Vibration on speed 30 or 40 miles

[alirzn]

Hi,
I feel rear vibration sometimes on speed 30 or 40 Miles. Specially when I turn to left or right and speed up to 30 or 40. It happens sometimes not all times. Does anyone know what is wrong with that?

[carid]

I would check the Guibo. (rubber disc bolted in driveshaft). They can go bad, and that is fairly common. definitely sounds like a drivetrain problem to me.

[alirzn]

Where is it? Do you mean the Brake disc?

Originally Posted by carid

I would check the Guibo. (rubber disc bolted in driveshaft). They can go bad, and that is fairly common. definitely sounds like a drivetrain problem to me.

[carid]

https://www.google.com/search?q=BMW+...w=1323&bih=886

here are some pictures of it.
it's also called a flex disc. it is bolted in the driveshaft. it could also be the center support bearing.

[alirzn]

How about balance the tires first?

Originally Posted by carid

https://www.google.com/search?q=BMW+...w=1323&bih=886

here are some pictures of it.
it's also called a flex disc. it is bolted in the driveshaft. it could also be the center support bearing.

[carid]

that could be it, but you said it was happening especially around turns. a tire balance problem would have nothing to do with turning.

[alirzn]

First it does not happen all the time. Sometimes and it is more when I turn and then go straight and while accelerating to 30 or 40. When I speed down and again speed up it will be removed. It also happen when I am going straight without turning. In general if the tires are not balanced what does happen?

Originally Posted by carid

that could be it, but you said it was happening especially around turns. a tire balance problem would have nothing to do with turning.

[carid]

If the tires are not balanced it would cause premature tire wear,and vibrate. from my experience it's usually at a higher rate of speed, but again, I'm not ruling that out.

[alirzn]

So where can I start to find out the problem?

Originally Posted by carid

If the tires are not balanced it would cause premature tire wear,and vibrate. from my experience it's usually at a higher rate of speed, but again, I'm not ruling that out.

[carid]

look under your car, if you see that the guibo or center support bearing is visably bad then proceed with that. if not then you could start by balancing the tires.

[alirzn]

My tires model are different. In rear one of them is continental and another is Goodyear. Do you think it is because of this?

[carid]

It could be, but i doubt it.