[SantaEugence]

Recently had my f30 xdrive lowered on H&R sport springs with stock adaptive suspension. The cars been crashing out a lot on even minor potholes or bumps and on ringing the Indy they told me this was pretty normal and an unfortunate consequence of fitting lowering springs to standard shocks.
On doing some more reading, I'm understanding that the issue is actually caused by the standard bump stops being too long for the shortened ride height, and the crashing I'm experiencing is in fact caused by an impact with these stops?
If so I'm a bit annoyed, I'm sure it's something the garage should have advised me about, especially when I subsequently rung up. I take it to change the stops requires full shock and spring removal and disassembly?

Anyway if the above is correct, what stops are people running with their H&R sport springs and did it solve the crashing issue?
I've read either F8x or bumps from the E 3 series will work well?
Thanks in advance

[Tengocity]

You'd be far better off with better dampers. Your garage is not wrong as such. Even if you fit shorter bumpstops, you'll still hit them, just perhaps not on the small stuff that's causing you issues now.

If you try carrying decent speed down a typical British B road I am sure you'll still be hitting them. If it's all just for looks and town driving then I guess that's fine.

[335dX]

As Tengocity said.

I had the same issue. Replaced dampers with ACS and now perfect.

I haven’t changed my standard bump stops and my car doesn’t crash like it did when I fitted my Eibach springs before dampers. The ride was awful.

[johnung]

Originally Posted by SantaEugence

Recently had my f30 xdrive lowered on H&R sport springs with stock adaptive suspension. The cars been crashing out a lot on even minor potholes or bumps and on ringing the Indy they told me this was pretty normal and an unfortunate consequence of fitting lowering springs to standard shocks.
On doing some more reading, I'm understanding that the issue is actually caused by the standard bump stops being too long for the shortened ride height, and the crashing I'm experiencing is in fact caused by an impact with these stops?
If so I'm a bit annoyed, I'm sure it's something the garage should have advised me about, especially when I subsequently rung up. I take it to change the stops requires full shock and spring removal and disassembly?

Anyway if the above is correct, what stops are people running with their H&R sport springs and did it solve the crashing issue?
I've read either F8x or bumps from the E 3 series will work well?
Thanks in advance

IMO your assessment is correct about the stock bump stops being incorrect for that much drop. It's not your high tech Adaptive dampers. (I'd never get rid of those. Bilstein has Damptronic replacements and upgrades if your Adaptives wear out and leak at some point)

Farkle! is the guy who does the most investigation and testing on bump stops- both on their size and various materials. Read his posts. I would bet that he's answered your exact question before.

[SantaEugence]

Thanks guys.
Unfortunately I'm not in a position to be able to upgrade the whole suspension set up hence settled for just the springs.
I've read quite a few posts but couldn't quite find a definitive answer from anyone who had HR on the xDrive with a similar crashing problem, and whether it was solved by shortened stops. Some users say they haven't had any issues at all.

Next problem is of course how I'd get them fitted, I'd be aggrieved to pay hundreds in labour again (and 4 wheel alignment) considering I'm starting to think the garage, being a specialist and having lowered countless and tracked numerous BMWs, should have advised me of this problem in the first place.

[Watsey]

My experience supports what others' have said. A few years ago my car had a hybrid of shorter springs with the OEM adaptive dampers and I found that the suspension didn't perform at all well.

BMW adaptive dampers are (IMO) don't perform well - too floaty in Comfort; over-damped in Sport/+. Well matched springs and high performance dampers are far superior if you want a decent suspension setup.

It's worth checking whether the crashing is actually the dampers bottoming-out, or whether it's simply a more brittle ride as a result of stiffer springs (which would be exacerbated if the car still has RFTs especially if on 19" rims).

The dampers may well be bottoming out as the lowered ride height will move the damper piston rod further towards the limit of its range of travel inside the damper body, and the bump stop is obviously there to try and prevent damage from occurring.

[SantaEugence]

Originally Posted by Watsey

My experience supports what others' have said. A few years ago my car had a hybrid of shorter springs with the OEM adaptive dampers and I found that the suspension didn't perform at all well.

BMW adaptive dampers are (IMO) don't perform well - too floaty in Comfort; over-damped in Sport/+. Well matched springs and high performance dampers are far superior if you want a decent suspension setup.

It's worth checking whether the crashing is actually the dampers bottoming-out, or whether it's simply a more brittle ride as a result of stiffer springs (which would be exacerbated if the car still has RFTs especially if on 19" rims).

The dampers may well be bottoming out as the lowered ride height will move the damper piston rod further towards the limit of its range of travel inside the damper body, and the bump stop is obviously there to try and prevent damage from occurring.

