hi there,

I am a DT teacher and one of my pupils is trying to make a wall mounted bike frame with arm brackets to mount and lift a peddal bike. He has done some stress/force testing of 45 newtons on each side as you can see  below the design seems to be completely buckling - this is happening in a range of material choices. I am not sure why that is or how to advise him. It should only be moving up and down by a couple of mm yet this is happening. Is the stress testing being over exaggerated here ? please help