The Shock/Strut Thread

[Drlu23]

I am doing the install myself. I'm waiting for the bilstein's to arrive and I am going to install the rear m3 sway bar, shocks, HR springs, subframe inserts and also brake discs and pads. This should be a fun weekend project when everything is here. Should I change the rear sway end links??? I've seen both yes and no.. So I'm not sure on this one yet.

[PrematureApex]

OE endlinks worked fine for me. Apparently if you go very low, they wind up being too long. But with just the H&Rs, plenty of room to use the stockers.

While it was tough, and I'd catch flack for it on most forums, I did the swaybar and bushings without disconnecting the brake lines by the subframe, and just making due with the little travel they provided before being stretched too far. Worked on both the X1 and my 135. Probably a good idea to disconnect them...but it can be done. Helps to have two guys for the rear sway though, as it requires a lot of pushing and shoving to get into place with such limited room.

[jaeezzy]

Originally Posted by Drlu23

I am doing the install myself. I'm waiting for the bilstein's to arrive and I am going to install the rear m3 sway bar, shocks, HR springs, subframe inserts and also brake discs and pads. This should be a fun weekend project when everything is here. Should I change the rear sway end links??? I've seen both yes and no.. So I'm not sure on this one yet.

Can you please provide the part numbers for M3 sway bar & subframe inserts? I'm planning to swap my rear sway bar with the m3's but will be keeping the stock sport suspension for now. So, do you or PrematureApex reckon the stock endlinks will fit fine? How thick are the m3's rear sway bar you are installing? Also are you just swapping the rear one? Thanks..

[PrematureApex]

Originally Posted by jaeezzy

Can you please provide the part numbers for M3 sway bar & subframe inserts? I'm planning to swap my rear sway bar with the m3's but will be keeping the stock sport suspension for now. So, do you or PrematureApex reckon the stock endlinks will fit fine? How thick are the m3's rear sway bar you are installing? Also are you just swapping the rear one? Thanks..

I use Whiteline KDT917 bushings in the rear. If you buy stock M3 ones, in addition to being MUCH more expensive, they're MUCH harder to install (requiring a press).

Stock endlinks will be fine with the M3 bar.

As for the part number, use realoem.com if you need the number.

I used an E93 M3 (vert) bar in the rear, as it's slightly thicker than the sedan/coupe rear bar. You'll also need the bushings/bracket.

Turner motorsports sells the M3 rear bar upgrade, along with bushings, but it's cheaper to look for one on ebay, etc. (I spent like $130 on an old vert rear bar with the bushings). Keep in mind when searching turner, etc. just use an E90 335 xdrive as your car. None of these parts/upgrades will show up if you use an X1.

Front swaybars from RWD E90s don't fit. The only option for a front bar on any of these xdrive cars as far as I know is a UUC E90 xdrive bar.

[PrematureApex]

Some part numbers...there's more earlier in the thread...

Originally Posted by PrematureApex

There are no front external bumpstops when you move to the Bilsteins. There are internal stops inside the strut housings.

It's pretty easy to open it up and trim it down if you want to be sure you won't bottom out.

But you can't fit an OEM bumpstop over an inverted strut, the "shaft" is like 3x as thick. Nor would you want to with the internal stops.

Regarding the rear shock install, I just pulled the control arm bolt so avoid having to compress the shock any significant amount. But the zip-tie method is probably easier/quicker.


My part numbers would be the same as yours, but I trimmed the factory rear stops, and added an M3 vert rear bar.

Rear Bar is 33552283962
Bottom bushings halves 33552283709
Top Bushings halves bushing 33552283710
Brackets 33552283714

[jaeezzy]

Originally Posted by PrematureApex

I use Whiteline KDT917 bushings in the rear. If you buy stock M3 ones, in addition to being MUCH more expensive, they're MUCH harder to install (requiring a press).

Stock endlinks will be fine with the M3 bar.

As for the part number, use realoem.com if you need the number.