It's pretty much exactly that kind of crash you get when hitting a pot hole in run flats, that kind of bang where your head hurts - except I've got MPS4S and it occurs on more minor road imperfections which is very annoying.
Interesting not everyone has the issue and some people report HR with xdrive adaptive as being fine.

I don't know what else the crashing could be other than hitting the bump stops? I've emailed HR to ask for their take on it, allowing more travel on the shock seems to be the recommended solution (other than performance shocks) but curious they don't list these springs as needing shortened stops.

[Tengocity]

How many miles has your car done? If it's higher mileage it could also be that your dampers aren't performing as well as they should be.

[Lorcan]

Shortening the bump stops could conceivably make things worse. "Bump stops" is a bit of a misnomer, the automotive industry now uses spring aids or spring assisters as the part description, as their function is not just to prevent the shock from destroying itself when it bottoms out - they also add to the spring rate in a progressive way to reduce body roll and pitch, and to stop you car bouncing off the road as might happen if you used a simple piece of rubber as a stop.

This article explains it rather well.

http://www.superstreetonline.com/how...mp-stops-here/

AC Schnitzer go to great lengths to test springs in the real world and on racetracks to ensure there is enough residual travel left in the spring when the ride height is lowered, and that the bump stops still function as intended.

We've swapped a number of customer's cars over from H&R to AC Schnitzer for precisely this reason and they've all been happy with the result. This includes Martin at DMS Automotive if you want to check with him for a reference. We then have a clear upgrade path to add matched sports dampers when funds allow.

[HighlandPete]

Originally Posted by Lorcan

Shortening the bump stops could conceivably make things worse. "Bump stops" is a bit of a misnomer, the automotive industry now uses spring aids or spring assisters as the part description, as their function is not just to prevent the shock from destroying itself when it bottoms out - they also add to the spring rate in a progressive way to reduce body roll and pitch, and to stop you car bouncing off the road as might happen if you used a simple piece of rubber as a stop.

Good to see you posting.

I have never understood cutting down the 'bump stops', as a solution to poorly matched spring/damper combinations.

I spent part of my career designing shock absorbers for the safety industry, much the same 'damping' design applies to vehicle suspension. Not every modification is an improvement to absorb energy. I completely follow how the bump stop is a spring assister, a secondary spring, also used to absorb energy. A shorter 'stop can mean the forces are higher, at end of the stoke. Not as much energy is absorbed during the stoke.

For me, the key is matched components. A 'mix and match' approach is asking for issues.

Adaptive damper function includes the vertical dynamics management (VDM), designed around body and wheel rate frequencies, spring rates and the 'resulting' damper characteristic maps. From my perspective, to get it to work without changing the 'maps', will take some serious development, like that of ACS.

[SantaEugence]

For me, personally, the ACS spring kit lowering wise is almost pointless as I'm doing it more for aesthetics and the drop is barely noticeable, in my opinion.

I get what you chaps are saying about altering standard bump stops, and cutting them will no doubt cause problems. However I'm aware that eg Dinan offer bump stop kits with progressive secondary damping to assist the shocks, so it seems that the damp stops can be altered on standard absorbers to better compliment lowering springs.
This is the kind of thing I'm after recommendations for - what kits or stock available bump stops have people used with the HR springs for the best effect?
Thanks

[HighlandPete]

Originally Posted by SantaEugence

For me, personally, the ACS spring kit lowering wise is almost pointless as I'm doing it more for aesthetics and the drop is barely noticeable, in my opinion.

I get what you chaps are saying about altering standard bump stops, and cutting them will no doubt cause problems. However I'm aware that eg Dinan offer bump stop kits with progressive secondary damping to assist the shocks, so it seems that the damp stops can be altered on standard absorbers to better compliment lowering springs.
This is the kind of thing I'm after recommendations for - what kits or stock available bump stops have people used with the HR springs for the best effect?
Thanks

Is this 'crashing' in comfort and sport mode? Better/worse in one or the other?

[SantaEugence]

Originally Posted by HighlandPete

Is this 'crashing' in comfort and sport mode? Better/worse in one or the other?

Mainly in comfort, I don't use Sport terribly often (hence wasn't fussed about the better handling with the ACS kit). I'll try it just in Sport and see if it makes a difference?
If I'd known the crashing would be this bad I'd probably have saved up longer and bought a whole set up, but it just seemed overkill as the ride (aside from said crashing) is fine for my uses since I don't race or track it either

[Sasquartch]

What's your mileage ?

Anything over 50k and your shocks will be well past their best.

