F31 340i Touring - coilover options?

[tomprestriidge]

I’ve collected a 2017 340i Touring and it’s got the M Performance splitter, side skirts, and rear diffuser. The car is currently on its stock suspension, so it sits quite high, which doesn’t compliment the body styling bits.

I’ve also just come from a 2016 M240i, so the 340i feels softer and less keen to turn in. I don’t want to lose more than, say, 25% of the ride comfort, but would appreciate improved turn in.

I’ve done a little research into coilover options (I’ve never modified a car’s suspension before):

• - Bilstein B14 kit - Reputable brand at a decent price; I’ve seen another forum post that approves this kit () and the ride height looks great.
• - HSD Dualtech kit - I’m aware of this kit as I follow DriftWorks on YouTube, so trust their experience, but am worried this kit will be too firm, and I’ve not seen any photos of F31s equipped with it.

I’m looking for a lower ride height without compromising too much ride comfort and quality. Budget is £1000.

Does anyone have any thoughts or experience?

[danb79]

tomprestriidge said:

I ve collected a 2017 340i Touring and it s got the M Performance splitter, side skirts, and rear diffuser. The car is currently on its stock suspension, so it sits quite high, which doesn t compliment the body styling bits.

I ve also just come from a 2016 M240i, so the 340i feels softer and less keen to turn in. I don t want to lose more than, say, 25% of the ride comfort, but would appreciate improved turn in.

I ve done a little research into coilover options (I ve never modified a car s suspension before):

• - Bilstein B14 kit - Reputable brand at a decent price; I ve seen another forum post that approves this kit () and the ride height looks great.
• - HSD Dualtech kit - I m aware of this kit as I follow DriftWorks on YouTube, so trust their experience, but am worried this kit will be too firm, and I ve not seen any photos of F31s equipped with it.

I m looking for a lower ride height without compromising too much ride comfort and quality. Budget is £1000.

Does anyone have any thoughts or experience?

I ran the Bilstein B14s on my previous E81 130i LE and they were superb; fitted as part of a full suspension overhaul (literally every part) with all new OEM BMW top mounts etc

I also run Bilstein B4S shocks with Eibach pro-kit springs on our F31 and for an every day car; that suspension is superb. Smooth, quiet; but handles and drives much better than OEM M Sport suspension did; plus it sits a lot better too

For £1k, personally; I'd go either the B14s if you can get them at that price with all new top mounts all round etc, or maybe consider the likes of the Bilstein B4S or B8 shocks with the Eibach pro kit springs and again, new top mounts all round etc

I personally wouldn't touch anything from HSD - they're cheap budget coilovers and your 340i deserves better

[tomprestriidge]

Thank you for the advice!

I was under the impression that B4 weren’t to be used with lowering springs, or have I misunderstood?

I’ve read that B4 with lowering springs reduce the life of the shocks; B6 and B8 are for lowering springs.

[Pizzaeatingking]

I really liked the B14s on my saloon. Rode well, less crashy than stock but certainly firmer, I ran them for 5 years without issue.

[danb79]

tomprestriidge said:

Thank you for the advice!

I was under the impression that B4 weren t to be used with lowering springs, or have I misunderstood?

I ve read that B4 with lowering springs reduce the life of the shocks; B6 and B8 are for lowering springs.

B4S are absolutely fine with the likes of Eibach pro-kit springs as they don't lower aggressively; 10-15mm max more than M Sport

B8s would be needed a) if you want a firmer ride and b) if you were to go with the likes of H&R springs or the Eibach Sportline springs which can lower 35mm or more - that's when B4s would be no good

This is our F31 as it stands:

[danb79]

Pizzaeatingking said:

I really liked the B14s on my saloon. Rode well, less crashy than stock but certainly firmer, I ran them for 5 years without issue.

They are superb; very tempted with them for my E39 - but want to see how I get on with the Sachs/Eibach combo first

[Cheddarbang]

I would personally stick to the tried and test B12 kit and save some cash.

Bilstein coilovers are the terrible for seizing up, which is useless on a daily driver.

The improvements to handling come from more than just struts/springs. Camber, tyre choice, body stiffening etc etc all come into play.

Doing just the struts/springs only addresses BMW's poor setup choices and damper quality of the stock M sport suspension.

There is a whole lot more on the table with the F3x platform to be tapped into, but with only £1000 budget, you're not ready to go down that rabbit hole.

[mmm-five]

Cheddarbang said:

I would personally stick to the tried and test B12 kit and save some cash.

Bilstein coilovers are the terrible for seizing up, which is useless on a daily driver.

