[Siberhius]

Hello, everyone!

I recently got a BMW M240i XDrive, 2017 with 15,500 miles.

Yesterday for the first time I went out to walk on the road and noticed it "unstable" at high speed (+120mph). It feels like a kind of "dead spot" on the steering wheel and I feel like the front of the vehicle is "snaking."

The vehicle is all standard, check the tire pressure (38psi). I'm running bridgestone potenza 245 35 18 runflat.

I have checked the chassis from end to end and it does not appear to have any crashes.

The suspensions look good and without losses or problems.

It has passed vehicle inspections without problems and has official BMW services.

I've read some similar cases, so I don't know if it's "normal" or if I have something to worry about.

Any recommendation?

Thank you and best regards!

[Dom147]

I would check to see if there is any play in any of the suspension parts and the wheel bearing possibly. It could even be something as simple as your wheels not being balanced properly

Your car should feel stable at even 160.

[WolfGTI]

Wrong - at 160 the 240I doesn't have the aero to feel rock solid. However at 120 it should feel stable albeit there will be some lift occurring, so it will not feel as stable as say 80mph.

Originally Posted by Dom147

I would check to see if there is any play in any of the suspension parts and the wheel bearing possibly. It could even be something as simple as your wheels not being balanced properly

Your car should feel stable at even 160.

[MarcoZandrini]

OP, try lower pressures cold. The front pressures should be about 1 psi less than the rears. Also, has the alignment been checked.

[John in VA]

Research "tramlining." It can be caused by the road surface or tire condition.

[Siberhius]

Good morning guys!

Originally Posted by Dom147

I would check to see if there is any play in any of the suspension parts and the wheel bearing possibly. It could even be something as simple as your wheels not being balanced properly

Your car should feel stable at even 160.

I imagine that at 160 it will be even more unstable...

Originally Posted by MarcoZandrini

OP, try lower pressures cold. The front pressures should be about 1 psi less than the rears. Also, has the alignment been checked.

I will try irt but I think that 1 psi It's not going to make a difference, wheels are aligned and balanced...

Originally Posted by John in VA

Research "tramlining." It can be caused by the road surface or tire condition.

Not tramlining! Because I test in different routes and the issue persists. But It feels like that! the car tries to follow a different line. Suggest?

Thanks guys!

[Apo Zubulthums]

Could it be a bad runflat tire?

[Mr. Bill]

Originally Posted by WolfGTI

Wrong - at 160 the 240I doesn't have the aero to feel rock solid. However at 120 it should feel stable albeit there will be some lift occurring, so it will not feel as stable as say 80mph.

+1 I can feel some lift at higher speeds. Until that starts to happen the car feels 100% stable. I just bought a C8 and the 240 feels more nimble, but once you get up to speed you can feel the C8 stay way more planted.

[Siberhius]

Originally Posted by Apo Zubulthums

Could it be a bad runflat tire?

Could be, checking the tires I noted that the car has the original tires (2017), so I'm going to put new tires next month.

[kenken662]

May be due to the floaty stock suspension combined with short wheelbase. Were you in sport mode when it felt unstable?

[morphomeman]

OMG, travelling at 120 mph with seven-year-old tires and OP wonders why the car feels unstable!
My suggestion is to slow down before you kill someone.

[Siberhius]

Originally Posted by kenken662

May be due to the floaty stock suspension combined with short wheelbase. Were you in sport mode when it felt unstable?

Sport +!

Originally Posted by morphomeman

OMG, travelling at 120 mph with seven-year-old tires and OP wonders why the car feels unstable!
My suggestion is to slow down before you kill someone.

My mistake! Never imagined that a seven-year-old vehicle could have original covers. When I started to review what the possible causes of the issue, I found the date of the wheels.
I tested the vehicle 100 kilometers away from the city, there were no other vehicles, so there was no danger of killing anyone except me!

[marksandygill]

Originally Posted by morphomeman

OMG, travelling at 120 mph with seven-year-old tires and OP wonders why the car feels unstable!
My suggestion is to slow down before you kill someone.

As long as the tires are maintained properly the age shouldn't really matter...

[Rocky58]

Originally Posted by marksandygill

As long as the tires are maintained properly the age shouldn't really matter...

Most manufacturers recommend replacement after 6-10 and most places will not service or mount 10 year old tires. They may look fine but have deterioration that is not visible. Even properly stored tires deteriorate. I check the manufacture date when I buy new tires because I got sold two-year old tires once. Week and year of manufacture are stamped on the tire.

[Siberhius]

My experience about old tires:

I used to have an Aprilia Tuono V4 1100, with modified exhaust, intake bodies, air filter, and race ecu. The bike has aproximately 195hp.

Runs Pirelli Diablo Rosso Supercorsa, fabrication 2012 in front tire and 2016 in rear tyre. Last year before I sell it I used to go to track days and running about 300 km/h, never have any issue, loss of grip, deformation, vibration, etc.

So. in my experience, If the wheels have been maintained correctly, without exposing them to the sun or sudden changes in temperature, there should not be too much of a problem.

[marksandygill]

Originally Posted by Rocky58

Most manufacturers recommend replacement after 6-10 and most places will not service or mount 10 year old tires. They may look fine but have deterioration that is not visible. Even properly stored tires deteriorate. I check the manufacture date when I buy new tires because I got sold two-year old tires once. Week and year of manufacture are stamped on the tire.

Indeed, Michelin and Conti say up to 10 years is fine for tires as long as they are maintained, so having 6 year old tires doesn't make them inherently dangerous!

[albertw]

If your car is a standard 240ix, the standard tires are 225 width. I don't know about the Bridgestone runflats, but I was interested in the 235 Continental runflats used on the CT4V because that car supposedly has better steering than any 2 series. The Conti website stated that the front wheels on my car were too narrow for that tire, so it might be worth checking with Bridgestone that your 245 tires are OK on the stock wheels.

[Ajowhan]

Originally Posted by Siberhius

Hello, everyone!

I recently got a BMW M240i XDrive, 2017 with 15,500 miles.

Yesterday for the first time I went out to walk on the road and noticed it "unstable" at high speed (+120mph). It feels like a kind of "dead spot" on the steering wheel and I feel like the front of the vehicle is "snaking."

The vehicle is all standard, check the tire pressure (38psi). I'm running bridgestone potenza 245 35 18 runflat.

I have checked the chassis from end to end and it does not appear to have any crashes.

The suspensions look good and without losses or problems.

It has passed vehicle inspections without problems and has official BMW services.

I've read some similar cases, so I don't know if it's "normal" or if I have something to worry about.

Any recommendation?

Thank you and best regards!

xdrive come standard with 225 wheels, is your 245 tire on stock wheels? If its the 7.5 width stock wheels. most likely your tire might be too big