Harsh yet floaty?
01-04-07, 09:43 AM
#1
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Harsh yet floaty?
The stock GS suspension is an enigma. How is it that the stock suspension can deliver a floaty highway ride (implying that the suspension is relatively soft and cushy), yet at the same time feel harsh over sharp bumps or uneven pavement (implying that the suspension is relatively firm). My mom used to own a late 70s Cadallic Eldorado. The car would float down the highway and transmitted very little if any of the bumps into the cabin. I don't get it. Maybe some of you suspension gurus can chime in.
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01-04-07, 11:34 AM
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Good question. I was thinking the same. Whys it so rough on some small bumps yet FLOATS smooth as silk on the freeway? I was wondering also because i just got my GS a few weeks ago.
01-04-07, 01:55 PM
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I guess what I'm trying to say (and not doing a very good job of it) is that it's like having the worst of both worlds. Not only is the handling sloppy because the suspension is so soft, but the ride is also harsh because the suspension doesn't soak up the bumps. I realize that handling/comfort is supposedly a trade-off, but assuming that's true, you would think that floaty/mushy would equate with comfort and firm/good handling would equate with harsh/less comfort. That just doesn't seem to be the case with the stock GS suspension.
01-04-07, 03:40 PM
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High speed vs. Low speed damping
I noticed the same thing on my GS4. The stock suspension was "floaty" on the highway, but rough on pavement irregularities, bridge joints, and small bumps. When I went to the Tein CS's, the ride actually improved.
I believe it has to do with the high speed damping of the stock struts. When the suspension had to react very fast (small bump or square edged lip) the struts seemed overdamped and didn't allow enough absorption, allowing the jolt up thru the body. However, when the suspension had to react slower items(dips and corners) it seemed underdamped causing foating and bobbing.
Yeah, it was the worst of both worlds, especially with the 17" tires. Larger sidewalls would probably mask the suspensions shortcomings.
I believe it has to do with the high speed damping of the stock struts. When the suspension had to react very fast (small bump or square edged lip) the struts seemed overdamped and didn't allow enough absorption, allowing the jolt up thru the body. However, when the suspension had to react slower items(dips and corners) it seemed underdamped causing foating and bobbing.
Yeah, it was the worst of both worlds, especially with the 17" tires. Larger sidewalls would probably mask the suspensions shortcomings.
01-04-07, 07:16 PM
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I noticed the same thing on my GS4. The stock suspension was "floaty" on the highway, but rough on pavement irregularities, bridge joints, and small bumps. When I went to the Tein CS's, the ride actually improved.
I believe it has to do with the high speed damping of the stock struts. When the suspension had to react very fast (small bump or square edged lip) the struts seemed overdamped and didn't allow enough absorption, allowing the jolt up thru the body. However, when the suspension had to react slower items(dips and corners) it seemed underdamped causing foating and bobbing.
Yeah, it was the worst of both worlds, especially with the 17" tires. Larger sidewalls would probably mask the suspensions shortcomings.
I believe it has to do with the high speed damping of the stock struts. When the suspension had to react very fast (small bump or square edged lip) the struts seemed overdamped and didn't allow enough absorption, allowing the jolt up thru the body. However, when the suspension had to react slower items(dips and corners) it seemed underdamped causing foating and bobbing.
Yeah, it was the worst of both worlds, especially with the 17" tires. Larger sidewalls would probably mask the suspensions shortcomings.
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01-04-07, 07:43 PM
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Sorry..I know...I know. But, people have been saying for years, "Just go with coilovers, b/c that's where most of us end up anyway". As much as I don't encourage expensive modding, this is one upgrade that really pays off, IMO.
01-04-07, 08:02 PM
#9
I completely agree with you e-man. it's absolutely true, and obviously worsens with poly bushings and bigger rims with shorter sidewall tires.
I think the soft springs are the biggest part of the floaty feeling.
I can only put the 'harsh' response to sharp bumps down to 1) lower profile tires (depending upon the comparison), 2) unsprung weight, 3) shock valving.
I'd be interested in hearing other opinions too.
HOW WEIRD: I swear that when I wrote this there were no replies showing up on my screen!!!! :-/ very very weird.
I think the soft springs are the biggest part of the floaty feeling.
I can only put the 'harsh' response to sharp bumps down to 1) lower profile tires (depending upon the comparison), 2) unsprung weight, 3) shock valving.
I'd be interested in hearing other opinions too.
HOW WEIRD: I swear that when I wrote this there were no replies showing up on my screen!!!! :-/ very very weird.
