KWs and non-standard wheels - inner/outer clearances?

[MrPT]

Hi,

Pulled the trigger on some OEM CSLs prior to getting my Z4MC and may have jumped the gun. It currently sits on KW V3s and 224s with 10mm spacers all round.

The front spacers mean that the 224s clear the V3 springs. The outer arch liners are rubbed clean through on both fronts, but I don't know whether this is from the current setup or a previous one. I haven't noticed any rubbing on full lock. Outer clearance looks marginal, but the drop is pretty big at the moment - maybe 2-3cm below stock - and I'm going to take it back up a little at some point. A shame, but speed bumps and rough B roads are just too dicey at the moment.

The problem I'm facing is that 19 x 8.5 CSL front rims (ET44) will reduce the clearances by the following amounts, relative to the spaced 224s:

• No spacer (ET44): 18mm LESS clearance inside / 6mm LESS protrusion outside
• 10mm spacer (ET34): 8mm LESS clearance inside / 4mm MORE protrusion outside

So the front CSLs won't clear the springs without a spacer and 10mm doesn't look like it'll be enough (only 2mm more inside clearance than stock 224s). CSs probably would have worked well, lolz... :roll:

For people who are running KWs on here - what are you doing, spacer-wise, and have you found an acceptable setup for 8.5" fronts which clears the arches on the outside (at full lock) and the springs on the inside? The shape of the V3 springs could be a factor because they are non-linear and therefore a bit fat.

At this point in time I'm actually thinking that I'll sell the CSLs (they are brand new and boxed) and buy ARC-8s. The car came with nearly new PSS all round, so it'd be good to re-use the tyres and keep my 224s for winter usage. The ARC-8s don't look quite as good, but are clearly an awesome wheel. These are the front clearances vs. the spaced 224s:

• No spacer (ET38): 12mm LESS clearance inside / same protrusion outside
• 10mm spacer (ET34): 2mm LESS clearance inside / 10mm MORE protrusion outside

If I re-use the tyres it'll mean a 225 section on an 8.5 rim instead of the obvious choice of 235, so this will help the arch clearance and I suspect will be ok if I also take the ride height up. I also looked at a square (19 x 9.5 all round) setup because of the aggressive front offsets, but that's a little too much poke for me!

Thoughts?

Cheers,

P.

 

[TomK]

If you're interested I have a set of cs's for sale...
http://www.z4-forum.com/forum/viewtopic.php?f=7&t=81527

 

[MrPT]

If you're interested I have a set of cs's for sale...
http://www.z4-forum.com/forum/viewtopic.php?f=7&t=81527

Thanks Tom. I did post in that thread earlier - lovely wheels - and yes, they are quite tempting.

Just stuck a camera up behind the front right. Clearance actually looks pretty good at the moment. Does anybody know how much the spring perch moves, relative to the sidewall, when the car is in motion? I'm just wondering whether there's a rule of thumb (vs the static clearance) to allow for any mechanical play + geo changes when steering. As it is it looks like I could get away with 5mm less clearance on the inside, assuming the perch doesn't rub, and I raise the ride height enough to clear the spring under compression.

 

[Mister T]

There shouldn't be any movement at all.

 

[MrPT]

There shouldn't be any movement at all.

Cool, thanks. So it's just the spring rub to be wary of.

I've decided to sell my CSLs and try and make 18s work. As well as the ARC-8s, EC-7s in Anthracite are starting to look pretty tasty. 8)

 

[Beedub]

Mr PT....

Aim for 4mm clearance between the perch and tyre, thats the kw stated distance, looks relatively close but it won't contact.... The KW perch sits right inline with the tyre so causes some clearance issues as you've found out.

Aim for an an 8.5 , ET32. this will give the inner clearance you need and no rub issues on the fender without having to run silly amounts of neg camber, you will need to lift the car slightly, its too low. You can get some nice cheap camber shims for the bottom bolts of the strut bolts that will give you some decent neg camber without needing expensive camber plates.

i keep getting emails asking how i get my front 8.5 ET28s to work, LOTS of camber, lots lots of neg camber, works really well for my application on the car , a couple of members have now purchased the same wheels as me and say they have zero rub without that aggressive geo setup??? wrong, it will rub and it will rub enough the blitz the fender liners very quickly if you drive the car as intended, your OP proves exactly the issue.

Fwiw mine doesn't touch anywhere and has plenty of strut clearance from the rim / tyre. Ive had 3-4 different wheel sizes on clubsports so can help you here, PM if you need specifics

 

[MrPT]

Cheers Beedub - great info, as always.

I can believe 8.5/ET28 rubs with standard geo. That's like running a 20mm spacer on the stock fronts! Looks like the CSLs will actually fit ok with a ride height increase and maybe 12mm spacers (to bring them to ET32).

Do the shims go behind the stub axle or literally just on the the lower strut bolts?

 

[Beedub]

Cheers Beedub - great info, as always.

I can believe 8.5/ET28 rubs with standard geo. That's like running a 20mm spacer on the stock fronts! Looks like the CSLs will actually fit ok with a ride height increase and maybe 12mm spacers (to bring them to ET32).

