[Smee]

Originally Posted by Dandanfings

awesome, now where can I find one?
I have googled and searched on eBay without any luck

i paid £150 delivered from BMW. we worth the investment. not sure on fitting my mate fitted it for free

[DriveS]

Originally Posted by Tengocity

If not joy on eBay then try a 1 series forum. That's where I got mine, from someone upgrading to H&Rs. Or just buy one from BMW, they're not that expensive.

So how much is involved in fitting the rear ARB? Do you nee to remove both wheels or can it be done from underneath on ramps?

[Tengocity]

Originally Posted by DriveS

So how much is involved in fitting the rear ARB? Do you nee to remove both wheels or can it be done from underneath on ramps?

Unfortunately quite a lot of effort- rear sub frame needs dropped, so you need access to a ramp ideally, or it'll be a few hours labour.

[DriveS]

Originally Posted by Tengocity

Unfortunately quite a lot of effort- rear sub frame needs dropped, so you need access to a ramp ideally, or it'll be a few hours labour.

So I could do it on my back with the car on ramps? What about the wheels?

[Tengocity]

Originally Posted by DriveS

So I could do it on my back with the car on ramps? What about the wheels?

Not sure that'd work I'm afraid.

[Watsey]

Originally Posted by DriveS

So I could do it on my back with the car on ramps? What about the wheels?

AFAIK the chassis needs to be fully supported and the entire suspension assemblies and rear sub-frame lowered from the vehicle. Having the vehicle on ramps won't allow you to do that.

[NISFAN]

Originally Posted by DriveS

So I could do it on my back with the car on ramps? What about the wheels?

No, car on axle stands (supporting chassis).

Both wheels removed. Rear subframe bolts loosened but not removed. Front subframe bolts and subframe lock brackets removed.

Drop diff supporting jack to allow access to roll bar brackets either side, then slide roll bar out.

Reverse to re-assemble.

[DriveS]

Thanks everyone. Got all that kit.

Any special tools required, such as odd sizes star drives?

[Smee]

http://f30.bimmerpost.com/forums/sho...&highlight=arb

[danb1979]

Is the M135i rear ARB the one to go for on a RWD F31 touring?

I'm wanting to upgrade the weedy one on my F31 when I do the suspension overhaul etc

[TurboWeasel]

Seems that way. A nice sensible size upgrade for a road car, and OEM fitment and quality

Every time I've fitted the big boy Eibach, Whiteline or H&R kits, to ANY of my previous cars, the ride quality got trashed.....as the guys explained on page 1. So they are staying well clear of my F30

[danb1979]

Originally Posted by TurboWeasel

Seems that way. A nice sensible size upgrade for a road car, and OEM fitment and quality

Every time I've fitted the big boy Eibach, Whiteline or H&R kits, to ANY of my previous cars, the ride quality got trashed.....as the guys explained on page 1. So they are staying well clear of my F30

Yup; made that mistake on an E39 530i Sport saloon; fitted the Eibach rear ARB and removed it after 2 weeks; made the car very twitchy and not fun at all...

Fitted the E39 M5 rear ARB to my E39 touring and that really. helped the ride & handling (along with new SLS Arnott SLS bags and Sachs Sport spec shocks etc)

That's what I'm aiming for re my F31

[TurboWeasel]

Originally Posted by danb1979

Yup; made that mistake on an E39 530i Sport saloon; fitted the Eibach rear ARB and removed it after 2 weeks; made the car very twitchy and not fun at all...

Fitted the E39 M5 rear ARB to my E39 touring and that really. helped the ride & handling (along with new SLS Arnott SLS bags and Sachs Sport spec shocks etc)

That's what I'm aiming for re my F31

Nice! OEMs generally get this sort of thing right.

Is the M135i front bar bigger than the F30 M Sport's as well? Might be worth doing as I find ARBs work better in pairs, otherwise the car can feel unbalanced like it's a table with a shorter leg at one corner.

OEM bars are usually hollow (if that's even possible on such a weedy 12mm one, lol) whereas the Eibachs et al are big solid lumps of pig iron and weigh a ton, which all adds to the mass the dampers have to control, as well as the additional spring rate when the opposite wheel is unloaded.

I hate arbs tbh, I think the active ones in Range Rovers, big Audis etc are far superior, but us lowly F3Xers can't have em'

[danb1979]

Originally Posted by TurboWeasel

Nice! OEMs generally get this sort of thing right.