Last edited by BA_GS400; 01-05-07 at 04:06 PM.
01-05-07, 01:17 PM
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OK, so I saw this thread a while back but didn't have time to respond. I have to admit I also wanted to see what kind of responses you would get. The simple answer is there isn't a simple answer. Forty years ago things were a lot simpler. In the olden days street car stiffness wasn't an issue and if you wanted to race it, well you cut the living daylights out of the thing and tried to find anything that wasn't rust to bolt or weld to in order to stiffen the car up.
But back then it was a lot easier to learn about suspensions and how different things would change the ride and handling without spending a bazillion dollars. In 1969 GM averaged $0.75 each for shock absorbers on their cars. They were worn out before you drove the car home. Monroe made huge 50/50 valved shock absorbers for the full size Ford station wagon that would fit in the Camaro as long as you ground out the lower A-arm to make room to push that huge shock up into the spring. Just marvelous for autocrossing. Heck, we even stiffened up factory rubber bushings for autocrossing by driving nails into them. The rules mandated no solid bushings but nobody bothered to look at if you had performed that trick. And yes, the bushings would totally come apart in short order but you might win a trophy or two before that. All right so enough of the walk down memory lane that no one is interested in anyway.
Today, the OEMs are probably the biggest customers of supercomputers and they use them to not only reduce costs by modelling assembly operations but spend a lot of money on computer time look at how huge amounts of subtle changes affect ride, handling, NVH, and cost. If you follow the claims of the mfrs on chassis stiffness it makes you believe that the cars we were driving five years ago should have come with rollers under the passenger cab to keep it from sliding along the road as we drove along. An automotive designer is constantly being beat over the head with costs but basically a guy, or a team, sit down and design the suspension to give them the ride/handling they or marketing dictate. Almost no part of the car has a linear response anymore. Everything has progressive rate springs, and shocks are very often progressive rate either by design or just by operation. The original design team designs to get the ride/handling that their company has dictated and it will involve everything from chassis stiffness to air pressure in the tires.
When you start modding, you are changing one or several components in a complicated system and the outcome may, or may not, be what you want. Using the internet to determine what mod works for you is like letting Congress determine what you should eat for dinner. Just figuring out whether the guy posting has just made the automotive big leagues because his Mom lets him ride shotgun in the minivan or whether the guy is only trying to sell you something (in between pumping stocks on his blog) is often impossible to determine. We each have our own ideas of what we want. Young guys often want a certain "look" regardless of what it does to the suspension dynamics. Lowered springs will have less ability to soak up bumps as they will have to inevitably have higher progressive rates as they reduce suspension travel. And I ripped enough spoilers off in my day to not want to do the speed bump two step with a lowered car anymore. Lower profile tires generally, but not necessarily always, have stiffer sidewalls. Z rated tires will often have a softer rubber compound but stiffer side walls than V rated which will have softer rubber and stiffer sidewalls than H rated and so on. Did you think that Z rated were just a way to get more money out of you? Maybe sometimes it is, but not always. But this is the reason for the higher speed (and quicker wear) rating.
I chose years ago to not pursue a career in the auto industry so I am not qualified to make a complete treatise on the GS suspension but I found out within the first year of owning mine that it was extremely easy to push it from floaty to harsh. In fact, it was surprisingly and annoyingly easy. There are things I have a lot of experience with that I will not put on a street car, such as solid bushings whether of some sort of polymer, filled or unfilled, or inorganic (we used machined aluminum on the 60s Trans Am cars). Why exactly the GS is so easy to get to the harsh side would be interesting to find out if you have the interest, connections, and time. Just one instance is unsprung weight. The designer at Lexus had a wheel/tire combination that had a spring rate and weight to deal with. And he had to deal with optional wheels and tires and make a compromise from the getgo as well. Aftermarket tires and wheels can wreak havoc with the original spring and shock rates specified by increasing or decreasing unsprung weight. Some cars aren't sensitive to this, some can be very sensitive to it. I can recommend a book or two to those of you who might be interested in doing some reading but you will not find the magic bullet on page 187 that says "If you want to get rid of the float on your GS but not have a harsh ride do A, B, and C." But you can learn what some of the factors are and how they interact. They are written for race cars which are a whole lot simpler than street cars but as far as finding out what things do, it is a help.
