Which frames have italian thread bottom brackets?

On Fri, 17 Apr 2009 09:22:28 -0700, wrote:

On Apr 17, 10:54Â*am, Mike wrote:
On 16 Apr 2009 23:04:05 GMT, wrote:

How do you explain the nearly universal adoption of the threadless
steertube?

Sometimes there is really no logic to the widespread adoption of
something new, for most practical purposes this is one of them.

--

There is great logic behind the adoption of the threadless steerer tube
on forks. Cheaper. One fork fits all sizes of a particular frame.
48cm to 62cm, same fork. No need to cut forks to fit the different
sizes within a frame range and thread every single one of them. And cut
the keyhole slot. That takes time and money and machining and people.
Cheaper stems too. I suspect threadless stems are cheaper and easier to
make than quill stems. Assembly time is likely reduced.

Most of Wal-Mart's cheapest bikes seem to use threaded stems:

http://tinyurl.com/cc8zb6

(I can't tell if they use removable face plates, but I doubt it.)

Granted, Wal-Mart bikes generally only come in one size, but these bikes
still require steps that you say generate increased cost -- threading and
slotting the fork and making stems with quills. Maybe threaded is more
expensive and Wal-Mart invests in the extra expense because their
customers probably aren't familiar with threadless stems. But even if
that were true, the fact that threaded stems are found on bikes at that
price point suggests that the price difference isn't all that great.





Probably you
can tape and assemble the bars before beginning to assemble the bike.
Use lower cost labor for this. Maybe contract with a supplier to
deliver already taped up bars with brake levers on them to the final
assembly plant. Then just bolt the completed bars to the bike with the
removable faceplates now used on all stems. And of course the
threadless fork/stem configuration allows for the use of aluminum or
carbon fork steerers instead of steel. Weight consideration. Only
steel for threaded forks.

Your claim that there is no logic to the widespread adoption of the
threadless fork/stem is illogical.

Still Just Me wrote:
On Wed, 22 Apr 2009 02:34:15 -0700 (PDT), Chalo
wrote:

The scheme you suggest is currently available in the form of "adapter
spindles", which are square taper spindles threaded in the OPC
pattern. Such spindles can also be made with 19mm splined interfaces
for BMX-style 3-piece cranks. The first version of Redline's
venerable Flite cranks had such a spindle. Inexpensive tubular
chromoly 3-piece cranks on OEM bikes are often fitted with a threaded
OPC-type spindle.

http://www.danscomp.com/451053.php

Yes, exactly what I was thinking of. This eliminates the oft described
"fretting" problem.

The one piece solution does further eliminate the crank attachment
issue but would require a BB shell size increase to implement. It
would not be backwards compatible with older bikes.

A one piece is less convenient when changing chainwheels though and
requires complete disassembly of the BB. I suppose for the number of
times we actually change chainwheels (vs thinking or talking about
it), that it's really not an issue.

Mid seventies innovation - OPC spider for 110mm rings.
Common item still.
--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971