weak design of control arm bushings, why?

[DesertBMW]

I wonder why did BMW design such poor weak control arm bushing from models E30/E36/e46. Seems like they all fail very quickly even if you buy the most expensive ones.
Does anybody know why would BMW do this, when we all know aftermarket solid rubber ones(m3) don't fail.

I wonder if anybody here knows.

[Vivek]

My guess would be comfort over durability.

[SkiFree]

Why did bmw used stamped steel housings for the mini cooper upper strut mounts, why did they think the e21 suspension would work, why was Elvis a car guy, where in the world is Carmen Sandiego?

"im CAD Hat's Passt."

[volvolover]

to save $$$?

[Roysneon]

why did they think the e21 suspension would work,

I'm not familiar with e21's, what was wrong with it? I thought it was a lot like E30.

[Bullet Ride]

I'm not familiar with e21's, what was wrong with it? I thought it was a lot like E30.

It's more or less the same, except that the rear is actually a coilover shock rather than the coil and shock being separate like the E30.

[LJ851]

I'm not familiar with e21's, what was wrong with it? I thought it was a lot like E30.

The front suspension uses the sway bar as the radius rods (forward suspension link) It was not a good idea !

[kronus]

eh, super beetles had that too. it's clever-ish.

[SkiFree]

The front suspension uses the sway bar as the radius rods (forward suspension link) It was not a good idea !

This. It's also why if you ever see an actual competitive E21 the front suspension has been heavily changed. On a budget (or to stay within class rules) the band-aid to making it work ok is to shorten the suspension travel with pretty dang stiff springs or a dual swaybar.

[Danny]

Car companies don't make money on a car that lasts forever.

[Bullet Ride]

This. It's also why if you ever see an actual competitive E21 the front suspension has been heavily changed. On a budget (or to stay within class rules) the band-aid to making it work ok is to shorten the suspension travel with pretty dang stiff springs or a dual swaybar.

This looks like a relatively straight forward approach to the 'problem'

[SkiFree]

This looks like a relatively straight forward approach to the 'problem'

Yep, by changing the suspension so that the swaybar no longer acts as a radius rod works fine as long as you get the geometry on par (thought this would constitute as "heavily modified", maybe that's a matter of opinion).

The big caveat is that by changing suspension mounting points means you are no longer class-legal in most of the classes where an e21 would MAYBE be competitive. If you did go ahead and change the mounting points you'd have a fun track-day car or be grouped in with car classes where the e21 wouldn't be competitive.

I think you found that picture here?

http://www.e21build.com/2013/03/swaybar-replacement-options.html

[Bullet Ride]

Yep, by changing the suspension so that the swaybar no longer acts as a radius rod works fine as long as you get the geometry on par (thought this would constitute as "heavily modified", maybe that's a matter of opinion).

The big caveat is that by changing suspension mounting points means you are no longer class-legal in most of the classes where an e21 would MAYBE be competitive. If you did go ahead and change the mounting points you'd have a fun track-day car or be grouped in with car classes where the e21 wouldn't be competitive.

I think you found that picture here?
http://www.e21build.com/2013/03/sway...t-options.html

Yup.

Most people aren't building their E21s into race cars, but it's good info to have in case you are.

I suppose for some people if you can't buy a kit off the shelf and bolt it on it's considered heavily modified. When I look at that all I think is fab a couple brackets, buy some bits and bobs, a little bit of welding and Bob's your uncle!

But for those who have no skills and deep pockets...

http://store.vacmotorsports.com/vac---e21-tubular-race-front-suspension-p2170.aspx

[Kevinl]

E21's are the bastard step child of the 3 series they should have went straight from 2002 to the e30. Who mounts the radio facing straight up?