[hokiedood]

I drive a 340i and I can feel every bump and the road surface. Is there a way to increasing damping for a more comfy ride. Can I do it without sacrificing handling?

[FaRKle!]

Feeling every bump is more likely due to over damping, not under damping. When compression damping is too high it prevents the shock from compressing and the suspension from absorbing the energy of the bump.

[Billfitz]

What do you have for wheels and tires?

[cfm56d7b]

Originally Posted by Billfitz

What do you have for wheels and tires?

... and whether the vehicle has M Adaptive suspension?

[johnung]

Originally Posted by hokiedood

I drive a 340i and I can feel every bump and the road surface. Is there a way to increasing damping for a more comfy ride. Can I do it without sacrificing handling?

If your 340i is pretty much stock and those highway seams are jarring your fillings loose, my guess is that roughly half of what you are feeling is coming from the stock dampers and springs. The other half is coming from the old wooden wagon wheel runflat tires with their ultra stiff sidewalls. There are many varying solutions depending on your priorities.

As others have mentioned, more information is needed to provide you with any useful advice. What year, mileage, adaptive or non-adaptive suspension option installed, what wheels/tires/sizes? Is everything stock, or what mods are on the car? How is the car used- anything from stock daily driver to a weekend track car? What types of roads do you drive and what climate? Winter weather or not? Do you intend any future mods or upgrades?

[hokiedood]

My 2016 340i is totally stock with 13k miles. It has the M Sport suspension with 18" wheels and RFTs.

The car is my daily driver. I'm in San Francisco where the roads aren't that good. Pot holes, those large plates, light rail tracks. Mild winters with no snow.

I have no plan to mod it atm unless there are options to smoothen the ride without sacrificing handling.

Originally Posted by johnung

If your 340i is pretty much stock and those highway seams are jarring your fillings loose, my guess is that roughly half of what you are feeling is coming from the stock dampers and springs. The other half is coming from the old wooden wagon wheel runflat tires with their ultra stiff sidewalls. There are many varying solutions depending on your priorities.

As others have mentioned, more information is needed to provide you with any useful advice. What year, mileage, adaptive or non-adaptive suspension option installed, what wheels/tires/sizes? Is everything stock, or what mods are on the car? How is the car used- anything from stock daily driver to a weekend track car? What types of roads do you drive and what climate? Winter weather or not? Do you intend any future mods or upgrades?

[FaRKle!]

Originally Posted by hokiedood

My 2016 340i is totally stock with 13k miles. It has the M Sport suspension with 18" wheels and RFTs.

The car is my daily driver. I'm in San Francisco where the roads aren't that good. Pot holes, those large plates, light rail tracks. Mild winters with no snow.

I have no plan to mod it atm unless there are options to smoothen the ride without sacrificing handling.

You absolutely can increase grip/performance and increase ride comfort. Just depends on how much that's worth to you...

If you're willing to spend the same amount as a good set of coilovers, I recommend you pick up this set of Bilstein B8s and send them to Fat Cat Motorsports for bespoke tuning. They're local in San Mateo.

You might consider moving to a stiffer rear spring too to increase the flat ride ratio. I know that sounds counter intuitive, however going stiffer can mean more comfortable. For example, I went from a 650lbs/in spring to 900lbs/in rear spring recently, and the ride smoothness increased. Terrible, broken, and uneven pavement in construction zones doesn't feel nearly as disruptive as it used to.

[johnung]

Originally Posted by hokiedood

My 2016 340i is totally stock with 13k miles. It has the M Sport suspension with 18" wheels and RFTs.

The car is my daily driver. I'm in San Francisco where the roads aren't that good. Pot holes, those large plates, light rail tracks. Mild winters with no snow.

I have no plan to mod it atm unless there are options to smoothen the ride without sacrificing handling.

I've got a similar car with similar poor road issues. 2015 335ix but in Philly with some snow in winter. I couldn't take the jarring of the stock suspension on the bad roads and especially highway seams that thump, thump, thump.

I installed Koni Special Active Dampers. See photo for part# for your car. Koni and McLaren codeveloped the technology. It's like a mechanical active suspension. One valve is based on frequency for handling curves and the other valve handles the frequency from sharp jarring bad roads. It really works. Best of both worlds.

The other change I made after a year of fighting it in my head, was to ditch the runflats. I kept the stock wheels which I like. Went from stock size 225/45-18 to 245/40-18 Michelin Pilot Sport 4S. Can't say enough about the grip in both dry and wet. And they handle the worst potholes beautifully. Got great advice on this from wheel/tire guru alohasurftoad Read his stuff for excellent advice.

