Best way to reduce body roll : Shocks or Springs ?

i have an old car (2001 saab 9-3) and the suspension is very very soft which is great on bad roads but horrible when taking a corner - the car just rolls like crazy. tires are new, shocks are brand new (stock shocks, sachs or kyb - can't remember exactly), the springs are the original ones.

i don't have any problems on rough roads, the wheels stick to the ground properly, the car is controllable, it's just that in corners it leans like crazy. the car is FWD, it understeers but i had other FWD cars that didn't lean like that at all.

i'm planning to do a suspenion upgrade but i'm on a tight budget. a set of shocks and springs are about $800-1000 (not too many options out there), coilovers are even more expensive.

the shocks are about $100-200 each (bilstein or koni, koni being the most expensive).

the springs are about $80 each (around 280-350 for the set, eibach, vogtland and a few other brands). these are lowing springs - the car sits a bit higher than i would like i to.

i can't afford both the shocks and springs (especially since i have new stock shocks all around) - so i wanted to ask what would make the car roll less in corners (if you were to choose just one option):

1) shorter, stiffer springs

2) more expensive shocks (which are presumably stiffer - or adjustable)

which one would have the most impact on the lateral body roll i get when cornering?

You want upgraded sway/anti-roll bars, not stiffer springs or different shocks. 

In reply to BoxheadTim :

Depends. 

Steve Hoelscher (national champion) would disagree. He removed the anti-roll bars and went entirely springs. 

In reply to andykauf :

The answer to your question (as asked) is springs. Sort of. 

Stiffer springs will stop the roll. But they will also rebound quicker and make the car hop (which is what the shocks are for).  

They work together.

In reply to SVreX :

But from the sounds of it, this is a street car. All springs and no sways is fine for a car built to do nothing but drive quickly around parking lots or racetracks, but would be miserable to drive on the street. Some stiffer sway bars should clean up the body roll and be able to balance out some understeer without ruining the compliance.

Springs, shocks and sway bars all play their part.  Stiff springs will limit body roll.  Shocks will slow the pace of the roll, but won't limit it a great deal.  Their job is to control the spring, so a weak shock will allow the spring to compress too much too quickly, which shows up as porpoising through the corner.

Sway- excuse me, Anti Roll bars will certainly limit roll, that's their purpose, but they do nothing to prevent front to back motion, so hard acceleration, braking, or undulating surfaces are not controlled.

Pure race car, big springs, enough shock to control the springs, and enough bar to balance the feel.  Adjustible bars are usually a quicker way to tailor the balance of the car to your desire, or the grip of the track.

Street driven car, 900 pound per inch springs get boring real quick, so smaller springs and bigger bars.

But that's just my opinion, I could be wrong.

In reply to SVreX :

EDIT: I am too slow again...

But then you have to live with enough rate to make up for the lack of anti-roll bars. Not that that's the end of the world, and the bars act like stiffer springs if you're hitting bumps with only one side of the car, to some extent. But it does seem like something that *might* be better suited to a dedicated autocross car rather than a street car. Possibly.

I think bars are the simplest answer to the specific question, but yeah, if it's generally soft and especially if it also pitches a bunch, springs may be a better first step?

To the OP, of the two options you ask about, springs determine how far the car will roll, dampers determine how quickly it will roll (there's plenty of rabbit hole here for steady state and transitional behavior...). Anti-roll bars are part of the springing equation.

In reply to SVreX :

But that's not a street car. 

To the OP, in general your shocks are only going to work with springs over a range of stiffness. Lowering springs are likely to be on the stiff side of that window leading to an underdamped or "bouncy" car. Shocks don't affect overall lean, but they do influence tha rate at which it happens. Make things stiff and you slow quick movements and can control a lot of the wallowing  that you feel on stock, and especially worn stock, suspension. The down side is that you also affect straight line damping and the car tends to feel harsh over small to medium road imperfections. Springs and dampers work together. 

Sway bars will add spring rate to the system while turning but leave things alone when going straight. They are also a good way to add dynamic spring rate to one end or the other to change balance. 

If someone makes a cheap lowering spring, that's where I'd start. You will probably still be in the range of stock or cheapish off the shelf dampers and you get some geometry advantages by lowering you COG and roll centers and all that math stuff. 

In reply to andykauf :

Tim’s suggestion is definitely good, but to answer your question directly - without knowing the stock spring rates vs. the aftermarket ones, there’s a very good chance your current shocks/struts don’t have the valving to handle higher spring rates. That means you end up with a car that bounces and/or gives you unpredictable handling around corners. 

