Z4 ride harshness: what can be done?

A

Antisocialite

Member
 Chicago, IL
So, I just picked up my Z4 roadster recently (2008 3.0si) after months of researching, waiting, and general lurking, and so far it's everything I'd hoped, with one exception:

The ride quality seems much harsher than I remember from the test drive, even without the sport package, which I avoided partly for that reason. The experience does vary depending on the road, obviously (though unfortunately the roads around here at the tail end of winter are pretty crappy in general), but it's really rather bothersome at times, especially over any sort of seam in the road.

So, I'm wondering what might be done to alleviate this issue, if anything.

I've heard that one candidate for improvement can be the tires (which are currently the run-flats on 17" wheels). So, for those of you who have switched from the run-flats to regular tires, does it reall make a substantially noticeable difference in reducing the "jarring" nature of the ride under certain circumstances? If so, it there a particular tire that you might recommend with this consideration in mind?

Are there any other possibilities for smoothing out the ride a bit?

Thanks!
 
Tyres, tyres, tyres & tyres.

I just swapped mine out about 3 weeks ago, much smoother ride now plus I don't get dragged off in every direction when there are dips in the road surface.
 
Agree. I changed tyres to regular and there is a lot better handling and smoother ride. My choises were either Continental 2 or Michellin. Decided for Conti. Very satisfied.
 
I have RFTs on 18" wheels. I get a much better ride by ensuring the pressures are all at 38psi. I cannot compare to non-RFTs, but if you have RFTs, pump them up. I think it has something to do with riding more on the sidewalls at pressures below about 35psi, making the ride more harsherer. The added psi also reduces tramlining substantially.

It might just be me, as no-one else has confirmed that the added air helps them too, but this is the cheapest and fastest "fix" I have found.
 
Yeah my ride got a little better once I put the correct pressures. My ride got ALOT better when I ditched the runflats.
Moral of the story.
Ditch the runflats!
 
Thanks for the replies, everyone. It sounds like switching to non-run-flats really will make a big difference on on the lousy roads around here.

So, a couple of more questions:

Does changing the tires to non-run-flats have any impact on the warranty?

This may be a dumb question, but I don't have much experience with this sort of thing: will I need to buy new wheels as well, or will the regular tires work on the original 17" wheels that came with the car?

How does the tire pressure monitoring system handle the switch? Are there any major issues from this perspective?

As far as options for regular tires go, will there be a significant difference in ride quality for, say, an all-season tire versus a more summer-oriented performance tire? Are there any particular brands/models with which people have had consistently good experiences that you'd recommend?

Thanks again for the help!
 
> Does changing the tires to non-run-flats have any impact on the warranty?

not in the uk, called customer services and aksed, was told lots of people make the change

>will I need to buy new wheels as well

no, the bmw rims are good for non run flats too, again asked customer services to confirm, i have the 103 style (same as the one's on the roadster in the logo image ^^^^ up there i think) and asked specificly about this model

>How does the tire pressure monitoring system handle the switch

zero difference, works the same, as before i asked BMW CS to confirm

sugestion woudl be to call BMW CS and ask them to confirm, if your concerned get them to put it in writing for you or at least ask if the call is recorded and wil be stored as evidence of the conversation
 
I'd also perhaps come at this from a different perspective.

Let me say I agree with ditching runflats based upon many people experiences of them on road and track. (I still run mine becuase they were brand new on purchase), however I strongly disagree with raising the pressure. All this does is bows the centre of the tyre, lifts the edges and reduces and a side effect reduces the tramlining. It also makes it feel smoother, but of course destroys the tyre, vastly reduces its grip for braking, water removal and cornering.

Firstly on test drives dealers spend their lives working out a route specific to each model of car. They know which corners to tell you to drive hard in, know where smooth surfaces and waht to avoid. They talk constantly and you are in a strange car anyway enjoying a new experience. Yo buy the car and are surprised at how different it feels.

