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.
“We need randomness, mess, adventures, uncertainty, self-discovery, near-traumatic episodes, all those things that make life worth living; compared to the structured, fake, and ineffective life of an empty-suit corporate leader with a preset schedule.” From Dr Nassim Nicholas Taleb, Antifragile: Things That Gain from Disorder