OE Suspension Bottoming Rant: Pathetic Attempt BMW...Oh How the Mighty Have Fallen...

[PrematureApex]

Excuse the rant...but my new-to-me 135i is my 5th BMW, and quite frankly, I'm embarrassed to say that.

BMW made its name (in addition to silky I6s) via suspension tuning. The ability to offer controlled, taught handling, without a ride penalty. In the past, this was accomplished via better-than-the-rest dampening, without having to resort to high spring rates.

Well, I just got back from my first significant weekend driving my '08 135i. I knew it would wallow, I knew it would pogo...but I dismissed the mentions of crashing into the bump stops/bottoming out the car in the reviews as just random, bad timing incidents.

Well, in 60 miles up and down I95, the car crashed into the bump stops no less than 4 times over normal for the north east expansion joints and other road irregularities. In each instance, my sleeping passenger awakened, startled that we'd just hit something.

Completely inexcusable on the suspension tuning front. The damn car crashes into its stops constantly.

It's no wonder so many mushroom the front towers.

What do you guys suggest?

Anyone cut the stock bump stops down?

Bilstein HDs? I'm wary to put lower springs on it, despite their stiffness, this thing doesn't have enough travel as it is.

I'm certainly moving to 17s, but that won't solve the issue.

Is this completely inadequate dampening and spring rate choice all just to make run-flat tires liveable?

Sorry for the rant. But my beloved BMW delivered an absolutely disgraceful piece of suspension tuning with this car. What a joke of a chassis to pair with this remarkable engine.

[631twentyeighteye]

yes it is to make the runflats liveable. get rid of the runflats, because those are half the problem, and get some bilsteins or koni FSD's with stock, or performance(or aftermarket, HR has a set that is barely any lower than stock) and that would solve your harsh ride issues.

[PrematureApex]

Originally Posted by 631twentyeighteye

yes it is to make the runflats liveable. get rid of the runflats, because those are half the problem, and get some bilsteins or koni FSD's with stock, or performance(or aftermarket, HR has a set that is barely any lower than stock) and that would solve your harsh ride issues.

Runflats are off. But they have nothing to do with the car bottoming out driving down the highway with one 130 lb. passenger in it.

[631twentyeighteye]

Wasn't blaming them for that, they only add to the harshness of bumps though. The stock dampeners are garbage, thats the real reason for the issue. you have it half fixed with the runflats gone, but Performance springs and koni's or perf shocks sound like your desired ride preference. the perf springs with either shocks is supple over bumps yet firm when turning, it's said to ride better than stock.

[tracer bullet]

I don't have any issues bottoming out, and I live in MN the land of potholes and screwed up expansion joints. I wonder if there's a chance there's a suspension part failing on you (design aside, maybe something is broken)?

I can't disagree they hobbled the car a little from the factory, which is unfortunate. Even as many comparison tests as our little car won the reviewers always had the same complaints. Luckily, we can pretty easily fix them all! I'd rather not have too, but glad I can.

[zoomnad]

How many miles are on the car? Most stock shocks are shot at 25-35,000 miles.

[PrematureApex]

Originally Posted by tracer bullet

I don't have any issues bottoming out, and I live in MN the land of potholes and screwed up expansion joints. I wonder if there's a chance there's a suspension part failing on you (design aside, maybe something is broken)?

This is review is on a car no more than one year old:

In fact, our logbook contained almost nothing but praise for the way the 135i drove. Great steering, powerful brakes, and smooth power - these are qualities we have admired in the current 3-series, the car upon which the 1-series is heavily based. Despite its sport package, our big-wheeled One even rode well - until you encountered a nasty bump in the road. As if the progressive bump stops were mistakenly omitted on our car, the 135i suddenly would run out of wheel travel, crashing over potholes and pavement seams and transmitting a horrifying whack to the cabin. "I hate this suspension," cried senior Web editor Phil Floraday. And that was months before he hit a double-whammy sequence of classic Detroit road craters severe enough to blow the left front tire. "I momentarily panicked since there was no shoulder on the road," he recalled. "Then I remembered those run-flat tires we've been complaining about forever - it turns out they work great. When I was able to pull over, I inspected the rim. It seemed fine, so I carefully drove home with no air in the tire."

So what's the kerfuffle about having too much power? Well, we roasted the rear summer tires in about 12,000 miles, so we obviously enjoyed every last bit of the thrust. The only problem is that we've all driven the 128i. It rolls on smaller wheels and tires, giving it a more supple ride and much greater resistance to bottoming out. It also costs about $6500 less, leaving lots more room in the budget for gadgets like Bluetooth, power seats, and navigation, which, for 2009, comes with BMW's vastly improved iDrive system.


Read more: http://www.automobilemag.com/reviews...#ixzz2X8SH6sfG

[PrematureApex]

Koni yellows on sale at Tirerack, making their price dangerously close to the Bilstein HDs (~$600).

