McPherson? Double Wishbone

Just wondering... I know the double wishbone configuration consists of 2
parallel control arms (to minimize camber change throughout motion). Then
there is the McPherson setup... BUT, from what I've read, the Mcpherson
setup is defined as a coil + damper combined into 1 unit. Now, could a
double wishbone setup include a McPherson strut for damping??? I guess my
question is what is the mechanism in a double-wishbone setup that provides
damping? Any good websites cover this???


Thanks!

 

See drawings at
http://www.chris-longhurst.com/carbibles/index.html?menu.html&suspension_bible.html

 

A McPherson strut combines a vertical control arm and damper in one.
The only other wheel connection is the bottom control arm.

 

Thanks! Great info.

 

The key about the strut design is that as well as having the concentric
damper/coil spring arrangement, the damper unit's upper mount also
functions to locate the axle hub unit laterally and longitudinally. In the
the MacPherson strut the damper upper mount is also the upper steering
pivot - IOW the strut turns with the wheel. In both cases the lower hub
mount is some kind of lateral arm with variations to cover longitudinal
location... either an A-arm or with an add-on radius rod or link.

You'll sometimes see reference to a MacPherson strut in the rear but it's a
misnomer, since the MacPherson is uniquely a front suspension design - when
a strut is used in the rear it's sometimes, more properly, referred to as a
Chapman strut... named after Colin Chapman of Lotus. This was the famous
design which caused Enzo Ferrai to shake his head in disbelief, since in a
RWD car of the day (racing car that is), it caused the drive shaft to be a
stressed member of the suspension.

In the double wishbone design you do not have a strut at all, though many
dealer service folks and mechanics will call any concentric damper/spring a
strut... again a misnomer. In the DW design the damper and spring are not
structural members in the suspension - they only have to do their
particular jobs of springing and damping.

BTW I disagree with Chris Longhurst's categorization which shows Coil
Spring Type 1 as different from a Double Wishbone. What he shows as DW is
really the Honda design - there have been many DW implementations which
used his Coil Spring Type 1 arrangement. An A-arm is, in most cases, only
a variation on a wishbone... which may allow elimination of a radius rod
for longitudinal location.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

I don't know much about car suspension design, but any Honda with
D-wishbone has precise handling, fun to drive, and even tread-wear. On
the other hand, any old Toytota I have use McPherson and they sucks.
If not for the engine reliability, i would never want to keep the
Toyota.

 

Toyota suspensions soak up the bumps well but I don't care for their
handling either. An 89 V6 Camry seemed to corner well but steering
wheel was abnormally low, making driving awkward. An 84 I4 Camry felt
solid but the back end would spin out on nothing. An 88 Tercel had well
balanced skids but it felt extremely unstable and it lifted the rear
wheels off the ground during hard stops! A 98 I4 Camry had so much
front-to-rear bobbing that I almost got sick during the test drive.

 

I agree, though there are claims that the MacPherson strut in the RSX -
dunno how much it's been tuned over the Civic version - actually works
quite well... said to even be an improvement in handling over the Integra.

The Toyota struts are the weak area of their cars - the only thing that
really wore out on our '93 Camry. When we sold it at 106K miles they were
umm, tired. The nasty thing about MacPherson strut is that when they go
and you get too much suspension travel it tends to break the boot which
seals the steering pivot from dirt and the cost for replacing the strut
goes up another notch.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

My Porsche 911 had McPherson struts and it had precise handling, was fun
to drive and showed even tread wear. The devil is in the details.