The modern standard 450 caliper can be positioned to just
clear a 28mm tire with the shoes all the way down. A
designer certainly could do a frame and fork geometry for
that- see Waterford with 27mm tire here:
http://www.yellowjersey.org/WIDE27.JPG
But that would require some sort of reasonable market for
the bike, which probably doesn't exist in any significant
numbers.
Another stumbling point is the prevalence of standardized
road bike forks and no product manager wants to pee away a
pile of money on a special fork for one model with unproven
volume. Heck I'm even sympathetic to the idea yet I would
bet against such a project breaking even.
There are sport bikes with the next size 500 caliper such as
Gunnar Sport and Soma Smoothie ES, inter alia. Maybe look
more in that direction or an actual touring bike such as
Bianchi Volpe or its new relative Bianchi Lupo.
--
Andrew Muzi
<
www.yellowjersey.org/>
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