Suspension refresh and upgrade - parts list and where to buy

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janijoeli
Joined: Wed 26 Jun, 2013 16:51
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  M roadster S50
Location: Isojoki, Finland
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Suspension refresh and upgrade - parts list and where to buy

Post by janijoeli » Wed 27 Aug, 2014 17:10

After a long 7k mile roadtrip, including some serious abuse on unbelievably rubbish Norwegian roads, my M Roadster needs a suspension refresh. It has started tramlining, the rear end is restless to say the least, there are some random clunks from the rear, etc. While refreshing, I wouldn't mind doing some upgrading as well, however this is still 100% road car, so I try to keep the suspension pretty close to stock what comes to firmness, travel etc.

I don't plan on lowering the car, as it is definitely low enough for me, especially with Strong Struts rear and body braces installed, thus I will be keeping the stock springs. However for shocks, I've just ordered a full set of highly rated Bilstein B6s for 640€ incl. shipping from MK-Fahrwerkstechnik. Apparently B8 is pretty much the same as B6, but just shorter and meant for cars lowered for 30mm or more. For others using this as a refresh guide but also wanting to change springs - apparently H&R 29520 springs work very well with both B6 and B8 shocks.

REAR:
After quite a lot of searching here and on The Interwebs generally:
- Shock mounts - Rogue Engineering's ones seem to be a popular upgrade. What is the best place to order them from? I'm in Finland at the moment, so euro priced EU sources are okay, even preferable. Any other suggestions than Rogue? Ireland Engineering seems to offer billet shock mounts with poly inserts, does anyone have these?
- Subframe bushes - widely regarded as the "best bang for the buck" suspension upgrade, especially Ireland Engineering's poly bushes. Where to buy, or other suggestions?
- Anti roll bar (ARB) bushes - mine have a bit of play, so worth changing. Which ones should I go for and from where?
- ARB drop links (also called stabilizer links) - again, which ones and from where?

Is there anything else worth changing, or anything I'd need to order in addition to the items above to complete installation?

FRONT:
Now for the front... I'm much more lost than with rear. :) I guess OEM front shock mounts are fine (and completely reusable), as I haven't seen any aftermarket upgrades? Anything in the front that commonly wears out quickly, and any suggested upgrades (e.g. poly kits)? How about front ARB drop links?

I'll update the above based on suggestions, so that it will hopefully be useful to other forum members refreshing/upgrading their suspension in the future. :)
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Mike123
Joined: Tue 21 Mar, 2006 14:34
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  M roadster S50
Location: Leamington Spa

Re: Suspension refresh and upgrade - parts list and where to

Post by Mike123 » Wed 27 Aug, 2014 23:05

It's always a bit daunting trying to improve a car developed by the M Division. I've just gone through a very similar exercise, reaching almost identical conclusions, and now there's a mixture of relief and delight that the car is riding as well as ever, if not better, and the handling is significantly improved.

Bilstein B6s from the same supplier
H&R springs and 28mm front ARB (original rear ARB), also from Germany
Rogue rear shock mounts
Front polybush set
OEM front shock mounts (badly worn at 93k miles) and drop links all round.
Falken 453s

I haven't changed the rear subframe mounts.

The car feels really well balanced, great turn in, no tramlining whatsoever, no discernible roll even on a very tight track, great traction. Just about perfect!

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janijoeli
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Re: Suspension refresh and upgrade - parts list and where to

Post by janijoeli » Thu 28 Aug, 2014 12:38

Great info, thanks Mike! My conclusions are at least partially, if not mostly, based on your conclusions in your "A little treat" thread.. :D What you wanted from your car is pretty much what I want from mine, although I won't be taking mine to track (although never say never!). I'll keep the stock springs and ARBs for now, but want to replace worn shocks, 16+ year old rubber bits and other consumables, and hopefully with more durable parts.

If you don't mind me asking, where did you buy the Rogue shock mounts and front polybush kit? I was thinking of ordering Rogue mounts directly from them, but their checkout sucks big time. Also, Finnish customs is a bit anal about non-EU purchases, so I probably wouldn't be able to sneak them into country without paying extortionate customs fees and 24% VAT on top of everything...

Did the Bilsteins come with all rubber gaskets etc. needed for shock replacement, or did you need to buy anything separately?