I too have been in your predicament of performance goals vs. money(as have many of us here), and I’ve traveled down this exact path on 2 different vehicles - a 2003 Protege & 1996 Miata - and I’ll tell you straight up don’t waste your money doing any upgrades without a fully developed plan. You’ll quickly grow frustrated with the results, and likely have to replace all the new parts you’ve bought to get where you want to be.

What I’d suggest you do:

1. Try to get some clearly defined goals. You mentioned previously wanting the car to remain your DD, and also use it for track days. Can you afford to ball it up after an on-track mishap, or alternately can you afford on-track insurance. 
2. How much DD practicality & comfort are you truly willing to sacrifice for on-track performance. Once you have that for your guideline...
3. You should probably focus on suspension first, brakes second, safety gear third, wheels/tires fourth, then power last. 
4. For suspension tuning, typically you want to determine the spring rates you need & the shocks needed to support those rates, then tune around that with swaybars. You’ll also need to consider where your camber settings will end up.
5. I don’t know your car enough to give specific advice regarding brakes, but if you can get enough performance on-track with stock-sized rotors, do that. Just realize that pads/rotors/fluid are all consumables that will need replaced frequently. 

Wheels/tires should be obvious once you get to that point, and you seem to have a plan in mind for power. 

You’re right. That wouldn’t be for a street car. 

I am gonna say _good_ shocks are going to make the most actual real-world public-road handling upgrade, IF any of the old ones are bad. While you may still lean as much, the contact with the road will improve. Since your shocks are decent and new currently, I would echo a swaybar. Its the fix to what you are specifically asking, but you need to be picky lest you introduce new under/oversteer behaivor. Springs will fix the lean, but unless carefully chosen, will make anything but smooth roads a chore. I tend to do springs when I put stupid wide tires on. Lowering on stock rubber just bounces with the increased rate, making the tires try to soak it up. Lowering and higher rate springs WILL blow your oem style kyb shocks yearly IME (although 'top-hats' can help mitigate that). That said, I personally prefer a hard spring, soft bar setup on small cars, but that might not be practical here. The suspension works as a package. 

Also, tires make a large difference. What tires and size are you running? Might affect some advise. 

Tldr; Swaybar, ideally front and rear both _slightly_ bigger if car is well balanced. Add one if no rear, etc. 

I admit I know nothing of saab handling specifics. You may do well to also ask a model specific forum, as many cars have common complaints, and thus have common modifications. 

Roll stiffness comes from both springs and sway bars. Springs also give stiffness in other modes, while sway bars work purely in roll. Sway bars are cheaper and easier to install (usually) and don’t require the shocks to be matched, so they’re the most common solution for a roly-poly street car.

Shocks are there to control the springs. Do not expect to use them for roll control. overworked shocks don’t usually blow from too much spring rate, but a shock that’s underdamped because it’s not valved correctly and a shock that’s underdamped because it has suffered a failure feel a lot alike. 

A question you didn't ask: How is the alignment? I believe that is a lower a-arm with a strut car right? That suspension with a lot of roll quickly goes into positive camber and rolls over the outside front tire dropping that corner more. It feels like a tricycle when cornering. Some positive static front camber would reduce that tendency and make it feel much more comfortable in roll. A wider wheel with a more stable tire will help reduce that tendency as well.

love this forum, 8 solid replies in 30 mins, can't get this anywhere else...

a bit more info about my car and the current situation : Saab 9-3 Aero (2001 model, coupe, 250 BHP at the moment). new shocks all around, a stiffer rear ARB mounted (could feel a bit of improvement), stock front ARB (i believe it's about 22mm in diameter), front strut top brace, new stock control arms and bushes.

my main problem is body roll (not sure if that's the correct term, but the car literally inclines itself every time i corner, it leans out of each corner, quite a lot). i don't mind the understeer (i will correct that in time)

as far as i understand car physics, i would guess stiffer and shorter springs would help - but like someone said, they will rebound quicker which will result in a jittery ride on rough surfaces (i think i can also fix this for my daily drive with 16 or 15 inch rims and softer tires).

as far as i experimented, anti roll bars help with understeer (having the rear ARB stiffer than the front ARB helps with understeering) but i don't know how it helps with body roll (please explain if anyone knows the science behind it).

SVreX  springs determine how far the car will roll, dampers determine how quickly it will roll - exactly what i was thinking about, so it should be the first thing to upgrade, the springs - and yes, i actually hate HOW MUCH THE CAR ROLL - wasn't sure about the exact thing until you said it...

