BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i)
 





 

Post Reply
 
Thread Tools Search this Thread
      09-14-2012, 08:46 AM   #1
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Hi Addicts!


I finally got around to installing my M3 Strut Tower Brace last week that I had sitting in my garage for quite a few weeks. As the kit doesn't come with installation instructions, I trawled the net for help. The only reviews or install DIYs I found were for E9x's but none for our E8x cars. Therefore, I thought that I would post up my feedback on the install for the M3 Strut Tower Brace kit for our 1 series cars.

I purchased the kit from HP Autowerkes and had it shipped to Australia.


Install Review

For the install I referred to the following DIY guide and therefore all credit goes to Bill. For photos, refer to his DIY.

http://www.billswebspace.com/335M3St...stallation.htm

From my research, experience and comparison with Bill's DIY, there are 2 differences between the kits for the E9x and for the E8x.

1. The centre mount is modified to fit our E8x's. A standard mount will not fit.

2. For some reason not yet known to me, rather than being supplied with 8 x 13mm hex bolts (4 for each side) and 4 nuts to secure the aluminum struts to the centre mount and to the strut tower mounts, our kit from HPA is supplied with 4 x 13mm hex bolts and 4 x Allen bolts (presumably 2 for each side). There are no nuts in our kit.

The only reason I could come up with for why they might have done this is that the Allen bolt head is considerably more low profile then the standard 13mm hex bolt. When I installed the brace there was less than minimal clearance between the new brace bolts and the cowl/rear bulkhead cover. It is possible that in the E9x they have more room under the cowl and therefore don't need the smaller bolts.

I had 2 issues with the install.

1. The Allen bolts are considerably softer than the hex bolts and it is impossible to torque them to the specified 34nM without stripping the Allen hole. Ask me how I know... The hex bolts are fine however. I installed all bolts from the top. I put 1 Allen bolt right up close to the centre mount and 1 near the strut tower. This way, I had the "low" profile of the Allen bolt where the cowl would contact the strut whilst also having one of the properly torqued hex bolts at each end.

2. Even putting a smaller Allen bolt up near the centre mount did not give me enough clearance to re-install the cowl. In the process of attempting to re-install the cowl, the centre clip on the cowl snapped off. This allowed me to re-install the cowl. There do not appear to be any issues with the seal or anything else so I didn't worry too much. It just makes the future process of taking the cowl on and off much easier =P


Performance Review

At the time of this review, my E88, suspension-wise, was bone stock. If you have other suspension mods and/or an E82 instead of an E88 your experience may vary.

If it matters to you, the M3 strut brace, being made of aluminium is considerably lighter than the stock steel brace. If I had to guess, the stock brace weighs approximately 4-5kg and the M3 brace would come in under 2-2.5kg.

With the stock strut brace, each side is a separate brace and 'ties' only one of the strut towers to the firewall in the middle. The issue with this is that whilst they will reduce compression between one of the struts towers and the firewall, it doesn't protect from extension or twisting forces on that or the other strut. In addition to this, it bolts only to 1 of the 3 bolts on each strut tower. The M3 strut brace bolts onto all 3 struts (3 is better than 1, true story) and connects each side to the centre mount, thus tying both strut towers together. In theory, this should be much stiffer between the strut and the firewall, but also between each of the struts themselves. So how does this work in practice?

The answer is brilliantly. Right after installing the strut brace I took it for a short drive down to the shops and I could immediately feel the difference. The front end was much more sorted, feeling more planted to the ground. The steering is more direct and points right where you wanted to. This could be felt even with just changing lanes. There also feels to be significantly less body roll around corners.

Upon further testing on a spirited bay drive a couple days later, the brace really proved itself. Previously, the car was quite sloppy, especially on the limit during cornering. The feeling I would get when cornering hard is that the front end could break grip unexpectedly at any time and I'd go understeering into the nearest gutter, tree, pole, cliff, river etc. Since installing the brace I can now corner harder and with much more confidence due to the improved grip and handling. It also feels much easier to predict and control over and understeer much more easily.


