Joined: Feb 2012
Posts: 19,362
Likes: 5,503
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
A ruler/tape measure will give you the other sides dimensions. Not every tool lives in a world independent of others. The 148mm isn't a number without relationships.
Since most all main frames are not true triangles but 4 sided, with unequal angles/sides, it's configuration can shift. The four sides can maintain their dimensions but the angles between adjacent sides can range/vary. Establish any one of the 4 angles and with set side lengths the remaining angles are also set.
I've tried to explain how this tool's data can be used. It seems that I can't find the words to do this. Sorry. Andy