[CnSky]

So can anyone advise the diameter of the sway bars in different G30 models.

From what I believe the sway(roll) bars on the 530e is much smaller in diameter at 18mm than the one used on a 550 but can't find the data anywhere. The M5 runs a 30mm ARB.

I find the rear of my 530e rolls or has lateral shake too much at slow speeds on uneven surfaces and plan to upgrade rear and the front but don't want to exceed what the chassis is designed for.

Headrace have some nice options 32 mm front 28mm rear as below.

The M5 runs 30mm bars just wondering if the chassis and subframe are the same on all G30s or is the M5 reinforced?

https://www.r-parts-store.com/index....30&search=

This seems an easier option than changing springs or shocks. Trying to increase rear rigidity and reduce rear body roll.

Thicker roll bar should reduce roll (although I see some say it will increase rear lateral shake)but thinking I should upgrade the front also so I don't create huge oversteer. 28mm rear and 18mm front would be a problem I think.

[Knifeedge2k1]

I spent most of my morning cataloging the different size bars the different trim levels use

Unfortunately I can't find the diameters of any of the front bars anywhere despite searching for hours.


On the rear the bars are anywhere from 18mm to 25.7mm stock G30 (non M5) and the M5 non competition has 32mm front and 30mm rear.

With that said, we can't really know how stiff any of the stock bars are as we don't know whether they are solid or hollow and if hole what the wall thickness is...

The best way to upgrade I guess is to buy them as pairs for aftermarket (so both front and rear same brand & "stage") or to upgrade to OEM parts as a set with maybe the rear bars one "step" thicker.

I'll go ahead and post the spreadsheet in the next couple days

[Knifeedge2k1]

Doc here

https://docs.google.com/spreadsheets...u_N1KQ/pubhtml

[Knifeedge2k1]

Depending on market, model, trim, option package you could have anything between 18mm to 25.7mm rear ARB in a non M car 5er sedan, the 5er wagons all run stiffer rear bars like for like compared to the sedan.

I still have no sources on diameters on the front, but again, because of different wall thickness & hollow vs solid bar you can't really draw conclusions on stiffness from diameter alone.

[430Scud]

You can also fit the M5 X chassis brace. I did this on my M550iX. It bolts right up. There is a thread in the G30 suspension section (which is where this thread belongs)...I posted in it as well with photos.

https://g30.bimmerpost.com/forums/sh....php?t=1827571

[Lancelot]

Originally Posted by CnSky

So can anyone advise the diameter of the sway bars in different G30 models.

From what I believe the sway(roll) bars on the 530e is much smaller in diameter at 18mm than the one used on a 550 but can't find the data anywhere. The M5 runs a 30mm ARB.

I find the rear of my 530e rolls or has lateral shake too much at slow speeds on uneven surfaces and plan to upgrade rear and the front but don't want to exceed what the chassis is designed for.

Headrace have some nice options 32 mm front 28mm rear as below.

The M5 runs 30mm bars just wondering if the chassis and subframe are the same on all G30s or is the M5 reinforced?

https://www.r-parts-store.com/index....30&search=

This seems an easier option than changing springs or shocks. Trying to increase rear rigidity and reduce rear body roll.

Thicker roll bar should reduce roll (although I see some say it will increase rear lateral shake)but thinking I should upgrade the front also so I don't create huge oversteer. 28mm rear and 18mm front would be a problem I think.

M5 uses the 530e rear subframe (probably the strongest on the g30 platform)

However the dynamics are probably very different due to the weight distribution being completely different