Steve <no@spam.thanks> wrote in article
<5pSdna5Wbc9fz8bYnZ2dnUVZ_v-dnZ2d@texas.net>...

The lower the roll center, the MORE leverage the Center of Gravity has on
it.

Straight axles actually have a HIGHER RC than most IFS and IRS
setups.....producing the "better rollover resistance" to which you refer.

Many of today's RWD, IFS cars actually have RC located below ground while
the rear IRS RCs are considerably lower than the solid axle's RC.

A 14-inch CoG acting on a 10-inch RC (solid axle) is going to roll the car
less than the same CoG acting on a RC that is two-inches below ground
(IFS)......A four-inch moment arm (solid axle) versus a 16-inch moment arm
(IFS) applying the CoG mass......but, the SUV CoG is much higher than the
passenger car's CoG.

The whole problem is that most solid-axle vehicles have such a high CoG
that they actually have a longer moment arm than the Independent
suspensions, ergo, apply the CoG mass with more force.

CoG of a 1978-1985 mid-sized GM car that we build for oval track use is at
approximately 14-inches above ground by the time I am done putzing with it.
The RC ends up at approximately two-inches above the ground.

CoG for a SUV is often at least a foot higher.....approximately at camshaft
height.

So now we're talking a 14-inch CoG applied to a two-inch RC giving us a
12-inch moment arm in a passenger car......

....versus a 26-inch CoG applying a heavier mass to a 10-inch RC in the SUV
- giving us a 16-inch moment arm.

Which vehicle will have the greater tendency to roll over????

Because its true....

Wrong, wrong, wrong. Lift is irrelevant. Solid axles have a lower roll
center, meaning they have better rollover resistance without massive
sway-bars (this is troe ON highway, not just offroad!) Solid axles also
articulate better when offroad with sway-bars disconnected, allowing
each wheel to have a better contact patch (the "high" wheel actually
helps plant the "low" wheel to the ground).

As far as IRs and towing, the differences are less dramatic than with
offroading and rollover resistance. But all those added bushings and CV
joints will *never* hold up to towing as well as a solid axle.

I don't know. Probably a marketing advantage. Calling something a mini-van
or a station wagon makes it undesirable to a large portion of US consumers.
Whether it makes sense of not, names do matter to many consumers. Do you
think Toyota would sell as many RAV4s or Highlanders if they called them
Camry Wagons (which is what they are)? If Ford renamed the Freestyle "Five
Hundred Station Wagon," how well would it sell? Or worse yet, suppose they
revived the Country Squire name and slapped on some vinyl wood trim on a
Freestyle?

Yes, I towed often with my 2003 Expedition with IRS. It towed just as well
as my 1997 with a solid rear axle.

Why would you say that? Only idiots who want to "lift" a truck are bothered
by IRS. Doing a suspension lift on an IRS vehicle is very difficult in
comparison to lifting a truck with solid axles. Unless you are doing some
really weird rock crawling, or tying to drive across a swamp, highly lifted
vehicles are ridiculous. For any sort of mundane off roading, IRS is better
than stick axles.

Compared to?

Probably true for most people. And several of these really are station
wagons.

What's the point of calling it an SUV if you cannot tow with it,
or take it off road?
Ever try towing with independent rear suspension?
Not good for off road either.
Did I forget to mention how small they are.
People who buy these would be better off with a station wagon.

Just another evidence that CR is a stupid useless magazine for evaulating
cars.

People are dumping their gas-guzzling SUV's right and left and buying
economy cars, due to the gas prices, yet CR is still bothering to review
SUVs.  Yeah, right, real intelligent there.

Ted

The new Mercedes-Benz GL- and R-Class luxury sport utility vehicles
outpointed competitors from Volvo, Audi, and Cadillac in tests for the
November issue of Consumer Reports.  The GL- and R-Class posted "Very
Good" overall scores in tests against the Volvo XC90, Audi Q7, and
new 2007 Cadillac Escalade. Though the Volvo, Audi, and Cadillac
finished lower in the scoring, those three vehicles still posted
"Very Good" scores.

To read the full text, please go to:
http://www.contactomagazine.com/bestluxurycars1106.htm