From the reviews-
"Was concerned about the size as it wasn't listed anywhere, but they fit great on my 7/8" bars (bar ends I ordered were 7/8" and fit well)."
They will fit the 636.
A few cruisers have 1 inch diameter grips for a fatter look, and most other motorcycles use 7/8 inch diameter grips.
“It is difficult to get a man to understand something, when his salary depends on his not understanding it.”
― by Upton Sinclair, who helped clean up the meat packing industry and other factories