5 stud rear offset question

[HairyScreech]

I know there are some wheel gurus on here that have been here before so:

I have 2 sets of trailing arms, 1 set of z3 arms and one set of e30 arms, both are 75mm bearings so I could use either.
I have z3 hubs and et-41 17" bbs to use.

The stock e30 arms with stock e30 hubs come out to 1440mm hub to hub, that would use an et-24 wheel @ 7j.

The stock z3 arms and hubs comes out to 1550mm hub to hub when on the same e30 beam.
Now that's 110mm wider, knocking off 17mm per side for the wheel offset difference means I am +38mm per side over a normal e30.

If I use the 328 rears at 8.5j and et-41 I assume I have no chance?

Put it another way a stock e30 would be buggered trying to mount et+17 wheels at 8.5" width?

Thus, my best option is to use the e30 arms with the z3 hubs for an e30 width +20mm per side for the deep hubs, leaving me 3mm per side wider once et-41 wheels are on. Right?
(1440mm +20mmx2 -17mmx2 = like having 3mm spacers in the rear)

[HairyScreech]

I also must note there are a few significant errors in the wiki which will need correcting.

[harry_p]

I'm not sure ive read of anyone using z3 arms, its usually a 318ti rear end, which sounds closer to your hybrid setup as quite a few people use high offset e36 type wheels on e36 based suspension on e30s.

[Grrrmachine]

Shoot me a PM with the Wiki errors and I'll get them sorted. If this is from the 5-Lug page, then that's just a copy/paste job from another site so it'd be good to have it corroborated.

[ajay]

Im not sure if this helps at all, but i am using z3m rear End with 17" et46 wheels. Bolt straight on and no clearance issues ( on a pre facelift) apart from when i offered up rear gaz coilovers ( did not fit). I don't know if there is s difference (in sizes) with a standard z3 set up!

[HairyScreech]

Ok, well looks like there are a few things at work here.

Z3 wise there are three possible hubs and two maybe three versions of the trailing arms.
Add in the compact and there is another trailing arm variant.

Hub wise early 4 pot cars share there hubs with the compact and I will call those the "standard" width hubs, these are sized for the 39mm inner diameter bearing. *The Z3 version MAY fit the 42mm bearing, can't confirm this 100% atm but I think they are the same as the compact*

The post 98/99 4 pot Z3 and all the 6 cylinder cars have a hub that is 23mm wider per side than the standard width hub, This is sized for the 42mm ID bearing and is what I have, this will go straight into E30 rear arms with the 42x75x37 bearing.

The Z3M uses a hub with the standard hubs offset but is sized for a much larger bearing, these really only fit the Z3M.

Trailing arms:

The compact has an arm that is pretty much identical to the E30 but has a lower hub offset, thus the compact must actually have a slightly reduced track from the e30, this I need to confirm as its possible the compact beam is spaced wider or something odd. Will have to measure on the Mcompact I am working on at the moment.
These arms use the smaller bearing, 39x72x37mm is it?

The Z3 has one maybe two versions of the trailing arm, The arms I have are from a late 1.9 and are the same as the six pot versions, these arms seem to be 32mm wider between the mountings and the wheel bearing location. These are braced and use a 75mm bearing.

There MAY be an early 4 pot z3 arm with a lower offset and a small bearing but i'm thinking that it has the same +32mm offset and the small bearing.

The Z3M uses a 6 pot arms but with a bigger bearing and a standard
offset hub and uses whopping offset wheels.



Thus it would seem for an e30 in this country your options are:
Compact arms and hubs with a 17mm spacer to get the same offset.

Z3 early 4 pot wide arms and standard hubs to give you +15mm per side.

Late z3 4 pot / any 6 pot hubs in e30 arms for +6mm per side.

Z3M arms and hubs to acheive the same as the early 4 pot Z3 arms but with bigger brakes and bearings.

Only a wide e30 would be able to use 6 pot z3 arms as they stand with the wide hubs as you would be +55mm per side

A stock 4 stud e30 could put e30 hubs into 6 pot Z£ arms to gain +32mm per side without spacers.