Originally Posted by Stan
...note that Lotus did all the pondering and knows a few things. The simple, light, affordable brace is strong enough to do the deed.
True, but even the best can make mistakes
I don't mean to digress too much (thread is Factory recommended what?) but there's an amusing and timely story involving Colin Chapman and the design of the Esprit (check out "Lotus Esprit The Complete Story" by Jeremy Walton).
The guys doing the original stress analysis added a cross brace for the rear suspension lower wishbone mountings. When Colin Chapman saw it he told them "No, no. That'll be OK without." They added it back in two subsequent times and each time he made them take it out. When he drove the prototype for the first time (they had picked him up at the airport with it) he only made it part way back to the factory before the rear suspension collapsed
Needless to say they added the brace back in.
Here's what it looked like:
You'll notice the lightweight design is in single-shear and the fix is in double-shear.
Actually the failure mode is different in the Elise so it is not directly comparable but it is amusing nonetheless.
Time will tell if the new design is good enough.
(8-year Lotus owner and loving every minute of it)