The IET has a reciprocal lending arrangement with the IMechE, enabling IET members to borrow books from the IMechE library at Birdcage Walk.
For more information, follow this link:
http://www.imeche.org/knowledge/industries/tribology/information
Please add links to other libraries in replies to this post! There should be several university libraries in the UK with substantial holdings of books and periodicals on Tribology. Please indicate whether visitors and non-students may access the library in each case, to prevent people from travelling without benefit.