Philip asks some questions about the deDion rear and I can
try and answer a couple:
>deDion suspension...
>Now the trick. The fore and aft location is still the trailing links,
On the tops of the hub carriers on the ends of the deDion tube, right?
(yes)
>the lateral location is still the A arm,
Mounted to the middle bottom of the deDion tube, right? (If it goes somewhere
else, how does the deDion tube get located laterally?) (right)
>and there is a tube running from the left wheel to the right wheel.
The deDion tube itself.
>Why they kept the A arm is a mystery. (I was speaking philosophically
here. I get caught up with the problems with my particular implementation
which is described later.)
>The end result is that this version of suspension is more reliable
Why would the deDion be more reliable? Because the torque of the
differential goes right to the frame and not to the suspension? What
about brakes? I would think the extra U-joints would be a minus on
reliability.
(Now we get to the problems with my impementation! The A arm has
normal suspension bushings at the legs of the A where they attach to
frame members directly behind the seats. The top of the A, where it
mounts to the differential housing is a real weak point for a number of
reasons. The housing was never meant to take the cornering loads
generated by the Seven, let alone those loads generated with the new
autocross tires I am running. The bushing here is a bolt with a bunch of
rubber washers isolating the vibrations. These rubber things tend to
deteriorate from the oil dripping out of the cracks in the differential,
designed into every LBC. I wonder how the designers of British cars
specified the leakage rate or the size of the cracks?
The main reliability problem is the torque handling capability of the
Ford rear axle used orginally in the Seven. They have a big 1/8 inch
plate welded to the axle running the full width to try and prevent
twist. I have replaced the rubber bushing at the top of the A with a
spherical joint and this helps a little.)
>but slower. The added weight is the problem.
Why should the deDion be that much heavier? Sure, you have the deDion
tube, but you don't need that heavy axle tube that the live axle
system uses. (I think it is slower just because of the extra weight of this
particular implementation. But I have not had direct contact with the
racing crews and my knowledge is second hand. Remember the story,
Chapman had a 25lb scale next to the car during construction. If a
mechanic wanted to add something, Chapman would put it on the scale
and if it went off the limit, he said no...
I'm not picking on you, Mike, I know YOU didn't design it!
I am still fuzzy on one point. Which suspension does yours have? (Can you not
tell? The better one! That is why I get so defensive!
Michael
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