Overall Opinion

This is an extremely worthwhile mod in my opinion and should be one of the first mods to consider when upgrading suspension on our non-M E8x models.


I hope that you guys find this review helpful and I am happy to take any feedback.

Alex
Attached Images
  
__________________
Procede Rev 3 | PWM Meth | Mr5 Intake | AFE Scoops | ER FMIC | ER CP | TiAl BOV | AR Catless DPs | CP-E Exhaust | Forgestar F14s | M3 Strut Tower Brace | M3 Front Arms | M3 F + R Sway Bars | M3 Rear End Conversion | Moton Clubsports with Swift Springs | Vorshlag Camber Plates | ECS 2-Piece Rotors | SS Lines | Cool Carbons | BR Half Cage | BMWP SSK | BMWP Interior/Exterior Goodies | Blacklines | P3 Gauge | 1M Interior |

Last edited by froop; 09-15-2012 at 06:58 AM.
froop is offline   Australia
0
Reply With Quote
      09-14-2012, 09:50 AM   #2
Clovef
Second Lieutenant
 
Drives: 2011 135i DCT
Join Date: Nov 2011
Location: Earth

Posts: 280
iTrader: (1)

Great write up, thank you for taking the time to do it. I feel like one of the issues of the stock 1ers is the very soft side to side resistance up front. This allows the front to lean so much that there front tires roll over from added positive camber and you suddenly lose contact patch, grip, and end up understeering while all kinds of rubber flexes and keeps it unpredictable. This is why a lot of people like the e92/93 m3 front sway bar. I think it and the strut brace both keep the front flatter which helps avoid some of those problems. Glad you like it.
__________________
2011 BMW 135i DCT M Sport, black sapphire metallic,Coral red tint, Apex ARC8, 235/265 Dunlop ZIIs, Ohlins coilovers w/ Swift springs, M3 front bits, Whiteline rear sub frame bushings, Vorshlag camber plates, Stoptech pads, custom exhaust, stud conversion, spacers
Clovef is offline  
0
Reply With Quote
      09-14-2012, 10:50 AM   #3
Dackelone
Moderator
 
Dackelone's Avatar
 
Drives: 135i Silber mit/Rot 6MT N54
Join Date: Feb 2010
Location: Bayern, Germany

Posts: 16,401
iTrader: (1)

Nice write up! Do you have any pictures?


For anyone looking for better steering control/feed back... as weird as this sounds... I swear when I had my rear suspension bushings replaced with the M3 units... my front end works so much better now. I guess that is bc the rear end isn't wiggling and changing the car's (intended) direction.
Dackelone is offline   Germany
0
Reply With Quote
      09-14-2012, 09:27 PM   #4
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Thanks guys! =D

I'll try and post up some photos the next time I take off the cowl. It looks very similar to the photos that Bill has up on his DIY though but I'll try and get some close ups of the Allen bolts etc.

My parents actually have an E90 320i (stock) and when I drive it, their front end is much more sorted than ours. Thats how I think our car should have come from the factory. Once I put in the M3 strut brace it feels more like theirs now but even better =P
__________________
Procede Rev 3 | PWM Meth | Mr5 Intake | AFE Scoops | ER FMIC | ER CP | TiAl BOV | AR Catless DPs | CP-E Exhaust | Forgestar F14s | M3 Strut Tower Brace | M3 Front Arms | M3 F + R Sway Bars | M3 Rear End Conversion | Moton Clubsports with Swift Springs | Vorshlag Camber Plates | ECS 2-Piece Rotors | SS Lines | Cool Carbons | BR Half Cage | BMWP SSK | BMWP Interior/Exterior Goodies | Blacklines | P3 Gauge | 1M Interior |
froop is offline   Australia
0
Reply With Quote
      09-15-2012, 10:15 PM   #5
Rukuss
Major
 
Rukuss's Avatar
 
Drives: 135i
Join Date: Aug 2010
Location: Portland

Posts: 1,325
iTrader: (-1)

Quote:
Originally Posted by froop View Post
Thanks guys! =D

I'll try and post up some photos the next time I take off the cowl. It looks very similar to the photos that Bill has up on his DIY though but I'll try and get some close ups of the Allen bolts etc.