Do the shims go behind the stub axle or literally just on the the lower strut bolts?

even noe stock geo it will rub, it need quite an aggressive setup to work well, not a DD-able setup. So when i see the Us guys putting 9.5 up front with 265 and sating zero rub, i find it very hard to believe. infact i don't believe. at all.

literally on the lower bolts.... Google turner camber shims for e36.

 

[BMWZ4MC]

I have KW Clubsports and run 5mm spacers with my CSLs, 12mm with my 224s and no spacers with my track wheels.
I have camber plates which enable me to modulate the distance of the wheel from the arch liner so the spacers are purely to prevent rubbing inboard of the wheel. I get minimal rubbing of the arch liner at full lock with the CSLs in my current set up, but I run less negative camber with the CSLs as these are my road wheels and I want to reduce tram lining and uneven tyre wear.

 

[MrPT]

I have KW Clubsports and run 5mm spacers with my CSLs, 12mm with my 224s and no spacers with my track wheels.
I have camber plates which enable me to modulate the distance of the wheel from the arch liner so the spacers are purely to prevent rubbing inboard of the wheel. I get minimal rubbing of the arch liner at full lock with the CSLs in my current set up, but I run less negative camber with the CSLs as these are my road wheels and I want to reduce tram lining and uneven tyre wear.

Thanks - your MC looks awesome! I think this highlights the problem with the V3s and an 8.5" front rim. The springs rub because they have a conical shape, unlike the Clubsports, which is why you can probably get away with 5mm spacers on your CSLs and retain conservative camber settings. I'd need 12mm spacers on the CSL fronts to be safe and that would mean that the wheels protrude 16mm relative to stock.

So at this point I need to raise the car a little and take some measurements. I'll probably take it up to the stock heights and baseline the inner clearance. This is what the current drop looks like:

Ideally I'll end up somewhere around the Eibach Pro drop (-2cm front / -1cm rear). At the moment it looks like 2-3cm all round.

 

[MrPT]

So, say ET32 is on the money for the fronts, would you go for:

18 x 8.5 ET35 with a 3mm shim and OEM bolts (looks to be about the limit on these)
18 x 8.5 ET45 with a proper 12mm Hubcentric spacer and extended bolts

?

 

[Beedub]

or get kw to send you a linear spring for the front as per the clubsport, it bolts right up!!! easy fix and cheaper than the wheel change!

 

[RedUn]

I agree, it has been confirmed that the dampers are identical on the V3 and Clubsports, new springs and top mounts - sorted

 

[Beedub]

I agree, it has been confirmed that the dampers are identical on the V3 and Clubsports, new springs and top mounts - sorted

pretty certain thats incorrect but seems two of us have had some differing conversations with KW...

http://www.kwsuspensions.co.uk/kw/info/coil_overs/

 

[Mister T]

You'll probably find that the shock bodies are the same for the V3 and Clubsport 2-way, but I'd expect the internal damping to be different.

 

[MrPT]

Either way, I think I'd prefer to stick to progressive springs and work around this fitment issue. The ride is pretty good at the moment. The car will be used for the usual road trips (LM24, F1, Rally GB etc) and as a weekend B-road muncher. My view isn't a particularly well informed one (although getting better all the time thanks to you guys!), but I think it's a safe assumption to say that KW put progressive springs on the V3 and linear ones on the Clubsports for a reason. Most people who buy Clubsports track their cars regularly, whereas I am going to be doing nothing this year and maybe only one track day next year.

 

[Beedub]

You'll probably find that the shock bodies are the same for the V3 and Clubsport 2-way, but I'd expect the internal damping to be different.

pretty much what i was told....

 

[RedUn]

would you like me to copy the email kw sent me when i asked this very question..... ??? i'll take the word of the guys building the units.... :evil: :evil:

Well, to shed some light on this matter once and for all I had contact with KW's developmentdepartment in Germany, and it's even a bit different than I thought:

Apart from the front springs, the shocks are exactly the same!
So the dimensions, construction and valving are the same.
This is both for the z4m and normal z4.
So if you have V3 for a normal z4, all you need is a (or 2; for each front shock 1) 170mm spring with 70N/mm springrate to turn it into a clubsport set.

And if you have a V3 for z4m, you need 2 170mm 70N/mm springs, 2 helper springs, 2 upper springcups and 2 springrings (ring between helper and mainspring).

But as valving is the same, you could also use the 170mm 50N/mm springs on a z4m clubsport set, so then you have the same V3 configuration as the z4 has with lineair springs.
I think that's cheaper than turning the z4m (progressive) V3 kit into a lineair kit as you don't need to buy the helpersprings, springcups etc etc (but I haven't calculated that..)

So that's it. They made it much simpeler for us than we could have ever imagined :lol:

Indeed as for settings, start with the 'recommended setting', which is the knobs about in the middle (exact position is in the booklet).
I set mine only on the front 3 clicks heavier on bump, and 2 clicks heavier on rebound. (that was the first setting I tried to get rid of a tiny bit more cornerdive in the front, and it was to my liking. It was not a long trial and error process....)

I've no reason to believe or not to believe this...seems logical to me, not all V3s come with progressive springs, my set on a previous car had linear all round as standard off the shelf V3s

FWIW, the ride was spot on, I'd happily run linear all round on the road