E90Post
 


Coby Wheel
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Suspension | Brakes | Chassis > Spring rate?



Reply
 
Thread Tools Search this Thread
      05-22-2024, 02:06 PM   #1
thormessiah
Lieutenant
thormessiah's Avatar
182
Rep
438
Posts

Drives: 2008 BMW 335i Coupe
Join Date: Oct 2017
Location: Texas

iTrader: (0)

Garage List
2008 BMW 335i  [0.00]
  [0.00]
Spring rate?

As the title suggests I have an E92 335i on BC Coilovers and swift springs but not super thrilled about the current ride. The rear is particularly bouncy over large bumps. I got the spring rates at 6K front and 12K rear and I’ve heard it’s preferable to keep the ratio 1:3. This is my daily driver and the Texas roads I drive in are pretty ass, so I’m more geared towards a comfortable/sporty ride. I have m3 rear subframe bushings and upgraded toe arms in the rear as well
Appreciate 0
      05-23-2024, 07:03 AM   #2
wrevilo
Private First Class
85
Rep
163
Posts

Drives: E91
Join Date: Feb 2023
Location: USA

iTrader: (0)

Do you need to play around with the damping to better match the spring rate?
Appreciate 0
      05-24-2024, 02:14 AM   #3
thormessiah
Lieutenant
thormessiah's Avatar
182
Rep
438
Posts

Drives: 2008 BMW 335i Coupe
Join Date: Oct 2017
Location: Texas

iTrader: (0)

Garage List
2008 BMW 335i  [0.00]
  [0.00]
Quote:
Originally Posted by wrevilo View Post
Do you need to play around with the damping to better match the spring rate?
I doing think these have damping unfortunately but I could be wrong, turn are standard bc coilovers
Appreciate 0
      05-24-2024, 05:44 PM   #4
whyzee125
Brigadier General
1995
Rep
4,021
Posts

Drives: Dinan stage 2 335i
Join Date: Jul 2014
Location: Chattanooga Tn

iTrader: (0)

BC's have rebound adjusters. You need to get your rebound dialed in, though BC's can greatly benefit from a revalve.

a 1:2 spring rate can cause a more pitchy feeling on the freeway, but if your complaint is bounciness, you'd likely be increasing your rear spring rate to get to 1:3 which would increase your bounciness. 12k isn't all that stiff really, I think if you play with your rebound you can eliminate a lot of it.
Appreciate 0
      05-26-2024, 02:53 PM   #5
scoopdawoop
Enlisted Member
scoopdawoop's Avatar
Canada
19
Rep
33
Posts

Drives: E90
Join Date: Jul 2020
Location: Canada

iTrader: (0)

Garage List
2009 BMW 335i  [0.00]
start with decreasing damping in the rear. my BCs were crazy bouncy if i have it too stiff it was unsafe on the highway. few clicks softer made a huge difference.
Appreciate 0
      05-30-2024, 11:33 AM   #6
zero2sixtyZ
Colonel
United_States
1034
Rep
2,721
Posts

Drives: e92 + f15
Join Date: Jan 2012
Location: Cambridge, MA

iTrader: (4)

Garage List
Are those the spring rates from BC or did you swap in different springs? If swapped, the rear struts would need to be revalved to match. What strut top mounts are you using?
Appreciate 0
      05-30-2024, 05:36 PM   #7
thormessiah
Lieutenant
thormessiah's Avatar
182
Rep
438
Posts

Drives: 2008 BMW 335i Coupe
Join Date: Oct 2017
Location: Texas

iTrader: (0)

Garage List
2008 BMW 335i  [0.00]
  [0.00]
Quote:
Originally Posted by zero2sixtyZ View Post
Are those the spring rates from BC or did you swap in different springs? If swapped, the rear struts would need to be revalved to match. What strut top mounts are you using?
They are definitely different from the ones that came with the Coilovers. Would I only need to revalve the rears?
Appreciate 0
      05-31-2024, 09:20 AM   #8
zero2sixtyZ
Colonel
United_States
1034
Rep
2,721
Posts

Drives: e92 + f15
Join Date: Jan 2012
Location: Cambridge, MA

iTrader: (4)

Garage List
Quote:
Originally Posted by thormessiah View Post
They are definitely different from the ones that came with the Coilovers. Would I only need to revalve the rears?
Yeah, if the spring rates don't match, the respective struts would need to be revalved. I had the bounce you described with the FA supplied 8k/12k setup. I went from the included swift 12k to swift 14k springs with my FAs, and sent out the struts to be revalved.
Appreciate 1
Reply

Bookmarks


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 11:58 PM.




e90post
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