Difference between 1M and M3 rear swaybar?

[bradsm87]

The 1M shares the exact same front swaybar as the E90/E92 M3 but the rear is a different part number (but the same diameter).

Does anybody know how the E82 1M rear swaybar is different to the E90/E92 M3 rear swaybar?

[Dackelone]

This is a good question! I wonder why that is because the 1M basically has the same rear axle and subframe as the M3 has.

[RimasRS]

Originally Posted by Dackelone

This is a good question! I wonder why that is because the 1M basically has the same rear axle and subframe as the M3 has.

Yes but 1M have shorter wheelbase so it makes sense...

My guess that M3 sway is stiffer

[Mr Kleen]

Shorter wheel base wouldn't necessarily affect sway bars, having a narrower track would.

[RimasRS]

Originally Posted by Mr Kleen

Shorter wheel base wouldn't necessarily affect sway bars, having a narrower track would.

1M is not narrower it is same like M3 but shorter and it does affect weight transfer and balance which is usually adjusted with sway bars.

[Mr Kleen]

I know the 1M is has the same track. Wheelbase might affect how BMW tunes the cars via the swaybar but would not, in itself, necessitate a different sway bar. A different track would. That's the point I was trying to make (poorly).

[RimasRS]

Originally Posted by Mr Kleen

I know the 1M is has the same track. Wheelbase might affect how BMW tunes the cars via the swaybar but would not, in itself, necessitate a different sway bar. A different track would. That's the point I was trying to make (poorly).

To difficult for me

[bradsm87]

Are there any resellers on here who would be able to compare them physically for differences in the bends and weigh them to estimate tube thickness? It'd be really good to know.

[RimasRS]

Originally Posted by bradsm87

Are there any resellers on here who would be able to compare them physically for differences in the bends and weigh them to estimate tube thickness? It'd be really good to know.

Why it is so important to you? Read more about rear sway a lot of people here saying that it is not worth to upgrade rear sway it causes higher track/auto x times. Though gives better more stable feeling.
And if you dont have LSD forget about it.

[flinchy]

Originally Posted by Mr Kleen

I know the 1M is has the same track. Wheelbase might affect how BMW tunes the cars via the swaybar but would not, in itself, necessitate a different sway bar. A different track would. That's the point I was trying to make (poorly).

possibly slightly softer rear sway to try and make it slightly more comfortable to overcome the shorter wheelbase?

[bradsm87]

Originally Posted by RimasRS

Why it is so important to you? Read more about rear sway a lot of people here saying that it is not worth to upgrade rear sway it causes higher track/auto x times. Though gives better more stable feeling.
And if you dont have LSD forget about it.

I always stiffen up the rear of my cars to have tendency to oversteer. It really makes the steering response and front-end grip amazing, as long as you know how to handle the occasional tail stepping out. Probably not as good lap times but the sharp turn-in is what I'm after on the street. Yes I will be installing a Quaife LSD and M3 subframe bushes at the same time as installing the swaybar.

It's pretty agreed around here that the M3 rear swaybar is on the stiff side so if the 1M rear swaybar is a little thinner tube, it'll be slightly softer and lighter as well, making it a better option for the 1 series than an M3 item.

[RimasRS]

Originally Posted by bradsm87

I always stiffen up the rear of my cars to have tendency to oversteer. It really makes the steering response and front-end grip amazing, as long as you know how to handle the occasional tail stepping out. Probably not as good lap times but the sharp turn-in is what I'm after on the street. Yes I will be installing a Quaife LSD and M3 subframe bushes at the same time as installing the swaybar.

It's pretty agreed around here that the M3 rear swaybar is on the stiff side so if the 1M rear swaybar is a little thinner tube, it'll be slightly softer and lighter as well, making it a better option for the 1 series than an M3 item.

You can also look into 335i convertible rear sway. But still be careful with rear sway on short 1 series wheelbase.
As you know E82 non sport came without any swaybar in the back.

[bradsm87]

Yep the 15mm E93 rear swaybar is another option I'm considering.

I think the reason why 1 series are known to understeer and the reason why they have small or no rear swaybar is that undersizing or removing the rear swaybar is a cheap way to get better rear traction without having to spend on an LSD from factory.

[RimasRS]

Originally Posted by bradsm87

Yep the 15mm E93 rear swaybar is another option I'm considering.

I think the reason why 1 series are known to understeer and the reason why they have small or no rear swaybar is that undersizing or removing the rear swaybar is a cheap way to get better rear traction without having to spend on an LSD from factory.

If you will do 15mm sway convertible/XDrive please report back Im really interested in doing that also. I think with LSD it would be best shot not to thick but thicker than OEM. It would be cheaper also as you can find it used from wrecked car for that money it is better to do rear M3 rods to get rid of rubber rear feeling under hard acceleration for example...

[MightyMouseTech]

Originally Posted by bradsm87

It's pretty agreed around here that the M3 rear swaybar is on the stiff side so if the 1M rear swaybar is a little thinner tube, it'll be slightly softer and lighter as well, making it a better option for the 1 series than an M3 item.

If they are the same outer diameter, and the only difference is the thickness of the tube, then they are essentially the same stiffness. The outer diameter is what determines the stiffness of a bar in torsion.

[bradsm87]

The OD has the biggest effect but thichness makes a small difference too. A solid swaybar is definitely stiffer than a hollow one of the same diameter. Softness isn't the only possible difference between the two. The 1M one might be bent to better suit the 1 series somehow. As title states, really keen to find out what the difference is.