My parents actually have an E90 320i (stock) and when I drive it, their front end is much more sorted than ours. Thats how I think our car should have come from the factory. Once I put in the M3 strut brace it feels more like theirs now but even better =P
How much for the M3 strut brace?
Rukuss is offline   United_States
0
Reply With Quote
      09-17-2012, 01:31 AM   #6
cvc 22349a
Colonel
 
cvc 22349a's Avatar
 
Drives: 335i
Join Date: Sep 2007
Location: SF Bay

Posts: 2,228
iTrader: (8)

^ Check out HPA's website or pm Harold. They sell an M3 brace kit that fits the e8x
__________________
2007 E90 335i, TiAg, 6AT, ZPP, ZSP, ZCW, 6FL, HD
Quaife lsd, ETS fmic, GIAC s/w, Dinan intake/exhaust/oc, KW/M3 susp, Apex Arc 8, Mich PSS
cvc 22349a is offline   United_States
0
Reply With Quote
      09-17-2012, 08:22 PM   #7
Rukuss
Major
 
Rukuss's Avatar
 
Drives: 135i
Join Date: Aug 2010
Location: Portland

Posts: 1,325
iTrader: (-1)

Quote:
Originally Posted by cvc 22349a View Post
^ Check out HPA's website or pm Harold. They sell an M3 brace kit that fits the e8x
I saw a flat bar on **********s web site (cusco OS Style strut brace) its similar to the e46m strut bar, I wonder if its any good??
Rukuss is offline   United_States
0
Reply With Quote
      09-17-2012, 11:33 PM   #8
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Quote:
Originally Posted by Rukuss
Quote:
Originally Posted by cvc 22349a View Post
^ Check out HPA's website or pm Harold. They sell an M3 brace kit that fits the e8x
I saw a flat bar on **********s web site (cusco OS Style strut brace) its similar to the e46m strut bar, I wonder if its any good??
I was actually thinking of getting that exact one but they wouldn't ship to Aust without me bank transferring them all the money first...

So I did a little more research and went with the E9x M3 strut brace.

It not only stiffens up the front end but due to it's construction and replacement of our stock brace, it will make it easier to adjust dampening or camber on aftermarket suspension upgrades. No other strut to strut 2 point brace can offer that for our cars.

I found it difficult to find good reviews for strut braces for our cars. M3, aftermarket, BMW Performance or otherwise.
__________________
Procede Rev 3 | PWM Meth | Mr5 Intake | AFE Scoops | ER FMIC | ER CP | TiAl BOV | AR Catless DPs | CP-E Exhaust | Forgestar F14s | M3 Strut Tower Brace | M3 Front Arms | M3 F + R Sway Bars | M3 Rear End Conversion | Moton Clubsports with Swift Springs | Vorshlag Camber Plates | ECS 2-Piece Rotors | SS Lines | Cool Carbons | BR Half Cage | BMWP SSK | BMWP Interior/Exterior Goodies | Blacklines | P3 Gauge | 1M Interior |
froop is offline   Australia
0
Reply With Quote
      09-21-2012, 01:24 PM   #9
Rukuss
Major
 
Rukuss's Avatar
 
Drives: 135i
Join Date: Aug 2010
Location: Portland

Posts: 1,325
iTrader: (-1)

Quote:
Originally Posted by froop View Post
I was actually thinking of getting that exact one but they wouldn't ship to Aust without me bank transferring them all the money first...

So I did a little more research and went with the E9x M3 strut brace.

It not only stiffens up the front end but due to it's construction and replacement of our stock brace, it will make it easier to adjust dampening or camber on aftermarket suspension upgrades. No other strut to strut 2 point brace can offer that for our cars.