The improvements to handling come from more than just struts/springs. Camber, tyre choice, body stiffening etc etc all come into play.

Doing just the struts/springs only addresses BMW's poor setup choices and damper quality of the stock M sport suspension.

There is a whole lot more on the table with the F3x platform to be tapped into, but with only £1000 budget, you're not ready to go down that rabbit hole.

I've had my B16s on my Z4MC for over 10 years and 60,000 miles...not seized up yet...but they're checked & cleaned every year when I get my annual Inspection I.

Maybe the cheaper kits are worse, or maybe Bilstein quality has degraded over the last decade...'cos Brexit

[danb79]

Cheddarbang said:

I would personally stick to the tried and test B12 kit and save some cash.

Bilstein coilovers are the terrible for seizing up, which is useless on a daily driver.

The improvements to handling come from more than just struts/springs. Camber, tyre choice, body stiffening etc etc all come into play.

Doing just the struts/springs only addresses BMW's poor setup choices and damper quality of the stock M sport suspension.

There is a whole lot more on the table with the F3x platform to be tapped into, but with only £1000 budget, you're not ready to go down that rabbit hole.

I know plenty of folk running B14s and B16s with zero issues. Look after them, clean them and treat them with the likes of BH DYNAX UC and they won't corrode nor seize...

Same with any coilovers really...

But don't do the above and they'll be fubar in a year or so...

And for me, the B12 kit on the F3x platform is just too stiff. Even with Eibach Pro kit springs.

I test drove an F30 330D with the B12 kit and it was superb on the country lanes when pushing on.. But driving back on normal roads doing normal speeds, and the car was bouncy and didn't take rough roads well at all... That was on 19s with Michelin non RFTs.

Everyone's different, but for every day driving and even pushing on, the B4S shocks with Eibach Pro kit springs work much better. Still firm, but have more compliance compared to the B12 kit

[Cheddarbang]

That is kind of my point. Who can be ar$ed to unwind the threads every year and relubricate the spring perches? That's why the B12 is better suited to daily drivers, and the inch or less of lowering keeps the roll centre sensible, and therefore bump steer to acceptable levels.

I don't believe any anecdotal "A mate of a mate's is fine" examples because I've been through many coilover brands and done all the anti seizing diligence, and they still effing seize up after the 2nd winter without fail, even the KWs with Inox bodies and composite perches.

If you use a car for 50-100 miles every day all year around, there is no way in hell coilovers don't seize up, unless you're out there regularly greasing the sodding things, or use some exotic greases like Metaflux.

19s and non-run flats is probably where you're going wrong then. I run 18" run flats and the B12 isn't bouncy in the slightest. Bouncy is a twin tube trait. Monotubes are the exact opposite. If the car is bouncing then either the dampers are shot, or its way over sprung.

B14s are over twice the spring rate of the B12, so I find it very hard to believe the B12 is crashy and the B14 isn't.

[Jamescrs]

I've seen on youtube recently people fitting a type of cover on coilovers to protect the threads and stop them seizing, I have no evidence they work but it seems like a good idea in theory

[Hammy98]

You can get sleeves/jackets which go over the coilovers to stop the elements getting into them, seen it recently on one of TopDeadCentre's YT videos. Should keep them from seizing.

[danb79]

Jamescrs said:

I've seen on youtube recently people fitting a type of cover on coilovers to protect the threads and stop them seizing, I have no evidence they work but it seems like a good idea in theory

Yes; coilover socks...

Issue is that the coilovers need to be fully cleaned, dried thoroughly and then treated before they're covered - this is something my pals see a lot of; where they haven't done that, but fitted them anyway, and then they're seized/corroded etc

They do work; but they're not fully water proof; so need to be removed and the coilovers cleaned every so often...

I'd rather stick to the likes of Dynax UC; its tried and tested stuff and does a great job

[danb79]

Cheddarbang said:

That is kind of my point. Who can be ar$ed to unwind the threads every year and relubricate the spring perches? That's why the B12 is better suited to daily drivers, and the inch or less of lowering keeps the roll centre sensible, and therefore bump steer to acceptable levels.

I don't believe any anecdotal "A mate of a mate's is fine" examples because I've been through many coilover brands and done all the anti seizing diligence, and they still effing seize up after the 2nd winter without fail, even the KWs with Inox bodies and composite perches.

If you use a car for 50-100 miles every day all year around, there is no way in hell coilovers don't seize up, unless you're out there regularly greasing the sodding things, or use some exotic greases like Metaflux.

