Sway bar Questions
11-05-2007, 06:22 PM
#22
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Join Date: 10-25-2007
Location: north carolina
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Front Sway Bar
The answer is yes, according to the parts department at my Chevrolet dealer. All Items, front and rear springs, shocks and sway bars are interchangeable as they are built on the same frame.
11-05-2007, 08:05 PM
#23
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Join Date: 10-08-2007
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11-09-2007, 08:52 PM
#24
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Join Date: 08-19-2007
Location: So.Cal.
Posts: 829
Check the sizes. I think the SS actually has smaller sway bars then the current sport suspension.
The Cobalt is not as heavy as the HHR, so unless you find a thicker sway bar, then you wont gain and roll stiffness.
I added Eibach springs and the Progress rear bar. No bigger front bar was available yet.
The Cobalt is not as heavy as the HHR, so unless you find a thicker sway bar, then you wont gain and roll stiffness.
I added Eibach springs and the Progress rear bar. No bigger front bar was available yet.
Last edited by Hotrodbob; 11-09-2007 at 08:56 PM. Reason: ms spilling
11-17-2007, 03:54 PM
#26
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Join Date: 10-02-2005
Location: VA
Posts: 1,245
A rear sway bar torsionally resists differing motion between opposite wheels.
For example, should both rear wheels hit a bump together, there will be absolutely no difference, since the wheels want to travel together anyway.
Now if only 1 hits a bump, some force will attempt to transfer to the other side, essentially stiffening the spring rate. In reality, that's not really noticeable.
The Progress Tech rear bar results in a much more balanced chassis in the HHR, with less body roll. Well worth it and extremely easy to install.
11-17-2007, 05:46 PM
#27
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Join Date: 11-04-2007
Location: Joppa, Maryland
Posts: 45
Not really.
A rear sway bar torsionally resists differing motion between opposite wheels.
For example, should both rear wheels hit a bump together, there will be absolutely no difference, since the wheels want to travel together anyway.
Now if only 1 hits a bump, some force will attempt to transfer to the other side, essentially stiffening the spring rate. In reality, that's not really noticeable.
The Progress Tech rear bar results in a much more balanced chassis in the HHR, with less body roll. Well worth it and extremely easy to install.
A rear sway bar torsionally resists differing motion between opposite wheels.
For example, should both rear wheels hit a bump together, there will be absolutely no difference, since the wheels want to travel together anyway.
Now if only 1 hits a bump, some force will attempt to transfer to the other side, essentially stiffening the spring rate. In reality, that's not really noticeable.
The Progress Tech rear bar results in a much more balanced chassis in the HHR, with less body roll. Well worth it and extremely easy to install.
11-18-2007, 10:41 AM
#28
Member
Join Date: 11-04-2007
Location: Joppa, Maryland
Posts: 45
12-27-2007, 10:50 AM
#29
Senior Member
Join Date: 08-29-2007
Location: CenCoast California
Posts: 256
Forum members-
Today, I see at least three different threads in the suspension forum about stabilizer bars. Unfortunately, there are a lot of misconceptions about them.
First, body roll. Many people, including some of the audience here, base their opinions about and/or their strategy to address body roll on false premises which were true 30 or 40 years ago, but are not true now.
Generally speaking, with modern cars, body roll is not always bad thing. Modern suspensions need some body roll to work properly..."properly" meaning providing the expected mix of comfortable ride and good handling. Further, modern suspension geometries usually maintain a higher level of wheel control through a wider range of ride travel than was the possible 30-40 years ago. What this means is a car can have some body roll and still have the suspension capable of substantial lateral grip.
So the idea that you can simply bolt a rear stabilizer bar on a base or midlevel HHR suspension and instantly see a significant improvement in handling because you've reduced body roll is faulty. The performance "improvement" you think the you may get near the truck's handling limits, might not be an improvement at all.
Yes, you may reduce body roll but, going from no rear bar to the typically large rear bar the aftermarket is selling, makes a huge difference in the car's balance at the limit. This is because bar rate (and its effect on roll stiffness along with, in the end, wheel rates) changes with the square of the bar size, i.e.: when you go from zero bar rate to the significant rate of, say, a 24mm bar (the one on the rear of an HHR SS), the increase in the car's rear roll stiffness is very significant. But, when you add a ton of rear roll stiffness but make no other changes, you're actually altering the car's balance at the limits of its handing in a detrimental, and perhaps, unsafe manner. Additionally, if you use your HHR the way it was originally designed, as a compact SUV, you'll find that as you load the car--add rear passengers or, worse yet, load the rear with cargo--the out-of-balance issue may become even more significant.
Where a car with a lot of rear roll stiffness can be a problem is when you abruptly reach the car's handling limits in a emergency evasive maneuver, ie: your swerve to avoid something. A vehicle with lots of rear roll stiffness can suddenly oversteer, or "get loose". This will happen too quickly for anyone but the most experienced race drivers to correct and then the driver will loose control of the vehicle as it spins.
