Rear springs need changing

[LisaLannister]

The two rear springs on my Z4 need to be changed (cracked) and I am wondering if there other less expensive brands I can buy other than a dealer's OEM?

Thanks

[pungo]

I'd go for something like H&R sport springs on all 4 corners.

[kaybat]

both sides? thats rare. Unless you're a suspension fanatic, I'd but some at a Jyard personally.

[TF07Z430i]

It seems pretty common that bmw springs fail. I had 2 on my X3 rust and break. I replaced them with Bilstein springs. I think they were around $100 for the pair. You can buy used factory ones but they may not last.

[KevinC]

The factory springs were inadequately coated (probably just spray painted?). Most of the spring failures you see is in cold weather climates with salty roads. Out west it's almost unheard of.

If you have to replace a pair of springs, what about the shocks? Are they original? If so I'd definitely do all 4 springs & shocks/struts at once, as well as all related bushings/mounts (FCABs and RTABs for sure).

[wdb]

I'm in a salty climate and the only spring I ever had fail on me was branded Prodrive (*wave* subiefolk). It had some kind of plasticky coating on the outside, which I imagine once it inevitably cracked, held the brine against the every-flexing steel spring, something which my very slight metallurgical knowledge tells me is a perfect storm for eating through steel.

[LisaLannister]

Thanks for the responses. Very helpful.

Just thought I would make you all have a good laugh knowing that I googled Jyard springs only to realize a few minutes later that it was short for junkyard

[Huz-Z]

Originally Posted by wdb

I'm in a salty climate and the only spring I ever had fail on me was branded Prodrive (*wave* subiefolk). It had some kind of plasticky coating on the outside, which I imagine once it inevitably cracked, held the brine against the every-flexing steel spring, something which my very slight metallurgical knowledge tells me is a perfect storm for eating through steel.

That’s what us mechanical engineers refer to as a corrosion cell - crevice corrosion. The differential oxygen content of the water combined with dissolved corrosive agents like salt create a perfect storm for inflicting damage to metal. Nasty things for sure.

https://www.nace.org/resources/gener...vice-corrosion

[wdb]

Originally Posted by Huz-Z

That’s what us mechanical engineers refer to as a corrosion cell - crevice corrosion. The differential oxygen content of the water combined with dissolved corrosive agents like salt create a perfect storm for inflicting damage to metal. Nasty things for sure.

https://www.nace.org/resources/gener...vice-corrosion

And then add torsion of the metal to the mix! I used to work for a specialty metals company that made drill collars, among many other things. They tested the material in a hot salt bath while applying torque.

[Huz-Z]

Originally Posted by wdb

And then add torsion of the metal to the mix! I used to work for a specialty metals company that made drill collars, among many other things. They tested the material in a hot salt bath while applying torque.

Yup!!

https://www.nace.org/resources/gener...rosion-fatigue


https://www.nace.org/resources/gener...osion-cracking


https://www.sciencedirect.com/topics...g/stress-riser

[Mantraxalos]

Originally Posted by LisaLannister

The two rear springs on my Z4 need to be changed (cracked) and I am wondering if there other less expensive brands I can buy other than a dealer's OEM?

Thanks

I didn't want to lower my car or firm up the suspension at all due to the awful roads in MI.
I bought the German brand Suplex from ebay for about 180.00 plus tax for both of my rears. They work fine and raised the rear back up to stock height. They are for NON sports package Z4s.

After my research these were the closest to OEM non sports package coils that I could get and the price was right.

[Lucky1]

Originally Posted by pungo

I'd go for something like H&R sport springs on all 4 corners.

I see that brand come up a lot on this forum for these Zed's and Zee's. What is so special about them and what does it do to the car's ride and handling compared to OEM? Must admit I'm always skeptical of aftermarket suspension parts.

[rsutoratosu]

Originally Posted by Lucky1

I see that brand come up a lot on this forum for these Zed's and Zee's. What is so special about them and what does it do to the car's ride and handling compared to OEM? Must admit I'm always skeptical of aftermarket suspension parts.

I'm interested in the same info, I can't lower the car anymore, bad nyc roads, is there HR that doesn't lower the car? I had H&R in my Acura TSX, I couldn't really tell if there were any difference

[pungo]

Originally Posted by pungo

I'd go for something like H&R sport springs on all 4 corners.

Originally Posted by Lucky1

I see that brand come up a lot on this forum for these Zed's and Zee's. What is so special about them and what does it do to the car's ride and handling compared to OEM? Must admit I'm always skeptical of aftermarket suspension parts.

They offer sport springs that provide a mild lowering with a progressive spring rate that's not harsh yet firms up when pushed into turns therefore reducing body lean.

Originally Posted by rsutoratosu

I'm interested in the same info, I can't lower the car anymore, bad nyc roads, is there HR that doesn't lower the car? I had H&R in my Acura TSX, I couldn't really tell if there were any difference

Not sure what model H&R springs you used on your Acura, some are close to stock. I believe the only H&R springs for the Z4 are sport springs (since it's a um, sport car) with mild lowering. Since you say your roads are bad, better stay with stock springs and not have better handling.

[maupineda]

The only H&R springs available for the Z4M are very aggressive, they lower the car an inch, and if you don’t want that low you are stuck. I have H&R coils and at their max height they are still lower than what I want.

[rsutoratosu]

Originally Posted by pungo

Not sure what model H&R springs you used on your Acura, some are close to stock. I believe the only H&R springs for the Z4 are sport springs (since it's a um, sport car) with mild lowering. Since you say your roads are bad, better stay with stock springs and not have better handling.

I haven't driven the car in almost 2 months.. They're building new overpass and replacing bridges on I95.. roads have been cut up for repaving for months and still not done. It be waste of money putting it in and letting it sit till 2021.. I mean I can drive the car to go get milk but I don't need springs for that..

spring 2021 is when I can drive it
https://www.thruway.ny.gov/oursystem...staging-v7.pdf

[rsutoratosu]

Well, might as well prepare for future when roads are fix.. I forgot where I read it, better off getting coil over if you change to non factory springs ? I'm looking at KW v1s now. lol I saw bc racing coils comes with shorter end links, I assume I will need it for KW ?

[Mantraxalos]

Originally Posted by kaybat

both sides? thats rare. Unless you're a suspension fanatic, I'd but some at a Jyard personally.

Both of mine were cracked at about 150k mi last summer. I noticed them both when I tried to change the diff fluid and the drain bolt could no longer be easily accessed since the ride height changed. They must have snapped while sitting over winter.