19s and non-run flats is probably where you're going wrong then. I run 18" run flats and the B12 isn't bouncy in the slightest. Bouncy is a twin tube trait. Monotubes are the exact opposite. If the car is bouncing then either the dampers are shot, or its way over sprung.

B14s are over twice the spring rate of the B12, so I find it very hard to believe the B12 is crashy and the B14 isn't.

I run 18s with non RFTs and the B4S and Eibach combo is firm enough; that's on Goodyear all-seasons too...

The B12s were very firm on my pals 330D; he loves it as he does rag it a lot as he travels to and from work via the back country lanes and only a small stretch of motorway - but he even admits that he needs to drop to 18s and will be doing when he needs to change tyres come Spring

And agree; I've run KW V1s and V2s a few times and they still corroded; my pals that have a motorsports garage up here in Preston have issues with KWs on a monthly basis... The only coilovers they rarely have issues with are Nitrons and Ohlins - but with them you get what you're paying for

I found the B14s on my 130i to be superb; but fitted and set up properly with corner weighting and a fast-road tracking & alignment; it drove superbly - again on 18s but with Protrack One wheels, at 8.3kg a corner, they made a difference in how the car drove on rough roads etc...

[Cheddarbang]

danb79 said:

Cheddarbang said:

That is kind of my point. Who can be ar$ed to unwind the threads every year and relubricate the spring perches? That's why the B12 is better suited to daily drivers, and the inch or less of lowering keeps the roll centre sensible, and therefore bump steer to acceptable levels.

I don't believe any anecdotal "A mate of a mate's is fine" examples because I've been through many coilover brands and done all the anti seizing diligence, and they still effing seize up after the 2nd winter without fail, even the KWs with Inox bodies and composite perches.

If you use a car for 50-100 miles every day all year around, there is no way in hell coilovers don't seize up, unless you're out there regularly greasing the sodding things, or use some exotic greases like Metaflux.

19s and non-run flats is probably where you're going wrong then. I run 18" run flats and the B12 isn't bouncy in the slightest. Bouncy is a twin tube trait. Monotubes are the exact opposite. If the car is bouncing then either the dampers are shot, or its way over sprung.

B14s are over twice the spring rate of the B12, so I find it very hard to believe the B12 is crashy and the B14 isn't.

I run 18s with non RFTs and the B4S and Eibach combo is firm enough; that's on Goodyear all-seasons too...

The B12s were very firm on my pals 330D; he loves it as he does rag it a lot as he travels to and from work via the back country lanes and only a small stretch of motorway - but he even admits that he needs to drop to 18s and will be doing when he needs to change tyres come Spring

And agree; I've run KW V1s and V2s a few times and they still corroded; my pals that have a motorsports garage up here in Preston have issues with KWs on a monthly basis... The only coilovers they rarely have issues with are Nitrons and Ohlins - but with them you get what you're paying for

I found the B14s on my 130i to be superb; but fitted and set up properly with corner weighting and a fast-road tracking & alignment; it drove superbly - again on 18s but with Protrack One wheels, at 8.3kg a corner, they made a difference in how the car drove on rough roads etc...

I think with the B14s/B16s, it can be car dependant on how well they perform. Harsh and horrible on some cars, but spot-on on others. Sounds like you got a winning match there.

As you say, ride quality is very subjective, but if anything I find the B12 slightly too soft on my 330d, lol. Well, it's spot on 95% of the time, but when pushing-on over summer, it could do with being a tad firmer. Maybe my roads are better, but it's hard to make an informed decision as there's too many variables.

Ohlins ride extremely well whilst making the car feel like it's connected to the road like a slab of granite......but their build quality isn't great. Not what you expect from Swedish products!

No experience of Nitron but I'm not paying their ridiculous prices, and from what I've seen review wise, they are way too stiff for road use.

[danb79]

Cheddarbang said:

danb79 said:

Cheddarbang said:

That is kind of my point. Who can be ar$ed to unwind the threads every year and relubricate the spring perches? That's why the B12 is better suited to daily drivers, and the inch or less of lowering keeps the roll centre sensible, and therefore bump steer to acceptable levels.

I don't believe any anecdotal "A mate of a mate's is fine" examples because I've been through many coilover brands and done all the anti seizing diligence, and they still effing seize up after the 2nd winter without fail, even the KWs with Inox bodies and composite perches.

If you use a car for 50-100 miles every day all year around, there is no way in hell coilovers don't seize up, unless you're out there regularly greasing the sodding things, or use some exotic greases like Metaflux.

