i need to carry 2 kids bikes i have a bike rack that i used on my old mondeo ( a universal halfords type thing) now the top of the rack hooks over the top of the spare wheel and the bottom sits flush against the spare wheel whilst the staps can be fixed to various fixing points the question is is will it be ok to put the extra weight on the spare wheel / mounting as i have noticed the proper bike racks actually bolt onto the spare wheel! thanks