1. I see some less expensive lowering springs on the market.
Why should I choose Swift Sport springs?

There are many reasons on why to pick Swift Sport springs. Swift provides you with the lightest, most durable, and most linear springs (our race springs) on the market. What do we mean? Well we use a material called H5S.TW. It is stronger, lighter and can sustain more wear and tear than the standard silicone chrome material that is used in most of other brands. Because of the material, we are able to use thinner wires, fewer coils and less material is used on our springs.

Also, Swift Sports Springs has been designed to give you your ride height immediately. That means the springs are preset and you would not have to wait 3 months for the springs to settle for alignment or camber adjustments. For all of our applications, the spring’s specifications were set by professional drivers on test tracks. We were able to maximize the amount of control while retaining the ride comfort of your vehicle. Installation on our springs is also straight forward. You won’t have to change out your shocks (unless if you want to) to compensate with our Sport springs. It is truly a plug and play part for your performance vehicle.

Swift Sport springs are designed for each specific vehicle type like sports, wagons and luxury. Drop rates, spring rates and rate characteristics are designed for each application.
For example, when we designed our sport springs for the Lexus LS430, Infinity Q45 and other luxury applications, our priority was ride quality, while maintaining a decent amount of drop and attaining a crisp handling.
When we designed our sport springs for performance oriented vehicles like the Evolution, Subaru STI and 350Z, our priority changes to lowering the center of gravity, the perfect amount of suspension stroke and crisp handling; While maintaining comfort for street driving.



2. Why Swift Sport springs don’t lower the vehicle as much as other manufactures?

Maximum drop does not always equal maximum performance. There is something called the optimal center of gravity. If you drop your car lower then this point, you are not increasing your performance but decreasing your handling capabilities. Swift Springs are designed to lower your car to the optimal center of gravity. We at Swift are driven to performance not style and appearance. If it is a second or two that you would like to shave off your track time or to navigate through technical roads faster with more control and less roll. Then Swift springs are what you are looking for.

We found that many brands of springs in the market are based on lowered looks. We have seen many springs that will bind on corners. Once a coil binds with another, they will no longer act as a spring. They actually become just a piece of metal. That is why the ride quality is never what you thought it would be.

If you look into other manufacture’s catalog specification data, you will find that they engineer theie springs only for drop in the ride height. They do this only by telling you the spring drop height. (Average of 2 – 2.5 inches) In comparison to our catalog, you can see the difference in data that we offer to our customers. We state our spring rates and drop height for both front and rear springs. This demonstrates we want to educate our customers, rather than selling just lowering springs.

Each vehicle on the market has its own designed maximum amount of stroke. We design the height for our springs based on the information provided by the manufacture. We can see that there are still room to improve the ride and handling quality with Swift Springs.



3. What is the difference in progressive and linear springs?

Linear
Well linear spring theoretically keep the same spring rate regardless of stroke.
If you have a 6kg/mm linear spring, if you compress it 10mm it should only take an additional 6kg to compress another mm. Therefore, if you compress a linear 6kg/mm spring with 60kgs of force, it will compress 10mm.

Linear Spring Characteristics
The benefit of a linear spring is consistency, meaning the weights transferring from side to side should be very smooth and consistent. After getting use to the car dynamics, drivers can anticipate weight transfers and body roll more accurately. While exiting a corner, a linear spring will return the body in a smooth manner because both sides are compressing and rebounding at the same rate, which keeps one mm of expansion to one mm of compression throughout the traction of the springs. This reduces the demand for excessive counter steering, which can result in fish tailing. For winding roads driving, this has great benefit and allows for more confident use of weight transferring because the driver won’t experience unpredictable weight shifts.

Progressive
Progressive springs are springs that gradually increase spring rate as the spring compresses. So, if the spring starts out with a 6kg/mm spring rate after 50mm of compression it may then measure 17.75kg/mm.
Using the above example a 6kg/mm linear spring will take 300kg to compress 50mm while it will take 594kg to compress the progressive spring.

Progressive Characteristics
Say you are cornering with these progressive springs, you have compressed your outside spring by 50mm (a little over 2”). While you are exiting the corner the centrifugal channeled inertia (the force that causes body roll during cornering), reduces, allowing the body roll to stabilize. You now have an outside spring that has stored 17.75kg/mm of force. As the centrifugal inertia reduces, it throws the outer side of the chassis up with 17.75 kilograms per/mm of force, roughly 950lbs/ inch of force.

Since suspensions are designed to keep the vehicle level that force throwing the outside of the chassis up will be partially transferred to the opposite side. But the outside spring has not compressed during cornering so it will absorb the transferred energy at 6kg/mm of compression so for the first mm the outside releases, will translate to almost 3mm of compression on the inside. As the outside spring releases the excess energy and the inner springs absorb it, the ratios gets closer to 1:1, it may even change back and forth. This is excessive body roll requiring more attention and finesse to effectively control. While negotiating chicanes it can make steering extremely complex and demanding compared to what linear spring would produce.


4. What is the advantage of lighter spring weight?
It seems like I can lighten up my car a little only.

Any weight under the suspension is called (un-sprung mass). Depending on the situation, un-sprung mass is equivalent from 5 to 7 times of the sprung mass (weight above suspension). For example, lightening the suspension by 2 lbs per spring will actually be equivalent to removing 40-56lbs of equipment from the interior.

The difference there depends on how heavy are the wheels and tires, and reasons like lower profile tires. They all have affects on un-sprung masses. Second, lighter the springs will have a faster reaction speed. A faster spring reaction means your spring will absorb road bumps and other conditions at a quicker pace. The tires will be able to grip better to the pavement. This in turn will provide you with a smooth, better ride quality and less work on your tires.