Shock absorbers - fooked or normal?

[matsmith749]

I'm lucky enough to have a late model 2016 35is with adaptive shocks on about 40k miles.

The ride can be a bit jarring and jiggly over rough surfaces, and in general I would love to improve the ride a bit - get it as good as it could be given the big 19" wheels (at least fitted non-runflats).

The adaptive shocks have a poor reputation for failing / wearing out - but that's a bit subjective.

So - the question - how do you go about getting the shocks actually checked? Assuming anywhere can do a look for leaks, but what about the performance?

I'm under BMW warranty which I reckon covers this (fingers crossed) - who do you guys use?

I have been to center gravity for porsche racing setups in the past - but that's a fair trek from the south of england.

[B21]

The only quantitive way to check damper performance is on a test rig..they’d need to know the standard parameters to make a definitive statement..but if they were shagged then probably the response curves would just look plain wrong.

The simple rigs look like these…

https://youtu.be/5oS1kJTyv9A?si=tXchp3T6rHYe_kmS

There are whole car test rigs but that’s way beyond anybody’s pay grade here..

Otherwise it’s qualitative assessment ie driving the car on a test road..problem being the owner accommodates deterioration over time and without a comparison very difficult to assess.

When I bought my 2011 35is in 2021 at 50k miles the suspension was utterly and completely shot…the front was not so easily discernible but the rear was truly disgusting with both dampers and springs gone..no fluid leaks no broken springs but still utterly shot..

[matsmith749]

I've reached out to center gravity to see if they will put the BMW on the test rig - it's a whole car setup that basicly shakes each wheel & logs all the data. Back in the days of fast porsches, this was a regular thing we all did. Proper engineers with all the fancy kit & no bullshit.

It might be that my shocks are within spec - but if I'm going to make a case at BMW whilst it is still covered, I will need more than my subjective opinion.

Will feed back here if anyone is interested?

[B21]

I'd be surprised if BMW would take a non BMW approved specialist for the basis or a warranty claim..but ..

[matsmith749]

More to inform me in the first place as to whether there is a problem (or not) - can take it from there after I know.

[Rockhopper]

From my experience shocks will generally be totally shot long before 50,000 miles so if yours have done 40K they will be well past their best.

[Busterboo]

Before wheels*, adaptive shocks, other suspension elements and Center [sic] Gravity, tyres! Which ones are you using and at what pressures?

*You already know that your 19" wheels, although pretty, ain't going to give you the sweetest ride on Earth. So, since they're a compromise you're prepared to make, tyres & pressures (and wheel alignment, of course) may well be your only economically viable route to somewhere near the ride you want.

[matsmith749]

I'm not looking to change out the 19" wheels TBH, although I did shift from the runflats to standard pilot sport 4 S tyres when I first bought the car. I chose those as they were decent performers with a high comfort rating (+ I could get them in my sizes from a local supplier).

I run 38 PSI in teh rears, 34 in the fronts.

I've had a ton of cars that managed similar wheel sizes with rubber band thickness profiles a little better - so as much as anything I just want to know where I stand with the shockers.

Hard to know if it's just normal / worn out by feel alone.

CoG haven't responded yet, but last time I went it was something like £100 for a full diagnostic session on their fancy suspension rig - well worth that (to me at least) to get some data & know if changing shocks would make any real difference.

[tomscott]

Unless the shocks are leaking or have failed in some sort of visible way I can't see BMW covering this as a warrantable item.

Part and parcel of owning a 10 year old car. I wouldn't waste your time and money getting someone to test it, if you're not happy with the ride have a look at some set ups to improve. Those dampers were never really that great anyway, they are expensive when they fail and a lot of people swap them out for coil overs.

[matsmith749]

I'm hearing you - but just swapping them out doesn't feel right when the car is under BMW warranty.

If they are fooked (if) then I would rather have the conversation with BMW as a first step & only change out the shocks if it's confirmed they won't try to wriggle out of other warranty claims if they were to happen in the future.

I'm certain adding non BMW shocks would invalidate the entire suspension warranty.