As has been said, decent suspension needs matched components, Unfortunately the fashion for lowered suspension and low profile tyres has killed the comfort of many cars, I remember being very surprised at how good the ride was on my son's old Renault despite the fact it was 15 years old

[Tengocity]

Originally Posted by SantaEugence

Mainly in comfort, I don't use Sport terribly often (hence wasn't fussed about the better handling with the ACS kit). I'll try it just in Sport and see if it makes a difference?
If I'd known the crashing would be this bad I'd probably have saved up longer and bought a whole set up, but it just seemed overkill as the ride (aside from said crashing) is fine for my uses since I don't race or track it either

Definitely try out sport. When you increase the spring rate the damper has to absorb energy more quickly than with a lower spring rate, and my experience a few years back when I first went to ACS springs on my F31 335d was that in comfort mode the damper was too soft, and in effect the sport damper setting was much better suited to that spring rate. With the H&R ones that effect will be even more exaggerated.

Personally, that's why I am less convinced by adaptive suspension set ups as for any given spring rate there is an ideal damper curve to match, and an adaptive options gives you either one decent option or two bad options, hence may as well stick with a well matched spring and passive damper.

[Lorcan]

Originally Posted by SantaEugence

For me, personally, the ACS spring kit lowering wise is almost pointless as I'm doing it more for aesthetics and the drop is barely noticeable, in my opinion.

You've actually got what you wanted - a kit aimed at aesthetics.

[SantaEugence]

Originally Posted by Tengocity

Definitely try out sport. When you increase the spring rate the damper has to absorb energy more quickly than with a lower spring rate, and my experience a few years back when I first went to ACS springs on my F31 335d was that in comfort mode the damper was too soft, and in effect the sport damper setting was much better suited to that spring rate. With the H&R ones that effect will be even more exaggerated.

Personally, that's why I am less convinced by adaptive suspension set ups as for any given spring rate there is an ideal damper curve to match, and an adaptive options gives you either one decent option or two bad options, hence may as well stick with a well matched spring and passive damper.

Thanks I'll give it a go

Originally Posted by Lorcan

You've actually got what you wanted - a kit aimed at aesthetics.

Haha well I walked into that one didn't I...

Originally Posted by Sasquartch

What's your mileage ?

Anything over 50k and your shocks will be well past their best.

As has been said, decent suspension needs matched components, Unfortunately the fashion for lowered suspension and low profile tyres has killed the comfort of many cars, I remember being very surprised at how good the ride was on my son's old Renault despite the fact it was 15 years old

Its on about 55k at the moment, but yes no doubt the low profile tyres don't help although I'm glad I don't have run flats as well

[johnung]

Originally Posted by SantaEugence

Mainly in comfort, I don't use Sport terribly often (hence wasn't fussed about the better handling with the ACS kit). I'll try it just in Sport and see if it makes a difference?
If I'd known the crashing would be this bad I'd probably have saved up longer and bought a whole set up, but it just seemed overkill as the ride (aside from said crashing) is fine for my uses since I don't race or track it either

I understand that you are being bombarded by opinions against the Adaptive dampers. I really think that is the minority opinion, even if it is vocal. You are going about your research of the issue correctly.

Bump stops are made of a variety of materials with different characteristics. It's not just length of the bump stop. Most of my knowledge is from reading Farkle! posts with all of the testing that he has done. I'm amazed at all of the different types that he has gotten his hands on.

Most often I've seen milder drop 1" or less springs such as some models of Eibach springs used with Adaptive dampers. But you haven't used some strange combination. H&R springs are widely available. It's doubtful that you are breaking new ground here. I'm curious to hear what H&R says. I hope that you get a response from someone knowledgeable there.

Some have suggested that maybe your dampers are worn. That is possible. There doesn't seem to be a specific mileage with Adaptives where they need replacement. Mostly one of them starts leaking, either at low mileage or high mileage. Then at least that pair needs to be replaced. They are more expensive than standard old technology shocks, so it's easier on the budget to replace in pairs anyway.

The Bilstein B4 Damptronic are their stock OEM replacement. But the Bilstein B6 Damptronic are a huge jump in technology and build quality. I would chose those every time. Bilstein also makes a Damptronic coilover if that is one's religious persuasion.

Check your Adaptives carefully at each corner for wear and leakage. If you suspect an issue I'd consider replacing the pair with Bilstein B6 Damptronic, especially if you find an issue in the front.

There could be some merit to Sport Mode over Comfort mode. I'm curious if you notice a difference. I have also read positive comments from guys who use Dinan Shockware with their Adaptives. I don't know enough about it to know if it applies to your circumstance. I've just heard that it's an enhancement to Adaptives.

Good luck!

[GEP77]

The U.K. part of this forum has traditionally focused more on the performance aspect of suspension primarily, with aesthetics taking a slight back seat so it's hardly surprising some of the answers you've had.

Certainly from my own experience of a 335d going from standard springs with adaptive to ACS springs made an enormous difference. Everything was improved. This was further improved once I'd ditched the runflats. I did it primarily for performance, the improved aesthetics were merely a nice by-product.