So to wind up, maybe the best information would be to get the car that comes closest to the ride/handling you want to begin with. There are other factors in the purchase decision compromise so unless ride/handling is number one, you may not be able to do this. But when you get a car that the original designer had a very different idea of what ride/handling it should have, you may never make it what you want regardless of how much time or money you want to spend. The more you know about suspensions, the better you will be ale to identify what to mod to make the improvement you want so get ready to do some reading and do some expensive hands on learning. Second bit of advice would be that if you are going to get a car that isn't quite what you want, make sure it is either an American performance model or one of the big name performance brand cars. They have the most parts available for them. And the American car parts will generally be a lot cheaper than anything for any import, luxury or not.
Just my two cents, feel free to ignore.
But back then it was a lot easier to learn about suspensions and how different things would change the ride and handling without spending a bazillion dollars. In 1969 GM averaged $0.75 each for shock absorbers on their cars. They were worn out before you drove the car home. Monroe made huge 50/50 valved shock absorbers for the full size Ford station wagon that would fit in the Camaro as long as you ground out the lower A-arm to make room to push that huge shock up into the spring. Just marvelous for autocrossing. Heck, we even stiffened up factory rubber bushings for autocrossing by driving nails into them. The rules mandated no solid bushings but nobody bothered to look at if you had performed that trick. And yes, the bushings would totally come apart in short order but you might win a trophy or two before that. All right so enough of the walk down memory lane that no one is interested in anyway.
Today, the OEMs are probably the biggest customers of supercomputers and they use them to not only reduce costs by modelling assembly operations but spend a lot of money on computer time look at how huge amounts of subtle changes affect ride, handling, NVH, and cost. If you follow the claims of the mfrs on chassis stiffness it makes you believe that the cars we were driving five years ago should have come with rollers under the passenger cab to keep it from sliding along the road as we drove along. An automotive designer is constantly being beat over the head with costs but basically a guy, or a team, sit down and design the suspension to give them the ride/handling they or marketing dictate. Almost no part of the car has a linear response anymore. Everything has progressive rate springs, and shocks are very often progressive rate either by design or just by operation. The original design team designs to get the ride/handling that their company has dictated and it will involve everything from chassis stiffness to air pressure in the tires.
When you start modding, you are changing one or several components in a complicated system and the outcome may, or may not, be what you want. Using the internet to determine what mod works for you is like letting Congress determine what you should eat for dinner. Just figuring out whether the guy posting has just made the automotive big leagues because his Mom lets him ride shotgun in the minivan or whether the guy is only trying to sell you something (in between pumping stocks on his blog) is often impossible to determine. We each have our own ideas of what we want. Young guys often want a certain "look" regardless of what it does to the suspension dynamics. Lowered springs will have less ability to soak up bumps as they will have to inevitably have higher progressive rates as they reduce suspension travel. And I ripped enough spoilers off in my day to not want to do the speed bump two step with a lowered car anymore. Lower profile tires generally, but not necessarily always, have stiffer sidewalls. Z rated tires will often have a softer rubber compound but stiffer side walls than V rated which will have softer rubber and stiffer sidewalls than H rated and so on. Did you think that Z rated were just a way to get more money out of you? Maybe sometimes it is, but not always. But this is the reason for the higher speed (and quicker wear) rating.
I chose years ago to not pursue a career in the auto industry so I am not qualified to make a complete treatise on the GS suspension but I found out within the first year of owning mine that it was extremely easy to push it from floaty to harsh. In fact, it was surprisingly and annoyingly easy. There are things I have a lot of experience with that I will not put on a street car, such as solid bushings whether of some sort of polymer, filled or unfilled, or inorganic (we used machined aluminum on the 60s Trans Am cars). Why exactly the GS is so easy to get to the harsh side would be interesting to find out if you have the interest, connections, and time. Just one instance is unsprung weight. The designer at Lexus had a wheel/tire combination that had a spring rate and weight to deal with. And he had to deal with optional wheels and tires and make a compromise from the getgo as well. Aftermarket tires and wheels can wreak havoc with the original spring and shock rates specified by increasing or decreasing unsprung weight. Some cars aren't sensitive to this, some can be very sensitive to it. I can recommend a book or two to those of you who might be interested in doing some reading but you will not find the magic bullet on page 187 that says "If you want to get rid of the float on your GS but not have a harsh ride do A, B, and C." But you can learn what some of the factors are and how they interact. They are written for race cars which are a whole lot simpler than street cars but as far as finding out what things do, it is a help.
