[Soul_Glo]

ACS being fitted next month.
Should I change the arb's? If so then to what?
Thanks

[Junebug85]

Originally Posted by 37psi

ACS being fitted next month.
Should I change the arb's? If so then to what?
Thanks

Some of the guys on here have been fitting a 15mm rear arb.

Dan930 was having one fitted soon. He maybe able to give you some feedback on it...

[DriveS]

Originally Posted by 37psi

ACS being fitted next month.
Should I change the arb's? If so then to what?
Thanks

I had ACS first then the 15mm ARB a few months later. I would advise to get them both done together. The ARB makes the car more planted on corners (as its supposed to). Also helps with understeer.

[Gerade_Sechs]

Interested the results too. Which brand will you be going for and what is recommended front and rear (435d).

[NISFAN]

Fitting the M140/240 rear ARB is a great mod. Remember to buy the 15mm rubbers that go with it.

[Watsey]

Fitting springs only is a simple and relatively cheap job. Replacing the ARBs requires the sub-frames to be dropped, therefore more hours = more £££.

It depends what you are trying to achieve and your preferred driving style.

As has been said, BMW rear ARB replacement can give a nice improvement. Much larger, and therefore stiffer, ARBs are available and they substantially reduce roll. I have the Birds ARBs on my F31 (H&R, I believe) and they massively reduce roll which is what I prefer. Combined with the other mods I'm very happy with the ride and handling, but others may find my suspension setup too stiff.

[Kal101]

Had the 15mm M140 rear arb fitted on my 335xd last week following some good advice on here. Was running standard ACS on adaptives prior for a couple of years.

Massive difference- car feels planted and steers much better. Ride is a little firmer but not uncomfortable, personally prefer the way it rides now.

Had it done via an independent ACS fitter as I reckoned they would know the car and work to a standard.

You may be able to wangle a bit of a reduction by getting the two jobs done together.

Have seen a couple of M4 Rear arb on eBay - not sure if they would fit though.

[NISFAN]

Originally Posted by Kal027

Have seen a couple of M4 Rear arb on eBay - not sure if they would fit though.

They don't, sadly :

[Kal101]

Originally Posted by NISFAN

They don't, sadly :

Thanks for that info.

Kind of glad they don’t, as was smarting at the thought of having paid more for an inferior upgrade.

Still well worth the effort.

Any thoughts on changing the front arb as I’ve been bitten by the bug?

[Dr Forinor]

I had my suspension done, and I got my rear ARB upgraded to the 15mm at the same time.

Have to say, it hugely helped the understeer that was present beforehand. It really is a must have upgrade if you like your twisty roads.

[Dan930]

Originally Posted by Junebug85

Some of the guys on here have been fitting a 15mm rear arb.

Dan930 was having one fitted soon. He maybe able to give you some feedback on it...

Yeah,collect my car today with the 15mm rear arb fitted
As I had the ACS springs fitted a few weeks ago,I liked it a lot,gave
me the confidence of going faster as it’s much more planted on the
motorway & the biggest difference is going round bends & roundabouts
a bit more quicker but I feel there’s room for a bit more improvement
so I ordered the 15mn rear arb & got it fitted today...TBH I found that there
Isn’t much of a difference at first when going on the twisty bits & round
roundabouts,THATS until I looked down on the Instruments cluster & got a bit
Shocked on the speed I was going...easily an extra 5-10mph+ On the twistys
& roundabout,bare in mind i got shit tires on,if I had a premium brand tires on my car there be a bigger improvement...
might start to think about the front ARB

[Soul_Glo]

Thanks all.

Is there a part number for the M140 rear arb? Seals?

Mines is a 2015 435d x auto M.

What kind of labour cost should I aim for, for the rear ARB as I am having the springs replaced?

[Soul_Glo]

Originally Posted by Dr Forinor

I had my suspension done, and I got my rear ARB upgraded to the 15mm at the same time.

Have to say, it hugely helpful the understeer that was present beforehand. It really is a must have upgrade if you like your twisty roads.

