Front lowered? Looks that way, need some professional advice...

[CharlesAFerg]

I've seen E34s that give the impression that the front is lowered and the rear sticks up a little bit more, is this the case or is this only some body work? Such as a lower kit in the front and nothing in the back? or is it a little of both? I've seen the same effect on some E39s that seem to ride low in the front.

Can someone explain this phenomena? I would be happy! All theories welcome...:)
-Charles

[Jehu]

I've seen E34s that give the impression that the front is lowered and the rear sticks up a little bit more, is this the case or is this only some body work? Such as a lower kit in the front and nothing in the back? or is it a little of both? I've seen the same effect on some E39s that seem to ride low in the front.

Can someone explain this phenomena? I would be happy! All theories welcome...:)
-Charles


very much lower than mine?
http://users.adelphia.net/~cpkver8/

[Kalevera]

That car has a case of stock gaposis, nothing lowered or abnormal about it.

Most good quality fitted springs for E34s (and E32s, for that matter) do not lower the rear much, if at all, for the simple reason that there are no alignment adjustments to be made at the rear axle without buying aftermarket bushings. Compare that to E36/E38/E39, all of which have better ability to compensate for rear spring/shock modifications.

I had Fritz on the alignment rack last week. It's the latest and greatest machine from Hunter, acquired a few months ago. I was surprised to notice that its database contains three different suspension specs for my specific model year 535, regular, sport, and something even more aggressive (don't recall the name of it at the moment). I found that the sachs kit rears fit Hunter's specs for "sport" almost dead on, while the fronts are a different story, intimating that the kit changes the rake of the car (by at least 10 mm unloaded, from what I could tell) over what I suspect to be the mtech suspension ("sport").

One other thing I noticed while I was aligning the car that wasn't apparent or necessarily obvious: with weight in the car (a la, how you'd drive it), the sachs kit drops from 1.5/2 fingers up front to around 1 and a sliver -- makes the car look a lot sportier, but you'd never notice it when you're behind the wheel (does it even matter? :) ) And I'm by no means a fatty.


best, whit

[genphreak]

Interesting observations Whit.


I found that the sachs kit rears fit Hunter's specs for "sport" almost dead on, while the fronts are a different story, intimating that the kit changes the rake of the car (by at least 10 mm unloaded, from what I could tell) over what I suspect to be the mtech suspension ("sport").Mine was on a similar machine a while ago after fitting the M-technik spring and sways (25mm front, 18mm rear) package with Bilstein Sports. We noticed some weird numbers at the rear that really didn't matchany of the Bently specs. The car is dead flat front to rear, with almost no rake at all- ie if you measure from the sill panel to the road it is the same front to rear. but there is a gap at the front from tyre to fender of about 2 fingers (unladen). At the rear there is no gap, the tyre is under the fender in fact.

The suspension is now much stiffer and the car sticks to the road through the corners like sh*t to a blanket. So I looked into it as I'd like to get it as close to spec as possible. What I worked out is this:

What BMW calls 'Sport suspension' equates really just a different set of springs to the stock ones- (ie but only a slightly lower setting). I believe it is sold as a cheap upgrade, or added to faster models to compete harder and/or get buyers more excited (ie 535is, 540iLE etc.), especially when models get towards the end of production.

Ed would know better about this perhaps... :)

Whereas M-technik is where real lowered springs and sports shocks are used- such as on M-cars. However to maximise ride and manage tyre wear, my research shows that BMW may do a whole lot more than change the dampers and ride-height: This is something no-one I've ever met has said yet, so it is just theory. But bare with me here for this is what I've found when looking at the part numbers used on each model.

On e34 at least, different arms, structural-members and bushings are used, hence the third set of more aggressive rear wheel settings you alluded to Whit.

ie. According to the online ETK:
On M5 the trailing arms (part 33321137837, Item#1) and trailing arm bushings (part 33321135808, Item#2- ROTARY SLIDE BEARING) are not common to other e34s. They are are only found on

E32: Details on E32 (http://www.realoem.com/bmw/partxref.do?part=33321135808&showus=on&showeur=on&series=E32)
E32 740i SEDAN, U.S.
E32 740iL SEDAN, U.S.
E32 750iL SEDAN, U.S.
E32 740i SEDAN, Euro
E32 740iL SEDAN, Euro
E32 750i SEDAN, Euro
E32 750iL SEDAN, Euro
E32 750iLS SEDAN, Euro

E34: Details on E34 (http://www.realoem.com/bmw/partxref.do?part=33321135808&showus=on&showeur=on&series=E34)
E34 M5 3.6 SEDAN, U.S.
E34 M5 TOURING, Euro
E34 M5 3.6 SEDAN, Euro
E34 M5 3.8 SEDAN, Euro

http://www.realoem.com/bmw/diagrams/o/k/10.png

And it gets worse.

