Arny Krueger wrote:
"Dave Plowman (News)" wrote in message
...
In article ,
Arny Krueger wrote:

But the better handling FWD cars also have decent rear suspension.

Right, but doing whatever you are doing right is far more important than
which general setup you pick.

Even longitudinal leaf springs with a live axle done right can work well
on reasonably smooth surfaces. High unsprung weight only matters on bad
surfaces, which unfortunately seems to prevail these days.

No suspension at all can work quite well on a smooth surface.

Yes. However, that kind of perfection is not required for a longitudinal
leaf springs with a live axle done right rear suspension to be effective.

They do loose traction on rough roads, badly.

For example people like to **** on FWD cars with simple trailing arms
and a beam axle at the rear. However the beam axle is unsurpassed for
keeping the wheels near vertical to the pavement which is very
important for developing maximum cornering force.

A beam axle keeps the wheels parallel to each other, but that's about all.

That's why you need to be careful with how you do the trailing arms.

Its all about things like roll center. Pick that right and the not only will
the wheels be parallel to each other, they will be perpendicular to the
pavement. Hitting those two goals goes a long way towards good cornering.
Most of the rest of the discussion then becomes about fore/aft balance of
which a great deal relies on the front suspension.

With body roll - and in practice all cars do this - the important thing is
to get the relationship between the wheel taking the load and the pavement
correct.

Agreed.

Which a beam axle is poor at.

Disagreed.

If the wheels are not powered, unsprung weight can be kept low. Get
the trailing arm geometry right which is often done, and you have a
nice vehicle - stable but still adequately nimble.
The gold standard is upper and lower control arms, but that soup gets
****ed in at least as often as it is done right. ;-) Many compromises
come when encroachments on the passengers and luggauge are to be avoided.

That is true. But it can be done.

So can the two variants of the beam axle we've discussed. I've owned
vehicles that handled well on even rough roads with unpowered beam
axle/trailing arm rear suspensions.

Just because someone screws up a car, doesn't mean that every technology it
embodies is inherently flawed.


yeah. You should try an XJS with a bent kingpin..

makes nonsense of a double wishbone


--
To people who know nothing, anything is possible.
To people who know too much, it is a sad fact
that they know how little is really possible -
and how hard it is to achieve it.