Btw, does anyone have experience of eBay stabilizer/drop links (Mapco etc)? Or know any worthy upgrades (i.e. longer life parts) compared to OEM?
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Joycey
Joined: Mon 11 Jul, 2011 23:15
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  M roadster S52
Location: Basingstoke

Re: Suspension refresh and upgrade - parts list and where to

Post by Joycey » Thu 28 Aug, 2014 13:54

Just for info,

When i refreshed my M the parts i ordered were as follows:

Koni adjustable shocks (deamon Tweaks)
Black diamond brakes / braded hoses
Was on standard springs later changed to Apex 35mm springs
Re inforced rear top mounts from ebay.
Powerflex bushes all round.

This was all ordered with no expense spared using preferred suppliers.

However on another z3 overhaul i just finished to a budget:

Sachs shocks and standard springs (Euro car parts)
Standard mounts
Standard bushes

Parts came in at £350

Lee
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Mike123
Joined: Tue 21 Mar, 2006 14:34
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  M roadster S50
Location: Leamington Spa

Re: Suspension refresh and upgrade - parts list and where to

Post by Mike123 » Thu 28 Aug, 2014 14:25

The Rugue mounts were directly from Rogue Engineering in the US - I couldn't find a local supplier. The Powerflex bushes were bought through eBay, although I can't see an equivalent current item - Larkspeed are stockists and usually helpful. The front polybushes are easy, the rears a bigger job, so I didn't bother. I would check track rod arms at the same time, and you will need to get wheel alignment reset at the end.

The Bilsteins were complete apart from the top mounts.

I regretted not changing my springs at the same time once I'd found out how much better the H&R progressive springs were than the tired (and broken!) originals. They state that they lower the car by up to 30mm, but in practice the lowering was minimal - maybe the originals had sagged, and the ride comfort better than new.

As I said, I'm really happy with the set up now, and can't feel any rear end issues, but interested in your comment about the rear subframe mounts - I'll look into them.

Best of luck!

roadvoyager1
Joined: Sun 19 Jan, 2014 18:30
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  Z3 roadster 2.8

Re: Suspension refresh and upgrade - parts list and where to

Post by roadvoyager1 » Fri 29 Aug, 2014 08:49

I have a pre-facelift 1999 2.8ltr which runs on stock (mainly original) suspension and 16" wheels. At almost 80K miles I am thinking it will soon be time for a suspension refresh. The car is for road use and must be comfortable for 200+ mile runs.

It would seem that almost all of the above posted recommendations for a Z3M would be applicable to a 2.8. Are there any additional items that I should consider (strut and body brace excepted)?

Del
Joined: Sat 19 Nov, 2011 18:35
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  Z3 roadster 1.9

Re: Suspension refresh and upgrade - parts list and where to

Post by Del » Fri 29 Aug, 2014 10:37

It depends on the size of your wallet and the features you want from your non-M car. The original shocks were Boge/Sachs which are identical to the Sachs Super Touring sold via Euro car parts. I'm sure that just replacing four shocks after 80k miles you would notice a huge improvement (as I did). I would also replace the original (Lemfoder) droplinks as my experience is that the rear droplinks in particular will also be very tired after 80k.

Whether you replace every rubber bush (which is in decent condition) with polyurethane ones is really a matter of opinion, when it comes to comfort/road use for a non-M car. The bush which seems to be the most troublesome is the bush at the back of the front control arm - that tends to be a favourite for replacement (non-M cars).

I've changed my ARB rubber mounts as well - using OE BMW items. However, on close inspection they appeared to be made from high quality neoprene type rubber which hadn't degraded much at all - the old ones still looked fresh.

If the car sits level and the coil springs are in good condition i.e. have most of their black coating intact, one could argue that there is no need to change them. As I said - it depends on the size of your wallet. :)

roadvoyager1
Joined: Sun 19 Jan, 2014 18:30
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  Z3 roadster 2.8

Re: Suspension refresh and upgrade - parts list and where to

Post by roadvoyager1 » Fri 29 Aug, 2014 20:29

Thanks Del,

I will see if there are any other opinions posted, but a basic restore to original seems to be your advice. My wallet would be happy with this as it will also need to fund a cooling system (pump, belts and hoses), exhaust (fully replacement) and brake (rear calipers/discs-front already done, plus flexi hoses all round) refresh before too long.

I know the old saying is that "If it ain't broke don't fix it" but when it comes to cars of a certain age/mileage I think it is best to anticipate what is likely to break and fix it before it lands you with a big bill. Is there anything else I should add to the list?

Del
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  Z3 roadster 1.9

Re: Suspension refresh and upgrade - parts list and where to

Post by Del » Fri 29 Aug, 2014 22:42

roadvoyager1 wrote: but a basic restore to original seems to be your advice
It's really up the owner. One could spend a lot of money on suspension. I'd probably spend more if I had a Z3M.

