Z4 Rear Springs - what to change for?

[GazHyde]

OEM or after market. :-\

Apparently it's a rite of passage to break a rear spring on a Z4! Now that's over and down with, what shall I change them for? I'm tempted to go non-OEM and go for a named brand like Eibach etc.

I've had a quote from the tyre centre to replace them with Sachs for £219 inc VAT and Fitting.

It doesn't need to be lowered, as it already is out of the factory. It already drags it's bum over the speed bumps near me already

 

[z3cade]

Adjustable coil overs Gaz :-bd

I would look into eibach, antrax, weitek springs as the standards seem poor if it's snapped already :-?

 

[GazHyde]

Just been doing a little bit of research and you don't even need spring compressors to change them! Not sure why the tyre centres computer reckons 1.5hrs work :-\

Also been looking on a Z4 specific forum, although making no headway through to the correct answer. Just seems to be lots of arguments caused by people asking the same question about springs. I would post a new question, but don't think I have the nerves for it :-s

The recommended replacement option there seems to be Eibach which sounds fine in principle. I can only find Eibach lowering springs, not anything which appears to be a direct replacement. The 3.0i is 15mm lower than standard off the production line, and I can only find 30mm lowering springs. It's bad enough over the speed bumps near me already to lose another 15mm ride height (and then there is the insurance premium to consider).

 

[Aceman]

Rear springs are dead easy to change as they can usually be extracted by unbolting the lower shock mount and lifting the car up so you get maximum rear suspension deflection. The spring should then just pull out but one little trick you can try without disconnecting the shock is to put a couple of small cargo straps around the springs coils whilst the suspension is loaded that way when you jack the back up the spring stays compressed and again just pulls out. Putting the new ones back in is slightly trickier as you need to tension the cargo straps up to tension the spring small enough to go back in but it's not that difficult.

Just to add me and a mate changed the rear springs on an Audi A3 in less than half an hour.

 

[zedonist]

I would go with OEM springs if you do not want to lower and like the stance and ride as it is.The chances are the springs will not break again during your ownership, how many miles has the car done? The failure i s due to corrosion they are plastic coated and once this is cracked or breached they rust, the cross sectional area reduces, they work harden, crack, all ending in a nice fatigue failure, it will happen on any spring

If you going for after market, then go for either Eibach or H&R, the manufacturing processes include tempering and shot peening, so you will not get any sag after a few miles like cheaper springs.

After market springs are generally made from thicker wire in order to increase the spring rate, the heat treatment and coating processes are generally the same as OEM, although some are powder coated. but even these will fail over time.

Never had this problem with good old leaf springs!!

 

[GazHyde]

OEM will probably be the way forward, despite the Eibachs only costing £5-10 more (and thats a full set of 4!).

I don't know how people cope with lowered cars :-\

 

[MAURICE THE MARTIAN]

So the bugger did break afterall,think your right not to lower, mines got the Mtech suspension and at 15mm lower than standard its enough,and no probs with the speed humps

 

[gookah]

got Eibachs on mine and just go careful over speed humps....
in fact I actually slow down for them, ...... who would have though a hump would have that effect? :bulb

 

[zedonist]

I am lowering my Z3 next month with a Bilstein B12 pack, this has Eibachs included, to be honest the Z3 needs lowering, but from what i have seen of the Z4's they look pretty much spot on in OEM Trim, but they do have low skirts which creates an illusion of being lowered. I have noticed also that the OEM's are taking handling and stance into consideration, even my new Volvo V50 has lowered sports suspension as standard, and the SRI Astra Estate i had on loan had adaptive sports suspension at the touch of a button.

 

[GazHyde]

I've just ordered a set of rears from my local stealer for £192. Had a look on a few of the usual suspects like Eurocarparts etc, but they all state 'non m-tech' on the Z4 springs. Couldn't be bothered to phone them up, and risk them sending the wrong ones out.

Also had to order a 'low profile' trolley jack, as a standard one won't fit underneath...