Alternative to Swift springs

[Coletrane]

So in reading up on Swifts I see that they are engineered to get more stroke. I see a lot of people run them, however the "nature of our work" puts the tires close to the fenders so wouldn't one want LESS stroke so it doesn't rub/destroy your quarter panel? I also see people run way higher spring rates to compensate for this, however my coilover manufacturer advised me not to go outside +-2k in spring rate. Is there a non name brand alternative to swift springs that are just like the springs your coilovers ship with? Looking for 4 inch springs around ID 62mm. Input on the topic is welcome as well.

[Byron]

Swifts are wound with less coils than other spring companies, but they are just as stiff. A swift spring at 14k will take just as much force to compress as any other spring at 14k, it will just take more compression until it starts to bind.

[Oh Damn, it's Sam]

^ Seconded. Spring rate is what you're interested in here.

[Coletrane]

Alright, that being said can anyone confirm if going above +2k in spring rate has given issues? It seems like it wouldn't be too haphazard since the shock would ultimately travel less right?

[Oh Damn, it's Sam]

The issue becomes whether your shock has enough damping to adequately control a spring that much stiffer. I would be hesitant to go too far beyond the range your coilover manufacturer has recommended.

[dc4dave]

Go with 44k youll be set... lol jk might aswell weld a steel rod

[Coletrane]

Looked at Landrum springs, never heard of them but their tech page is actually really impressive. Cheaper than swifts too. Any experience?

[MommysLittleMonster]

Looked at Landrum springs, never heard of them but their tech page is actually really impressive. Cheaper than swifts too. Any experience?

Swift springs > All

You get what you pay for. Base your judgement on their product, not their website.

[GabeS]

springs

For alternatives:
besides Swift
Hyper co is a pretty bad ass spring company.

and 20kg should be fine, very stiff and will protect your fenders, I assume you know what your getting into, your going for looks and not comfort..?
I ordered 32kg for my M3.
and what some guys mentioned about shock not dampening for those springs correctly, it is true till the point when you go extremely stiff because at that point you are riding on the springs only and the dampers will only work if you hit a hard bump fast enough to compress that spring.

[Coletrane]

I may end up just doing swifts in the front, depends on where it sits after I put cups on it. What do you set your dampening at with that?

[Oh Damn, it's Sam]

The cups you're looking at - are they the kind that are intended to be driven on inflated or the kind that are to be driven on deflated?

If the latter, which are the most common by far in my experience, they should not affect your spring rate, as they're essentially solid when deflated. Thus, you'll set your damping wherever it ought to be for the springs you select.

[Coletrane]

I chatted with StanceSolutions facebook and they said they can be ridden on with the cups all the way up, like slam the front and then just have it low while driving. They have to either be all the way up and all the way down. I'm interested to see how stiff it makes it, cause even my front at 10k could be a bit stiffer. I feel like the back is what controls the comfort of the car more.

[Oh Damn, it's Sam]

Just so you know, air cups cannot add spring rate to your system, they can only subtract.

[Coletrane]

See I wondered that. I cant help but wonder how solid it would feel riding with it all the way up

[Oh Damn, it's Sam]

It'll depend on what pressure you decide to run your cups at. Take the equation in the other thread and exchange w in the numerator for p * a where p is the pressure you plan to run your cups at and a is the area of the cap at the inside of the bag. This will describe the rate curve for the cup.

The overall rate curve is described by the following equation:



where:
k1 is the spring rate of the air cup at a given deflection x at the air cup
k2 is the spring rate of your coil spring
k is the overall spring rate

You'll have to work backwards from that equation to find the amount of deflection at the air cup for a given amount of overall suspension compression, but that's easy enough.

EDIT: Added the above equation and explanation.