That's a nice tool, glad you like it. Definitely works for its singular purpose. I took a tape measure, measured slack from resting to pulled upward, but didn't measure to the swingarm which seems silly as it's pretty obvious if it's an issue being too loose. I don't know a manufacturer that gives a specific measurement to the swingarm, but could be wrong. Used the same tape measure the next day for a project around the house. Motion pro has great tools, but a lot of them are a tool in search of a need, IMO.