[AllaVodka]

340i thp rwd. 19" thp rims with rf tires

Ive added dinan springs bumps and shockware, and uca + lca vac sealed monoballs.

Which of those do you think is causing the most nvh, and crashing effect when hitting bumps and potholes?

Beginning to drive me mad, and debating either removing the springs or the vca monobals (likely just lca to start)

[Watsey]

In my experience, the RF tyres.

The suspension upgrades will transmit more NVH to the chassis, but the root cause will certainly be attributed (at least in part) to the run-flats.

BMW uses hydro bushes for a reason - to isolate NVH caused by rock hard tyres which it fits as standard on its non-M cars.

As we 'tighten' the suspension on our cars there's almost always going to be some compromises.

[AllaVodka]

Originally Posted by Watsey

In my experience, the RF tyres.

The suspension upgrades will transmit more NVH to the chassis, but the root cause will certainly be attributed (at least in part) to the run-flats.

BMW uses hydro bushes for a reason - to isolate NVH caused by rock hard tyres which it fits as standard on its non-M cars.

As we 'tighten' the suspension on our cars there's almost always going to be some compromises.

Interesting ty. Maybe its time for new tires

I will say though, before adding the suspension mods it was not nearly as brutal… so thats why I'm attributing it to either the springs or bushings. I'm sure the rft's are good to get rid of though

[smrtypants44]

I would probably say the springs. I've done spring only mods on various cars and they've always been subpar to a full coilover replacement.

[cfm56d7b]

Originally Posted by AllaVodka

340i thp rwd. 19" thp rims with rf tires

Ive added dinan springs bumps and shockware, and uca + lca vac sealed monoballs.

Which of those do you think is causing the most nvh, and crashing effect when hitting bumps and potholes?

Beginning to drive me mad, and debating either removing the springs or the vca monobals (likely just lca to start)

How many miles have been accumulated on the current set of RF tires? Can you share RF tires details: brand, model?

As RF tires lose tread, they become progressively noisier.

[Logicoeur]

The RF tires are the cause. They are bricks. The LCAs and bushings only transmit NVH better than OE bushings.

[AllaVodka]

Originally Posted by cfm56d7b

How many miles have been accumulated on the current set of RF tires? Can you share RF tires details: brand, model?

As RF tires lose tread, they become progressively noisier.

They're actually fairly new. I've had the rft since Feb21 and have only put on 6,000 miles. Theyre potenza S001's

[AllaVodka]

Originally Posted by Logicoeur

The RF tires are the cause. They are bricks. The LCAs and bushings only transmit NVH better than OE bushings.

But my car before the springs + damper tune, and bushings was way less harsh. Same tires etc… that's what's leading me to think its one of those

[Logicoeur]

Originally Posted by AllaVodka

But my car before the springs + damper tune, and bushings was way less harsh. Same tires etc… that's what's leading me to think its one of those

Again the new arms just transmit the NVH the rft tires are emitting. The bushings don't create NVH themselves. The ride seemed less harsh before because the oe bushings dampened the rft NVH. Trust us. Moving to go flat rites is a marked improvement in NVH and performance.

[Watsey]

Originally Posted by AllaVodka

They're actually fairly new. I've had the rft since Feb21 and have only put on 6,000 miles. Theyre potenza S001's

In my experience/opinion Potenza S001s are one of the worst tyres for anything other than steady motorway (freeway) cruising i.e. they can/will achieve a good lifespan if treated carefully.

Beyond that they are rock hard, create a lot of noise and harshness, have dubious grip/traction in the dry, and are downright dangerous in the wet.

Get rid ! Fit some UHP tyres (my go-to is Michelin MP4S) and you'll notice a huge improvement in refinement and performance.

[alohasurftoad]

imo, while shockware can somewhat extend OEM adaptive damper lifespan, i believe your dampers are starting to fail, causing a poor ride and bottoming out on large compressions.

lowering springs causing a degraded ride and premature failure of OEM dampers on any car is not a new topic. i always recommend pairing lowering springs with shorter aftermarket dampers. however if retaining OEM dampers is desired, Eibach Pro-Kit(s) 6-22 or 5-22 would have the least detrimental affect on OEM dampers because it lowers the least. ride comfort is also better due to lower spring rate than Dinan or H&R.

[cfm56d7b]

Originally Posted by Watsey

In my experience/opinion Potenza S001s are one of the worst tyres for anything other than steady motorway (freeway) cruising i.e. they can/will achieve a good lifespan if treated carefully.

Beyond that they are rock hard, create a lot of noise and harshness, have dubious grip/traction in the dry, and are downright dangerous in the wet.

Get rid ! Fit some UHP tyres (my go-to is Michelin MP4S) and you'll notice a huge improvement in refinement and performance.

Bridgestone Potenza S001 are indeed very harsh - even when new. I retired these tires as soon as I could.

Michelin PS4S tires will be a better choice by a wide margin.

If your budget permits, coilovers with independent compression and rebound controls will provide the broadest range of tuning options.

[AllaVodka]

Originally Posted by alohasurftoad

imo, while shockware can somewhat extend OEM adaptive damper lifespan, i believe your dampers are starting to fail, causing a poor ride and bottoming out on large compressions.

lowering springs causing a degraded ride and premature failure of OEM dampers on any car is not a new topic. i always recommend pairing lowering springs with shorter aftermarket dampers. however if retaining OEM dampers is desired, Eibach Pro-Kit(s) 6-22 or 5-22 would have the least detrimental affect on OEM dampers because it lowers the least. ride comfort is also better due to lower spring rate than Dinan or H&R.