So to wind up, maybe the best information would be to get the car that comes closest to the ride/handling you want to begin with. There are other factors in the purchase decision compromise so unless ride/handling is number one, you may not be able to do this. But when you get a car that the original designer had a very different idea of what ride/handling it should have, you may never make it what you want regardless of how much time or money you want to spend. The more you know about suspensions, the better you will be ale to identify what to mod to make the improvement you want so get ready to do some reading and do some expensive hands on learning. Second bit of advice would be that if you are going to get a car that isn't quite what you want, make sure it is either an American performance model or one of the big name performance brand cars. They have the most parts available for them. And the American car parts will generally be a lot cheaper than anything for any import, luxury or not.
Just my two cents, feel free to ignore.
01-05-07, 01:50 PM
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Reducing unsprung weight has a big effect on steering input mechanically. This is the way you do it without or before you factor in power steering. Now, if you haven't gotten there ahead of me, the more you reduce unsprung weight the more responsive the suspension is, to steering input and bumps. So you get better handling right before you wind up in the back seat if you don't have your belt on good and tight. The shocks, springs, chassis stiffness, bushings, all work with a specific unsprung weight. When you leave the unsprung weight alone but change springs and shock valving, you are going somewhere the mfr didn't want to go. When you change the unsprung weight and leave all the other bits alone, ditto. Tirerack posts most or all of the weights of the tires in the individual makes and sizes. When you get truly nutso on this issue, you will watch those closely along with wheel weights. Otherwise, just go to Costco and be happy.
Is that enough of an answer?
01-05-07, 02:26 PM
#13
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LOL. You have no idea. This comment is more insightful than your suspension advice.Business has made me a sporadic visitor but here goes. Sprung weight is the weight of the car that the springs support. This means the chassis body, engine, etc. Unsprung weight is that weight that is not supported by the springs. So wheels, tires, brakes, some of the suspension bits are unsprung as they have to go up and down.This is the portion of the car tha is most susceptible to road shock and cornering forces, that is sort of a statement of the obvious but if you think about it, you will see it is just a statement of the obvious. No nuclear physics here. This is a hugely critical factor affecting handling, lower unsprung weight means the suspension has an easier job keeping the tire contact patch in touch with the road. The opposite generally will ruin your whole day.
Reducing unsprung weight has a big effect on steering input mechanically. This is the way you do it without or before you factor in power steering. Now, if you haven't gotten there ahead of me, the more you reduce unsprung weight the more responsive the suspension is, to steering input and bumps. So you get better handling right before you wind up in the back seat if you don't have your belt on good and tight. The shocks, springs, chassis stiffness, bushings, all work with a specific unsprung weight. When you leave the unsprung weight alone but change springs and shock valving, you are going somewhere the mfr didn't want to go. When you change the unsprung weight and leave all the other bits alone, ditto. Tirerack posts most or all of the weights of the tires in the individual makes and sizes. When you get truly nutso on this issue, you will watch those closely along with wheel weights. Otherwise, just go to Costco and be happy.
Is that enough of an answer?
Reducing unsprung weight has a big effect on steering input mechanically. This is the way you do it without or before you factor in power steering. Now, if you haven't gotten there ahead of me, the more you reduce unsprung weight the more responsive the suspension is, to steering input and bumps. So you get better handling right before you wind up in the back seat if you don't have your belt on good and tight. The shocks, springs, chassis stiffness, bushings, all work with a specific unsprung weight. When you leave the unsprung weight alone but change springs and shock valving, you are going somewhere the mfr didn't want to go. When you change the unsprung weight and leave all the other bits alone, ditto. Tirerack posts most or all of the weights of the tires in the individual makes and sizes. When you get truly nutso on this issue, you will watch those closely along with wheel weights. Otherwise, just go to Costco and be happy.
Is that enough of an answer?
As always, thanks for your help, Ron.
e
01-05-07, 03:42 PM
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(a) ride around in a few other GS's that have aftermarket suspensions to see how they feel;
Best idea yet, lots of guys have spent lots of time and money doing lots of R&D that you can take advantage of for free, or for the cost of a Happy Meal at worst. Or maybe you should invest in a quick weekend hop out here, like Cliffud said you can drive just about any setup you're considering. That might be the best couple hundred bucks you could spend on the matter.
Best idea yet, lots of guys have spent lots of time and money doing lots of R&D that you can take advantage of for free, or for the cost of a Happy Meal at worst. Or maybe you should invest in a quick weekend hop out here, like Cliffud said you can drive just about any setup you're considering. That might be the best couple hundred bucks you could spend on the matter.