my commuter (82 nishiki) has 700/28 panrace tserve.....I do 100-110 ps (cr18 rims, deore hubs)
my road bike (89 miyata) has 700/25 Continental gator skin at 110-115 (velocity deep v, ultegra hubs)
I'm 268
Back when the miyata was new and I was 190....I rode 700/23 and go rid of them.....too rough for me and I never noticed a speed diff from 700/25
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)