I wonder how much firmer the yellows will be at full soft vs. the HDs.

[runnin9z]

I notice the same things and cringe everytime it happens. I'm used to this happening on my old cars but that is when they are lowered 2in or more, I am with you I am pretty disappointed in the suspension in this car. And yes i did change out my runflats.

[flinchy]

i never experienced anything like that! (sport suspension)

i didn't like the comfort, felt stock suspension was too bouncy

but never came close to bottoming out on stock stuff

[TS135i]

As soft & bouncy the M-sport suspension is I have never bottomed out on our crappy roads.
In fact I find it necessary in order to live with such road conditions, that's why I have purchased M3 bushings & M3 rear lower/upper control arms only, everything else remains stock.

[jafo1701]

Just remember BMW designed the suspension to work with runflats. That's why all the bushings are soft. Also why the suspension seems to get worse when you swap to non runflat tires. Switching out to the M3 bits seems to really help, especially the M3 subframe bushings.

[dsh135]

Switching out to the M3 bits seems to really help, especially the M3 subframe bushings.

This is very true. I found that M3 control arms, rear subframe bushings, and fr/rr sways transformed the stock suspension. That said, I too have bottomed-out the rear a few times on large compressions in the road. Doesn't happen frequently however.

[IGoFast1589]

The stock dampers, bump stops and springs are fucking terrible. The bushings are pathetic and the suspension arms are weak. In my opinion, the whole suspension is a joke from the factory. The rear suspension links look like tooth picks in comparison to a Nissan 370Z, Porsche or any good sports car really.

Yes, my suspension crashed CONSTANTLY also! I tightened the rear subframe up with powerflex inserts, added M3 sway bars for control front and rear, limited slip differential and Bilstein dampers and Eibach springs and FINALLY it is sufficient...

[Ginger_Extract]

Originally Posted by zoomnad

How many miles are on the car? Most stock shocks are shot at 25-35,000 miles.

Unless you're buying China-bay shocks, that is not the case at all. For a street car, getting less than 60-80,000 out of a set means that they are garbage parts.
To the OP, you have found out the hard way as have many of us how BMW neutered the car to not be competitive against the M-brand. Needs more dampening front and rear, and a lot more spring rate in the rear.

[Clovef]

I think your assessment is a little harsh but I know what you are describing. I have never before experienced a jolt that made me pull over because I thought something caught in any of my cars prior to my 135i. I thought I must have done damage but did not. If you are having this happen over and over I think I would get it checked out, it should not happen so easily that it is multiple times a drive.

[PrematureApex]

Originally Posted by Clovef

I think your assessment is a little harsh but I know what you are describing. I have never before experienced a jolt that made me pull over because I thought something caught. I thought I must have damage but did not. If you are having this happen over and over I think I would get it checked out, it should not happen so easily that it is multiple times a drive.

So it's never happened to you, so it can't be true?

Plenty of others have experienced it. Did you read the article I posted?

How many people have mushroomed their towers again?

That happens from bottoming out. It happened multiple times on a longer drive, with a passenger in the car, and a god-awful stretch of I-95 doing 80-85 MPH.

It's not happening more than once or twice a week during my normal commute, normally you can avoid it if you know your route and trouble spots. But it's completely unacceptable.

Where do you live? The conditions of the roads you drive on makes all the difference. In a NE city, you could easily bottom the car out on a daily basis if you weren't being midful of your speed and pothols, buckled roads, etc.

[Zombie1]

Stock suspension is garbage rant away

[John_01]

Unfortunately it doesn't take much to bottom out the front suspension. The 3 series has the same issue, but the 1 series is a bit worse for some reason. Neither of the cars have a lot of suspension travel and it seems like bump stop is there to assist the spring. The cars are basically designed for smooth roads. However the wobbly, soft suspension bushings and runflat tires still rates as the #1 worst feature of the car IMO. [/Rant]

[Clovef]

Sorry, my above post was unclear. I have had this happen and it made me feel that I must have hit something substantial and done damage. It has not been often but I have changed out the springs and shocks after about 17k miles. For some reason, if it hits wrong it slams through the cabin and it can be jarring.

[BrokenVert]

Originally Posted by John_01

Unfortunately it doesn't take much to bottom out the front suspension. The 3 series has the same issue, but the 1 series is a bit worse for some reason. Neither of the cars have a lot of suspension travel and it seems like bump stop is there to assist the spring. The cars are basically designed for smooth roads. However the wobbly, soft suspension bushings and runflat tires still rates as the #1 worst feature of the car IMO. [/Rant]

Thats actually the truth. The 1 series and the 3er's suspension design incorporated progressive bumpstops. They are about 2 inches long and the suspension only has half an inch of travel before them.

The bump stops compress and take away a bit of energy (much like a helper spring.