when to replace stock springs and what would pair well with bilstein b4's?

[Dekdo]

when to replace stock springs and what would pair well with bilstein b4's?

[ShocknAwe]

Originally Posted by Dekdo

when to replace stock springs and what would pair well with bilstein b4's?

Replace springs if you have sag or if wanting to tune spring rates or height.

I'd advise sticking with stock springs if you have B4s. Ideally switch to B6/8 and perf springs or specR. Not a fan of Koni dampers.

[Dekdo]

Originally Posted by ShocknAwe

Replace springs if you have sag or if wanting to tune spring rates or height.

I'd advise sticking with stock springs if you have B4s. Ideally switch to B6/8 and perf springs or specR. Not a fan of Koni dampers.

Ok I’ll just stick with stock then, car likely won’t see a track

If I do get sag eventually is it ok to replace with bmw performance springs?

[ShocknAwe]

Originally Posted by Dekdo

Ok I’ll just stick with stock then, car likely won’t see a track

If I do get sag eventually is it ok to replace with bmw performance springs?

No reason not to.

[gjm120]

Originally Posted by Dekdo

Ok I’ll just stick with stock then, car likely won’t see a track

If I do get sag eventually is it ok to replace with bmw performance springs?

The BMWP springs are a 10mm (~0.5" drop) from sport, which is stock for a 135i. Dig into this a bit and decide if you think B8's are more suited for those springs. I'm not going to advise either way b/c it's not absolutely clear what the answer is

[Dekdo]

Originally Posted by gjm120

The BMWP springs are a 10mm (~0.5" drop) from sport, which is stock for a 135i. Dig into this a bit and decide if you think B8's are more suited for those springs. I'm not going to advise either way b/c it's not absolutely clear what the answer is

I am still considering b8 with bmwp but it’s likely too stiff for daily needs. If I wanted to maintain stock sport suspension feel it sounds like b4 with stock springs is the way to go... but what do I replace the springs with when that time comes?

[gjm120]

Originally Posted by Dekdo

I am still considering b8 with bmwp but it’s likely too stiff for daily needs. If I wanted to maintain stock sport suspension feel it sounds like b4 with stock springs is the way to go... but what do I replace the springs with when that time comes?

I would say springs don't normally need replacing, but, notice that you're in Chicago (salt = rust). Lesjofors is the only supposedly stock replacement I've seen other other than OE BMW springs. Can't comment on their quality, but, worth looking into. For some reason, OE BMW springs actually cost more than BMWP springs.

Alternatively, be on the lookout for a used set from an area where rust isn't as likely. Also, springs from an E90 fit. If you go used, make sure you get the same spring code (alpha-numeric on a tag or painted on the spring) you have now or you will get an increase or drop in ride height.

[Dekdo]

Originally Posted by gjm120

I would say springs don't normally need replacing, but, notice that you're in Chicago (salt = rust). Lesjofors is the only supposedly stock replacement I've seen other other than OE BMW springs. Can't comment on their quality, but, worth looking into. For some reason, OE BMW springs actually cost more than BMWP springs.

Alternatively, be on the lookout for a used set from an area where rust isn't as likely. Also, springs from an E90 fit. If you go used, make sure you get the same spring code (alpha-numeric on a tag or painted on the spring) you have now or you will get an increase or drop in ride height.

Nice, thanks for the help!