Is the M135i front bar bigger than the F30 M Sport's as well? Might be worth doing as I find ARBs work better in pairs, otherwise the car can feel unbalanced like it's a table with a shorter leg at one corner.

OEM bars are usually hollow (if that's even possible on such a weedy 12mm one, lol) whereas the Eibachs et al are big solid lumps of pig iron and weigh a ton, which all adds to the mass the dampers have to control, as well as the additional spring rate when the opposite wheel is unloaded.

I hate arbs tbh, I think the active ones in Range Rovers, big Audis etc are far superior, but us lowly F3Xers can't have em'

The E39 touring did very well with just the rear; the front one was already chunky and didn't really need the upgrade

From my reading the F31s are similar; the rear ARB makes a big difference

Not sure re the F30s etc

I doubt the rear ARB is hollow; not at the thickness it is; you'd be bending it all the time...

[danb1979]

Is this the correct version from an F20 135i?

https://www.realoem.com/bmw/enUS/sho...diagId=33_1612

Pt number 1

[TurboWeasel]

I would have thought it would be the F20 135i?

[danb1979]

Originally Posted by TurboWeasel

I would have thought it would be the F20 135i?

It is; I put up the wrong link

Amended

[TurboWeasel]

Originally Posted by danb1979

It is; I put up the wrong link

Amended

Looks to be the one in that case £180ish.

Strange that only the 1, 2 and 4 series got it. Maybe BMW consider the 3 series to be less sporty than those cars?

[danb1979]

Originally Posted by TurboWeasel

Looks to be the one in that case £180ish.

Strange that only the 1, 2 and 4 series got it. Maybe BMW consider the 3 series to be less sporty than those cars?

Yup; very odd...

The E39 non M5s all got the 12/14mm rear ARBs; never knew why. The M5 16.5mm one was a superb upgrade

It would have made a lot of sense on E39 Sport Tourings due to the SLS system etc

When I fitted it, it reduced the roll that was left over and the car felt so much more planted

Added the 15mm F20 135i rear ARB to my parts list; same with the necessary poly bushes

The list is growing

My pals popping round tomorrow with his F31 320D; he's having the B4 shocks and Eibach pro kit springs fitted as I type this; it'll get a full fast road set up in the morning as they've had some bad luck with a few bolts that have snapped/needed to be drilled out etc... Always the way

I'll be soaking all mine in Wurth Rost Off Ice well before it goes in to get all the bits fitted!

[TiredGeek]

15mm on the 140i as well. I got one for £45 on eBay and when I need something doing on the rear it'll be going on. Oh, and judging by it's weight there's no way it's hollow.

[TurboWeasel]

Yeah I guess at 12-15mm, it's too thin for some hollow action. And also, in VAG world, the hollow ones tend to be weird diameters, like 15.7mm or something. Not sure of the advantages of hollow ones tbh, other than less material, so less cost And less weight.

Originally Posted by danb1979

Yup; very odd...

The E39 non M5s all got the 12/14mm rear ARBs; never knew why. The M5 16.5mm one was a superb upgrade

It would have made a lot of sense on E39 Sport Tourings due to the SLS system etc

When I fitted it, it reduced the roll that was left over and the car felt so much more planted

Added the 15mm F20 135i rear ARB to my parts list; same with the necessary poly bushes

The list is growing

My pals popping round tomorrow with his F31 320D; he's having the B4 shocks and Eibach pro kit springs fitted as I type this; it'll get a full fast road set up in the morning as they've had some bad luck with a few bolts that have snapped/needed to be drilled out etc... Always the way

I'll be soaking all mine in Wurth Rost Off Ice well before it goes in to get all the bits fitted!

Maybe BMW propped the 3 series up with stiffer rear springs instead?

Anyway, looking forward to your feedback on the rear arb and on your mate's upcoming upgrades

[danb1979]

Originally Posted by TurboWeasel

Yeah I guess at 12-15mm, it's too thin for some hollow action. And also, in VAG world, the hollow ones tend to be weird diameters, like 15.7mm or something. Not sure of the advantages of hollow ones tbh, other than less material, so less cost And less weight.



Maybe BMW propped the 3 series up with stiffer rear springs instead?

Anyway, looking forward to your feedback on the rear arb and on your mate's upcoming upgrades

Aye could be; never thought of that...

Still think the ARB will make the best upgrade in terms of handling and reducing body roll etc