Coil-binding: Reprecussions?

[Erick]

Ok... so I know that coil-binding is when the coils of the spring come in contact, but what are the consequences that follows? Is it just some matter of comfort or does it mess up the entire handling of the car?

[1991 318is]

Answer = both!

When the coils hit each other the spring rate approaches infinity. The only springing left is the play in mounts and tire deflection. Imagine replacing the strut and spring with a large rod the same length.
Answer = both!

[Erick]

When the coils hit each other the spring rate approaches infinity. The only springing left is the play in mounts and tire deflection. Imagine replacing the strut and spring with a large rod the same length.
Answer = both!

So it makes the suspension stiffer? I dont quite follow.

[E30-323ti]

You will have no suspension!! The spring becomes a solid block, therefore if you encounter a bump etc... the tyre and bending chassis/suspension components is all that is left. Oh, and you flying off the road if you weren't ready for it and manage to keep control.

It is a V.dangerous thing to have happen, more so if it is a road car (ie. not on a cloased circuit/auto-x).

[Beej '86 325es]

Not sure if you're running a G-C setup, but watch it if you're having coil bind in the rear. My first setup, G-C recommended spring rates that were way too soft and I had coil bind very badly. Eventually, the repeated impact broke off the nubs on the trailing arms that locate the springs.

[robweenerpi]

GC's low rate spring is a 475 pound barrel shaped spring to avoid coilbind. There are some alternative rates out there but this is stiff enough to handle well on most cars and soft enough for most enthusiasts to drive daily. With a standard 5 inch racing spring commonly used on lightly lowered street cars you will need a spring in the range of 600 pounds roughly with hi tensile wire to avoid binding.

Most progressive springs do it on purpose to control the rate. On a spring that's not designed for this you will have poor control of the vehicle and inconsistent handling. Long term use will result in spring failure. Generally the finish is quickly removed then left to pit and corrode making a stress riser in the spring. Coilbinding will produce more stress in other areas of the suspension as well. You'll see it show up on the front of your rear springs first because the spring is flexed just about as much as it is compressed on the rear suspsension of the E30.

[David325is]

Is this coilbind? I am experiencing this on both rear springs.

[87Blue325iC]

Is this coilbind? I am experiencing this on both rear springs.

Funny - that looks exactly like my rear springs. Same type: H&R 50406, but mine didn't come from BMP. I figured it was because I was using coupe springs on a heavier cabrio.

[David325is]

Does anyone know if the spring shown is suffering coil-binding issues?

[MrK]

According to www.afcoracing.com:

"Coil bind occurs whenever a spring is compressed and one or more of the springs active coils contacts another coil."

So that would mean the pic DOES have some coil bind visible.

[Van Westervelt]

some, not 100% though. You still have play in the spring until the centering nubs hit. if they arent already, then it doesnt matter if its 100% bound, as the spring is not doing anything

[MrK]

some, not 100% though. You still have play in the spring until the centering nubs hit

Coil bind is still coil bind, whether it's 1% or 100%. Once coil bind exists on any level, it alters the behavior of the spring. The question was "did this picture show coil bind". The answer was "Yes."

Nothing more to it.

[nando]

keep in mind most springs are designed with "dead" coils that only serve to keep the spring in place when the suspension is fully extended. with weight on the car they will be touching each other but the coils that actually support the car should not.

[MrK]

keep in mind most springs are designed with "dead" coils that only serve to keep the spring in place when the suspension is fully extended. with weight on the car they will be touching each other but the coils that actually support the car should not.

Point very well-made nando... I forgot about that completely