[G82Dude]

Bad idea given xDrive's tolerances and hardware. Don't you think BMW would have already done it with their "M Sport" models?

[Tengocity]

Originally Posted by uke92dude

Bad idea given xDrive's tolerances and hardware. Don't you think BMW would have already done it with their "M Sport" models?

Not necessarily. From a marketing perspective they want RWD to be seen as the performance car option as it's a BMW brand position. They market xdrive as being about safety and security, and is massively popular in the Snow belt of the USA and Alpine countries. So extra clearance for snow and snow chains makes sense.

Also, note that Alpina have a xdrive F30 models and they do not have a raised ride height, so it clearly is feasible from a technical perspective, and I doubt they've done much more from a mechanical perspective than fir lower springs and better dampers. They may have been able to adapt the xdrive ECU though, which would deal with Highland Pete's thoughts perhaps.

[Waitey]

Now I've got my 335d and had it on a ramp, I see no harm in all at fitting the full 330d S drive set up to it. I'd be willing to be BMW wouldn't even notice.

The ride in the 335d is far better than the 330d S drive I had on loan though for what I do. So I won't be changing it.

[F30AM]

Originally Posted by Waitey

Now I've got my 335d and had it on a ramp, I see no harm in all at fitting the full 330d S drive set up to it. I'd be willing to be BMW wouldn't even notice.

The ride in the 335d is far better than the 330d S drive I had on loan though for what I do. So I won't be changing it.

Standard suspension with the extra ride height over sDrive M Sport = more wheel travel + a bit more roll-y poll-y. sDRive with adaptive seems the best compromise

[Waitey]

Originally Posted by F30AM

Standard suspension with the extra ride height over sDrive M Sport = more wheel travel + a bit more roll-y poll-y. sDRive with adaptive seems the best compromise

S drive is far too over damped. Bordering on uncomfortable on the roads round here.

Sadly the masses equate hard to equal sporty. I've driven more forgiving race cars than M sports.

20mm X drive ARB's versus 24.6mm M sport ARB's play a lot in the roll stakes.

[HighlandPete]

Originally Posted by uke92dude

Bad idea given xDrive's tolerances and hardware. Don't you think BMW would have already done it with their "M Sport" models?

I wonder about this as well.

You would think BMW would have offered the same M-Sport suspension package in the 335d xDrive, if it was simply just fitting it. Particularly as in the UK the 335d is the most sought after performance 3-series.

Would appear it is a case of fitting the 330/335d engines in an already developed xDrive chassis, (all markets) rather than take it one step further.

Alpina on the other hand, will 'out of the box' develop their own chassis characteristics, xDrive (we imagine) is an integral part of that honed chassis. Alpina typically have a more 'supple' set of working parameters, may be a lowered chassis, but still retains more suspension compliance than the typical M-Sport settings.

As Waitey says, we don't have to "equate hard to equal sporty", maybe a firmer ride/handling package just doesn't add anything to the real performance. Perhaps Alpina have been left to fill the small niche of offering the sportiest xDrive 3-series at present.

HighlandPete

[Happy Williams]

Hi guys, I have spoken to hartge, h&r & eibach, they all have specific springs for the 335d lowering around 25mm... Perfect! I have also spoken to Kevin Bird BMW specialist who has a demo car already done albeit a f32. Anyway, I'm going tomw to seem them with a view to getting booked in ASAP! Boom! Lol

[Tengocity]

Originally Posted by Happy Williams

Hi guys, I have spoken to hartge, h&r & eibach, they all have specific springs for the 335d lowering around 25mm... Perfect! I have also spoken to Kevin Bird BMW specialist who has a demo car already done albeit a f32. Anyway, I'm going tomw to seem them with a view to getting booked in ASAP! Boom! Lol

I don't think Kevin's car is an xdrive is it? I'm sure he told me he had a 435i coming. Following with interest!....

[Happy Williams]

We'll I'll find out more tomw and let you know, I spoke to Kevin and he gives a 3 year warranty, he assured me of no issues whatsoever with the 335d, I'll take before and after pics anyway and let you all know, I'm only after a subtle drop do bring inline with my previous e92 335d, looks so much better! I really can't see it affecting traction etc, but I'm willing to try anyway, worse case scenario is I swop it back but can't see that happening!! Exciting eh!!?

[Tengocity]

Exciting indeed! Good to see when people actually do the mods rather than just talk about them! (like me)

If I do it then I would probs do the ARBs at the same time and hopefully save a little labour costs. That change involves dropping both front and rear subframes, so takes a bit of time. However I do think it could add a little extra turn in agility. Not worth doing if it is just the cosmetic change one is after though!

[G82Dude]

Originally Posted by Tengocity

Not necessarily. From a marketing perspective they want RWD to be seen as the performance car option as it's a BMW brand position. They market xdrive as being about safety and security, and is massively popular in the Snow belt of the USA and Alpine countries. So extra clearance for snow and snow chains makes sense.

Also, note that Alpina have a xdrive F30 models and they do not have a raised ride height, so it clearly is feasible from a technical perspective, and I doubt they've done much more from a mechanical perspective than fir lower springs and better dampers. They may have been able to adapt the xdrive ECU though, which would deal with Highland Pete's thoughts perhaps.

This was the opinion of a mechanic - I kinda take on board his view. xDrive hardware not designed on 3, 4 for the reduction in suspension travel for M Sport, nothing to do with marketing.

[G82Dude]

Originally Posted by HighlandPete

I wonder about this as well.