Wasn't that difficult to prep for goflat. Now I keep a few things in trunk compartment. An "8-minute" Slime compressor (about $45 at Walmart). And from Harbor Freight: cheap mechanic's gloves, long breaker bar with 17mm socket and a scissor jack that fits right into BMW jack point on car. See photo. For long trips I throw a spare in the back consisting of a used stock wheel that I bought and one of my old runflats. I just don't want a trip disrupted with having to stop to have a tire fixed or replaced.

Good luck. Hope this helps!

[dsc888]

Originally Posted by hokiedood

My 2016 340i is totally stock with 13k miles. It has the M Sport suspension with 18" wheels and RFTs.

The car is my daily driver. I'm in San Francisco where the roads aren't that good. Pot holes, those large plates, light rail tracks. Mild winters with no snow.

I have no plan to mod it atm unless there are options to smoothen the ride without sacrificing handling.

I too have a 340i and I am almost positive your issue is mostly the Runflat tires. I upgraded mine with the Eibach Pro Kit suspension and Bilstein B8s, which I believe is firmer than your stock MPerformance sport suspension and the one common denominator is the OEM tires, that I had suffered with for the last 2 years.

The RFT are firm by design to self sustain the sidewall should you have a puncture but that is also the reason why you feel very crack and imperfection in the road and get a ton of tire noise. It makes the suspension feel down right “fragile” and “crashy” over anything but the smoothest surfaces.

My new solution (courtesy of eBay’s recent 10% eBay Bucks promo) was to get new non-RFTs. I ordered Michelin Pilot Sport PS4s and they are sitting in my kitchen as I type this response to be installed this week. I will gain a more complaint ride, much better non winter grip/handling, a quieter cabin and most importantly true enjoyment of my German sporty sedan!

[johnung]

Originally Posted by dsc888

I too have a 340i and I am almost positive your issue is mostly the Runflat tires. I upgraded mine with the Eibach Pro Kit suspension and Bilstein B8s, which I believe is firmer than your stock MPerformance sport suspension and the one common denominator is the OEM tires, that I had suffered with for the last 2 years.

The RFT are firm by design to self sustain the sidewall should you have a puncture but that is also the reason why you feel very crack and imperfection in the road and get a ton of tire noise. It makes the suspension feel down right “fragile” and “crashy” over anything but the smoothest surfaces.

My new solution (courtesy of eBay’s recent 10% eBay Bucks promo) was to get new non-RFTs. I ordered Michelin Pilot Sport PS4s and they are sitting in my kitchen as I type this response to be installed this week. I will gain a more complaint ride, much better non winter grip/handling, a quieter cabin and most importantly true enjoyment of my German sporty sedan!

Pack a lunch, because once you put those tires on you won't be home for a while!

[dsc888]

Originally Posted by johnung

Pack a lunch, because once you put those tires on you won't be home for a while!

Haha! I take it the hype is REAL with the PS4s! I can’t wait till the suffering ends with my wooden wagon wheels tires.

I saw that some folks even can run them down to near freezing temps with only slight drop in both dry and wet traction. I got them in the 245/40 18 size and will put them on my OEM 400M wheels. I’m saving the OEM RFTs for when I trade or sell my car.

[hokiedood]

Let me know how the PS4s work out for you!

Originally Posted by dsc888

Haha! I take it the hype is REAL with the PS4s! I can’t wait till the suffering ends with my wooden wagon wheels tires.

I saw that some folks even can run them down to near freezing temps with only slight drop in both dry and wet traction. I got them in the 245/40 18 size and will put them on my OEM 400M wheels. I’m saving the OEM RFTs for when I trade or sell my car.

[johnung]

Originally Posted by dsc888

Haha! I take it the hype is REAL with the PS4s! I can’t wait till the suffering ends with my wooden wagon wheels tires.

I saw that some folks even can run them down to near freezing temps with only slight drop in both dry and wet traction. I got them in the 245/40 18 size and will put them on my OEM 400M wheels. I’m saving the OEM RFTs for when I trade or sell my car.

The compounds on these tires are very temperature specific. MPS4S are good down to about 40 degrees. Many guys I've talked to in Philly/NJ area around early December take them off and either put stock runflats back on or winter tires.

I've heard great things about Blizzak WS90's in snow but since we get more cold and ice I'm leaning towards Michelin X-Ice. Also stock size with higher sidewall is best for snow so I'm getting them in 225/45-18. The compounds on these winter tires are meant for 40 degrees and under so around April, the summer tires will go back on.

Some living in winter climates will attempt to compromise with an all season tire. But the tire gurus say it's just that, a compromise. A tire that's not great in either situation. I envy the CA and other folks who can leave the summer tires on all year.

