It isn't in a menu, you have to edit a file to change it and to do that the way I'd recommend doing it is going to C:\program files(x86)\steam\steamapps\common\beamng.drive\content\vehicles then find the zip of the car you want to edit, and then go to documents\beamng\ and make a folder called vehicles then in that folder make another folder with the same name as the zip of the car you want to edit, then drop the suspension Jbeam from the zip to your newly created folder and now you are ready to start editing, after that you are going to want to open the jbeam with notepad, notepad++ or a similar program then you are going to want to press control+F and type "precompression" into the search bar without the quotes and then press next until you find the proper area you want to edit.
