1M rear end quirky

[jeandp]

Joined this forum today - thanks.

I have owned my 1M Coupe for about 4 years now and still find the rear end "squirmy". The steering is razor sharp (love it) and back end is planted once you've dialled into the corner. The back end just feels like it wanders under normal driving conditions - like the springs are too soft or something. The suspension is stock with 45K Km on the odo. The rear shocks were replaced under motorplan about 10 000 km ago. I've had BMW check all the linkages and the like as well as having the wheel alignment done more than once. Also played round with tyre pressures which did not solve the "problem".

This is not to be confused with traction control switched off and in "drift" mode - different chapter of the book.

Anybody experienced similar feel?

[PRTSB1M]

Originally Posted by jeandp

Joined this forum today - thanks.

I have owned my 1M Coupe for about 4 years now and still find the rear end "squirmy". The steering is razor sharp (love it) and back end is planted once you've dialled into the corner. The back end just feels like it wanders under normal driving conditions - like the springs are too soft or something. The suspension is stock with 45K Km on the odo. The rear shocks were replaced under motorplan about 10 000 km ago. I've had BMW check all the linkages and the like as well as having the wheel alignment done more than once. Also played round with tyre pressures which did not solve the "problem".

This is not to be confused with traction control switched off and in "drift" mode - different chapter of the book.

Anybody experienced similar feel?

I'd say this is why the F8x cars have solid mounted rear subframes. I've read that swapping to solid rear subframe bushings doesn't increase NVH, but mine are still in the box so I can't comment personally. Having owned a 2012 135i and an F80 M3 before the 1M, I believe that the 1M and 135i both have a rear-end shimmy under hard throttle where the F80 M3 doesn't. The other possibility is the rear diff, the 135i is open and the GKN unit in the 1M does slip one wheel a bit before locking. I'm pretty sure the F8x cars don't have the same initial slip of the GKN.

[ayao]

Originally Posted by jeandp

Joined this forum today - thanks.

I have owned my 1M Coupe for about 4 years now and still find the rear end "squirmy". The steering is razor sharp (love it) and back end is planted once you've dialled into the corner. The back end just feels like it wanders under normal driving conditions - like the springs are too soft or something. The suspension is stock with 45K Km on the odo. The rear shocks were replaced under motorplan about 10 000 km ago. I've had BMW check all the linkages and the like as well as having the wheel alignment done more than once. Also played round with tyre pressures which did not solve the "problem".

This is not to be confused with traction control switched off and in "drift" mode - different chapter of the book.

Anybody experienced similar feel?

The 1M rear is very alive. It will bite you hard if you aren't paying attention, injudicious about throttle application with DSC off, or run out of skill.

There is a left turn at a stoplight with uneven pavement near my home. Even with normal acceleration into this left turn from a stop, driving over this section causes the car to feel like you're riding a horse that's trying to throw you off its back. Other cars that I drive with more compliant suspensions are completely drama-free and unnoticed.

[jeandp]

Thanks for the feedback gents

[HP Autosport]

Originally Posted by jeandp

Joined this forum today - thanks.

I have owned my 1M Coupe for about 4 years now and still find the rear end "squirmy". The steering is razor sharp (love it) and back end is planted once you've dialled into the corner. The back end just feels like it wanders under normal driving conditions - like the springs are too soft or something. The suspension is stock with 45K Km on the odo. The rear shocks were replaced under motorplan about 10 000 km ago. I've had BMW check all the linkages and the like as well as having the wheel alignment done more than once. Also played round with tyre pressures which did not solve the "problem".

This is not to be confused with traction control switched off and in "drift" mode - different chapter of the book.

Anybody experienced similar feel?

What is the final toe for the rear of the vehicle? The 1M needs less compression damping and more rebound damping to feel more planted. Dropping the center of gravity a little helps too.