For Sale: Rory O'Brien 58cm singlespeed

well yes they work, just massively limits the tyre and tube choice. dont really get why you would fit 27" over 700c unless its a restoration project, which this isnt.

I doubt the OP specced them, I would have thought they were standard on a frame that age and converted for SS. BTW you can use 700c tubes in 27" tyres, no drama.