In short, the load capacity of a tyre determines the weight that each tyre is able to hold. It's important that when selecting your tyre you do so appropriately. Assuming that previous tyres have been replaced correctly then the new load capacity should match your old tyres, or if in doubt you can check the vehicle handbook.
It is rare that tyres will affect your insurance but in some cases, selecting the wrong tyre can void your insurance. If you have any doubts, or simply want peace of mind then give us a call on 0333 9000 201 or consult your insurer.
The load rating is normally shown after the rim size on your tyres sidewall as highlighted below:
205/55 R16 91 W