Wheel lining beer tun in development (5,4)
I believe the answer is:
inner tube
'wheel lining' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'beer tun in development' is the wordplay.
'development' indicates anagramming the letters.
'beer'+'tun'+'in'='beertunin'
'beertunin' is an anagram of 'INNER TUBE'.
Can you help me to learn more?
(Other definitions for inner tube that I've seen before include "rubber ring" , "Circle line?" , "What cyclist pumps up" , "inflatable ring" , "Tyre filler" .)