When it comes to traveling at high speed, stability is the number one factor that should be considered before everything else. Nothing is scarier than getting into a speed wobble when you’re off the clock because you hit a dip or bump in the road/track. This article covers everything you need to know about improving your car’s handling and stability at high speed.
1 Improve aerodynamics
By far the most important factor when it comes to improving the stability of a car at high speed is aerodynamics. Cars are built to be as aerodynamic as possible to improve fuel efficiency and handling. Unfortunately, some manufacturers choose aesthetics over handling and went with a less aerodynamic design compromising performance for visual appearance.
Luckily improving the aerodynamics of your car is completely doable and doesn’t need to cost a fortune. The quickest and easiest way of improving the aerodynamics is by installing a rear/trunk spoiler. By doing this you’re increasing the drag the air has on the rear of the car, this drag will push the rear of the car into the road, drastically increasing handling and stability at high speed.
There is a massive range of spoilers to choose from, with a lot being car manufacturer specific. If your car currently has no spoiler on the rear at all, you would really benefit from purchasing a stock second hand spoiler from the same model car as yours.
If your car already has a spoiler and you think it’s not as effective as it could be, you can always buy an adjustable aftermarket spoiler. The beauty of an adjustable spoiler is you have full control of the angle the spoiler breaks the wind whereas with a stock spoiler, its in a fixed position and usually not designed with high-speed aerodynamics in mind, resulting in a very shallow angle, usually not being very aerodynamic at all, but still being better than nothing.
An easy way to judge if your spoiler is effective or not is if you notice the rear of the car beginning to feel light, loose, or unstable on the road when traveling at high speed, if it does then you need to improve aerodynamics in the rear to stick the car to the road, rather than let the air under the car and make the car feel light or loose on the road.
2 Install performance suspension
Upgrading your suspension to an aftermarket set up will completely transform how your car handles. The benefit of upgraded suspension are stiffer spring rate a lower and ride height, meaning your car will sit closer to the ground, giving the car a lower centre of gravity, which results in far greater stability and handling.
There are a couple of different options available when it comes to suspension set up:
1 Lowering springs
Installing lowering springs onto your stock suspension will give you the benefit of a slightly stiffer spring rate and a lower ride height. The ride height depends on the size of lowering springs you choose.
Lowering the height of your car also drastically changes the car’s center of gravity, this means the car is much more stable and has less body roll on the road at high speed.
Lowering springs come in sizes from 20mm to 80mm. This measurement is an indication of how much lower the car will be although it’s not 100% accurate, for example, 40mm lowering springs will lower your car by 40mm.
This is definitely by far the cheapest option, however, stock dampers are not designed to take the extra force lowering springs put on them, meaning the life span of the damper is drastically reduced, especially if the dampers are already well used.
If you do decide to use lowering springs the maximum spring size I would recommend using on-stock dampers is 40mm, this will prolong the life of your dampers as much as possible while still making a noticeable improvement to the car’s stability and handling at high speed.
Going lower than 40mm on stock dampers is completely possible, but you should expect a very bouncy ride, the car possibly bottoming out with people in the back and damper replacements every 20k.
This is because with the shorter springs installed, the damper then has to take a lot more of the car’s weight before the spring comes under compression, this then results in insufficient bump travel length of the damper, meaning less shock absorption.
2 Upgraded suspension kit
An upgraded suspension kit is the next step up from lowering springs. With an upgraded suspension kit you get lowering springs plus new shock absorbers all pre assembled as a set. The beauty of this is that the shock absorber is designed and manufactured to match the stiffness of the new spring.
This results in a much stiffer yet firm ride with a subtle difference in the overall height of the car. You can expect to see a big improvement on how the car handles in corners plus at high speed you will notice the car will have much more stability due to the lower centre of gravity and less body roll.
Upgrading to a new suspension kit will cost you more than just lowering springs, but the benefits far out weight the cost, plus what you spend on the new setup now, you will save in the future by not replacing stock shock absorbers every six months.
3 Coilovers
The daddy of all suspension set ups is the coilovers. The difference in coilovers over everything else is incomparable. Most high end coilovers come fully adjustable, meaning you have full control over ride height, stiffness, and camber.