Pete Gossett i know doing a full suspension upgrade is key, but with limited budget (at the moment) and not knowing where this car is going, i can't afford to invest a lot in it at the moment. I was planning to build a 500 bhp race car, but since i cannot find any good solution for the transmission, i'll probably keep this car for weekend driving (if i manage to stop the roll) and occasional track days (if i upgrade the shocks / ARBs). I don't mind a harsher ride, i have a few other cars as well, so depending on the road i'll be driving i will be able to choose - and also i have owned (and run as a DD and track day car) a Renault Megane R26 with a Renault Cup Chassis (stiffer chassis and stiffer springs / shocks) and it was decent around town...

In reply to Nugi :

shocks are new, oem i guess and i got them for cheap, so i don't mind if they get destroyed (question is, how much are they going to last, how many miles). also what do you mean when you're referring to " top-hats "? i also have a soft bar / hard spring setup on my alfa romeo, and it really great to drive (FWD also) - but i was able to get the coilovers for cheap (low quality ones i guess, but they are ok after 2 years).

Andy, I think you and I have similar ideas in mind for what we want our cars to be. Fun street cars that see the occasional track day that won't beat you up when running errands.

My car is equipped with Koni Sports, Eibach Pro-Kit springs with matching bumpstops, Eibach antiroll bars, and lightweight wheels w/Hankooks RS4s. The Konis are set at 3/4 turn from soft and the ARBs are on their soft setting.

My car is perfectly comfortable on the street, wife approved, and feels very much at home on a track or fun backroad. Eventually I plan to go with Ground Control coilover sleeves so I can increase the static spring rates to reduce my reliance on bumpstops as supplemental springs, but right now I'm very happy with the car,

In reply to MrJoshua :

i know what's you're saying about alignment and you're right, but it's not my case. My car heavily rolls when taking a corner even at 20 MPH. I now strongly believe it's the springs...

In reply to MrFancypants :

yea, we probably like the same type of setup... just to give you an idea, i spent about $1500 on the car (fixed her up myself, minor stuff here and there, shocks, bushes, a few electrical things, etc). leather seats, sunroof, all the works... running a stage 1 tune with 240-50 BHP and 350 lbft torque. all this for $1500. since i'm not sure where this is going, i'm a bit reluctant to invest $1000-1500 in proper suspension upgrades (konis + eibach springs are about $1200). so that's why i'm looking to make it a bit better while not breaking the bank...

In reply to andykauf :

Top hats raise the top attachment for the shock, to put it back into its expected range of travel. This seems to be the best bandaid if available or easily fabbed. They are common on lowered cars, I run them in my honda. Expected lifetime is a gamble. I have had slammed shocks last years, and mildly lowered setups blow monthly. I just remember being ready to cry after replacing the 3rd shock on the back of my crx in one year.

On the other hand, Bilstiens are monotube, so less issue compared to double tube designs. Something like a koni will have better seals and valving to withstand higher spring rates and lowering also.

I may be overstating this, many people maybe don't have this issue, but I sure did. 

In reply to Pete Gossett :

pete, how do i determine the spring rates i need? i'm a bit of a noob when it comes to these specific suspension details.

In reply to Nugi :

top hats seem to be a good bandaid to keep your shocks alive for more time, not sure if i can find some for my saab, but they look pretty easy to manufacture...

I had Vogtland springs with KYB replacements on an e30, was still fine when I sold the car 4-5 years later. 

I also ran them on my then new mk3 focus, they were fine on that too, lasted 2-3 years before hitting massive potholes on each side of the car about a week apart blew them out. 

I swear, Vogtland/KYB is the best riding aftermarket combo there is.  

Anyway, all of which to say, you can run them on stock dampers, but since they're progressive rate, they aren't serious cornering units, which usually  require better dampers anyway. 

You'll see a little improvement from a lower CG, but bars would be your best bang for the buck as far as flatness.

I'm going to ask a slightly different question: What tires are on it and what size?  Tire squish can feel an awful lot like body roll, and some tires are much squishier than others. 

Good talk. Here are some articles from the archives that might help:

Roll With It

Lean Less

How to Dyno Anti-Roll Bars

G-Whiz

Miata Mission

Dialing In

10 Simple Steps to Better Handling

andykauf said:

In reply to MrFancypants :

yea, we probably like the same type of setup... just to give you an idea, i spent about $1500 on the car (fixed her up myself, minor stuff here and there, shocks, bushes, a few electrical things, etc). leather seats, sunroof, all the works... running a stage 1 tune with 240-50 BHP and 350 lbft torque. all this for $1500. since i'm not sure where this is going, i'm a bit reluctant to invest $1000-1500 in proper suspension upgrades (konis + eibach springs are about $1200). so that's why i'm looking to make it a bit better while not breaking the bank...

Ah well, in that case I'd stick with the struts and springs you have and see about a pair of stiffer antiroll bars. Watch the Saab forums and maybe you can snag a pair used for cheap.