I love my twists but haven't been able to enjoy them since I gave up my E92 M for my 435d. That's about to change.

[Dr Forinor]

Originally Posted by 37psi

I love my twists but haven't been able to enjoy them since I gave up my E92 M for my 435d. That's about to change.

I would still say my E90 330D MSport (with MSport suspension) had the sharper handling, but then it brought with it the horrible horrible ride.

[Tengocity]

I think that if you think you'll do the ARB change then may as well do it together, and means you can do the alignment just the once and know all is ok afterwards.

The only downside is you miss knowing what each change to the set up contributed to how the car drives afterwards, but you'd just get on and enjoy it.

[Soul_Glo]

Is it worth doing the front as asked above?

How long does the job take?

[Tengocity]

Originally Posted by 37psi

Is it worth doing the front as asked above?

How long does the job take?

Depends what you're trying to achieve really. By changing the rear you change the handling balance of the car front to rear with regards to taking away understeer by adding rear stiffness. If you add a thicker bar at the front you could still have more understeer, though it would happen at higher speed as your overall roll stiffness is higher.

I didn't need to do that as I also have ACS RS coilovers fitted, so my level of roll stiffness was already much improved, so just wanted a more neutral handling balance.

If I was still on ACS springs and standard dampers then I may have gone for the front too.

I did have Birds ARBs like Watsey, but didn't like the impact on ride comfort so much, so took them off when I went to coilovers. The lesson I took away is to use ARBS to adjust the balance rather than the primary way to sort the handling overall.

[Soul_Glo]

Originally Posted by Tengocity

Depends what you're trying to achieve really. By changing the rear you change the handling balance of the car front to rear with regards to taking away understeer by adding rear stiffness. If you add a thicker bar at the front you could still have more understeer, though it would happen at higher speed as your overall roll stiffness is higher.

I didn't need to do that as I also have ACS RS coilovers fitted, so my level of roll stiffness was already much improved, so just wanted a more neutral handling balance.

If I was still on ACS springs and standard dampers then I may have gone for the front too.

I did have Birds ARBs like Watsey, but didn't like the impact on ride comfort so much, so took them off when I went to coilovers. The lesson I took away is to use ARBS to adjust the balance rather than the primary way to sort the handling overall.

So it's a no to rear ARB as it compromises comfort?
I want sharp handling and balance with minimal comfort loss. My E92 was on Meyle HD arms and it was on point with some bearable stiffness. I don't want the ACS to mess up the steering.

[Dan930]

Latest update:
I’ve had the chance to give it a good blast as the rain is gone...went round a few roundabouts VERY quick & the front end is starting to lose grip but the rear is very planted (maybe I need to change tires as I’m on some cheap
ACCELERA PH 20”
My question is do premium tires really
Make a difference

[NISFAN]

[QUOTE=37psi;23240888]

Originally Posted by Tengocity

So it's a no to rear ARB as it compromises comfort?
I want sharp handling and balance with minimal comfort loss. My E92 was on Meyle HD arms and it was on point with some bearable stiffness. I don't want the ACS to mess up the steering.

Only if you fit the scaffold pole Birds ARB's. This thread is about fitting the BMW m140i 15mm version. Stock 335d is 12mm and M Sport is 13mm. A little but noticeable uplift.

[NISFAN]

Originally Posted by Dan930

Latest update:
I've had the chance to give it a good blast as the rain is gone...went round a few roundabouts VERY quick & the front end is starting to lose grip but the rear is very planted (maybe I need to change tires as I'm on some cheap
ACCELERA PH 20"
My question is do premium tires really
Make a difference

ACCELE......what?

Sounds like ditchfinders to me

I subscribe to "you get what you pay for!" When it comes to tyres.

[Tengocity]

Originally Posted by 37psi

So it's a no to rear ARB as it compromises comfort?
I want sharp handling and balance with minimal comfort loss. My E92 was on Meyle HD arms and it was on point with some bearable stiffness. I don't want the ACS to mess up the steering.

I don't think the upgraded 15mm rear bar changed the ride comfort in the slightest for me. I would definitely do that change.