How to set a "must be greater than a value" condition in Rules I need to check with the Rules module whether a field is greater than some value. To be more precise, if the size in cm of a product (the field size is created through the Commerce Physical module) is > than 5000. 

How can I do this?  I tried to add a 'Data comparison' but i only get "equals" or "is one of" when i select the comparison operator. I would have expected an "is greater than".
Check what kind of field you have.  If you have an Integer field, "is greater than" and "is less than" will be available for Data comparison.  Perhaps you mistakenly set it to text?  If so, you may need to delete the field and create it again.