Modest suspension advice

[skyscraper_g80]

Originally Posted by TS135i

If your not happy with the rear then why not try the bushings, from what I've read it sorts out that unpredictable feeling.

So what's the difference between M3 control arms vs M3 FSB For dialling out street understeer? one or both.

I don't think the FSB would dial out understeer, it would make the front roll less which may potentially contribute to more understeer.

On the other hand, the M3 lower controls arms are slightly longer than stock, which would give the front wheels slightly more negative camber (0.75 degrees if i'm not mistaken), which would aid turn-in and front end grip through cornering.

[TS135i]

Originally Posted by evolution42

I don't think the FSB would dial out understeer, it would make the front roll less which may potentially contribute to more understeer.

On the other hand, the M3 lower controls arms are slightly longer than stock, which would give the front wheels slightly more negative camber (0.75 degrees if i'm not mistaken), which would aid turn-in and front end grip through cornering.

Ok, it's actually more difficult to set up suspension which is warranty friendly and incognito.
Sure I can fork out for top shelf coilovers which I have done many times in the past, but this 135i street suspension project is a tricky one. I'm going to do it bit by bit using BMW parts so more likely will settle with M3 bushings, FSB & control arms. If I'm still not satisfied then tough I can't have the best of both worlds and expect BMW to warrant any issues I may encounter.

[John_01]

Originally Posted by TS135i

If your not happy with the rear then why not try the bushings, from what I've read it sorts out that unpredictable feeling.

I hesitated because its not a small job, but recently I'm more keen to get it done.

Originally Posted by TS135i

So what's the difference between M3 control arms vs M3 FSB For dialling out street understeer? one or both.

Its hard to answer that question directly. If only doing one thing, many people add the M3 front bar. However, in my opinion springs and dampers would be the place to start because the standard car is just too soft and floaty for my preference. If you get the Performance suspension, the kit already includes an upgraded front bar, so you may not absolutely need the M3 bar.

The M3 arms are probably the thing that makes the biggest difference in terms of reducing understeer. 1 degree of extra front negative camber makes a big difference for street driving. The stiffer bushings also change the steering feel making it more tactile and giving better feedback. If you only want more negative camber, then Dinan camber plates are a simpler, cheaper mod. On top of that I'd strongly recommend at least getting better dampers as an absolute minimum. I don't think it makes much sense to only do one mod and leaving it at that. What I did with M3 front arms and Performance suspension was a very good outcome for what I wanted.

[RimasRS]

BMW AG made simple answer to OP question BMW Performance suspension kit (including sway bar)

[TS135i]

That option was mentioned on the previous page, I'm nutting out all options before I decide what to do, its been interesting to hear what others have done with their suspension in order to extract maximum street driving pleasure.

[Zombie1]

Originally Posted by evolution42

I don't think the FSB would dial out understeer, it would make the front roll less which may potentially contribute to more understeer.

On the other hand, the M3 lower controls arms are slightly longer than stock, which would give the front wheels slightly more negative camber (0.75 degrees if i'm not mistaken), which would aid turn-in and front end grip through cornering.

I think your correct in assuming more under steer

[froop]

I've read quite a few times on this forum that it reduces understeer in our cars. The theory is that in its stock form, the 'excessive' body roll results in effective positive camber and a reduced contact patch on the outside front wheel during hard cornering. This results in understeer. By reducing this body roll it reduces the roll induced reduced grip by maintaining neutral camber during cornering and thus reduces understeer. That's the theory anyway.

Of course with the addition of more negative camber via camber plates etc it will have an effect on this theory however in reality who knows.