd not recommend a change--even if you were thinking about my springs. Clearly something has you pondering it, you just need to decide how much you want to do something different. 
Ok, here we go (and remember who's telling you this stuff- Strano Performance Parts).
ALL springs in actuality are progressive in the sense they take more and more force to compress them and will not continue to compress with a given force on them like a shock will.
"Progressive" rate springs have rates that are not static. Say you can quantify it and it takes 100lbs for the first in, but 200 for the second and 300 for the 3rd. You can't actually do that on a truly progressive spring like a Hotchkis as it's rate is never set (you can see that in the way it's wound). You are left with an unknown. You never know how stiff the spring is in any particular situation, and the shocks can't tell (they work on piston speed not "spring force"). Also there are times where softer springs ride worse then stiffer linears because you hit something hard and blow through the softer rates with so much speed that the stiffer end can't really control things and you smack off the bumpstops a lot harder than you might have otherwise.
Linear springs are a set rate. You know it'll take X lbs to compress the spring 1", and than amount again to get 2". It's a known, it's not a variable. Variables are hard to deal with when trying to make things work, be it a car's shocks, or putting up a skyscraper....
Then there are what I call dual-stage progressive springs. Let's talk about rear springs. My rears are this way and if they were not they'd fall out of the car when the axle droops. I use an initial rate of 100 lbs/in as a built-in tender spring. It's very short, and soft enough that the weight of the car collapses those coils even when just sitting--meaning they are out of play in the dynamic, working rate of the springs. We then change directly to a 150 rate which is the only rate that the car sees in motion. Hotchkis varies their coils from top to bottom, which means the rate is always climbing. Those springs are rated @ 100-140, but only at the very end reaches 140 and 100 is a rate you see while driving the car. My springs are "rated" 100/150, but because they are wound completely differently, what you get with mine are 150 linear working rate.
Front springs are sometimes dual-stage, LT1 Pro-kit are a prime example. Strano springs for the front are 100% linear because no take-up/tender type rate is needed to keep the spring in located correctly like on the rear--and having that setup where it's not needed adds weight and material cost both for no good reason. Hotchkis fronts are like their rears, actually progressive top to bottom.
I've had customers report they feel my springs ride better than Hotchkis. Mine are firmer, but because we use more spring and less bumpstop (though they are still in play) the ride is more consistent. And you get less roll and pitch too.
Ok, here we go (and remember who's telling you this stuff- Strano Performance Parts).
ALL springs in actuality are progressive in the sense they take more and more force to compress them and will not continue to compress with a given force on them like a shock will.
"Progressive" rate springs have rates that are not static. Say you can quantify it and it takes 100lbs for the first in, but 200 for the second and 300 for the 3rd. You can't actually do that on a truly progressive spring like a Hotchkis as it's rate is never set (you can see that in the way it's wound). You are left with an unknown. You never know how stiff the spring is in any particular situation, and the shocks can't tell (they work on piston speed not "spring force"). Also there are times where softer springs ride worse then stiffer linears because you hit something hard and blow through the softer rates with so much speed that the stiffer end can't really control things and you smack off the bumpstops a lot harder than you might have otherwise.
Linear springs are a set rate. You know it'll take X lbs to compress the spring 1", and than amount again to get 2". It's a known, it's not a variable. Variables are hard to deal with when trying to make things work, be it a car's shocks, or putting up a skyscraper....
Then there are what I call dual-stage progressive springs. Let's talk about rear springs. My rears are this way and if they were not they'd fall out of the car when the axle droops. I use an initial rate of 100 lbs/in as a built-in tender spring. It's very short, and soft enough that the weight of the car collapses those coils even when just sitting--meaning they are out of play in the dynamic, working rate of the springs. We then change directly to a 150 rate which is the only rate that the car sees in motion. Hotchkis varies their coils from top to bottom, which means the rate is always climbing. Those springs are rated @ 100-140, but only at the very end reaches 140 and 100 is a rate you see while driving the car. My springs are "rated" 100/150, but because they are wound completely differently, what you get with mine are 150 linear working rate.
Front springs are sometimes dual-stage, LT1 Pro-kit are a prime example. Strano springs for the front are 100% linear because no take-up/tender type rate is needed to keep the spring in located correctly like on the rear--and having that setup where it's not needed adds weight and material cost both for no good reason. Hotchkis fronts are like their rears, actually progressive top to bottom.
I've had customers report they feel my springs ride better than Hotchkis. Mine are firmer, but because we use more spring and less bumpstop (though they are still in play) the ride is more consistent. And you get less roll and pitch too.
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18 SCCA National Championships in house, many more for our customers prove we know our stuff.Talk is cheap, results matter.
Check out our KONI prices, our Master Cylinder Brace, and new Xtracker Hub/wheel bearing upgrade kits!
10-01-2010, 03:17 PM
#6
Thanks for the response Sam. I'm one of those guys that is always wanting the best for my car, maximizing the potential of all the components. So even if I'm happy with my setup, I look around / and research if I could be happier haha ... And I would ONLY buy springs from you ... Thanks!
10-01-2010, 03:39 PM
#7
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I have Hotchkiss in the front, which are progressive.
I picked them as a compromise between comfort (the
initial rate is near stock) and not-bottoming (final rate
is pretty high).
I took the Hotchkiss rears off, because they felt harsh
-and- bottomed (rear hit the stops). Stock plus hose
mod was better for rake, ride and travel.
Progressive springs work by successive coil bind. The
upper coils are tightly spaced and get further apart
as you go. You could have all kinds of profiles - a
linear rate increase, or two fairly-constant regions with
a fairly abrupt transition (like "main" and "tender") or
anything in between.
I think a progressive spring will tend to be heavier for
the same "final rate". You will have a constant wire
diameter, and to lower the "initial rate" you have more,
and closer spaced turns. My Hotchkiss springs were
well heavier than my stockers. Probably not helpful.
Live and learn.
Thing about progressive springs is, you can't just pick
a shock damping rate because the ideal damping is
dependent on the spring rate and unsprung mass. If
the shock is not position-dependent as the spring is,
you won't have ideal damping across the range of
travel. What is the "effective rate", where the car
sits and where it rolls? I sure don't know. I went with
SLP Bilsteins up front going by the notion that since I
had a high bump-rate on the spring I didn't need so
much bump-damping on the shock to inhibit up-travel,
but would want plenty of extension-damping to fight
the spring rate in that direction. All I can say is that
it feels and behaves OK enough, not to want to go to
the trouble of changing it; I have no idea if the reasoning
is sound, or just lucky. If I had it to do over, I'd have
gone adjustable. Even though I don't know what I'm
doing, at least I'd have the option to do it.
I picked them as a compromise between comfort (the
initial rate is near stock) and not-bottoming (final rate
is pretty high).
I took the Hotchkiss rears off, because they felt harsh
-and- bottomed (rear hit the stops). Stock plus hose
mod was better for rake, ride and travel.
Progressive springs work by successive coil bind. The
upper coils are tightly spaced and get further apart
as you go. You could have all kinds of profiles - a
linear rate increase, or two fairly-constant regions with
a fairly abrupt transition (like "main" and "tender") or
anything in between.
I think a progressive spring will tend to be heavier for
the same "final rate". You will have a constant wire
diameter, and to lower the "initial rate" you have more,
and closer spaced turns. My Hotchkiss springs were
well heavier than my stockers. Probably not helpful.
Live and learn.
Thing about progressive springs is, you can't just pick
a shock damping rate because the ideal damping is
dependent on the spring rate and unsprung mass. If
the shock is not position-dependent as the spring is,
you won't have ideal damping across the range of
travel. What is the "effective rate", where the car
sits and where it rolls? I sure don't know. I went with
SLP Bilsteins up front going by the notion that since I
had a high bump-rate on the spring I didn't need so
much bump-damping on the shock to inhibit up-travel,
but would want plenty of extension-damping to fight
the spring rate in that direction. All I can say is that
it feels and behaves OK enough, not to want to go to
the trouble of changing it; I have no idea if the reasoning
is sound, or just lucky. If I had it to do over, I'd have
gone adjustable. Even though I don't know what I'm
doing, at least I'd have the option to do it.
