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      07-13-2014, 11:02 AM   #23
Twix
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Even my heavy weight 28i is unstable at high speeds. It's caused by the poor aerodynamics of the X1. Too much air under the car, not enough down force. Plain and simple. Even with my car lowered 1 1/4" it still sits much higher than a sedan.

The reason bigger SUVs don't have this problem as much is because they have so much more height that the pressure underneath can be more easily matched by the wind coming over the hood and windscreen.

I dare you to put a chin spoiler and rear wing on an X1 and see if this problem still exists to the point that it scares you.

I felt this same problem when I test drove the Infiniti EX37 before I purchased the X1.
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      08-12-2014, 04:13 PM   #24
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I am experiencing the same OP described and I am researching for options to fix it:

1. 12 mm spacer on the front wheels. I want to spacer on the rear wheels for aesthetic purposes. I am thinking 18front/15rear or 15front/12rear. Do you think I need bigger difference like 18front/12rear?

2. Tire pressure. The Owner's manual states two different pressures for the rear tires??! Below is for staggered tires:
Tire inflation pressures X1 sDrive 28i
Tire inflation pressure values up to 100 mph/160 km/h
Front: 225/45 R 18 91 V RSC: 2.4bar/35psi
Rear: 255/40 R 18 95 V RSC: 2.6bar/38psi

Tire inflation pressure values over 100 mph/160 km/h
Without high-speed tuning feature (<-WHAT IS THIS???)
Front: 225/45 R 18 91 V RSC: 2.4bar/35psi
Rear: 255/40 R 18 95 V RSC: 2.9bar/42psi

3. Sway Bar. Nobody mention it in this thread but isn't this only for stability in turns at high speeds?

4. Lowering the car. Not an option for me since I don't like the look.

I would like the knowledgeable people to elaborate (not so knowledgeable like me can too )
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      08-12-2014, 06:42 PM   #25
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You have the same X1 s28i M Sport like me, so I think they mean "high speed tuning feature" is M Sport with bigger anti-sway bars, etc.

I have summer tires Pirelli P7, and like 38 front @ cold (60-90 deg), and 40 rear cold.

I'm written about the high speed instability several times, and put Burger 12mm front spacers which tightened up steering, and keeps the roll to a minimum under 130 mph which is fast enough for me.

You can put spacers in back also if you like and will probably make it even more stabile, but will understeer more or be harder to corner.

If you don't drive fast on curvy roads more spacers in back might be what you like, but try 12mm in front first.
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      08-12-2014, 09:24 PM   #26
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There are X1 owners in Taiwan and Japan that have retrofitted a 3 way lower subframe brace to their cars along with 20mm + F/R sway bars and noticed a significant amount of improvement through turn in and out. Those mods along with better tires, coilvers and the AC Schnitzer rear spoiler members tremendously saw a improvement in the X1's aerodynamic and stability.
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      08-13-2014, 09:48 AM   #27
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My tires were way too underinflated about 30 psi!!! Stability improved!

When the TPM warns about low pressure?!
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      08-13-2014, 10:24 PM   #28
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Quote:
Originally Posted by d1saster View Post
My tires were way too underinflated about 30 psi!!! Stability improved!

When the TPM warns about low pressure?!
Maybe the system is designed to catch one or two tires different which means something happened after you started driving.

They assume that you will air up several times a year because of normal tire porosity.

Now be sure and set tire pressure with stalk when starting off cold.
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      08-16-2014, 01:09 AM   #29
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just confirmed with some X1 owners. The S drive models is missing the V-brace which is present in the x drive models. This could be a possible reason why x drive models feel more stable at speeds above 50 mph+ Also rear suspension portion of the s drive model looks different from underneath. Trying to find out if the v brace can be retrofitted onto rwd cars...
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      08-18-2014, 01:23 PM   #30
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Quote:
Originally Posted by tw4life View Post
just confirmed with some X1 owners. The S drive models is missing the V-brace which is present in the x drive models. This could be a possible reason why x drive models feel more stable at speeds above 50 mph+ Also rear suspension portion of the s drive model looks different from underneath. Trying to find out if the v brace can be retrofitted onto rwd cars...
When you refer to v brace are you talking about #17 from the diagram:

http://realoem.com/bmw/diagrams/r/w/240.png

For vehicles with
Electric panoramic roof
S402A=Yes
17 Tension strut 1 33326777637 $67.83 +core

If that's the correct part I confirm I have it on my s28i with panoramic roof.
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      08-18-2014, 01:57 PM   #31
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So a thread starts and there are at least 6-7 "known" reasons why this is happened. Tire pressure, EPS, strut brace, aerodynamics and on and on or in other words these are all guesses. Why someone would drive an SUV 120+ is the first problem, get a sports car not an SUV and expect it to handle like an M. I have an sdrive M Sport and have not experienced a problem yet I don't drive it 100+ so maybe I'll go to a race track so I can create a problem that doesn't exist. Go back from the start and there are maybe 5 total people saying it might be an issue. BMW has literally sold well over 500,000 of these and they have sold them for almost 5 years now so if there was an issue don't you think it would be all over the internet by now, just saying.
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      08-18-2014, 06:36 PM   #32
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Quote:
Originally Posted by d1saster View Post
When you refer to v brace are you talking about #17 from the diagram:

http://realoem.com/bmw/diagrams/r/w/240.png

For vehicles with
Electric panoramic roof
S402A=Yes
17 Tension strut 1 33326777637 $67.83 +core

If that's the correct part I confirm I have it on my s28i with panoramic roof.
That explains it. My car has no sunroof. Therefore the v brace is probably there to accommodate the extra weight on top of the car.
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      09-13-2014, 05:30 PM   #33
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I don't know if this is helpful as a data point, but my 2014 28 xDrive feels wonderful and planted at high speed cruising in excess of 80mph even in windy conditions with a bike rack on the back.
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      09-13-2014, 10:14 PM   #34
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Same here. I have a 2013 xDrive 28 with roof-mounted base supports and the thing is rock solid stable at highway speeds 75-90.
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      09-13-2014, 10:58 PM   #35
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I have a 2013 xdrive 28i and I regularly cruise at 100 mph on the highway and it's planted and rock solid.
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