[shenanigans01]

Just bought the car and it has 85k on the clock. Sounds of compressed air is coming from at least the front struts when I go over a bump so I'm thinking it's time for new struts.
Car is my daily driver and have no plans to track or anything.


So my questions:

• Do I need to replace the springs as well?
• Why should I not buy the Bilstein B4 struts since they are supposed to be the equivalent to the OEM M-Sport strut?
• If I shouldn't do the B4's, what do you suggest? Granted, I'd like to keep this between $400-$800 for the parts.

[feuer]

Originally Posted by shenanigans01

Sounds of compressed air is coming from at least the front struts...

They do that even when new. Doesn't mean they are bad.

[Needbmwpartzz]

You shouldn't need to replace springs unless they are broken....springs last forever usually.
What is the reason you want to replace other than shocks making noise,do the car ride more sloppy or?
You are at a good mileage to refresh the strut/shocks if they haven't,just make sure you look over all the other suspension bits while your at it and replace any with damage/play.
Are you doing the replacement yourself or paying a shop?
If your paying a shop I recommend that you have them give the chassis a once over to check for other problems.

[shenanigans01]

Originally Posted by Needbmwpartzz

You shouldn't need to replace springs unless they are broken....springs last forever usually.
What is the reason you want to replace other than shocks making noise,do the car ride more sloppy or?
You are at a good mileage to refresh the strut/shocks if they haven't,just make sure you look over all the other suspension bits while your at it and replace any with damage/play.
Are you doing the replacement yourself or paying a shop?
If your paying a shop I recommend that you have them give the chassis a once over to check for other problems.

Good to know the noise is normal.
I just figured 85k miles is about the lifespan of struts so it was a good time to replace them, which I would likely do myself.
What other 'suspension bits' do you recommend replacing while doing this job?

[Needbmwpartzz]

Check all tension struts and bushings for wear/play as well as ball joints and I would recommend changing strut mounts even though yours may not be worn as well as strut bushings and all related hardware as the aluminum are once only use although you could get away with using a second time but the strength is definitely compromised at that point....drive for a week or so then get alignment done as things settle or right away if its way off(you will be able to feel this)

[jfranci3]

The "TISSSS" sounds are the shocks "blowing off" - making them go soft for bumps rather than rattle you.

Sport suspension OEM shocks are Sach units. I did mine at 50k and there was a big difference in ride between then Bilstein B6 units and Sachs units. The rear shocks were more worn than the fronts.

As stated, springs shouldn't even need to be replaced, just the strut mounts.

[shenanigans01]

Originally Posted by jfranci3

The "TISSSS" sounds are the shocks "blowing off" - making them go soft for bumps rather than rattle you.

Sport suspension OEM shocks are Sach units. I did mine at 50k and there was a big difference in ride between then Bilstein B6 units and Sachs units. The rear shocks were more worn than the fronts.

As stated, springs shouldn't even need to be replaced, just the strut mounts.

bmwfans.info says that the M-Sport struts are Bilsteins.

Also, it seems like the OEM equilvalents are B4's and not B6's (according to ECS). Am I missing something.

[jfranci3]

They used both. My 2009 sedan sport pkg had Sachs. I think the Sachs are the units with the more distinctive TISS. The bilsteins were B4 units.

https://www.ecstuning.com/BMW-E90-32.../Shocks/Front/

[shenanigans01]

Dumb question: What goes on the rear?
ECS doesn't have one for 'sport suspension'.

The P/N is 33526784978 from bmwfans.info but I also see 33526772927 other places. What's the aftermarket equivalent to the rear? Everywhere I look it seems like it would have the be the B8's...am I wrong?

Edit: I'm a moron, I finally found this http://cart.bilsteinus.com/product/19-135052/206763/RWD

[slupie]

Originally Posted by shenanigans01

Dumb question: What goes on the rear?
ECS doesn't have one for 'sport suspension'.

The P/N is 33526784978 from bmwfans.info but I also see 33526772927 other places. What's the aftermarket equivalent to the rear? Everywhere I look it seems like it would have the be the B8's...am I wrong?

Edit: I'm a moron, I finally found this http://cart.bilsteinus.com/product/19-135052/206763/RWD

See my thread. The consensus of few members is that preferred strut/shock is the Bilstein B8 at double the cost.

http://www.e90post.com/forums/showth...0#post18642360

[jfranci3]

Originally Posted by slupie

See my thread. The consensus of few members is that preferred strut/shock is the Bilstein B8 at double the cost.

http://www.e90post.com/forums/showth...0#post18642360

His question involved factory sport springs your question involved shorter stiffer springs. Sorry you didn't like the answer.