1. Why do I feel softer and more roll on Swift springs compare to same spring rate of other brands?

Swift engineers design all of our coilover springs to be a true linear spring. Unlike most other brands, Swift springs rates are tested to stay linear from 20% – 80% of the available stroke. While most other brands claim they have linear ratings (after testing) turn out to have a progressive rate change the further you compress down on the spring. A constant (linear) rate change will always feel softer then a progressive rate change. .



2. Why Swift's longer springs (some of 10" and longer springs) are trapezoid
designed?

We designed our longer coilover springs for one purpose only; to minimize the chances of the spring from bowing. (Just imagine a spring that buckles as your knee would buckle). That is why we picked the barrel shaped design instead of having a straight shaped spring. Say you have two springs that carries the same free length. One of the springs has more coils wound then the other. The one with more coils will not bow as much as the one with fewer coils. However, when you add more coils, in turn you add more weight while limiting the available stroke in the spring. Swift choose a different approach. We decided to develop a spring that has a barrel shape (Smallest circumference gradually increasing till the center coil of the spring, then decrease in the same ratio). With the barrel shape design, it allows us to utilize fewer coils on the spring, as well as less weight, and also allows us to keep our accurate liner spring characteristics.



3. Swift uses the term of (usable stroke), where other brands state (stroke). What is the difference between them?

Stroke is the free space from the top of the spring to the bottom of the spring. The length of the spring can be compress before coil bind.

Swift's (Usable Stroke) = length of spring where desired rate starts to the length of the spring where starting point of spring rate rises.

If Swift was to use the same measuring method as other brands manufactures, our “Stroke” statistics would be a lot longer then other companies due to our less coil design. However, we think that would be unfair.

We understand that when spring rates starts to increase after a certain measurement of compression, we should not call it stroke. Since the rating is not at the ideal rate, the spring is no longer in the range of the “Usable stroke”.

If other brand manufacture were to use the same method of testing on usable stroke. They will find that most of the springs in the market today have an extremely limited usable stroke. Most springs that we had tested had shown signs of increase in rates with a minimal compression of the spring.


4. Why does Swift Springs lowers tire temperatures and not other brands?.

This is one of the reasons why we designed our springs with less coils. Swift springs are able to compress and rebound faster (Reaction Speed) than other manufacture springs. Think in terms of traction! With a faster reaction spring, the tires are consistently following the road condition and not skipping on the road. When the tires are skipping on the road surface, it generates excessive friction and in turn equals excessive heat on the tires..



5. There are many different brands of coil springs on the market, and they all say theirs are the best. How should I choose the best springs for me?

Base your choices on what kind of driving you will be doing. And what kid of performance you are looking for.

When we talk about springs, there are four main characteristics that we look for.

1. The most usable stroke (see above No.3 question)
For optimizing your suspension setup, and to prevent coil binding.
2. Lightest weight
For less un-sprung mass, and to increase reaction speed for track or road conditions.
3. Accurate spring rate consistency
For easy suspension setup, and smooth weight transfer.
4. Durability
For the amount of spring ware before sagging.



6. How can I figure out the spring rate when assist springs are installed with main springs?

Here is the formula for that.

A=main spring
B=assist spring

For example,
When Main springs (700 lbs) & assist springs (300 lbs) are combined,

A X B		700 X 300
	=		=	210
A + B		700 + 300

You get 210 lbs of spring rate until assist spring completely binds.
After that, you get 700 lbs spring rate.

7. How do I prevent (bow) on longer springs?

Refer to question #2



8. 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 weight transferring from side to side should be very smooth and controllable. After learning the cars 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 expanding at the same rate, which keeps one mm of expansion to one mm of compression thought most of the compression of the springs. This reduces the demand for excessive counter steering, which can result in fish tailing. For chicane driving this has great benefit and allows for more confident use of weight transferring because the driver won’t experience such a dramatic unpredictable weight transfer.

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. Please use the chart below to see the differences in the linear and progressive spring characteristics.



9. Many other springs manufacture states that their springs are linear. Aren’t all spring the same as far as spring rate linearity?

All manufactures claim that their springs are linear, but many of them are not!
We had tested numerous springs in house and these are the results.
Please take a look at some of our data: