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Steering geometry

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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Felixlamb
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Steering geometry

Post by Felixlamb » Thu Jan 26, 2023 12:11 am

Hey peeps!

I’ll be getting a fresh set of tyres installed in the next couple of months. Since owning the car it has never had an alignment, so probably worth getting that sorted too, as the old set had pretty uneven wear. I’ve been trying to find the stock geometry information but haven’t been able to, and through searching forums I’ve now come across threads where people are suggesting running alternative geometry variations.

Sooo…. What geometry do you guys run? I’m in the countryside, so primarily do more of the windy B-road-blasting, than long straight motorways.

Cheers!
E89 sDrive20i M Sport

brillomaster
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Steering geometry

Post by brillomaster » Thu Jan 26, 2023 9:06 am

nothing out the ordinary, any decent alignment shop will have the right setting for toe and camber. make sure you get both done, not just the toe.

only change i'd recommend is maxing out the negative camber on the front - there are three nuts to loosen on the top mount, and then the shock can slide inwards a bit, adds half a degree or so of negative camber. its still not enough for track work, but it'll feel better on a B road.

Busterboo
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Steering geometry

Post by Busterboo » Thu Jan 26, 2023 12:07 pm

Kwik Fit ... no sniggering, please ... have a 2-year deal with effectively unlimited re-alignments. Pay once, go back as often as you like. Good if, like me, you live in an anti-car People's Socialist Democracy like Leicester, where road & repair are dirty words.

As for the effects of alignment, remember that they depend to a degree on tyre pressures. Slopping about on 28psi all round is beyond the help of any alignment.
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B21
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Steering geometry

Post by B21 » Thu Jan 26, 2023 2:41 pm

Here's the BMW settings for non MSport versions with stock springs..

So with stock suspension castor is fixed, very limited front camber and toe, rear camber a bit more and limted rear toe.

General advice is to keep toe in stock, as suggested you can remove the pin on the strut housing to get maybe 0.5 degrees difference in camber.

After market springs (lowering) screw up rear camber especially as well as a little toe front and rear and front camber.

Note BMW states that the car should be ballasted as follows: few ecer do which screws the camber readings especially..

Vehicle with complete equipment for normal operation with:
2 x 68 kg on front seats (seats in central position);
1 x 14 kg in luggage compartment (centre) and full fuel tank

Tyre pressures as normal and OE tyres with OE alloys and all treads same +-2mm

FWIW depending on age I check bushes etc..rear toe is badly affected by worn rear trailing arm bushes..you get dynamic effects with toe adjusting under load creating a rear wheel steering E89..

Front tie rods and front steering link bushes can cause bad handling effects plus spurious readings.

You say twisty B roads but often stability in turns is preferrential to speed of turn in..

As stated you won't be able to do much within the limits of the stock fittings...you need adjustable versions...camber plates, adjustable toe plates, adjustable rear camber arms to do much.

I suggest you get it aligned to stock readings and see how that feels..

Often you can't get rear camber and toe in perfectly as they effect each other and there is a lack of adjustment.
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Busterboo
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Steering geometry

Post by Busterboo » Thu Jan 26, 2023 8:35 pm

Just be very careful, Felixlamb. If you follow B21's advice, your car will turn YELLOW. :dizzy:
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Busterboo
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Steering geometry

Post by Busterboo » Fri Jan 27, 2023 9:53 am

In the context of B21's post, the only specialist I've used that does wheel alignment and suspension adjustment 'properly' is Center Gravity*, who did my 911.

For general pot-hole dodging improvement, most Hunter-using garages are OK and a large percentage better than nothing at all.

(*Yes, the spelling's right.)
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