Sometimes gas springs can be a little stiff, especially the first few times that they are used. If a gas strut has been lying in stock for a while, the seal with which the nitrogen gas is kept inside can stick to the rod of the gas spring. This sometimes causes the gas strut to retract heavily on the first part during its first use. You can then take the gas spring off the hatch and push it in with a lever. Then it will move better.
If the gas struts are too strong, you can choose to let some gas out. Please read the following instructions for this:
Hold the gas spring facing away from you, whilst being careful not to damage the gas strut. You can then allow the gas to escape incrementally until the desired force is reached.