Changed to B4s and the rear is still a bit crashy

A

Any1else

Member
As the title - I changed the shocks and the car is definitely better poised but the rear is a bit crashy going over bumps. Sounds a bit like the car is tramping but it can’t be. It has sports suspension and I wondered if changing the springs to the more progressive Eibachs would help cos I have no clue why it is doing what’s its doing.

Does anyone have a link to the correct eibachs for a sports suspension E85? Or an idea why the rears are so solid.
 
BMW sports suspension is the work of the devil, designed to crush your spine.
Eibachs are a thing of beauty! There is just one version for the e85, fits all models, so buy from whoever is doing a good price.
 
Not super convinced at the idea that lowering springs will improve your ride, in honesty. But, either or.

What tyre pressures are you running? I've bumped mine up to 37 on the rear and it's a lot less crashy...
 
Capa said:
Not super convinced at the idea that lowering springs will improve your ride, in honesty. But, either or.

What tyre pressures are you running? I've bumped mine up to 37 on the rear and it's a lot less crashy...
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Yep, they do. The Eibach's are progressive springs, meaning they are softer than the M Sport springs over the first part of their compression and then become increasingly firm. So they are less crashy over ridges and other small imperfections, giving an improved ride quality. It's all relative though - you'll never get a limo style ride!
 
I get the progressive nature - but... What makes you think they're softer than M-Sport during the beginning of the stroke? Due to the lower nature they're shorter in length which - to my simple mind would mean they're at a higher tension. I'd have thought they'd have been equivalent to M-sport then getting harder.

I mean, happy if I'm wrong - and I'll be going and buying a set if I can be proven such!
 
Capa I went for less tyre pressure in the rears hoping that it would reduce the crashyness but will try a higher pressure and see if it makes a diff.

I have to say that I am a bit confused about the Eibachs too. They say that in the Fitment Notes: "If not separately named, for vehicles with OE-lowered suspension, the dimension of lowering is reduced by the dimension of lowering carried out by manufacturer. " . Does this mean, if the M-Sport is lowered by 20mm then fitting these would lower the car a further 10mm?

How much lower than the SE suspension is the M-Sport?
 
Davz said:
BMW sports suspension is the work of the devil, designed to crush your spine.
Eibachs are a thing of beauty! There is just one version for the e85, fits all models, so buy from whoever is doing a good price.
Click to expand...


Nope, E10-20-010-04-22 for the ///M
 
Capa said:
I get the progressive nature - but... What makes you think they're softer than M-Sport during the beginning of the stroke? Due to the lower nature they're shorter in length which - to my simple mind would mean they're at a higher tension. I'd have thought they'd have been equivalent to M-sport then getting harder.

I mean, happy if I'm wrong - and I'll be going and buying a set if I can be proven such!
Click to expand...

Nothing more scientific than going from m sport to eibachs on my own car and noticing the difference...
 
z4pilot said:
Capa said:
I get the progressive nature - but... What makes you think they're softer than M-Sport during the beginning of the stroke? Due to the lower nature they're shorter in length which - to my simple mind would mean they're at a higher tension. I'd have thought they'd have been equivalent to M-sport then getting harder.

I mean, happy if I'm wrong - and I'll be going and buying a set if I can be proven such!
Click to expand...

Nothing more scientific than going from m sport to eibachs on my own car and noticing the difference...
Click to expand...

I agree from personal experience - Eibachs much more compliant/comfortable than M sport springs.
 
:lol: higher tyre pressures improving the ride - now I've heard it all

OP are your oe springs definitely not broken? This can cause ride issues....
 
Any1else said:
Does this mean, if the M-Sport is lowered by 20mm then fitting these would lower the car a further 10mm?

How much lower than the SE suspension is the M-Sport?
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A car on OE sport springs will be 15mm lower than a car on the SE springs, so a car that had sport springs and is now running 15mm lowering springs will sit 15mm lower than sport, or 30mm lower than SE.
 
Silverzedtom said:
A car on OE sport springs will be 15mm lower than a car on the SE springs, so a car that had sport springs and is now running 15mm lowering springs will sit 15mm lower than sport, or 30mm lower than SE.
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Thanks Silverzedtom - that’s what I thought.
 
Took the rear shelf out this morning and undid all the securing bolts and torqued up the bottom bolt before tightening the top two. I think I tightened the tops first when I installed them. Also made sure that the sound insulation covered the top of the tower (stuck some extra in too) because the plastic might have been hitting the strut and causing the noise. Stuck it all back together and the noise is gone. Always good to get a free fix :D
 
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