Imagine this...your wife takes the HHR, sticks your two grandkids in the back seat, then goes shopping at Home Depot for garden stuff. She's got, maybe, 150 lbs of kids in the back seat and another 150-200 lbs of plants, fertilizer, garden tools etc in the cargo area. She's headed home, buzzing along the Interstate at the speed limit when, out of nowhere, an 18-wheeler starts a lane change and cuts her off. She jams on the brakes (transferring weight to the front) then swerves left to avoid the truck. Your HHR, already light in the rear due to braking, has plenty of weight in the back (grandkids and cargo) adding to the truck's inertia at the rear and, because of the rear roll stiffness causing oversteer, the back end breaks loose. Within a split second, the HHR spins and is sliding at 50 mph, sideways down the interstate with 2 screaming kids in the back.
Bottom line:
When you do nothing but add a big rear stabilizer bar to an otherwise reasonably well-balanced suspension, you're setting yourself up for possible trouble.
Another idea I see posted here from time to time is that the simple addition of a rear sway bar makes the car more stable in turns over bumpy roads. That also is a faulty belief. In fact, putting a rear stabilizer bar on the HHR's rear "twist axle" (GM calls it a "semi-independent suspension) decreases stability on bumpy roads in turns because you're making the rear axle more susceptible to the problems beam axles have when one wheel has ride movement and the other does not and the suspension is generating lateral acceleration in a turn.
A couple of suggestions to those with base or mid-level HHRs.
If you can't live with the body roll and you just can resist drinking the aftermarket's coolaid, don't just put on a rear bar. Do a package of aftermarket front *and* rear stabilizer bars which compliment each other. When you add a rear bar then increase the size of the front bar in the correct proportion, you'll reduce body roll *and* do more to preserve the car's balance.
That said, my first choice in a handling upgrade would not be stabilizers. I have an HHR with Sport Suspension. With better handling as my goal, I'd first do a upgrade of the tires and shocks. The practical improvement in the truck's limit handling will be greater than if the sole modification was a rear stab bar and the truck will end-up a lot more forgiving at the handling limit. HHRs, even with Sport Suspension, come with tires which are crap, from a handling perspective. You put a set of good set of ultra-performance radials (Goodyear F1 GS-D3s or the newer F1 Asymmetric, come to mind) you'll be amazed at the improvement in the car's at limit handling and the on-center steering feel. Swap the OE. shocks for a set of premium shocks with valving intended for performance driving and you'll see another noticeable gain in handling.
My second step, if more still more aggressive handing is desired and if I'm willing to take a hit to ride comfort, would be to add a combination of stiffer springs, bigger front bar and a rear bar. I'd also think about a slightly larger wheel/tire package, too.
Lastly, let's talk about lowering. Just about everyone likes the look of a lowered hot rod. HHRs are no exception, they look cool when lowered, but lowering, especially if you really slam the truck, has some significant compromises in ride quality and the ability to carry a load, especially if the lowered truck uses stock springs. Additionally, if you slam the truck such that suspension travel is too limited, handling actually is degraded.
When you lower the vehicle, ride quality decreases because the suspension hits the bump stops more often. Once the suspension is on the stops, spring rate skyrockets almost to infinity and that, obviously, makes for a stiff ride. In addition, the truck's handing becomes more unpredictable. You can mitigate these problems somewhat by going to higher rate springs and shocks with more aggressive valving but they *also* stiffen ride somewhat, however--you're better to have stiff springs and shocks and the suspension bottoming sometimes rather than soft springs and shocks and the suspension bottoming all the time. Lastly, the HHR, because it's actually a compact SUV, has a lot of suspension travel built into the rear to give it some ability to carry a load and also ride reasonably well when doing that. Once you start reducing ride travel (lowering) you give-up all that.
So, yeah, lowering an HHR looks cool but it does reduce ride quality and the truck's utility. Make sure you're comfortable with those trade-offs.
Today, I see at least three different threads in the suspension forum about stabilizer bars. Unfortunately, there are a lot of misconceptions about them.
First, body roll. Many people, including some of the audience here, base their opinions about and/or their strategy to address body roll on false premises which were true 30 or 40 years ago, but are not true now.
Generally speaking, with modern cars, body roll is not always bad thing. Modern suspensions need some body roll to work properly..."properly" meaning providing the expected mix of comfortable ride and good handling. Further, modern suspension geometries usually maintain a higher level of wheel control through a wider range of ride travel than was the possible 30-40 years ago. What this means is a car can have some body roll and still have the suspension capable of substantial lateral grip.
So the idea that you can simply bolt a rear stabilizer bar on a base or midlevel HHR suspension and instantly see a significant improvement in handling because you've reduced body roll is faulty. The performance "improvement" you think the you may get near the truck's handling limits, might not be an improvement at all.