Those are three very important factors when it comes to improving your car’s handling and stability. First of all, being able to adjust your ride height to your road or track conditions means you can control how much shock bump occurs when you hit a bump at high speed. The lower the ride height the more severe shock bump occurs due to the damper having less bump travel causing the damper to hit the bump stops.
Lowering the cars ride height is done by moving the adjustment collars seen in the picture. A lower ride height also means you have a lower center of gravity resulting in reduced weight transfer when cornering, this means the car will be much sharper around corners, less top heavy, and have very little body roll at high speed while keeping far more surface area of the tire on the ground to improve handling and traction.
Another benefit of coilovers is that you have control over the stiffness of the damper by an adjustment screw on top of the coilover. This adjustment is more for fine-tuning, the ultimate decider of stiffness is down to the coil spring.
You can check them out here on Amazon.
Every set of coilovers comes with a spring rating to allow you to choose which stiffness suits your needs. Stiffness plays an important role in cars handling, if the springs are too stiff you will have no body roll while cornering at all meaning the sideways momentum (weight transfer) of the car will have nothing to absorb it which will cause the tires to slip and lose traction, on the other hand if there not stiff enough it will cause excessive body roll. The front springs are rated heavier than the rear to compensate for the weight of the engine.
I have a set of BC Racing coilovers in my DC2 Integra with a spring rate of 10kgF/mm in the front and 5kgF/mm in the rear and it handles like it’s on tracks with just enough body roll to absorb the weight transfer.
Another important thing to note is that once you install your new coilovers be sure to get the car tracked and corner weighted to ensure the wheels are all correctly aligned and the car is balanced.
3 Get your car corner weighted
To get your car corner weighted means to have each wheel of the car exert the same amount of force on the ground as each other. This is done by placing a special weighing scales under each wheel of the car. All four wheels should have the same measurement, if not it means the car is out of balance and needs to corrected.
Check out your own corner weights here on Amazon
This is done by adjusting the height of each coilover individually until you achieve the correct measurement on all four wheels. Corner balancing is only needed when the ride height has been lowered using coilovers. This is because when you lower the ride height, if each corner of the car is not 100% even it will result in an imbalance.
If you can imagine a table that rocks because of uneven legs, well a car is balanced the same way. There should be 50% of the weight of the car on the front left and rear right wheel and 50% on the front right and rear left wheel, anything other than that and the car is imbalanced.
Depending on the severity of the imbalance and which wheel it’s at will decide how your car will react, the most common symptom of an imbalance is oversteer when cornering in a certain direction, or a waviness or unstable feeling at high speed.
Getting the car corner weighted is a slow tedious job that requires a lot of fine-tuning and tweaking, that’s why it’s worth paying a good alignment shop about $200 to get the car correctly set up. Trust me you will not spend a better $200 you can be guaranteed this will effectively improve the cars stability and handling at high speed.
4 Get your four wheels aligned
When it comes to handling and stability the very minimum you should do is be sure all four wheels are pointing in the same direction, this is just good practice and common sense, if not for economical reasons then for handling reasons.
Over time a car will gradually lose its four-wheel alignment due to hitting potholes and curbs etc… That’s why it’s important to have your wheel alignment checked every 20,000kms or if you notice uneven tire wear or the car steering pulling to one side or the other, those would be the main tell tail signs your wheels are out of alignment.
Although sometimes it may only be evident at high speed that your wheel alignment is out, you might notice the steering wheel feeling like the wheels are floating or not responsive to the steering wheel.
Luckily getting four-wheel alignment will only cost you between $80-$100 in any tire shop and should be done if you make any changes to the car’s suspension assembly or if you notice any symptoms above. Getting the wheels aligned will drastically improve the car’s stability and feel on the road, plus the car won’t wear out tires as fast.
5 Widen your cars track
A simple yet effective way to improve car handling and stability is by widening the car’s track. This can be done two ways, you can either install wheel spacers or replace your wheels with wider wheels and tires.
The benefits of wider tires are obvious, you have more surface area of the tire in contact with the road creating more traction and giving you far more stability when it comes to cornering at high speed.
Having wider tires will also make a huge improvement to acceleration and brake ability, also due to having more contact with the road through the tires but that doesn’t mean the wider the better.
