530 to 540 Suspension Compatibility

[RuskiE39]

Question... would 540 OEM suspension work in a 530? I looked up the part numbers on real oem and they are different but I am not sure why that is and what the difference is?

[777300ER]

Different materials because of different steering boxes and subframe designs.

[dannyzabolotny]

The rears should be more or less the same in theory, but the front has a completely different suspension design due to the different steering boxes.

[BimmrMeUpSnotty]

The sway bar links are definitely different, so the sway bar has to be different.

[auaq]

Technically speaking the suspension would have remained the same between an I6 and a V8, but due to the stearing gearbox, they had to move the thrust control arm behind the front axle. The front sway bars are different too. Pretty much that's all the differences between the two suspensions. Everything in the rear is basically the same.

[Jason5driver]

I can hear the 530i screaming...
"Help, I am under the knife...!"
I sure hope the 530i is not becoming a parts car...

[blackknight530i]

Even if the struts do fit (I've heard somewhere that they physically do, but never tried myself), they are designed for completely different weights of engine/subframes. Just putting M5 struts on a 540i will make the front end raise up and look like a 4x4, so I can only imagine on what it does to go from the I6 with aluminum subframe and R&P steering to V8 with steel subframe and recirculating ball steering box. I also know that the strut mounts on top have much different heights and different designs. The I6 has a much shorter mount if I recall than the 540i. I can tell you that you're way better off just getting new suspension that is properly sized/damped for the car.

[RuskiE39]

I can hear the 530i screaming...
"Help, I am under the knife...!"
I sure hope the 530i is not becoming a parts car...

Unfortunately it has in some aspects, like checking part functionality to rule out needing to buy other things. My plan was to put lowering springs on the 530 and the coilovers on the 540 but I don't have the stock suspension. If the rear stuts will work then that's great, I'll just need front 530 struts.

[bE34ST]

Even if the struts do fit (I've heard somewhere that they physically do, but never tried myself), they are designed for completely different weights of engine/subframes. Just putting M5 struts on a 540i will make the front end raise up and look like a 4x4, so I can only imagine on what it does to go from the I6 with aluminum subframe and R&P steering to V8 with steel subframe and recirculating ball steering box. I also know that the strut mounts on top have much different heights and different designs. The I6 has a much shorter mount if I recall than the 540i. I can tell you that you're way better off just getting new suspension that is properly sized/damped for the car.

I question this as the 540i M-Sport and the M5 have the same struts.

[blackknight530i]

I question this as the 540i M-Sport and the M5 have the same struts.

I'm pretty sure that's not correct, but even if the struts are the same, the springs definitely aren't. People have been misinformed if they are told they are the same, because several people have put M5 front suspension on 540is and found the front end to rise up about 1" or so.

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Ok, so strut does seem to be the same, but like I said, the springs are not, which is why the front rises when running M5 springs on 540is.

[Jason5driver]

Unfortunately it has in some aspects, like checking part functionality to rule out needing to buy other things. My plan was to put lowering springs on the 530 and the coilovers on the 540 but I don't have the stock suspension. If the rear stuts will work then that's great, I'll just need front 530 struts.

Do the BC's have their own strut/ shock mounts?
I should be able to use the BC's on the 540i.
You just need the OEM 540i front strut bearings and washers.

[blackknight530i]

Do the BC's have their own strut/ shock mounts?
I should be able to use the BC's on the 540i.
You just need the OEM 540i front strut bearings and washers.

He would likely still want to get correct springs for a 540i. I think they are the same coilover though, just different spring rate and upper mounts.

[bE34ST]

I'm pretty sure that's not correct, but even if the struts are the same, the springs definitely aren't. People have been misinformed if they are told they are the same, because several people have put M5 front suspension on 540is and found the front end to rise up about 1" or so.

- - - Updated - - -

Ok, so strut does seem to be the same, but like I said, the springs are not, which is why the front rises when running M5 springs on 540is.

I have M5 lowering springs on my 540 and they sit just as they should. Interesting, I've never even thought about that.

[blackknight530i]

I have M5 lowering springs on my 540 and they sit just as they should. Interesting, I've never even thought about that.

I found your post in a discussion specifically about this that mentioned the springs up front were different, but struts were the same.

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