Yes, you may reduce body roll but, going from no rear bar to the typically large rear bar the aftermarket is selling, makes a huge difference in the car's balance at the limit. This is because bar rate (and its effect on roll stiffness along with, in the end, wheel rates) changes with the square of the bar size, i.e.: when you go from zero bar rate to the significant rate of, say, a 24mm bar (the one on the rear of an HHR SS), the increase in the car's rear roll stiffness is very significant. But, when you add a ton of rear roll stiffness but make no other changes, you're actually altering the car's balance at the limits of its handing in a detrimental, and perhaps, unsafe manner. Additionally, if you use your HHR the way it was originally designed, as a compact SUV, you'll find that as you load the car--add rear passengers or, worse yet, load the rear with cargo--the out-of-balance issue may become even more significant.
Where a car with a lot of rear roll stiffness can be a problem is when you abruptly reach the car's handling limits in a emergency evasive maneuver, ie: your swerve to avoid something. A vehicle with lots of rear roll stiffness can suddenly oversteer, or "get loose". This will happen too quickly for anyone but the most experienced race drivers to correct and then the driver will loose control of the vehicle as it spins.
Imagine this...your wife takes the HHR, sticks your two grandkids in the back seat, then goes shopping at Home Depot for garden stuff. She's got, maybe, 150 lbs of kids in the back seat and another 150-200 lbs of plants, fertilizer, garden tools etc in the cargo area. She's headed home, buzzing along the Interstate at the speed limit when, out of nowhere, an 18-wheeler starts a lane change and cuts her off. She jams on the brakes (transferring weight to the front) then swerves left to avoid the truck. Your HHR, already light in the rear due to braking, has plenty of weight in the back (grandkids and cargo) adding to the truck's inertia at the rear and, because of the rear roll stiffness causing oversteer, the back end breaks loose. Within a split second, the HHR spins and is sliding at 50 mph, sideways down the interstate with 2 screaming kids in the back.
Bottom line:
When you do nothing but add a big rear stabilizer bar to an otherwise reasonably well-balanced suspension, you're setting yourself up for possible trouble.
Another idea I see posted here from time to time is that the simple addition of a rear sway bar makes the car more stable in turns over bumpy roads. That also is a faulty belief. In fact, putting a rear stabilizer bar on the HHR's rear "twist axle" (GM calls it a "semi-independent suspension) decreases stability on bumpy roads in turns because you're making the rear axle more susceptible to the problems beam axles have when one wheel has ride movement and the other does not and the suspension is generating lateral acceleration in a turn.
A couple of suggestions to those with base or mid-level HHRs.
If you can't live with the body roll and you just can resist drinking the aftermarket's coolaid, don't just put on a rear bar. Do a package of aftermarket front *and* rear stabilizer bars which compliment each other. When you add a rear bar then increase the size of the front bar in the correct proportion, you'll reduce body roll *and* do more to preserve the car's balance.
That said, my first choice in a handling upgrade would not be stabilizers. I have an HHR with Sport Suspension. With better handling as my goal, I'd first do a upgrade of the tires and shocks. The practical improvement in the truck's limit handling will be greater than if the sole modification was a rear stab bar and the truck will end-up a lot more forgiving at the handling limit. HHRs, even with Sport Suspension, come with tires which are crap, from a handling perspective. You put a set of good set of ultra-performance radials (Goodyear F1 GS-D3s or the newer F1 Asymmetric, come to mind) you'll be amazed at the improvement in the car's at limit handling and the on-center steering feel. Swap the OE. shocks for a set of premium shocks with valving intended for performance driving and you'll see another noticeable gain in handling.
My second step, if more still more aggressive handing is desired and if I'm willing to take a hit to ride comfort, would be to add a combination of stiffer springs, bigger front bar and a rear bar. I'd also think about a slightly larger wheel/tire package, too.
Lastly, let's talk about lowering. Just about everyone likes the look of a lowered hot rod. HHRs are no exception, they look cool when lowered, but lowering, especially if you really slam the truck, has some significant compromises in ride quality and the ability to carry a load, especially if the lowered truck uses stock springs. Additionally, if you slam the truck such that suspension travel is too limited, handling actually is degraded.
When you lower the vehicle, ride quality decreases because the suspension hits the bump stops more often. Once the suspension is on the stops, spring rate skyrockets almost to infinity and that, obviously, makes for a stiff ride. In addition, the truck's handing becomes more unpredictable. You can mitigate these problems somewhat by going to higher rate springs and shocks with more aggressive valving but they *also* stiffen ride somewhat, however--you're better to have stiff springs and shocks and the suspension bottoming sometimes rather than soft springs and shocks and the suspension bottoming all the time. Lastly, the HHR, because it's actually a compact SUV, has a lot of suspension travel built into the rear to give it some ability to carry a load and also ride reasonably well when doing that. Once you start reducing ride travel (lowering) you give-up all that.
So, yeah, lowering an HHR looks cool but it does reduce ride quality and the truck's utility. Make sure you're comfortable with those trade-offs.
