Are E30 axles too short for Z3 trailing arms???

[Aptyp]

ANSWER: YES

I have an '86 325eS. I am in the middle of the 5-lug swap, and ran into an interesting issue... My axles do not stretch far enough between diff flange and axles. When I tighten axle at the hub, axle pulls diff hub out buy 1/2 inch.


What's happening? Where's the problem? Do I need z3 axles?

[E30Idea]

I am in the middle of the 50lug swap,

Thats alot of lugs...... im no help. sorry

[asubimmer]

We can try my longer small case diff "hubs" if you want.

[Aptyp]

lol, should have proof read.... I'm installing school bus suspension.

[Aptyp]

are E and I axles the same length?

[EN318isPDX]

are E and I axles the same length?

I think that they are.. I know they are different part #s.

[Mossman]

With the wheels drooped this might be a problem, and with them on the ground not. Don't want to find out the hard way and piss all the diffs fluid out though.

Now that I think of it, my e30 is up on stands and I did notice that one of the output shafts on the diff had popped out an inch or so. I'm running 318ti rear suspension and stock 325i axles. Hrm....

I ran it like this for 1000 miles and had no issues on the road, but maybe the hubs do pull the axles out a smidge, enough to cause a problem.

I say it is fine with car on the ground and axles taking a straight path more or less from hub to diff

[Aptyp]

SO here's the scoop...


Axles are too short for Z3 trailing arms. Buy about 1.5 inches when fully stretched. This doesn't apply to ti trailing arms. And this can be seen by the shock connection. On e30 shock mounting extends only about 2" from brake caliper mounting. On Z3, it's 4.2". So you see, e30 axle must stretch about 2" to between flange and hub.

I was told Z3 axles/flanges, would solve the problem, but I was unable to find an affordable set in a short period of time, so I could not test this theory.


Ti used leftover 84-85 trailing arms with puny bastard bearings. So trailing arms and axles fit.

[bimmer630]

you need to use 318ti parts i think because the Z3 trailing arms are wider than an E30. if you had a newer E30 you could just gut the hubs and brakes from the z3 arms and put them on your e30 arms but the bearing sizes are different, arent they?

[Aptyp]

Seriously, you need to spend a few hours reading through this sub-forum, it's getting really pointless answering questions which are answered, and only because you refuse to see what others have done.


If you're looking to blaze trails, start project and then add info, not use info you read in my threads to answer questions in my early threads.

[bimmer630]

Seriously, you need to spend a few hours reading through this sub-forum, it's getting really pointless answering questions which are answered, and only because you refuse to see what others have done.


If you're looking to blaze trails, start project and then add info, not use info you read in my threads to answer questions in my early threads.

i didnt even realize you were the same guy who wrote that how-to. why would you say not to use Z3 trailing arms and then have a thread saying that you installed Z3 trailing arms. im confused haha.. anyway i was just trying to pass along info that i read to help ya.

oh and BTW I have read almost every thread under the 5 lug swap section and there are still a couple questions I never did find answers to untill I went to, for example the use of MZ3 front struts (yes they can be used i talked to some people who have done it) and the other question is still kinda unanswered.. how to make abs work right

[Aptyp]

why would you say not to use Z3 trailing arms and then have a thread saying that you installed Z3 trailing arms. im confused

No, I used z3 hubs and brakes, but not trailing arms. I did buy trailing arms with everything attached, because it was a lot cheaper.


You can see a pic in one of those threads about installed z3 trailing arms, and axles didn't stretch far enough, and et15 wheels stuck out by 2 inches with rear quarter panel resting on tires.

[bimmer630]

uh... the first post in THIS thread says "are my axles too short for Z3 trailing arms......???? YES"

Im confused

[Aptyp]

YES, stock axles are too short for z3 trailing arms... what's not to understand? The reason I did my write-up is because I've tried every option for the rear offered by other members, and posted my thoughts/ideas and the simplest way of accomplishing 5-lug swap.

You are making it way too complicated by trying to reinvent the wheel. Either do like I tell you, or come up with a better original way. I love seeing all new ways of doing any swap, and currently working on yet another way of rear 5-lug. Try not to over analyze all the info, if you plan to use it. I wouldn't post something unless I learned it the hard way, trust me.

[bimmer630]

YES, stock axles are too short for z3 trailing arms... what's not to understand? The reason I did my write-up is because I've tried every option for the rear offered by other members, and posted my thoughts/ideas and the simplest way of accomplishing 5-lug swap.

You are making it way too complicated by trying to reinvent the wheel. Either do like I tell you, or come up with a better original way. I love seeing all new ways of doing any swap, and currently working on yet another way of rear 5-lug. Try not to over analyze all the info, if you plan to use it. I wouldn't post something unless I learned it the hard way, trust me.

dude... I am new here but im not trying to reinvent the wheel or anything like you are saying.... i was just saying i was a bit confused because when i first joined the forum I found your thread about using the hubs and brakes on the rear and not using whole trailing arms... and then i come across another thread written by you talking about installing Z3 arms..

I am not trying to post anything and claim it to be my own findings.. all i did was relay info to somebody who I Thought was having trouble with an issue that i had just before that read about.. My mistake i didnt even realize that it was the same member that wrote both threads haha.

that said i do wanna say i appreciate all the writeups with the how-to stuff because if it werent for that i would be sitting in a garage with a car torn all apart and ordering every part under the sun to see if it would fit