Recently got my hands on this bike that was still fitted with the original tires, 2" wide on 18mm internal width rims. They're pretty old and I intend to use this on trails so I thought I'd get some new tires, probably ones that are 0.2" or 0.25" wider. There's still about 1cm left between the shoulder knobs and the frame. The tires I have my eyes on are either the Schwalbe Thunder Burt or Racing Ray-Ralph combo in 2.25" width. Should I go for the 2.25"s or play it safe and get 2.1"s.
Other things to note:
– I stay in a tropical climate, so it does get muddy sometimes but I probably don't need UK-levels of mud room
– The frame is made of cromoly steel so it probably flexes quite a bit
– I know 18mm is super narrow, but they all thought it was the way to go in the old days of the sport
by CRA_55