Another Frame builder talked about TCO.

http://davesbikeblog.squarespace.com/blog/2006/11/5/toe-overlap-no-problem.html

"
There was a discussion recently on Classic Rendezvous Bike list; the
tread titled “Toe overlap even on good bikes,” implied that toe
overlap was a design flaw and one should not expect to see this on
quality bikes. Toe overlap is a result of other critical design
factors and cannot always be avoided especially on smaller frames.

When a framebuilder designs and builds a racing frame, his main
criteria are to: (1.) Place the rider in a position where he can pedal
with maximum efficiency, and (2.) Design the frame so the finished
bike will handle at speed in the best way possible. If the result of
the design is toe overlap then the builder can do little because to
achieve toe clearance other aspects of the frame’s design would have
to be altered.

For example the picture above shows my own bike. It has a small 52 cm.
(C to T) frame and has about an inch of toe overlap. If I were to make
the front end of the bike one inch longer to avoid toe overlap, I
would have to do one of the four following things or a combination of
all four.

(1.) I could make the seat angle steeper, or (2.) the top tube longer.
(3.) I could make the head angle shallower, or (4.) the fork rake
(offset) longer. The first two would effect my riding position; the
last two would affect the handling of the bike.

Toe overlap is not a problem because riding and cornering at normal
speed the front wheel never turns far enough for the toe to hit the
front wheel. The only time it becomes an issue is when turning sharply
at a very slow speed; doing a U-turn on a very narrow road for
example.

Caution and common sense are all that is required when executing a
tight U-turn. If you are turning left then your right pedal will be
down for maximum ground clearance as you coast into the turn. By the
time you need to start pedaling again you are already half way through
the turn, and the right crank has to complete ¾ of a turn before the
toe is opposite the front wheel.

By that time, you should be all the way around and the front wheel is
straight ahead again. If you are not the coast again, or ratchet the
crank back again on the freewheel.

Doing the same maneuver with a fixed gear is a little trickier; but it
is a matter of timing. Go very slow and start to turn as the toe
passes the front wheel; that way the crank has a whole revolution to
go before it makes contact again. If the front wheel is still turned
the next time round; straighten the front wheel so the toe clears,
then turn sharply after it has passed.

Fixed gear and fenders (Mudguards.) is going to make this move a
little difficult, but not impossible. With clipless pedals, you could
unclip the outside foot and move your toe back to give more clearance.
I sometimes get out of the saddle and simply point my toe downwards to
give more clearance.

What you need to avoid is a situation where you get your toe on the
wrong side of the wheel in a turn; if you do, try not to panic.
Ratchet the crank back if you have a freewheel, or if you are riding
fixed gear, keep going and let the toe pass the front wheel so you can
straighten up again.

Lastly, I would like to point out that a racing motorcycle with narrow
swept down handlebars; turning is restricted because the handlebars
touch the fuel tank. Here is a machine that will go 200 mph plus, and
restricted turning seems not to be a problem. Therefore, I maintain
the opinion that toe overlap on a bicycle is neither a design fault
nor a problem."

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