I forgot to mention shock top mounts. It's good practice to replace the rear top mounts - I used the Meyle HD ones which are widely available on ebay with a target price of up to £20 per pair. Many owners have used these and been happy, Lemforder (OE maker ?) ones via carparts4less cost a bit more. For the front bearings/strut mounts the premium choices are probably either Lemforder again or a top bearing manufacturer like SKF. :)

Kornknarr
Joined: Fri 05 Aug, 2011 20:07
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  M roadster S50
Location: Uppsala, Sweden
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Re: Suspension refresh and upgrade - parts list and where to

Post by Kornknarr » Sun 31 Aug, 2014 08:53

I changed my suspension last vinter to H&R lowering springs and matching Bilsteins. I am very satisfied. The car is well planted on the road, and looks much better. It does eat more tire on the inside on the rears since I have not added any possibilities to change camber.

The vinter before I put on Rogue rear upper mounts, but also did a major overhaul of the rear end including welding in of a Randy Forbes kit due to popped spot welds and torn crossmember and differential mount. I take for granted that you have checked your spot welds? In that process I also changed to PolyU-bushings all over the rear (Ireland engineering for the subframe). I had to change back to rubber though this year for the the rear trailing arm because the squeaking were driving me nuts!

Living in Sweden I ordered directly from the US (Rogue and Ireland engineering) or from Swedish dealers. The RF-kit I bought trough a Swedish guy who import a few each year. Otherwise Schmiedman.se is a good retailer of all BMW-things in Sweden, and it ought to work also for you in Finland I guess?

Per
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janijoeli
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Re: Suspension refresh and upgrade - parts list and where to

Post by janijoeli » Sun 31 Aug, 2014 11:12

Thanks for all the brilliant info chaps!

Spot welds were re-welded in April before I left UK, however I don't know if I was partially scammed. I told them to seam weld everything, but the only thing I can see is the repair work in the boot, underside of the car looks completely untouched. And they charged over £400 for it. :/ One job I want to do while refreshing the suspension is to check the underside, and seam weld / strengthen everything.

So far I've ordered Bilstein B6s from MK-Fahrwerkstechnik as mentioned before, and rear shock mounts directly from Rogue Engineering. ARB bushes, drop links, outer tie rod ends (thanks for the tip Mike!) and other OEM bits and bobs are on their way from Schmiedmann Finland. I'm still trying to find a EU dealer selling Ireland Engineering subframe bushes, as the price of the delivery from US is about the same as the price of the bushes themselves! Add customs and VAT on top of everything, and the price of the bushes will triple. :evil:
Mike123 wrote:OEM front shock mounts (badly worn at 93k miles)
Mike, which bits of the front shock mounts were worn? I've had a look at this:
http://bmwfans.info/parts-catalog/Z3-Ro ... ing_parts/
I'm guessing only a few items of those need to be replaced?

Once I have completed all my shopping, I'll update the original posting.
Last edited by janijoeli on Fri 05 Sep, 2014 08:40, edited 1 time in total.
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Kornknarr
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Re: Suspension refresh and upgrade - parts list and where to

Post by Kornknarr » Sun 31 Aug, 2014 18:46

I'd might go for another source for the subframe bushings, I received a rather poor quality one from IE. I had some trouble and waiting time to get it corrected. I know they have a good reputation in the US, so it can have been a rare mistake on their part.
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Mike123
Joined: Tue 21 Mar, 2006 14:34
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  M roadster S50
Location: Leamington Spa

Re: Suspension refresh and upgrade - parts list and where to

Post by Mike123 » Sun 31 Aug, 2014 22:47

[quote=Mike123]OEM front shock mounts (badly worn at 93k miles)[/quote]
Mike, which bits of the front shock mounts were worn? I've had a look at this:
http://bmwfans.info/parts-catalog/Z3-Ro ... ing_parts/
I'm guessing only a few items of those need to be replaced?

Just Item 1 on the diagram - the ball bearings were shot.

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janijoeli
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Re: Suspension refresh and upgrade - parts list and where to

Post by janijoeli » Fri 05 Sep, 2014 09:45

Great, thanks again Mike!

Kornknarr, thanks - I've been looking at alternatives, mostly due to the poor availability and high price of IE bushings. I cannot imagine Powerflex equivalents being much different or worse, so might go with them. Another option is AKG motorsport bushings which I just saw a thread about, but don't know too much about them yet.
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