BMW 1-Series Forum (F20) 135i - 1Addicts.com > Second Generation 1 Series Forum > 2012 BMW 1-Series Sporthatch (F20) Discussion > Strut tower brace and sway bars for F20/21
Post Reply
 
Thread Tools Search this Thread
      09-24-2013, 07:15 AM   #1
Callthecops
New Member
Belgium
1
Rep
27
Posts

Drives: F20 118i
Join Date: Dec 2012
Location: Belgium

iTrader: (0)

Strut tower brace and sway bars for F20/21

Hello

I want to reduce bodyroll without using stiffer springs or dampers.
I'm trying to find a strut tower brace (STB) and/or bigger sway bars for my F20 118i.
The only company I can find is SPR racing.
Are there others options ?
Appreciate 0
      09-24-2013, 09:54 AM   #2
ovekvam
Brigadier General
Norway
266
Rep
3,290
Posts

Drives: 2021 Galvanic Gold i3S
Join Date: Jun 2012
Location: Bryne, Norway

iTrader: (0)

Modern cars have a very stiff body, so I highly doubt that any sort of brace will make any difference to how the car drives. Stiffer swaybars is the way to go if you refuse to change springs/dampers.

Which suspension do you have from the factory? There might be stiffer factory swaybars available from BMW, meant for some other option, or the M135i.
Appreciate 0
      09-25-2013, 01:19 PM   #3
Callthecops
New Member
Belgium
1
Rep
27
Posts

Drives: F20 118i
Join Date: Dec 2012
Location: Belgium

iTrader: (0)

Quote:
Originally Posted by ovekvam View Post
Modern cars have a very stiff body, so I highly doubt that any sort of brace will make any difference to how the car drives. Stiffer swaybars is the way to go if you refuse to change springs/dampers.

Which suspension do you have from the factory? There might be stiffer factory swaybars available from BMW, meant for some other option, or the M135i.
I have the standard shocks, springs and swaybars at the moment.
An option is to install the M-sport swaybars, but a friend with racing car set-up experience says going from 12mm to 13mm swaybars will have almost no effect.
So I was looking for 16mm or more swaybars with hard Polyurethane bushings, but without succes.
KW or Bilstein coil shocks are too hard for me (and my kids), so that option is a no go.
Appreciate 0
      09-25-2013, 01:50 PM   #4
ovekvam
Brigadier General
Norway
266
Rep
3,290
Posts

Drives: 2021 Galvanic Gold i3S
Join Date: Jun 2012
Location: Bryne, Norway

iTrader: (0)

The stiffness of a swaybar is proportional to diameter to the fourth power, so going from 12 to 13 mm is a 38 percent increase in stiffness.
Appreciate 0
      09-26-2013, 02:40 AM   #5
Callthecops
New Member
Belgium
1
Rep
27
Posts

Drives: F20 118i
Join Date: Dec 2012
Location: Belgium

iTrader: (0)

Quote:
Originally Posted by ovekvam View Post
The stiffness of a swaybar is proportional to diameter to the fourth power, so going from 12 to 13 mm is a 38 percent increase in stiffness.
I didn't know that the amount of stiffness would be that much more.
Following that rule a 16mm would be extremely stiff and probably cause side effects that I don't want.
Because once you start changing suspension related parts,
you know it 's very easy to make the handling worse instead of better.

The BMW 13mm swaybar is not that expensive, so I'm going to install one
and try to find polyurethane bushings.

Thanks for the advice ovekvam.
Appreciate 0
      09-26-2013, 04:07 AM   #6
ovekvam
Brigadier General
Norway
266
Rep
3,290
Posts

Drives: 2021 Galvanic Gold i3S
Join Date: Jun 2012
Location: Bryne, Norway

iTrader: (0)

But remember that the springs and dampers are contributing quite a lot when it comes to reducing body roll, so a 38 percent increase in swaybar stiffness will not be very significant. If you only upgrade one end of the car, you will however notice a change of balance (making front end stiffer will make the car understeer more). Beware that polyurethan bushings can be noisy, making squeaking sounds. They need to be lubricated, as the bar is rotating inside them. The stock rubber bushings are twisting with the bar.

Also notice that adding stiffer swaybars with stock dampers will make the car feel slightly underdamped when driving in bumpy corners.

Last edited by ovekvam; 09-27-2013 at 12:55 AM..
Appreciate 0
      09-27-2013, 12:30 AM   #7
johnnydad
Captain
johnnydad's Avatar
Australia
108
Rep
931
Posts

Drives: 17 BMW M2 - 05 RS Clio 182 Cup
Join Date: Nov 2008
Location: Sydney, NSW

iTrader: (0)

Yes, my understanding is that if you are intending to reduce body roll to any significant degree, you first invest in firmer springs with matched dampers. Sway bars do help a little, but are more for tuning the balance - thicker front increases understeer, thicker rear increases oversteer. You may also find you get a more progressive, consistent and safer response from improving springing and damping rather that just putting big sway bars on.
__________________
John
17 F87 M2 Pure - long beach blue
10 E91 320d LCI - space grey - black dakota - steptronic - innovations - 157s - front PDC - Konis
99 BMW Baby Racer - red; 05 Renaultsport Clio 182 Cup - French Racing Blue - Konis - Eibachs - Remus - Turinis
Appreciate 0
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



All times are GMT -5. The time now is 10:21 AM.




1addicts
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
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