Do you think stiffer springs will help with side to side swaying type motion?

[lizpat]

I just installed a TEIN Street Basis suspension kit for recently purchased my 2012 Honda Fit (base model.) It's considered a coilover but it's really just for daily driving, and not racing or any kind of sporty driving. It features height adjustability and that's it. Think of it as a matching set of springs and dampers for this car. It's been a nice improvement over the stock suspension which was very loosy goosy vague with motions left right front back and just awful. Had I not been able to rectify that with this kit, I would HAVE to sell the car, it was not livable on daily basis especially since I bought this Honda Fit to ultimately replace my 2007 Corolla (which is a VERY solid car.)

I'm still bothered by the amount of body roll and side to side swaying motion, especially when hitting a pothole or a bump or some quick change in elevation. The kit has indeed improved everything, but not enough for me to be truly happy.

Since this is a coilover, the springs can be replaced with a stiffer unit of the same length and inside diameter (70MM ID, TEIN springs) I have been assured by their tech support that going 1K stiffer (56 lb/in.) is within the tolerances of the damper. For the front we'll be going from 3K (168 lb/in.) to 4K (224 lb/in.) the rear will remain at 2K (112 lb/in.)

So, anyways, I'm hoping to remedy that type of unwanted motion which is evident especially during higher speeds. Do you think stiffer springs will do it? If I need to get another kit, I may go that route ultimately, but hopefully not.

 

[Passport1]

Heavier sway bars are the remedy. Maybe poly bushings also.

 

[lizpat]

Heavier sway bars are the remedy. Maybe poly bushings also.

The sway bars don't mitigate the side to side motion when hitting a bump though.. sway bars only come into play during cornering.

 

[Lubener]

I would check your front end parts for wear. Worn ball joints can act as you describe when hitting potholes and irregularities on the road.

 

[adams355]

Yep those things above and check front wheel bearings as well

The sway bars don't mitigate the side to side motion when hitting a bump though.. sway bars only come into play during cornering.

The heavier sway bar spreads out the force more evenly

 

[PoorMans180SX]

Another vote for larger sway bars. Going up 1K in spring rate will help a little, but if you're looking to control body motion with spring rate, that's not going to do it. Sway bars will help much more, and keep the ride comfort basically the same.

Do not put poly bushings in your control arms, you'll ruin the whole car IMHO.

 

[Jetronic]

I just installed a TEIN Street Basis suspension kit for recently purchased my 2012 Honda Fit (base model.) It's considered a coilover but it's really just for daily driving, and not racing or any kind of sporty driving. It features height adjustability and that's it. Think of it as a matching set of springs and dampers for this car. It's been a nice improvement over the stock suspension which was very loosy goosy vague with motions left right front back and just awful. Had I not been able to rectify that with this kit, I would HAVE to sell the car, it was not livable on daily basis especially since I bought this Honda Fit to ultimately replace my 2007 Corolla (which is a VERY solid car.)

I'm still bothered by the amount of body roll and side to side swaying motion, especially when hitting a pothole or a bump or some quick change in elevation. The kit has indeed improved everything, but not enough for me to be truly happy.

Since this is a coilover, the springs can be replaced with a stiffer unit of the same length and inside diameter (70MM ID, TEIN springs) I have been assured by their tech support that going 1K stiffer (56 lb/in.) is within the tolerances of the damper. For the front we'll be going from 3K (168 lb/in.) to 4K (224 lb/in.) the rear will remain at 2K (112 lb/in.)

So, anyways, I'm hoping to remedy that type of unwanted motion which is evident especially during higher speeds. Do you think stiffer springs will do it? If I need to get another kit, I may go that route ultimately, but hopefully not.

Time to read up about roll centers... I'm assuming a honda fit has mcpherson front suspension, torsion beam rear and fwd? Lowering can make body roll worse due to the roll centre dropping much faster than the centre of gravity, and the roll is a result of the distance between roll centre height and centre of gravity height.

Stiffening the springs will reduce sway, but stiffening just the front will introduce extra understeer.

 

[MRC01]

I've done similar changes to cars for SCCA autocross fun. Most recently my Mazda 3. Most FWD cars have too much understeer and stiffening the rear swaybar helps reduce that, making steering more precise and responsive, at the same time reducing body roll. But it doesn't affect overall stiffness, squat or dive. Don't stiffen the front swaybar, unless you want more understeer! You said their recommendation was to stiffen the front springs while keeping the rear rates the same. That doesn't sound right, as it tends to increase understeer which is typically the opposite of what you want for precise handling.

The suspension is a system that works together, so a single change taken too far can be counterproductive. For example, the aftermarket rear swaybar in my Mazda 3 has 2 settings, roughly 2x and 3x the OEM rate. When I used the 3x rate on the stock (soft) springs, the car got darty. Any upset (like a bump or uneven pavement) during cornering make it want to suddenly change direction. But after I replaced the springs with stiffer ones (+20%), then the rear swaybar's 3x setting was perfect, the dartiness was gone.

