Why isn’t wide base (to the dif carrier) McPherson strut rear suspension used? The loads are transmitted in the chassis better than with a double wishbone setup, and it is much more tolerant of wheel diameter/width variation, and the modification from a live axel/dedion very simple. Also as an added benefit it would free up room for either a bigger boot (trunk) or allow the floor to be raised and add a rear diffuser? The design geometry is very much easer to sort out, and very little if anything would be lost in terms of handling, etc.
I am a bit puzzled by your theory that a strut suspension "is much more tolerant of wheel diameter/width variation".
To make a strut work and fit with in the packaging room available the strut would have to be specially made not just front strut transplanted on to
the rear.
There was a discussion on this at length two or three months back, in which the advantages and disadvantages of the Chapman strut were discussed at
length. it is worth a look.
Significant Lotus themselves stop using the Chapman strut after the classic Elan and Plus2S and went on to a form of double wishbone for the 70s
Elite/Eclat.
Also a lot of classic Lotus Elan and Plus2 owners are spending a lot of money on converting thier cars to use Sierra based double wishbone suspension
at the rear not that disimilar to the MK Indy.
In terms of more tolerant - a double wishbone has to be designed round a diameter/offset, and when the wrong wheels are used the rotation point will be in a space inside the tyre or under the ground dependent on the geometry. The strut projects the point down to the tyre surface, but the point will move in/out depending on the size of the tyre/rim. As the rear is not used for steering - this has little to no effect on the dynamics of the car. This is the reason why most of the rally cars use this setup (stratos, 037, 205-16) plus the load transfer is more direct in the chaise
quote:
Originally posted by u401768
In terms of more tolerant - a double wishbone has to be designed round a diameter/offset, and when the wrong wheels are used the rotation point will be in a space inside the tyre or under the ground dependent on the geometry. The strut projects the point down to the tyre surface, but the point will move in/out depending on the size of the tyre/rim. As the rear is not used for steering - this has little to no effect on the dynamics of the car. This is the reason why most of the rally cars use this setup (stratos, 037, 205-16) plus the load transfer is more direct in the chaise
I fully agree about the front suspension - but for the rear, the flexability is a posative thing. And if u get a double wishbone setup wrong, you can get poor/none operative suspension