I found it difficult to find good reviews for strut braces for our cars. M3, aftermarket, BMW Performance or otherwise.
Any pics froop?
Rukuss is offline   United_States
0
Reply With Quote
      09-23-2012, 06:35 AM   #10
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Quote:
Originally Posted by Rukuss
Quote:
Originally Posted by froop View Post
I was actually thinking of getting that exact one but they wouldn't ship to Aust without me bank transferring them all the money first...

So I did a little more research and went with the E9x M3 strut brace.

It not only stiffens up the front end but due to it's construction and replacement of our stock brace, it will make it easier to adjust dampening or camber on aftermarket suspension upgrades. No other strut to strut 2 point brace can offer that for our cars.

I found it difficult to find good reviews for strut braces for our cars. M3, aftermarket, BMW Performance or otherwise.
Any pics froop?
I actually uploaded pics of the engine bay to the original post. If you have a look at either photo zoom in on one of the strut towers. You will see the circular mount on the strut tower (black). There is a plastic cap that covers the bolts and the hole in the strut tower. It can be easily removed to access camber plates or coil over dampening adjustments.
__________________
Procede Rev 3 | PWM Meth | Mr5 Intake | AFE Scoops | ER FMIC | ER CP | TiAl BOV | AR Catless DPs | CP-E Exhaust | Forgestar F14s | M3 Strut Tower Brace | M3 Front Arms | M3 F + R Sway Bars | M3 Rear End Conversion | Moton Clubsports with Swift Springs | Vorshlag Camber Plates | ECS 2-Piece Rotors | SS Lines | Cool Carbons | BR Half Cage | BMWP SSK | BMWP Interior/Exterior Goodies | Blacklines | P3 Gauge | 1M Interior |
froop is offline   Australia
0
Reply With Quote
      09-26-2012, 03:13 AM   #11
hyphy1
Private First Class
 
Drives: 2010 135i
Join Date: May 2012
Location: Fairfield, CA

Posts: 190
iTrader: (0)

Quote:
Originally Posted by cvc 22349a View Post
^ Check out HPA's website or pm Harold. They sell an M3 brace kit that fits the e8x
Seems like the gold standard/best option for our 1series seeking a functional and lightweight strut tower brace.

I checked the website, its not available under M3 nor 1series. the picture is available under the category, but the item isn't shown.

still available?
__________________
2010 135i
Black on Black | Premium Package | Sports Package
Cobb AP Stage I | Dinan Oil Cooler | BMS OCC | Michelin PSS
Valentine 1 RD | BlackVue DC
hyphy1 is offline   United_States
0
Reply With Quote
      09-26-2012, 03:24 AM   #12
cvc 22349a
Colonel
 
cvc 22349a's Avatar
 
Drives: 335i
Join Date: Sep 2007
Location: SF Bay

Posts: 2,228
iTrader: (8)

Quote:
Originally Posted by hyphy1 View Post
Seems like the gold standard/best option for our 1series seeking a functional and lightweight strut tower brace.

I checked the website, its not available under M3 nor 1series. the picture is available under the category, but the item isn't shown.

still available?
idk. Give 'em a call. I remember reading HPA modified the M3 strut tower brace so it'd fit the 1 series. btw, it's a waste of money unless you need easy access to strut adjusters or track your car w/a stiff suspension. I wanted the access to adjust my Koni's, but I don't feel that the front end is stiffer w/the M3 brace.
__________________
2007 E90 335i, TiAg, 6AT, ZPP, ZSP, ZCW, 6FL, HD
Quaife lsd, ETS fmic, GIAC s/w, Dinan intake/exhaust/oc, KW/M3 susp, Apex Arc 8, Mich PSS
cvc 22349a is offline   United_States
0
Reply With Quote
      09-26-2012, 05:55 AM   #13
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Quote:
Originally Posted by cvc 22349a
Quote:
Originally Posted by hyphy1 View Post
Seems like the gold standard/best option for our 1series seeking a functional and lightweight strut tower brace.