Many on this forum have done their suspension modification in stages and have kindly fed back to us the benefits and sometimes unexpected consequences along the way. The general rule is very similar to Pringles, once you pop you can't stop! It's an addictive and slippery slope to go down!

I'd certainly head advice from some on here, they certainly know what they're talking about, most who've replied have done this work themselves before. Getting well matched springs and dampers is pretty much essential if you want to preserve road manners, regardless of how far you drop the car. I've never really understood the slammed look myself (too many speed bumps, potholes and other hazards in the road really), but a good setup like the ACS one can yield a great understated look while at the same time offering great comfort and performance. Similar combined spring and damper packages from other firms obviously also exist. But the key thing here is combined.

And your question about alignment, you should have the alignment checked every time you dismantle suspension as a matter of course. This is obviously an added incentive to get it right first time!!

[HighlandPete]

Originally Posted by johnung

There could be some merit to Sport Mode over Comfort mode. I'm curious if you notice a difference. I have also read positive comments from guys who use Dinan Shockware with their Adaptives. I don't know enough about it to know if it applies to your circumstance. I've just heard that it's an enhancement to Adaptives.

Good luck!

I was going to make comment on the Dinan Shockware, as I see this as a natural progression for some spring/adaptive damper combinations.

Terry has raised the issue of fitting higher spring rates, where the adaptive damper is now really only suited to the Sport mode damping map. Comfort, (unless you like a really underdamped chassis), is pretty much made redundant. Hence the Dinan Shockware, to get back to damping maps either side of the spring rate.

Adaptive is always going to be a compromise, when there are several damping maps, unless one is tuned to 'match' the spring rate. In that case the 'matched' mode will give the best driving dynamics.

Years back when more into tuning cars, I held the opinion, gleaned from my own and other guy's experience, one of the 'cheapest' ways to improve the chassis was a better/sport/adjustable damper. Work with the existing spring, as that is usually pretty well matched for a wide range of use. Many a car, even those with sporty intentions, are often underdamped to give a wider range of user benefits.

I've never really understood the appeal to 'just fit' a shorter spring with a higher spring rate, other than to lower the car. Many a car becomes a less than ideal chassis in that condition.

[G50]

I had eibach springs with xdrive, had it bottom out to the bump stops only on severe road compressions at speed (trying to keep up with a golf R in the north york moors). It wasn't otherwise crashy, but the drop wasn't quite as much as yours I guess.

I now have H&R sports on Sdrive, and still haven't hit the bump stops, but do get a clang (metal on metal sound) every now and then from the front end, which I am 80% sure is the bushes in my lower control arms that are past their best.

I can't see you hitting the bump stops on "minor imperfections", even with the toilet x-drive dampers. I'd be more inclined to think bushes, even though 55k is fairly low, if previous owner lived in an area with really poor roads, and didn't bother avoiding potholes, bushes could well be shot.

Tyres, tyre pressures and alignment can make a difference to a bushes (knackered or otherwise) ability to cope with minor imperfections.
Rule tyres out (you have mps4s), but what PSI are you running, and have you had an alignment to make sure your wheels are pointing in the right direction(s)?

One other test that should highlight your bushes would be to over inflate the tyres (assuming they are not already so), and drive over some minor imperfections, not huge potholes, and if the banging increases, I would say that it's your lower control arms that need replacing, as as I've said, you won't hit bump stops on minor imperfections.

ETA: If you really are hitting the bump stops on normal driving with the blue H&R sports, you must have bought the wrong springs for your car, as the spring rate sounds far too soft.

[Stew_Pid]

Originally Posted by SantaEugence

Thanks guys.
Unfortunately I'm not in a position to be able to upgrade the whole suspension set up hence settled for just the springs.
I've read quite a few posts but couldn't quite find a definitive answer from anyone who had HR on the xDrive with a similar crashing problem, and whether it was solved by shortened stops. Some users say they haven't had any issues at all.

I've had exactly that issue. H&R Sports on standard 330d Xdrive Dampers. Shocking, simply shocking (forgive the intended pun).
I cut the bump stops down by one section with the reasoning that, with the shortened spring, I was shortening the damping stroke accordingly however it still bottoms out (crashes/thuds) very easily on fast compressions and as has been stated, this is simply because stock shocks are designed for a compromise between comfort and handling. As soon as you take them out of their designed damping cycle, negative effects WILL be noted. The dampers are designed to operate throughout say 90% of their piston stroke complemented by the supporting spring rates and the bump stops are only there for the extremes and the last 10% of that normal 'duty cycle' to prevent metal on metal damage, don't expect bump stops to do anything more than that.

I came to my senses and realised that I was never going to best what BMW have probably spent millions on - B14 Coilovers, arrived yesterday and I'm fitting them on Saturday, can't wait for that crashing to feck off to the shocking underwurld.