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      01-14-2013, 05:17 PM   #9
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Drives: BMW F11 535i Touring
Join Date: Mar 2007
Location: Scotland, Highland Region

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Originally Posted by jasonprice07 View Post
As the title suggests, does anyone think the recommended tyre pressures are high? I've been doing some testing of the Birds suspension I fitted over xmas. For the most part it's an improvement over stock, but I was surprised that I can still feel every little imperfection on the road, I was hoping the new kit would isolate me a bit more, especially as I'm on my 17" non runflat winter tyres.
Came across the following on a Jag XF website, I think the Jag is roughly the same weight and RWD, I found it interesting there is very little change in their recommended pressures, even on the 20" staggered set-up. From memory the pressures for the 35D go up quite a lot as the wheels get bigger.
Anyway, I lowered my pressures to 2.2F and 2.3R and went for a drive around the lanes. Much less feeling of minor road imperfections and the handling still felt ok, was not really pushing it too much as it started to snow

I'm a bit surprised you can feel everything on 17" non run-flat winters. I used to run that size and tyre on my E91 330d touring in winter, and were a very supple tyre at 2.4 bar front and 2.6/2.7 bar rear. I was on standard suspension with Koni FSD dampers.

Have you got the Bird B3 suspension? Isn't the Bird suspension also following a similar concept, to improve secondary ride quality, while retaining primary control?

BMWCar wrote: ....and ride quality is streets ahead of any other E92 we've driven. The setup isn't designed to provide a wafty limousine-type ride, but even then the first time you pilot the car, you do feel that it's at the softer end of the spectrum. But then you realise just how much your backside has been conditioned by all of the crazily stiff chassis' that BMW now offers. As mileage builds, you start to realise that it isn't at all soft, but it can eliminate all normal bump shocks from upsetting the chassis and the driver. Hey, isn't that what suspension is supposed to do?
Just thinking outside the box... Is the Bird suspension conflicting with the wheel size? What wheel size and combination is it designed around?