Hmm I got you. Is there any way to tell if my dampers are failing? I've only had springs and shockware for like 6k miles, and bushings for like 2-3K miles. My car only has 40k miles on it

[dmanb2b]

19" stock wheels are really heavy, as are RFTs. Reducing unsprung weight helps ride comfort tremendously, which is why I run 18" go flats and the lightest wheels I can find, despite preferring the look of 19's

[alohasurftoad]

Originally Posted by AllaVodka

Hmm I got you. Is there any way to tell if my dampers are failing? I've only had springs and shockware for like 6k miles, and bushings for like 2-3K miles. My car only has 40k miles on it

I'm not sure of an objective way to determine damper wear/failure. Since the springs are shorter than OEM, I believe the damper is supporting more weight than it should be and compressed a bit already, reducing travel. This seems to be the root cause of degradation and early failure.

While some have no problems with lowering springs and OEM dampers, more people do than not and I believe yours is such a case.

[Onizukachan]

Originally Posted by Watsey

In my experience, the RF tyres.

The suspension upgrades will transmit more NVH to the chassis, but the root cause will certainly be attributed (at least in part) to the run-flats.

BMW uses hydro bushes for a reason - to isolate NVH caused by rock hard tyres which it fits as standard on its non-M cars.

As we 'tighten' the suspension on our cars there's almost always going to be some compromises.

Ditto. Changing to regular tire ( dws06+) completely eliminated that harsh thud when hitting any kind of modest road imperfection. several places within a block or two of my house that I had to scootch out of the lane for or slow for to not have a panic attack and check tpms screen.. I mean stuff like slightly protruding manhole covers or pavement sections that were 3/8“ out of level to each other that now… I just glide over.

And I went from 18” 400m with frf pirelli 225/45/18 to 235/40/19 on not light Alzor 758 wheels.

The first two days I found myself cruising at 20-25 over what I thought I was doing… like cruising 85+ when I thought I was going about 60-65, because the harshness and noise levels were so much lower that I didn’t realize I was going that fast.
Yes. That much of a difference.

[Watsey]

Originally Posted by alohasurftoad

I'm not sure of an objective way to determine damper wear/failure. Since the springs are shorter than OEM, I believe the damper is supporting more weight than it should be and compressed a bit already, reducing travel. This seems to be the root cause of degradation and early failure.

While some have no problems with lowering springs and OEM dampers, more people do than not and I believe yours is such a case.

We need to be careful not to misinform the OP.

Dampers can easily be tested on a damper dyno - some tyre fitters may have them, but a specialist suspension shop may be more likely. The damper dyno will provide data which allows the health/performance of the dampers to be assessed.

Dampers do not support weight - that's the job of the springs. Dampers, in simple terms, just provide resistance to the relative movement of the suspension components (the damping effect) to help achieve control and desired ride/handling characteristics. The only time that they may support weight is at the limit of the compression travel when the bump stops come into play.

[alohasurftoad]

@Watsey, you are correct, dampers do not support weight. I shouldve wrote, with lowering springs, OEM dampers are being compressed slightly and travel is reduced. imo, this what often causes the ride to degrade and reduced longevity.

i've seen lowering spring/stock damper issues in the past, present and know i'll continue to see it in the future.

[AllaVodka]

Originally Posted by alohasurftoad

@Watsey, you are correct, dampers do not support weight. I shouldve wrote, with lowering springs, OEM dampers are being compressed slightly and travel is reduced. imo, this what often causes the ride to degrade and reduced longevity.

i've seen lowering spring/stock damper issues in the past, present and know i'll continue to see it in the future.

Yeah I've seen that too.. my understanding was that with the shockware tune on the dampers was to be used in conjuction with the springs to prevent that. I'm also slightly skeptical if they could possibly cause damage with only 6k miles. I'm thinking its a combo of the stiffer suspension + sealed monoballs that are making things brutal.

Honestly, I'm a bit of a noob, so I appreciate the help and feedback

[alohasurftoad]

yes, i've read shockware was to reduce and even mitigate the affect of lowering springs on OEM dampers. when shockware 1st came out, there was a lot of "hoopla" about it, but lately not so much. maybe it's not what it's cracked up to be?

i have VAC UCA(only) and dont think its the problem. however the sum of RFT tires, susp and VAC, i suppose it could be...

i'd swap to go flats with more sidewall(if possible) and Eibach Pro-Kit 5-22 springs before losing what the VAC provides.

what rim and tire size do you currently have?

[AllaVodka]

Originally Posted by alohasurftoad

yes, i've read shockware was to reduce and even mitigate the affect of lowering springs on OEM dampers. when shockware 1st came out, there was a lot of "hoopla" about it, but lately not so much. maybe it's not what it's cracked up to be?

i have VAC UCA(only) and dont think its the problem. however the sum of RFT tires, susp and VAC, i suppose it could be...

i'd swap to go flats with more sidewall(if possible) and Eibach Pro-Kit 5-22 springs before losing what the VAC provides.

what rim and tire size do you currently have?

I have the 19" 442m rims with potenza s001 rft. The ones that come with the thp wheel upgrade

[Watsey]

Originally Posted by alohasurftoad

@Watsey, you are correct, dampers do not support weight. I shouldve wrote, with lowering springs, OEM dampers are being compressed slightly and travel is reduced. imo, this what often causes the ride to degrade and reduced longevity.

i've seen lowering spring/stock damper issues in the past, present and know i'll continue to see it in the future.

In that case we are on the same page

Keeping the damper piston within its operating range is definitely a 'must' and helps to prevent riding the bump stops when the dampers aren't matched to the reduced ride height caused by lowering springs.

Whenever I read people asking about lowering springs and harder grade bump stops it always prompts the question "why are you doing this ?". Cost is a factor, of course, but lowering springs and standard dampers is not a great solution.