You would think BMW would have offered the same M-Sport suspension package in the 335d xDrive, if it was simply just fitting it. Particularly as in the UK the 335d is the most sought after performance 3-series.

Would appear it is a case of fitting the 330/335d engines in an already developed xDrive chassis, (all markets) rather than take it one step further.

Alpina on the other hand, will 'out of the box' develop their own chassis characteristics, xDrive (we imagine) is an integral part of that honed chassis. Alpina typically have a more 'supple' set of working parameters, may be a lowered chassis, but still retains more suspension compliance than the typical M-Sport settings.

As Waitey says, we don't have to "equate hard to equal sporty", maybe a firmer ride/handling package just doesn't add anything to the real performance. Perhaps Alpina have been left to fill the small niche of offering the sportiest xDrive 3-series at present.

HighlandPete

They should do what they do on the X5 - put adaptive on as standard in lieu of M Sport suspension for xDrive vehicles

[dopper99]

Originally Posted by Happy Williams

We'll I'll find out more tomw and let you know, I spoke to Kevin and he gives a 3 year warranty, he assured me of no issues whatsoever with the 335d, I'll take before and after pics anyway and let you all know, I'm only after a subtle drop do bring inline with my previous e92 335d, looks so much better! I really can't see it affecting traction etc, but I'm willing to try anyway, worse case scenario is I swop it back but can't see that happening!! Exciting eh!!?

Sounds very interesting.

So, how much will this cost to lower it?

[Happy Williams]

Hi Guys, yep I've had the opinion of several BMW specialists who have been In business for decades, as I said in an earlier thread also, I done 2k miles through France with 400kg of load in my car, it performed faultlessly even with a very heavy right foot! The wheels were under the arches it was that low so I personally cannot see an issue with dropping around 25mm. The system is clearly designed to be used at all angles of travel by bmw.

[Happy Williams]

Btw, will cost around 750 with a 3 year warranty!

[Cootie]

Originally Posted by Happy Williams

Btw, will cost around 750 with a 3 year warranty!

Look forward to your review as I could be very tempted to go down this route myself.

[HighlandPete]

Originally Posted by Happy Williams

Btw, will cost around 750 with a 3 year warranty!

What is warranted? The whole suspension and xDrive system? Any consequential damage included? If so, that is a pretty good warranty for fitting basic aftermarket parts.

HighlandPete

[HighlandPete]

Originally Posted by Happy Williams

Hi Guys, yep I've had the opinion of several BMW specialists who have been In business for decades, as I said in an earlier thread also, I done 2k miles through France with 400kg of load in my car, it performed faultlessly even with a very heavy right foot! The wheels were under the arches it was that low so I personally cannot see an issue with dropping around 25mm. The system is clearly designed to be used at all angles of travel by bmw.

I see where you are coming from and you are clearly looking for whether it works 'mechanically' at a lower ride height.

My comments in earlier posts are more to the xDrive capability and sensitivity.

If I put on my engineering "R&D hat" and imagine being given this problem as a design study, I'd not just be looking at the integrity of the mechanical function. As you guys are buying into xDrive for the xDrive capabilities, what is happening to xDrive function with a lowered and stiffer chassis?

I'd be starting with what is happening at software level and how a lightly loaded car, (just the driver) effects the weight transfer around the car and front to rear drive ratio, in all the conditions BMW have tested and honed the software to suit.

I don't know the answer, I'm sure your average 'specialist' hasn't any data either. Probably hasn't even thought to test or address any differences in the xDrive performance across a wide range of parameters.

If they have, then they'll have some data to pursue and study, to see where there are changes. They'll have a tested baseline and be mapping the variations around the BMW designed benchmark.

xDrive isn't like a simple RWD layout, where you have only two wheels to sort the grip. Guys like Kevin Bird clearly know how RWD is best sorted, which includes careful honing of spring, damping and ARB rates, or grip is compromised. I wonder if that expertise has been gained for xDrive, or are we still all in a learning curve?

I'd love to see some serious data gathered from track testing "before and after", to see whether it does change how xDrive works in various conditions such as aggressive cornering, on and off the throttle, slalom manoeuvres, etc. etc.

Interesting subject from my engineering perspective.

HighlandPete

[dopper99]

Also, how does lowering affect the active dampers? A lot of people come on here and say "its makes no difference" - but on what evidence? No doubt BMW have designed the active dampers to work for the range of the current spring height and rate? Or maybe 20-25mm drop really does make no difference?

[Waitey]

I won't lower an adaptive system on an X drive, without fitting the adaptive dampers from a S drive.

[HighlandPete]

Originally Posted by dopper99

Also, how does lowering affect the active dampers? A lot of people come on here and say "its makes no difference" - but on what evidence?

Forum evidence doesn't always have an engineering perspective. Car looks good, still goes well, after a "suck it and see" approach. User is satisfied... easy to say it "makes no difference".

Can go the other way, a product gets rubbished when users go beyond the design parameters. I fitted Koni FSD dampers to my E91, they worked as described by Koni on my stock suspension. The solution I was after. I know other users rubbished them for not working, or having odd characteristics... wearing fast, even leaking... why? They wanted more from the product, the refined ride and tighter handling, but were adding lowered springs, even hitting the bump stops. No wonder they didn't work correctly, as they were not designed to work on short, restricted stroke applications. Koni were quite specific on their limitations, wasn't the product at fault, but a "user adapted" application.

HighlandPete

[dopper99]

My guess that changing springs in an xdrive will probably have no obvious detrimental affect in the short term. But long term? Who knows. Depends on how long you want to keep the car or how many miles you do.