I used an E93 M3 (vert) bar in the rear, as it's slightly thicker than the sedan/coupe rear bar. You'll also need the bushings/bracket.

Turner motorsports sells the M3 rear bar upgrade, along with bushings, but it's cheaper to look for one on ebay, etc. (I spent like $130 on an old vert rear bar with the bushings). Keep in mind when searching turner, etc. just use an E90 335 xdrive as your car. None of these parts/upgrades will show up if you use an X1.

Front swaybars from RWD E90s don't fit. The only option for a front bar on any of these xdrive cars as far as I know is a UUC E90 xdrive bar.

thanks mate but mine is sdrive 18d with sports suspension. Does it matter?

[Drlu23]

Originally Posted by jaeezzy

Can you please provide the part numbers for M3 sway bar & subframe inserts? I'm planning to swap my rear sway bar with the m3's but will be keeping the stock sport suspension for now. So, do you or PrematureApex reckon the stock endlinks will fit fine? How thick are the m3's rear sway bar you are installing? Also are you just swapping the rear one? Thanks..

OEM M3 sway + bushing and after market STI end link. These are the part numbers:

Sway Bar (BMW OEM):
E90 M3 rear sway bar - 33552283655
Rear Sway Bar Bushing Bracket (x2) - 33552283714
Top Sway Bar Bushing (x2) - 33552283710
Bottom Sway Bar Bushing (x2) - 33552283709

[PrematureApex]

Originally Posted by jaeezzy

thanks mate but mine is sdrive 18d with sports suspension. Does it matter?

All the same out back.

[PrematureApex]

Originally Posted by Drlu23

OEM M3 sway + bushing and after market STI end link. These are the part numbers:

Sway Bar (BMW OEM):
E90 M3 rear sway bar - 33552283655
Rear Sway Bar Bushing Bracket (x2) - 33552283714
Top Sway Bar Bushing (x2) - 33552283710
Bottom Sway Bar Bushing (x2) - 33552283709

No need for the shorter endlinks at stock ride height, or H&R ride height. But they're not going to hurt either. I'm a suby guy so I fitted the same WRX endlinks...no reason for them unless you're really low.

The E90 bar is fine, but if you're buying new, no reason not to go with the bigger E93 bar. Then again, with not much available up front, perhaps going milder in the rear isn't a bad thing.

[jaeezzy]

Drlu23 & PrematureApex Thanks...

[dirtye84]

which sti rear endlinks should i use? wrx 07?

[PrematureApex]

You should use stock ones, but IIRC, paradoxical used GD chassis ones...so yeah, 07. But he'll have to chime in.

Again, unless you're really low on coilovers, you don't need them. And even then, I've never heard of anyone else on coilovers needing anything but stock.

[Mr_Jack]

Got the rears today, fronts show up tomorrow! Will install tomorrow as well.

[GrantE83]

Just for a rough idea on my behalf....

That white x1 on the black bbs looked sweet!

Are there any photos of an X1 with H&R Springs & B6 Struts on 19" wheels?

[PrematureApex]

Originally Posted by Mr_Jack

Got the rears today, fronts show up tomorrow! Will install tomorrow as well.

I'd cut the front internal bumpstops if I were you, not worth the risk of not enough travel. Takes all of 5 minutes.

[Mr_Jack]

Originally Posted by PrematureApex

I'd cut the front internal bumpstops if I were you, not worth the risk of not enough travel. Takes all of 5 minutes.

Doing that right now!

[Mr_Jack]

Got them in last night after work.

Trimmed the front internal bump stops as PrematureApex did (Cut them in half, then cut the one that fits the shock shaft snug in half and stacked them back together, THIS IS A MUST. Travel is increased by a little over an inch) For the rear, I used non sport bump stops and cut the lower half and was still able to get the dust boot on.

