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      08-28-2012, 07:35 PM   #44
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Drives: E82 N55 DCT
Join Date: Nov 2010
Location: STL, MO

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2011 BMW 135i  [3.53]
Originally Posted by flinchy View Post
the 'upper control arm' is more correctly called the tension rod
and yes it's 'upper'

correction, it consists of the lower control arms (2), headlight rod, and tension rods (2)

can you provide more links/pics to the rear conversion? i'm assuming it also requires some pretty hefty modification?

ED: ok so "rear camber links" are the offending part, and installing these lets you run ACTUAL M3 coilovers/shock/spring combos? even for the front (which i'm guessing match up exactly like stock?)

Yes, I guess it can be considered "upper" because it is on top of the tie rod end. The tension rod keeps the upright rotating around the same pivot point. The steering tie rods push and pull the upright back and forth around this pivot point. The control arm keeps the upright/strut movement up and down on the correct plane.

The front control arms are a direct bolt on that you can use with the stock struts. Replacement coilovers would be a stock replacement. Obviously you can change top-hat configurations to run linear springs (some aftermarket, same stiffness through the whole spring travel) vs. progressive (like stock or KW V1/V2, stiffness increases as spring travel increases).

Great post by Berk:

Here is what you would need to do the full conversion on the front:


The rear suspension is quite complicated. Multi-link (which is similar to double wishbone) changes dynamically to more negative camber as the suspension travels upwards, where the front does not.

Installing the rear M3 camber link allows you to run shocks with the M3 bottom (this is different than the bottom of a shock for the stock 135i). Top of the shock and spring is the same.

Good rear bushing DIY:

Here are diagrams of the rear suspension:

Here is what you would need to do the full rear conversion: