Or more aptly, has anyone replaced their springs for any other reason other than to lower their car?

iv never heard of them wearing out.. the only time iv heard of changing springs is if they break.... like on the ford focus... pos

I'm confused by this post. Obviously many members of this forum get replacement aftermarket springs for the performance...

We had a customer that needs front spring replacement due to rust (New England weather).

Over time springs due being to sag. It is definetly a high mileage replacement item, if you can get it cheap from a junkyard.

If you ever replace the struts it is a good time to get the springs replaced too.

Yes they do. Spring designs had been around for a long time so the spring manufacturers have calculators to design springs and predict the time to failure. The diameter of the coil, thickness of the wire gauge and the range it operates (min and max compression and extension) all affect life time of a spring.

When I was design locks, they have several springs inside and we typically ask for a million cycles minimum. The car suspension springs should be more. Coil spring typically fails with a fracture on the inside diameter and not on the outside diameter.

Does anyone know the life cycle on 4th Gen springs? Like after how many miles do they begin to lose their original damping characteristics? It seems reasonable to assume that springs would sag over time, and that the rougher the roads on which they have traveled, the quicker they would lose their responsiveness.

When you think about it, you could get a rough estimate by counting how many times your springs recoil over a set distance -- let's say your route to and from work -- and then multiply that by your total mileage divided by the set distance.

I might also expect the springs to be affected more by sudden recoils (potholes, speed bumps, etc.) versus gradual up-and-down motions.

How likely is it that when people have their struts and shocks replaced that a mechanic might damage the springs in the process?

On my car, the lifetime is 100k. My rear springs are sagging pretty badly. It seems Nissan used the cheapest manufacturer they found.

Typically they don't wear out (as in sag or loose stiffness, maybe a little but not a whole lot) they will just one day break as a result of fatigue. There are other things to worry about than your springs breaking (that is something that doesn't normally happen). Also springs do not have damping charateristics, that's what the struts are for. It is also very unlikely to damage the springs yourself. Only way I could think you would damage them is to "acidentally" notch the spring somewhere, which is kinda hard to do.

My take is there is no way anyone can damage the springs. The stuff is real strong like a hammer, it just looses its dampening over time, but rarely have I seen anyone on this forum talk about springs. That in itself is an indication these last the life of the vehicle.

agreed i've had my sprints springs 8 years and hasnt lost a step.

I dropped my maxima about 3 years ago. I live and in New York, and that was a bad idea. I want to get the stock springs but i cant find them anywhere online. Does anybody have and idea where i could get them and how much would they cost? Also what are you thoughts on getting them from a junk yard? Good or Bad Idea?

i've seen a lot on here go for $100 used all 4 often times with oem shocks as well.

springs dont wear out they just sag and there are is no to determine how long it will last mainly because it has to many varibles. Like a FAT person VS a skinny person, if you haul a tranny in the trunk for a week. crazy 50lb subs. road conditions, weather. if you ever get into accidents. hit curbs. ANYTHING and EVERYTHING can play a factor. But for the most part i say lifetime.

When I said, "damping," I was thinking of spring rate, to the extent that I wondered if, after let's say 200K (and you replaced your struts/shocks), the original set of springs are now taking "noticeably" longer to rebound that they did when they were new.

Or, alternately, you are now noticeing more body lean on turns.

+1 on damping != springs. (NOT equals for you noobs)

I've recently replaced my ~120k old Progress springs with new progress springs, I noticed a finger gap or so increase. It wasn't necessary but I wanted the original drop and spring rate back, as I was sick of bottoming out.