Next you just purchased a low wide sports oriented car running on wide low profile tyres. You already have the non sport suspension so it's the most compliant anyway so what are you expecting? What is the benchmark you are measuring against. Compared to any normal saloon or even 4x4 it may seem harsh, sensitive, bangs on bumps and tramlines. Put it through a series of bends and you get the payback.

I just suggest this so you don't spend ages chasing something that may not be there.

Personally mine is on runflats, m suspension and I love the way it's alive on the road.
 
cj10jeeper said:
I'd also perhaps come at this from a different perspective.

Let me say I agree with ditching runflats based upon many people experiences of them on road and track. (I still run mine becuase they were brand new on purchase), however I strongly disagree with raising the pressure. All this does is bows the centre of the tyre, lifts the edges and reduces and a side effect reduces the tramlining. It also makes it feel smoother, but of course destroys the tyre, vastly reduces its grip for braking, water removal and cornering.

Firstly on test drives dealers spend their lives working out a route specific to each model of car. They know which corners to tell you to drive hard in, know where smooth surfaces and waht to avoid. They talk constantly and you are in a strange car anyway enjoying a new experience. Yo buy the car and are surprised at how different it feels.

Next you just purchased a low wide sports oriented car running on wide low profile tyres. You already have the non sport suspension so it's the most compliant anyway so what are you expecting? What is the benchmark you are measuring against. Compared to any normal saloon or even 4x4 it may seem harsh, sensitive, bangs on bumps and tramlines. Put it through a series of bends and you get the payback.

I just suggest this so you don't spend ages chasing something that may not be there.

Personally mine is on runflats, m suspension and I love the way it's alive on the road.
Click to expand...

Have to agree i personally do not think the ride is harsh at all a little bumpy at times but as said its a sports car on low profile tyres my old Calibra was lowered on low profiles and that could really create a crash through the cabin over a pothole but my Z on RFs and M Sport Suspension is a lot smoother over the same roads.

Yes she will tramline but most cars on big wide low profile tyres will.
 
wow, i have the sports pkg on my 07 si and i thought it was pretty good. granted u can feel the imperfections in the road but after coming from a car which ran 2 diff aftermarket setups (neuspeed/bilstein and h&r/koni), i thought the oem sports suspension was "soft", haha.

adjusting tire pressure and going down a wheel size may help. and yes, ditch the run-flats.
 
I have a 3.0si with the Sports Package and have to commute over a stretch of roadway that definitely reminds you this is no Lexus. I slapped on a set of winter wheels last fall that are 225/45R17 (non RFT) and the ride difference was quite notable for my daily commute.

I just put the summer 18"s back on last weekend so I can attend a track day tomorrow and was once again reminded of the difference the height of the tire can make. FWIW my summer wheels are shod with Michelin PS2s instead of the OEM RFTs too. The 18" OEM RFTs are one of the worst tires I have ever experienced for both ride quality as well as tramlining.
 
Antisocialite said:
Does changing the tires to non-run-flats have any impact on the warranty?
Click to expand...
First welcome to the forum... :thumbsup:
and no effect on USA warranty.
 
Really just to reiterate what others have said. 2 weeks ago changed from 17s with run flats to 18s without, and the ride quality was instantly better. I went with the Falken tyres, and now I have run them in a bit, the handling difference is also truly remarkable. I have a short sharp corner leading up to my house which I can see is clear, and no matter what speed I throw the car into it at it just grips!
 
I have the falken's as well (and no this has nothing to do with the original post) but today upon leaving the shop I decided to do some hard accelerating (i.e. peeling out) and floored it with the DTC off. Well those falkens slipped only a little and the car took off. So I figure I did something not quite right. So at the stop sign I rev'd it to around 3k rpm and dumped the clutch (I know not good for the car) an let her rip. Slipped a little bit more but again they grabbed like a guy does when he's with a girl on top and he calls out the wrong name then has to hang on.
So yeah I love my Falken 452's.
Oh the tires were not warmed up either.
 
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