The axle carrier itself; Part 33312226620 (Item 1) is only found on

E34: Details on E34 (http://www.realoem.com/bmw/partxref.do?part=33312226620&showus=on&showeur=on&series=E34)
E34 M5 3.6 SEDAN, U.S.
E34 M5 TOURING, Euro
E34 M5 3.6 SEDAN, Euro
E34 M5 3.8 SEDAN, Euro

http://www.realoem.com/bmw/diagrams/o/k/9.png

So there we have it- M-technik finally explained?

Perhaps there is a 'perfectly good' explanation for all these items being different (anyone care to suggest one?)?

No wonder EVERYONE who lowers the rear of their e34 suffers tyre wear on the inside.
Changing all this is not easy and would be bloody expensive to do. I think I'll be happy to turn my rear tyres round on a regular basis from now on :) Nick

EDIT: Actually I just remembered, the trailing arms are different on 7er and M-cars as they deliver a different rear wheel offset. This somehow prevents e32 rear brake rotors from fitting e34. They also have different hub assemblies on the trailing arms (?). But we do know e32 rear brakes can be retrofitted without modification if using 540 rotors. However if one was prepared to change the trailing arms and whole axle carrier housing to M5/e32 parts it could be done using e32 rotors. The question then is; what happens if you do not change the whole axle carrier (but do replace the trailing arms with M5 versions (for example attempting to attain M5 rear wheel geometry)- what difference would you get in rear wheel track and would the alignment come into spec?

That is what I am chasing here; what is actually required to adjust the rear wheel alignment into the M-technik alignment specification?

I don't know if the rear track is different between M5 and standard e34 (and one has to be careful to remove any differences in wheel offset as they have different offset rims), but this may actually be the only reason why the axle carrier housing is (and for that matter the trailing arms) different. Perhaps it was done to allow for the staggered wheels offered on M5 and all one has to do to get M-tech suspension geometry on a stock e34 is change to the M5 bushings after all!

I guess to find out, one would need to have all the parts and be able to compare them.

[angrypancake]

Lee in Ottowa's car has the straight up badass drop. But I think he has GC coilovers.... I'd guess they could be configured to have the desired effect

[CharlesAFerg]

very much lower than mine?
http://users.adelphia.net/~cpkver8/

Just for the record, thats sorta what I am talking about yeah. Oh, and those pictures are sick. B-E-A-U-tiful E34.

[Jehu]

Just for the record, thats sorta what I am talking about yeah. Oh, and those pictures are sick. B-E-A-U-tiful E34.


Why thank you. I haven't had time to detail it yet but Bavarian Autosport is about an hour away from me so soap, crack filler and wax will be coming soon. I was thinking of shadowlining the trim at some point too.

[632 Regal]

I read that swaping to the ///M rear trailing arms was the ticket for camber issues on dropped cars...this was a long time ago.

Interesting observations Whit.

Mine was on a similar machine a while ago after fitting the M-technik spring and sways (25mm front, 18mm rear) package with Bilstein Sports. We noticed some weird numbers at the rear that really didn't matchany of the Bently specs. The car is dead flat front to rear, with almost no rake at all- ie if you measure from the sill panel to the road it is the same front to rear. but there is a gap at the front from tyre to fender of about 2 fingers (unladen). At the rear there is no gap, the tyre is under the fender in fact.

The suspension is now much stiffer and the car sticks to the road through the corners like sh*t to a blanket. So I looked into it as I'd like to get it as close to spec as possible. What I worked out is this:

What BMW calls 'Sport suspension' equates really just a different set of springs to the stock ones- (ie but only a slightly lower setting). I believe it is sold as a cheap upgrade, or added to faster models to compete harder and/or get buyers more excited (ie 535is, 540iLE etc.), especially when models get towards the end of production.