I do wish Bilstein would man up and offer a B8 for the X1, I feel the struts/shocks are still too long for the lowering springs(when compared to when we do other BMWs with H&R's and B8s)

BUT nonetheless, the ride is MUCH improved. My ride home was way more enjoyable then ever. Feels a lot more planted with the the road around corners. I may do the M3 rear sway bar if I can pick one up from a friend who builds them for road coursing. Girlfriend also approves of the ride quality now.

The ride height did not change as someone stated somewhere, shocks to don't dictate ride height. You also must PRELOAD your suspension bushings when doing lowering springs, I know a lot of people and shops who have no idea what that term means and what it can do for longevity of the control arm bushings.

[PrematureApex]

Originally Posted by Mr_Jack

The ride height did not change as someone stated somewhere, shocks to don't dictate ride height.

That is not true when it comes to high pressure gas monotubes, on a car that came with twin tubes. they effectively raise your spring rate a little (and thus, add a bit of ride height).

I posted a link to Bilstein's own FAQ stating that some amount of additional ride height is normal, here...

Do BILSTEIN shock absorbers push the car up?

The greater extension force of BILSTEIN gas pressure shock absorbers will at the most raise the vehicle slightly, compared with worn-out original shocks.

This is a common, known thing when it comes to monotube shocks/struts.

Second thing about monotubes. They require high gas pressure to operate. Gas pressure creates a shaft extension force. This force works directly against the weight of the chassis; essentially a static spring rate (constant force, does not increase/decrease with travel like a coil spring). The force is the gas pressure x the shaft diameter. The larger the shaft dia. or the gas pressure, the greater the extension force. If you install a monotube shock on a vehicle that originally comes with low gas twin tube shocks the ride height will increase due to the increased extension force, unless you provide a way to change ride height like adj. coilovers, shorter springs, etc. The difference between a monotube and twin tube gas pressure is 2 bar vs 20 bar; fairly substantial.

[Drlu23]

Can you explain "You also must PRELOAD your suspension bushings when doing lowering springs, I know a lot of people and shops who have no idea what that term means and what it can do for longevity of the control arm bushings."

Do you mean raising the height of the suspension to normal ride height when tightening down the shocks struts?

[PrematureApex]

Originally Posted by Drlu23

Can you explain "You also must PRELOAD your suspension bushings when doing lowering springs, I know a lot of people and shops who have no idea what that term means and what it can do for longevity of the control arm bushings."

Do you mean raising the height of the suspension to normal ride height when tightening down the shocks struts?

He means loosening any control arm bolt that's associated with a rubber bushing (they have a limited amount of radial travel before they begin to bind), raising the control arm to about ride height, and tightening the bolt back down.

You could also raise the arm to ride height, loosen the control arm bolts associated with a rubber bushing sufficiently such that they can "unwind", the tighten them back down.

Just playing with the loose arm, they didn't have lot of bind over a significant range of upward travel, so while it's a good sound practice, don't lose sleep over it if you didn't do it.

[fw_fw]

Originally Posted by Mr_Jack

Got them in last night after work.

For the rear, I used non sport bump stops and cut the lower half and was still able to get the dust boot on.

Do you have a pic that shows how much travel you have on the rears before the shortened non sport bump stops engage?? Mine, with H&R springs, Bilstein B6s, and Z4 rear bump stops started off with a 1/2" gap when I first installed the Bilsteins, and now after they have settled have less than a 1/4" gap. I'm tempted to try the non sport bump stops to see if that removes that last bit of bounce out of the rear.....

[Mr_Jack]

Originally Posted by PrematureApex

That is not true when it comes to high pressure gas monotubes, on a car that came with twin tubes. they effectively raise your spring rate a little (and thus, add a bit of ride height).

I posted a link to Bilstein's own FAQ stating that some amount of additional ride height is normal, here...



This is a common, known thing when it comes to monotube shocks/struts.

Funny that I have installed a ton of the B6/B8 shocks on multiple BMWs after springs and the ride height always measure out the same.

But anyways, she rides better now. I know there is more to be desired if they had shorter shocks like a B8.