More on 'unstable at high speed'

[RPM90]

As I'm getting ready to order my 135i, I got really worried about all the comments about instability at speed. The speed numbers have ranged at over 120mph to as low as 60-70mph. So, I did some web searching on the subject. I was surprised to find that this instability issue comes up with not with just 1 series but with 3 series coupes and sedans.

GOOD NEWS: Most of this seems to come from overly inflated tire pressures, and/or very unequal tire pressures among the tires.
And, that would make sense. Higher pressures are good for high speed running, but only to a point. If you start with high pressures they will only go higher as the speed increases and the tires heat up increasing the air pressure.

So, can some of you comment on the tire pressures (cold tire pressures) you are running and if you have this "instability" at high speed?

[mtla4]

Honestly its normal that the 1er becomes unstable.They're by no means sports cars. They're sporty cars but no sports car. The stock suspension doesn't help either.

[RPM90]

Originally Posted by mtla4

Honestly its normal that the 1er becomes unstable.They're by no means sports cars. They're sporty cars but no sports car. The stock suspension doesn't help either.

I don't buy that.
Why? Because only some 1's claim this instability. It's a minority.
Most say this does NOT happen.

It doesn't make any sense that BMW would build a car designed to run over 100mph all day long, that would be unstable at those speeds.
That would actually be very UNnormal.

Also, it would seem that we would have read much more about this, if it were normal, from the auto press who test vehicles at very high speeds.
And, this model has been around since 2004 in other parts of the world.

My A4 sport and former 325i sport were not sports cars either, but they are very stable over 100mph.
Some people here are saying that even at modestly high speeds like 80 or 90 are "scary" or dangerous, and other words like that.

[jmr_70]

I was on the highway running at over 140(kms) earlier this evening...no issues here, my 1er handled and drove just fine. Most of the time it doesn't actually feel like i'm going as fast as I am because it rides so smoothly. I guess it would only be scary if i'm not used to driving that fast to begin with.

[Jay's128i]

I got to drive my 128i for about six months in Germany. The average speed on the autobahn is well over 100mph. And I did not have any problems. I would check tire pressure.

[UR2SLOW1]

I've been up to 140 in my 135i (on a closed course and the car seemed just as stable as my NSX. JM2C

[penny]

Smooth for me at any speed.

[lib]

Originally Posted by RPM90

Some people here are saying that even at modestly high speeds like 80 or 90 are "scary" or dangerous, and other words like that.

If someone feels the 1's are "scary" or "dangerous" at 80-90 there is either something wrong with the car, the road or the driver. It can be a bit bouncy/floaty when the road is not smooth but it does that at all speeds.

If there was a legitimate problem at those speeds BMW would be opening itself up to severe legal problems. Not everyone in the world is limited to 55mph.

[BrokenVert]

I find that at higher speeds the back becomes light. Like there is an airpocket underneath it. But I am talking about speeds that are kinda stupid on US roads.

Looks like I just need to buy a new diffuser. Maybe one of those two-tier ones. I hear those work well.

[hot_ride]

My 1er reminds me of my motorcycle... it starts to feel in it's zone at 100mph.

Keep in mind that these are German, better highways, higher speeds. If there was a systemic issue it would not only ruin BMW but also be reported by all users.

[lib]

Originally Posted by BrokenVert

Looks like I just need to buy a new diffuser. Maybe one of those two-tier ones. I hear those work well.

With the amount of money they've been throwing at the problem I'm sure Ferrari has a few you could borrow

[xbook]

Originally Posted by RPM90

As I'm getting ready to order my 135i, I got really worried about all the comments about instability at speed. The speed numbers have ranged at over 120mph to as low as 60-70mph. So, I did some web searching on the subject. I was surprised to find that this instability issue comes up with not with just 1 series but with 3 series coupes and sedans.

GOOD NEWS: Most of this seems to come from overly inflated tire pressures, and/or very unequal tire pressures among the tires.
And, that would make sense. Higher pressures are good for high speed running, but only to a point. If you start with high pressures they will only go higher as the speed increases and the tires heat up increasing the air pressure.

So, can some of you comment on the tire pressures (cold tire pressures) you are running and if you have this "instability" at high speed?

I have had my 135 well over 100mph, and have yet to feel any instability. Maybe the source of the criticism is suspect.

[1013mm]

i guess you get used to it after a while, my first time well above 80 it was unstable and wobbly... now its fine...

[pimmy]

I have a convertible, and drove it in Germany yesterday .
On GPS i drove 225 km/h (140 mph) and didn't feel ANY instability at all!!! I find it very stable instead!
I had a Mini cooper S before, and that was a little instable at high speeds (+ 200km/h, 125 mph).
It's an 125i with the M-sport package!

[imported_mega]

Originally Posted by mtla4

Honestly its normal that the 1er becomes unstable.They're by no means sports cars. They're sporty cars but no sports car. The stock suspension doesn't help either.

yeah, and the m3 is not a sports car either right?

[lib]

It depends on your definition of is, er sports car. It's subjective and some don't count the m3 as a "sports car."

[M3_Dust]

it's not the tire pressures

most people who drive the 1'er don't have a great basis for comparison of high speed stability, the fact is that the suspension is quite soft and the car becomes very floaty and unstable with an inconsistent feel at very high speeds, it becomes more pronounced the faster you go and with uneven surfaces.

that's really all there is to it, accept it or not, it's a reality

[RPM90]

Originally Posted by M3_Dust

it's not the tire pressures

most people who drive the 1'er don't have a great basis for comparison of high speed stability, the fact is that the suspension is quite soft and the car becomes very floaty and unstable with an inconsistent feel at very high speeds, it becomes more pronounced the faster you go and with uneven surfaces.

that's really all there is to it, accept it or not, it's a reality

But.....not according to real life experience posted here.

SO, this "reality" is not consistent, nor the norm it seems.
And, it happens with the 3 series too. Check the E90 forum and you'll read some posts saying the same things.
Yet, my E46 325i didn't have even one hint of "float", "instability", "danger", etc...

"Very floatly and unstable" are serious descriptions. They describe a downright scarry vehicle that shouldn't be on the road.

[M3_Dust]

I guess you should just get one and see for yourself then

[Robert]

Instability changes from person to person because it is based on perception. One person's instability maybe be the norm for others. Without a metric we will be arguing all day.

[jmr_70]

Originally Posted by Robert

Instability changes from person to person because it is based on perception. One person's instability maybe be the norm for others. Without a metric we will be arguing all day.

+1 (Thanks for putting an end to this one)

[Dave Mac]

My 1er has always been rock solid at any speed.

There is a rather large cross section of people driving these cars now, not just experienced enthusiasts. You must consider that fact and understand that not everyone know's what a car is really doing at higher speeds or knows how to communicate effectively. BMW has done enough testing on these cars at all speeds and I'm sure that they are safe.