I checked the website, its not available under M3 nor 1series. the picture is available under the category, but the item isn't shown.

still available?
idk. Give 'em a call. I remember reading HPA modified the M3 strut tower brace so it'd fit the 1 series. btw, it's a waste of money unless you need easy access to strut adjusters or track your car w/a stiff suspension. I wanted the access to adjust my Koni's, but I don't feel that the front end is stiffer w/the M3 brace.
If you have other mods that appear to stiffen up the car (front sway bar, coilovers etc) it's likely that you won't feel much difference.

On a car with completely stock suspension the difference is night and day. That's my experience anyway.
__________________
Procede Rev 3 | PWM Meth | Mr5 Intake | AFE Scoops | ER FMIC | ER CP | TiAl BOV | AR Catless DPs | CP-E Exhaust | Forgestar F14s | M3 Strut Tower Brace | M3 Front Arms | M3 F + R Sway Bars | M3 Rear End Conversion | Moton Clubsports with Swift Springs | Vorshlag Camber Plates | ECS 2-Piece Rotors | SS Lines | Cool Carbons | BR Half Cage | BMWP SSK | BMWP Interior/Exterior Goodies | Blacklines | P3 Gauge | 1M Interior |
froop is offline   Australia
0
Reply With Quote
      05-18-2013, 11:03 PM   #14
PeteA
Captain
 
PeteA's Avatar
 
Drives: 135i
Join Date: Sep 2012
Location: Melbourne

Posts: 723
iTrader: (2)

Hi buddy,

Is this the kit you bought?
http://www.hpashop.com/BMW-128i-135i...tbrace-e82.htm

Shipping to OZ is quite deer, how much did you end up paying AUD?
__________________
PeteA is offline   Australia
0
Reply With Quote
      05-19-2013, 03:29 AM   #15
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Quote:
Originally Posted by PeteA View Post
Hi buddy,

Is this the kit you bought?
http://www.hpashop.com/BMW-128i-135i...tbrace-e82.htm

Shipping to OZ is quite deer, how much did you end up paying AUD?
Hi Pete,

Yes that is the one that I bought.

I did a little bit of researching recently however and it appears that you can buy the parts separately for cheaper. Of course if you buy the M3 parts the centre mount won't fit however you can buy the 1M centre mount which should work for our 1ers. Of course I haven't completely thoroughly checked this out but it should in theory be right.

I priced up all of the separate parts from ECS tuning using the part numbers listed on another thread and you can get it shipped for about $100-150 cheaper. Good luck!
froop is offline   Australia
0
Reply With Quote
      05-19-2013, 05:22 AM   #16
PeteA
Captain
 
PeteA's Avatar
 
Drives: 135i
Join Date: Sep 2012
Location: Melbourne

Posts: 723
iTrader: (2)

Thanks for the clarification. I have an N55 135i so would like to give this mod a go.

Given your first hand experience, did you have to modify anything to make it fit using this kit? I've read there is some trimming required bit you didn't seem to have done so.
PeteA is offline   Australia
0
Reply With Quote
      05-19-2013, 11:10 AM   #17
Pablito1702
Pablo
 
Drives: 2009 135i
Join Date: Dec 2009
Location: Orange County, CA

Posts: 251
iTrader: (3)

[quote=froop;12679144]Hi Addicts!

Performance Review

The answer is brilliantly. Right after installing the strut brace I took it for a short drive down to the shops and I could immediately feel the difference. The front end was much more sorted, feeling more planted to the ground. The steering is more direct and points right where you wanted to. This could be felt even with just changing lanes. There also feels to be significantly less body roll around corners.

Upon further testing on a spirited bay drive a couple days later, the brace really proved itself. Previously, the car was quite sloppy, especially on the limit during cornering. The feeling I would get when cornering hard is that the front end could break grip unexpectedly at any time and I'd go understeering into the nearest gutter, tree, pole, cliff, river etc. Since installing the brace I can now corner harder and with much more confidence due to the improved grip and handling. It also feels much easier to predict and control over and understeer much more easily.


