There is evidence of a potential design fault on the atom that has recently come to my notice. I will not undertake training or track days in the car unless this has been checked prior to the event.
This warning results from recent experience of a foreign owner coming to grief when the right hand front suspension failed.
The cap-head bolt fixing the lower suspension arm to the upright is unscrewed by the action of the steering under lateral load; The rose-joint at the outer end of the lower control arm apparently locks under load and the action of steering can unscrew the cap-head bolt which is supposed to retain it in place at the foot of the front upright.
Ariel presumably have known about this for some time because they have apparently added locking wire and subsequently a small grub screw to stop this occurrence.
The picture apparently shows that these modifications are inadequate.
The picture shows the left hand bottom arm after the car returned from Spa, it was the right hand that had failed on track; you can clearly see a gap between the cap head bolt and the spherical element of the rose joint, the lock wire and grub screw.
The spherical element should be firmly fixed to the upright by the action of the cap-head screw. The gap indicates that this is not the case after only 700 miles. Neither the locking wire nor the grub screw have prevented the cap-head bolt from unscrewing from the front upright.
As this action continues the front upright can no longer stay in place. Steering and handling precision may not deteriorate because the suspension loads promote contact between the spherical element and the upright. Consequently the malady goes unnoticed until the front suspension eventually collapses with subsequent loss of control.
It is strongly suggested that you check your screws after and during every outing – especially if you use the vehicle on track since large side loads will exacerbate the problem.
For the avoidance of doubt: I will not undertake training or track days in the Ariel unless this has been checked prior to the event.