19s and non-run flats is probably where you're going wrong then. I run 18" run flats and the B12 isn't bouncy in the slightest. Bouncy is a twin tube trait. Monotubes are the exact opposite. If the car is bouncing then either the dampers are shot, or its way over sprung.

B14s are over twice the spring rate of the B12, so I find it very hard to believe the B12 is crashy and the B14 isn't.

I run 18s with non RFTs and the B4S and Eibach combo is firm enough; that's on Goodyear all-seasons too...

The B12s were very firm on my pals 330D; he loves it as he does rag it a lot as he travels to and from work via the back country lanes and only a small stretch of motorway - but he even admits that he needs to drop to 18s and will be doing when he needs to change tyres come Spring

And agree; I've run KW V1s and V2s a few times and they still corroded; my pals that have a motorsports garage up here in Preston have issues with KWs on a monthly basis... The only coilovers they rarely have issues with are Nitrons and Ohlins - but with them you get what you're paying for

I found the B14s on my 130i to be superb; but fitted and set up properly with corner weighting and a fast-road tracking & alignment; it drove superbly - again on 18s but with Protrack One wheels, at 8.3kg a corner, they made a difference in how the car drove on rough roads etc...

I think with the B14s/B16s, it can be car dependant on how well they perform. Harsh and horrible on some cars, but spot-on on others. Sounds like you got a winning match there.

As you say, ride quality is very subjective, but if anything I find the B12 slightly too soft on my 330d, lol. Well, it's spot on 95% of the time, but when pushing-on over summer, it could do with being a tad firmer. Maybe my roads are better, but it's hard to make an informed decision as there's too many variables.

Ohlins ride extremely well whilst making the car feel like it's connected to the road like a slab of granite......but their build quality isn't great. Not what you expect from Swedish products!

No experience of Nitron but I'm not paying their ridiculous prices, and from what I've seen review wise, they are way too stiff for road use.

Agree; the B14s were absolutely superb on my E81 - they suited the car to a tee & vice versa; firm, but not stupidly but very compliant when driving on normal roads. Took our local rough country lanes with zero issues too

However, the F31 that hd the B16s fitted I was a passenger in was horrible; far too firm and set to soft... Car just bounced a lot and it was properly set up! As far as I recall the fella removed them ASAP and went for a set of KW Street Komfort and apparently they were night and day

I've read about issues with Ohlins; think you mentioned it over on the F3x forums on the other side... The Nitrons I had on my Integra DC5 in late 2000s were absolutely fantastic for the track; but getting there could be tedious. Definitely not an every day driver suspension

[Pizzaeatingking]

It's funny how everyones perceptions are different, there are a couple of guys I remember on the F30 FB group who swear by B16s on theirs.

When it comes to coilovers, the biggest advantage for me is the ability to set the ride height perfectly. Once I set them up, I don't tend to adjust them up and down from then on.

[danb79]

Pizzaeatingking said:

It's funny how everyones perceptions are different, there are a couple of guys I remember on the F30 FB group who swear by B16s on theirs.

When it comes to coilovers, the biggest advantage for me is the ability to set the ride height perfectly. Once I set them up, I don't tend to adjust them up and down from then on.

Yup; this is why I'm still seriously considering a set of E39 M5 ST XAs for my E39 - I love how the car drives and handles on the current Sachs sport spec shocks / Eibach pro-kit springs, more so with the E39 M5 rear ARB

But it's stance for me isn't as good as it could be.

I wouldn't want low at all; but absolutely want level




My pals got my E81 set up perfectly; even raised the rear end 3mm, it made all the difference. I wouldn't go that low with my 540i; but enough to get it level and the wheel/arch gap even all round

[Pizzaeatingking]

Yeah, my E90 doesn't even need lowering at the back, just want the front dropping slightly, can't stand reverse rake! (also, forgot how good your 1er looked )

[danb79]

Pizzaeatingking said:

Yeah, my E90 doesn't even need lowering at the back, just want the front dropping slightly, can't stand reverse rake! (also, forgot how good your 1er looked )

Typical of BMW; that's why the likes of H&R and a few others only do the front springs for the E39 M5 as an example

My E39s the other way; a touch too low at the front, and a touch too high on the rear... The rear does need to settle, but it won't settle that much. I may be able to tweak the front a bit as I've a feeing I've put the shock through the knuckle a bit more than I should have; but it'll still be raked...

And thanks; the 130i was a lovely car, just sods law I wasn't able to keep it and use it as I wanted... The new owner Chris is very happy with it; I'm still in touch with him which is good