Quote:
a) the cantilevered mountings for the lower A arm
I havent had an issues with it on the Eleven, nor did i have any issues with it on the Seven. Also, every Lotus and Caterham Seven use the same set up, and I havent heard of many if any failures.
Quote:
b) does the joint between the top of the tube connecting the side of the chassis to the rear bulkhead flex much ?
I havent noticed any flexing, though to be honest at speed I'm usally pre-occupied with keeping it between the hedges (or away from any bloody great SUV's). One of these days i'm going to have to learn how to use the FEA portion of Solidworks and "build" the Eleven chassis (and Seven chassis) in SW and apply stresses to it.
In terms of chassis failures, I havent really seen or read about any major failures in the Eleven S2 chassis, nor the Lotus Seven S1. The later Lotus 7's had various faults, and in my opinion these faults were due to the chassis re-design to save money.
On a side note, i dragged the car out of hibernation yesterday (had to get it running and cleaned up in order to sell it). It took a little coaxing to bring it to life, but i got it running in very little time. I did however find a failed rear axle mounting bracket. If I hadnt of disconnected the battery pre-hibernation i wouldnt have noticed the cracked bracket. Surprisingly my weld held up, the parent material in the HAZ had failed. Once i get it removed i'll have a close look at the crack.