Ed would know better about this perhaps... :)

Whereas M-technik is where real lowered springs and sports shocks are used- such as on M-cars. However to maximise ride and manage tyre wear, my research shows that BMW may do a whole lot more than change the dampers and ride-height: This is something no-one I've ever met has said yet, so it is just theory. But bare with me here for this is what I've found when looking at the part numbers used on each model.

On e34 at least, different arms, structural-members and bushings are used, hence the third set of more aggressive rear wheel settings you alluded to Whit.

ie. According to the online ETK:
On M5 the trailing arms (part 33321137837, Item#1) and trailing arm bushings (part 33321135808, Item#2- ROTARY SLIDE BEARING) are not common to other e34s. They are are only found on

E32: Details on E32 (http://www.realoem.com/bmw/partxref.do?part=33321135808&showus=on&showeur=on&series=E32)
E32 740i SEDAN, U.S.
E32 740iL SEDAN, U.S.
E32 750iL SEDAN, U.S.
E32 740i SEDAN, Euro
E32 740iL SEDAN, Euro
E32 750i SEDAN, Euro
E32 750iL SEDAN, Euro
E32 750iLS SEDAN, Euro

E34: Details on E34 (http://www.realoem.com/bmw/partxref.do?part=33321135808&showus=on&showeur=on&series=E34)
E34 M5 3.6 SEDAN, U.S.
E34 M5 TOURING, Euro
E34 M5 3.6 SEDAN, Euro
E34 M5 3.8 SEDAN, Euro

http://www.realoem.com/bmw/diagrams/o/k/10.png

And it gets worse.

The axle carrier itself; Part 33312226620 (Item 1) is only found on

E34: Details on E34 (http://www.realoem.com/bmw/partxref.do?part=33312226620&showus=on&showeur=on&series=E34)
E34 M5 3.6 SEDAN, U.S.
E34 M5 TOURING, Euro
E34 M5 3.6 SEDAN, Euro
E34 M5 3.8 SEDAN, Euro

http://www.realoem.com/bmw/diagrams/o/k/9.png

So there we have it- M-technik finally explained?

Perhaps there is a 'perfectly good' explanation for all these items being different (anyone care to suggest one?)?

No wonder EVERYONE who lowers the rear of their e34 suffers tyre wear on the inside.
Changing all this is not easy and would be bloody expensive to do. I think I'll be happy to turn my rear tyres round on a regular basis from now on :) Nick

EDIT: Actually I just remembered, the trailing arms are different on 7er and M-cars as they deliver a different rear wheel offset. This somehow prevents e32 rear brake rotors from fitting e34. They also have different hub assemblies on the trailing arms (?). But we do know e32 rear brakes can be retrofitted without modification if using 540 rotors. However if one was prepared to change the trailing arms and whole axle carrier housing to M5/e32 parts it could be done using e32 rotors. The question then is; what happens if you do not change the whole axle carrier (but do replace the trailing arms with M5 versions (for example attempting to attain M5 rear wheel geometry)- what difference would you get in rear wheel track and would the alignment come into spec?

That is what I am chasing here; what is actually required to adjust the rear wheel alignment into the M-technik alignment specification?

I don't know if the rear track is different between M5 and standard e34 (and one has to be careful to remove any differences in wheel offset as they have different offset rims), but this may actually be the only reason why the axle carrier housing is (and for that matter the trailing arms) different. Perhaps it was done to allow for the staggered wheels offered on M5 and all one has to do to get M-tech suspension geometry on a stock e34 is change to the M5 bushings after all!

I guess to find out, one would need to have all the parts and be able to compare them.

[genphreak]

Sweet Jeff. That's good news. So M trailing arms fit the standard e34 axle carrier housing (as well as the M5 and 740/.750 housing)! Was this a reliable source and how does the car then align ie as an M5? This swap would include the M-bushings too I guess as arms are supplied with the bushes...

So if this is reliable info, the question remains whether this varies the vehicle's track at all, or whether the axle flange/hubs are part or wholly responsible for this... (and whether e32 rear rotors fit of course...)

This would certainly give us some good choices at the bone-yard! :) Nick