[dsc888]

I'll preface this reply and apologize to the OP for this longwinded tire review. But I feel this adds to the discussion as rough riding RFTs that many complain about can be easily remedied with non-RFTs. For those who don't know my F30, I had recently installed Eibach lowering springs and Bilstein B8 struts and while the handling was great on glass smooth roads, the ride took a turn for the worse on almost all roads. I felt that the suspension couldn't be fully enjoyed unless I were on a track. So I decided to get new Michelin Pilot Sport 4S tires to kill 2 birds with one stone...1) Get a supple, compliant ride that even the OEM setup never had and 2) Gain markedly improved handling that a BMW should have always had.

So I finally had my MSP4s mounted early today and can definitely say that they are one gem of a tire! To recap, I got the 245/40 18 size and had them mounted onto my OEM 400M wheels because I didn't want to spend money on new ones and kinda actually like the OEM look. It gave me 20mm or tread width vs OEM and the overall diameter was about 1% less at 25.7 inches vs 26.0 OEM. Weight of the OEM tires were 25.2 lbs and the Michelins were 23.3 lbs per my bathroom scale. So there was almost 2 lbs of unsprung mass savings per corner.

The Continental RFTs that came from the factory still had a decent amount of meat on them but they felt hard as a rock especially after I had my Eibach Pro Kit suspension installed. They felt great in terms of turn in immediacy but that was about all they are good for. The ride was unnecessarily stiff. They got noisier and noisier after about 10k miles and traction limits were on the low side.

PROS:

1) They grip like superglue! In 60 degree F ambient air temps today, I could not break traction with moderately aggressive acceleration or cornering. The car just takes a set line and goes where it is pointed. No muss.No fuss. I was able to take on of my local expressway onramps with a 90 degree turn right before merging with the flow of traffic at 50 MPH (with room to go even faster) where as the day before I was maxed out at 43 MPH with tires starting to protest. Not scientific but it's a turn I take daily that I am very familiar with.

2) The ride is markedly better. These tires are firm vs your run of the mill all season non-RFT but they are downright comfy vs the Continentals RFTs that were on my car for the last 2 years. I "glide" over road imperfections now vs taking them though my seat. You hear the bumps lightly "thump thump" as the sidewalls absorb the pavement vs telegraphing it to the seat without filter. The ride is remarkably close to my OEM factory setup! So now I have BETTER handling and grip with much improved ride. Gone is the crashy and fragile ride that seems to be the Achilles heel of the F30 suspension (especially for those like myself who lowered their cars with a stiffer setup).

3) The car's interior is quieter. I didn't have a sound meter with me but the drive is quieter on all surfaces. It's most noticeable on smooth pavements. The F30 isn't known for being quiet so noise reduction was limited. Highway speed road noise levels seem slightly reduced.

4) Better dynamics! By choosing a slightly shorter tire, I effectively shorted my gear ratios and with the 2 lb reducing in unsprung mass, acceleration, braking and corning had improved a noticeable amount. I wasn't expection to feel the improved braking or acceleration gains but was shocked at how much more of the engine's power and brake pads clamping force I was able to achieve even on normal daily commuter driving.

5) Going from 225 to 245 width tread not only gained traction laterally but it gave my wheels a slightly wider stance. The tire now hangs about 1cm outside of the wheel. It's almost as though I added a 10mm spacer to the hub. It's a nice little bonus in the looks department.

Cons:

1) They are only for 3 seasons! With a tire this good, I wish there was a 4 season PS4S.

2) These things pick up everything on the road and will sandblast your car unless you add mudguards (uh...no) or at least a clear bra like solution to your fenders and rear bumps.

3) Steering sharpness at turn in is reduced. I expected this when transitioning from RFT but I gladly trade it for improved ride, noise and handling anyway.

4) There seems to be slightly decrease steering effort. I might have to revisit this one after a few hundred miles as new tires are a bit slippery due to the mould release agents on the surfaces of the tire. I read folks not liking the Michelin Pilot AS3+ tires due to much decreased steering effort, which I would not like.

So all in all, get good tires if you want to love your car all over again. BMW obviously wanted to save $$$ and weight when they defaulted most of their cars to be delivered with RFT and marketed it was "added safety and convenience" which is true to some level. But you pay the price of expensive replacement tires, rock hard ride and diminished handling capability. The Michelin PS4S is not the only option but it is one of the best ones on the market. You owe it to yourself to consider them if you want to squeeze every ounce of performance out of your car with comfort to boot.

[dsc888]

Originally Posted by hokiedood

Let me know how the PS4s work out for you!

(see above reply)

[Billfitz]

Going from RFT to non-RFT should help. Where shock absorption is concerned a taller sidewall is better than shorter. Air and rubber damp shocks, aluminum doesn't.