[Busterboo]

I've reached out to center gravity to see if they will put the BMW on the test rig - it's a whole car setup that basicly shakes each wheel & logs all the data. Back in the days of fast porsches, this was a regular thing we all did. Proper engineers with all the fancy kit & no bullshit.

It might be that my shocks are within spec - but if I'm going to make a case at BMW whilst it is still covered, I will need more than my subjective opinion.

Will feed back here if anyone is interested?

1 In my experience, adaptive suspension failure isn't a matter of opinion, but simply of visible leaks.
2 Mine was replaced 1 1/2 times, i.e. 6 corners, under BMW insured warranty. This was expensive to the insurer.
3 The next time they fail, I'll abandon the system, because my 105k-mile car has only limited insured warranty now, and replace it with 'normal' shocks.
4 That said, I find the system very good and think it's a pity it's not more durable.
5 Center Gravity is excellent, as we both know. I took my 911 there.
6 However, they are perfectionists and will find something wrong with your car, because there will be something 'wrong'. It's in the nature of 40k-mile cars, of course. I look forward to your feedback.
7 Compared to a 911 (996 & 997), the ride in 'Normal' of the 35iS is more like our previous Jags, or so my wife says.
8 The 35iS is, nonetheless, a sub-5-seconds-to-60 quick cruiser and, when the adaptive system comes into play in Sport+, it has to work hard and, in my experience - albeit without the wife present - it does so efficiently.
9 I have a 12-mile 'bumble route' - a winding countryside road - that, at quiet times of the day & evening is sometimes empty. In the 911, I used to try to drive it at above 60 without using the brakes. It's not as easy as it might sound. In the 35iS, I can do it at above 70. I attribute this to the adaptive suspension and DCT. The point of the story? That perhaps the suspension is worth it.

[matsmith749]

Center gravity came back to me - been a few years since my last visit & inflation has bitten - cost for a health check is now £250.

There service is top notch, but it does make me think twice now the cost is higher than my ancient memories

First step might be a good visual checkover somewhere.

[Busterboo]

Center gravity came back to me - been a few years since my last visit & inflation has bitten - cost for a health check is now £250.

There service is top notch, but it does make me think twice now the cost is higher than my ancient memories

First step might be a good visual checkover somewhere.

Come on! £250 at Center Gravity will provide you with authoritative information - i.e. correct - that your local indy can use and put your mind to rest.

[matsmith749]

I was swayed by your impeccable statement that shockers are diagnosed by visible leaks (one post up).

I've always been a data driven person, but come to the forum to seek (& share) wisdom - do you now disagree with yourself & recommend the trip up to CoG?

Or just wanna see a nice data set (kinda like I do) & put some quantitive data to play in this subjective conversation?

As well as cost - didn't mention they were booked up for a while & this would be a late May / June checkup.... I'm also impatient & want to do something to ease my mind sooner if I can

I'm also surprised that nobody has chimed in that has done this already - does everyone just dive stright into parts swapping?

[B21]

I was swayed by your impeccable statement that shockers are diagnosed by visible leaks (one post up).

I've always been a data driven person, but come to the forum to seek (& share) wisdom - do you now disagree with yourself & recommend the trip up to CoG?

Or just wanna see a nice data set (kinda like I do) & put some quantitive data to play in this subjective conversation?

As well as cost - didn't mention they were booked up for a while & this would be a late May / June checkup.... I'm also impatient & want to do something to ease my mind sooner if I can

I'm also surprised that nobody has chimed in that has done this already - does everyone just dive stright into parts swapping?

Of the four 35is I have driven , not one was a patch in terms of suspension to a Bilstein B8 suspended E89…I was ‘quite pleased’ when I bought my 35is that the shocks were on their way out…I had factored that into the reason /logic ..this time of buying a 35is..previously I wasn’t in a position to cope with large unexpected bills and the handling was so uninspired that I walked away from purchases 3 times before..

There is significant group of people who think the stock suspension is less than brilliant to start with..obviously many may be coloured by the effects if tired suspension…although why they don’t see that on non adaptive E89s who knows..