steering geometry

Can someone in the newsgroup please enlighten us all on what car
companies make cars with good steering geometry as well as the car
companies with cars with bad steering geometry.

I we told that BMW made it's sedans with excellent steering geometry.
Apparently all the steering components are all attached as one unit
onto the cars frame.

On a more common car like the Accord, Taurus, and Camry the front
steering is all attached to the subframe. The subframe is attached to
both the engine and the cars frame.

BMW uses all alluminum steering components except for the wheel
bearings. The lighter weight probably improves feed back and reduces
some unsprung weight.

But really, what are the major deciding factors that makes one car have
a superior steering design than another cars steering design?

How does a car company realy deliver crisp, precise steering to the
driver the way BMW and Porche do?

Or is what is utilized on the Accord and Taurus the standard for this
automotive era? Attaching the steering gear to the subframe.

On the new Fusion the steering gear is still on the subframe.

On the BMW is the steering gear really on the subframe? Shoot, what is
the big difference, what makes BMW's design so much better than what
the majority of the motoring public can afford?

Maybe BMW puts everything on the subframe. Steering gear, wheel
spindles, strut towers, etc.


TIA

> wrote
> Can someone in the newsgroup please enlighten us all on what car
> companies make cars with good steering geometry as well as the car
> companies with cars with bad steering geometry.
>
> I we told that BMW made it's sedans with excellent steering geometry.
> Apparently all the steering components are all attached as one unit
> onto the cars frame.
>
> On a more common car like the Accord, Taurus, and Camry the front
> steering is all attached to the subframe. The subframe is attached to
> both the engine and the cars frame.

Since BMWs are uni-body cars just like Hondas and Toyotas
and GM - even the so-called space-frame Saturns are similar - and
virtually every other car made these days, you have a serious
mis-understanding. From a front-suspension standpoint, BMWs
are very similar to most other cars. Almost all use rack-and-pinion
steering (in fact, some BMWs use the less pricise circulating ball type).
Virtually all front suspensions are strut-type - actually, some Hondas
have the more-complicated (and expensive) control-arm type. BMW
and Porsche are no different in this regard than most other cars.

> BMW uses all alluminum steering components except for the wheel
> bearings. The lighter weight probably improves feed back and reduces
> some unsprung weight.

The 5-series has had Al suspension components since around '97/E39
time. The most recent 3-series has Al (the last year or so.) Al doesn't
matter - you're confusing light weight/expense with "goodness".

> But really, what are the major deciding factors that makes one car have
> a superior steering design than another cars steering design?
>
> How does a car company realy deliver crisp, precise steering to the
> driver the way BMW and Porche do?

Mostly, the type and size of tires, the type of bushings used on tie-rods,
the fact that BMWs and Porsches are RWD, the fact that they don't
have as much % of weight on the front wheels, the stiffness of the
springs and shocks, etc. IOW, everything.

> Or is what is utilized on the Accord and Taurus the standard for this
> automotive era? Attaching the steering gear to the subframe.
>
> On the new Fusion the steering gear is still on the subframe.
>
> On the BMW is the steering gear really on the subframe? Shoot, what is
> the big difference, what makes BMW's design so much better than what
> the majority of the motoring public can afford?
>
> Maybe BMW puts everything on the subframe. Steering gear, wheel
> spindles, strut towers, etc.

You're confused. But the most important difference is that FWD cars
have a harder time having precise steering than RWD or mid-engine
designs. Look up understeer (and oversteer). Consider the polar
moment of inertia of RWD/FWD/mid-engine designs.

FloydR