In summary, the typical recommended steps for your situation are, in order: (1) stiffer rear swaybar, (2) stiffer springs and shocks. You already have (2), so I suggest doing (1). And double check the rates on your aftermarket springs -- they're not always stiffer than stock!

PS: my wife's Subaru Forester had the same problem as your Honda: way too soft suspension, cornered like a boat with excessive body roll. I replaced the rear sway bar with one having twice the rate (still an OEM subaru part). Total cost about $100 and 30 mins of work, the improvement was like night & day. If you make only 1 mod to the suspension, stiffer rear swaybar is usually the thing to do. Even if you end up doing more, that's usually the best place to start.

 

[Astro14]

How many miles on this?

 

[UG_Passat]

Heavier sway bars are the remedy. Maybe poly bushings also.

When you hit a bump or pothole, a stiffer sway bar will make it behave more like a live-axle. Since it has a torsion beam suspension, it's just going to make it worse.

To me, it sounds like the dampers are not up to the job, it's more on the underdamped side of things

 

[Jetronic]

Time to read up about roll centers... I'm assuming a honda fit has mcpherson front suspension, torsion beam rear and fwd? Lowering can make body roll worse due to the roll centre dropping much faster than the centre of gravity, and the roll is a result of the distance between roll centre height and centre of gravity height.

Stiffening the springs will reduce sway, but stiffening just the front will introduce extra understeer.

just wanted to add, by stiffening the front 1lb, you can reduce body roll by 10% or so. Don't think it's significant in your case.

 

[lizpat]

The rear is a torsion beam, do you think adding a rear anti-sway bar (made by Progress) will help?

The torsion beam is already a sway bar....

 

[UG_Passat]

The rear is a torsion beam, do you think adding a rear anti-sway bar (made by Progress) will help?

The torsion beam is already a sway bar....

For what you're describing, a rear sway bar isn't going to help.

If body roll around bends is the problem, a sway bar will help.

The torsion beam isn't already a sway bar. It's a more flexible live axle. There is a tube welded inside of the torsion beam, that act as the swaybar, and closest to the theoretical best sway bar.

 

[Pew]

To me, it sounds like the dampers are not up to the job, it's more on the underdamped side of things

I agree with this, it doesn't sound like the dampers are setup properly.

Body roll can be controlled with stiffer sways. The side to side jerkiness can be fixed with better dampers.

 

[PoorMans180SX]

When you hit a bump or pothole, a stiffer sway bar will make it behave more like a live-axle. Since it has a torsion beam suspension, it's just going to make it worse.

To me, it sounds like the dampers are not up to the job, it's more on the underdamped side of things

The rear is a torsion beam, do you think adding a rear anti-sway bar (made by Progress) will help?

The torsion beam is already a sway bar....

While the Tein's might be underdamped, if the goal is to add roll couple/stiffness, a sway bar will help. The car does have springs in the rear, the torsion beam isn't the only thing resisting body roll/suspension motion.

 

[UG_Passat]

While the Tein's might be underdamped, if the goal is to add roll couple/stiffness, a sway bar will help. The car does have springs in the rear, the torsion beam isn't the only thing resisting body roll/suspension motion.

If you read his original post, his problem is not body roll around a bend. It's hitting a bump or pothole and the body swaying.

Adding an additional rear sway bar won't help the problem. The torsion beam is more like a "Semi-independent" rear suspension. So, the stiffer you make the rear torsionally, the more it's going to behave like a live axle when

 

[UG_Passat]

While the Tein's might be underdamped, if the goal is to add roll couple/stiffness, a sway bar will help. The car does have springs in the rear, the torsion beam isn't the only thing resisting body roll/suspension motion.

If you read his original post, his problem is not body roll around a bend. It's hitting a bump or pothole and the body swaying.

Adding an additional rear sway bar won't help the problem. The torsion beam is more like a "Semi-independent" rear suspension. So, the stiffer you make the rear torsionally, the more it's going to behave like a live axle when you hit a bump or pothole.

 

[MRC01]

If you read his original post, his problem is not body roll around a bend. It's hitting a bump or pothole and the body swaying.

Actually, he says it's both. At least that's how I interpret his words: I'm still bothered by the amount of body roll and side to side swaying motion, especially when hitting a pothole or a bump or some quick change in elevation.

 

[Dave9]

Seems to me like you just need to slow down. Or replace it with something built for your driving style.

A Honda Fit is not a race car. You're going to twist and rattle it to pieces, or get in a wreck because you thought it could go faster still.

 

[lizpat]

I appreciate the discussion.

I'm thinking going 1K stiffer on the springs (first the front, then stiffing up the rear to 3K from 2K,) will make the car feel more "planted." That's ultimately the goal. The Corolla feels more planted to be honest, but this is a modified Corolla with a Blistein B12 kit (= Eibach Pro-Kit springs + Bilstein B8 dampers.)