Hi All New to this forum. I just am no expert in this field and I'm a little bamboozled at this problem I have. I am in the process of constructing a storage box in the garden. Mainly for a couple of bicycles. I want to put a hinged lid on it. The lid will be constructed from timber and corrugated sheet metal. When getting the bikes in and out of the (open fronted) box, I would like the lid to stay where it's put when I lift it, without the use of wooden props etc. This points to the used of gas struts. The kind of things that hold the tailgate in the air on a car. I can buy these on Ebay, but they come in different levels of force, anywhere between 30N and say 170N. I do not entirely understand Newtons vs Kilograms and need to buy the models best suited to the eventual weight of the lid. Using the diagram as a guide...Lets say the lid once constructed weighs 25kg. Then I fix it to the box. The gas struts (I'll use one each end) are not very long, maybe 400mm at most, will be fixed close to the hinge of the lid, between the rear of the box and the lid itself. The thing that is bamboozling me is I figure that the weight (or Newtons) at the front of the lid is going to vastly increase the nearer you get to the hinges. So: N at point A will be a lot greater than N at point C. How the heck do I work out which pressure of gas strut I need? My brain is in meltdown, lol. It has to be enough to hold the lid open, but easy enough to close also. Also, I'm guessing that the angle the strut is set at is also going to have an impact in performance...would it be better set vertically? Many thanks in advance.