If your car is stock or close to stock, with just some simple bolt-ons, etc.. id recommend going no more than one size above your stock wheels. When it comes to tires you should only use what you need, if you go much bigger it will kill your car’s power because it takes more horsepower to turn the wheels due to extra weight and friction with the surface of the road.
I’m currently running a set of 15x7J Buddyclub P1s alloys wrapped in Yokohama ADVAN AD08 tires on the front and Yokohama Parada Spec2s on the rear and so far I have no complaints, the car is extremely stuck to the road at high speed and acceleration off the line is excellent with minimal tire spin from a car that’s putting out 216 WHP which isn’t bad by an account.
The other option is installing wheel spacers, this will widen the offset of your car’s wheels giving you a wider track without the need to use wider wheels or tires. Wheel spacers are installed between the wheel and wheel hub and come in a range of sizes as seen in the picture below.
The benefits of using wheel spacers are they are cheap (compared to wheels and tires), quick and easy to install, they come in a range of sizes and they will improve a cars handling and stability significantly due to the car having a broader wheelbase on the road.
Find wheel spacers here on Amazon.com
The most important thing to remember when choosing wheel spacers is DO NOT BUY CHEAP, if you get cheap wheel spacers and they aren’t 100% concentric with the wheel it will cause a wobble or vibration from the wheels. If you buy good quality from a known brand you can be sure they are 100% safe and machined to the finest tolerance and will cause no problems.
Another thing to consider is the length of your wheel studs. If you buy a wheel spacer that’s too thick there’s a possibility your wheel studs wont be long enough to put back on the wheel correctly so make sure to measure your wheel studs first, or you could always install longer wheel studs if you want to go wide but the recommended size would be no more than 10mm on stock wheel studs.
6 Install strut bars for more rigidity
Strut bars are a great way of improving the rigidity of a car. Although a car may seem solid the body and chassis of a car actually flex ever so slightly under load while cornering. If you can imagine a car that turns a sharp left will want to body roll to the right because of the car’s weight and momentum.
This opposing force causes strain and flexibility in the chassis, especially on parts that are in direct contact with the road like suspension mount towers. Installing strut bars helps to eliminate the reactional force and flex by transmitting the energy across both sides of the car instead of just one point, it basically ties the whole car together resulting in a much stiffer chassis.
Check out the perfect strut brace for your needs here on Amazon
Strut bars can be installed in many places in the car, the most common place is the suspension tower in the engine bay along with both suspension mounts in the trunk. Strut bars come in a variety of shapes and sizes depending on the model of the car.
Along with both strut bars mentioned above I also have an adjustable strut brace in my DC2 Integra that goes on the floor between the driver and passenger side seat belt mounts which improves rigidity in the body and floor of the car, this not only improves handling and stability but also prevents the chassis of the car cracking over time due to stress.
7 Stiffen your cars suspension with a Polybush kit
Polyurethane bushings also known as a poly bushes are an excellent way of tightening up your car. Stock rubber suspension bushings wear down and crack over time causing unwanted movement in your suspension resulting in the car steering feeling sloppy, unstable, and unresponsive.
The benefit of installing poly bushes is polyurethane will not break down and crack like conventional rubber which means no deflection while cornering at high speed. Polybushes also come in ratings such as semi-solid or solid.
I currently have Powerflex semi-solid bushings in the trailing arms and anti-roll bar of my Integra and they have made the car much sharper and responsive while cornering at high speed, DC2s are notorious for being tail happy while cornering but once I installed strut bars and poly bushes it completely transformed how the car handled and performed.
Polybushes can be bought individually or in a complete kit for your specific car, the complete kit is perfect for a track car but when it comes to a daily driver a full poly bush kit can be overkill and sometimes a headache, largely because of the squeaking noise that will come from the bushes when the car is moving.
This noise is completely normal its just because the moving components of the suspension setup is so tight with the poly bushes that it causes the bushes to squeak, the squeaking is not outrageously loud but it’s still noticeable and to some people having their pride and joy squeaking down the street isn’t a look they’d be happy with.
My recommendation is to replace your trailing arm, anti-roll bar, and front wishbone bushes with poly bushes, this is more than enough for a road driven and it will also be effective in significantly improving your car’s handling and stability at high speed.
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