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Rear end movement over bumps in road

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Cropperlaa
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Rear end movement over bumps in road

Post by Cropperlaa » Fri Jun 15, 2018 4:45 am

Im unsure on the best way to describe this. Whilst driving the wifes 2013 sdrive 18i m sport, when accelerating if I go over a bump in the road, it feels like the backend moves slightly like it jumps/jerks slightly to a side, is this an issue we should be worried about? Or is it just a standard roadster thing? I thought it would be quite firm or have substantial grip, has anyone every come across this or got any advice?

ihadablackdog
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Rear end movement over bumps in road

Post by ihadablackdog » Fri Jun 15, 2018 7:54 am

I get the same occasionally and I thought it was due to the run flat tyres.

A lot of people recommend switching to nom runflats, which are meant to improve the ride.

I’m sure someone will be along to give a better opinion.
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Silverzedtom
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Rear end movement over bumps in road

Post by Silverzedtom » Fri Jun 15, 2018 8:52 am

I get this every once in a while. Just a trait of the car that could probably be solved by better damping imo.

A firm ride and 19” wheels won’t be helping matters in my case at least.
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philbo909
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Rear end movement over bumps in road

Post by philbo909 » Fri Jun 15, 2018 10:30 am

Bump steer is just something you get on a car that's too firm for British roads, msport and low profile rft will be the cause of it most probably
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Crazy Harry
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Rear end movement over bumps in road

Post by Crazy Harry » Fri Jun 15, 2018 10:41 am

I bet it happens on long sweeping curves - I can think of one long right hander near me with a slight bump in the road; in fact I now approach it tight on the white line so I don't get off the black stuff and into the ditch when the back end hops. Over the years I've seen the remains of other cars that didn't make it :thumbsdown:

Its not just the Zed that does it I've had other cars with a tight set up an they have done the same - now you know its there you can start to enjoy it :lol:

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mr wilks
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Rear end movement over bumps in road

Post by mr wilks » Fri Jun 15, 2018 12:24 pm

Whether 18inch or 19 it's worth checking tyre pressures . 33-35 psi front / 34-36 psi rear seems to work well but some do run up to 44psi .
Age & tread depth also has bearing as does runflat V standard
Also if you are on 19s the rear 255 30 profile will be doing nothing for the car , comfort or wheel itself :cry:
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Z4 Gaz
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Rear end movement over bumps in road

Post by Z4 Gaz » Fri Jun 15, 2018 1:07 pm

Could be a worn bush somewhere.
My E85 did this and it was worn rear outer upper rose bushes. Just enough play in them that a mid corner bump would change the geometry enough to make the car 'shimmy'.
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Busterboo
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Rear end movement over bumps in road

Post by Busterboo » Fri Jun 15, 2018 4:12 pm

Mine does it, too, Cropperlaa.
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Rear end movement over bumps in road

Post by john-e89 » Fri Jun 15, 2018 5:15 pm

Just one of the many reasons why I regrettably sold mine... :(
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