I had the same strut bar (also purchased from Harold), but removed it when I took off the Dinan suspension. Since I still have my M3 front end bits (sway, tension rods, etc) on the car, I did not expect that I some of the steering sloppiness to return, but it did. I had assumed this was a result of the stock springs (linear) and dampers, but after reading this I wonder if it is the due to the strut brace.
__________________
BMW PPK V2, M3 26mm sway bar, M3 front control arm kit, M3 steering wheel, BMW 313 wheels w Michelin PSS
Pablito1702 is offline   United_States
0
Reply With Quote
      05-19-2013, 11:18 AM   #18
katsooba
Private First Class
 
katsooba's Avatar
 
Drives: bmw 135i
Join Date: Apr 2012
Location: Israel

Posts: 116
iTrader: (0)

Quote:
Originally Posted by Dackelone View Post
Nice write up! Do you have any pictures?


For anyone looking for better steering control/feed back... as weird as this sounds... I swear when I had my rear suspension bushings replaced with the M3 units... my front end works so much better now. I guess that is bc the rear end isn't wiggling and changing the car's (intended) direction.
What he said!

right on the spot!
just opened a thread after getting my rear subframe replaces and front end CAME TO LIFE!
heck yeah!
__________________
135i N55 / KW V3 / custom charge pipe / M3\M1 Bushings / CP-E 5" DP / JB4 S2 / K&N inbox
katsooba is offline  
0
Reply With Quote
      05-19-2013, 09:00 PM   #19
froop
Colonel
 
froop's Avatar
 
Drives: 08 AW 6MT E82
Join Date: Jul 2012
Location: Sydney, Australia

Posts: 2,166
iTrader: (2)

Quote:
Originally Posted by PeteA View Post
Thanks for the clarification. I have an N55 135i so would like to give this mod a go.

Given your first hand experience, did you have to modify anything to make it fit using this kit? I've read there is some trimming required bit you didn't seem to have done so.
With the HPA kit I did not need to modify anything in order for it to fit. There was no trimming required at all.

The only thing you need to watch out for is if you remove the brace, make sure you use new stock nuts to re-install the stock brace. They're made of aluminium and when I tried to re-install it I ended up ripping the welds or the bolt itself from the top strut mount which then needed replacement $$$.

The nuts which come with the M3 brace appear to be much stronger and I was able to re-use them however it's still probably not advised.


Quote:
Originally Posted by Pablito1702 View Post
I had the same strut bar (also purchased from Harold), but removed it when I took off the Dinan suspension. Since I still have my M3 front end bits (sway, tension rods, etc) on the car, I did not expect that I some of the steering sloppiness to return, but it did. I had assumed this was a result of the stock springs (linear) and dampers, but after reading this I wonder if it is the due to the strut brace.
It possibly could be and if you still have it I would recommend putting it back on. I ended up transferring it from my E88 to my E82. The difference when just driving normally on the street wasn't as obvious on the E82 however it definitely provides more confidence in harder cornering still and seems to provide a more progressive breakaway with better feel.
froop is offline   Australia
0
Reply With Quote
      05-20-2013, 12:41 AM   #20
PeteA
Captain
 
PeteA's Avatar
 
Drives: 135i
Join Date: Sep 2012
Location: Melbourne

Posts: 723
iTrader: (2)

Quote:
Originally Posted by froop View Post
With the HPA kit I did not need to modify anything in order for it to fit. There was no trimming required at all.
Ah okay that is good to know. I think that is because you are on the N54. The N55 has a slightly different arrangement for the heater closing pannel as per the following post:

http://www.1addicts.com/forums/showp...6&postcount=17

Not able to find the part number for the N54 heater closing pannel though. Might jsut trim the N55 one back a bit as the thread says.
__________________
PeteA is offline   Australia
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 07:34 AM.




1addicts
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST