The B492 was a short B-road in Acton, west London. The road was originally unclassified. Going by its number the road came into existence in the late 1920s - it must have post-dated the construction of the Western Avenue - although it is not known on maps before the 1950s, possibly due to its short length.
The road started on the A40 (formerly A403) Western Avenue and headed northeast along Wales Farm Road, which sounds rural although it currently runs through a retail park as well as being residential and 1950s maps show it lined with industry. Following a couple of bends the A4000 Victoria Road came in from the left and took on the road ahead, thus being the northern end of the B492.
It is not known for certain exactly how long the B492 lasted. However, the road is now one-way southbound as part of a one-way system on the A4000 in this area.