Ah yes, as I previously mentioned...the DeRosa method!
Chain Reaction Bicycles
>:>With all that said, your beloved 531 will not be a problem to cold set.
>:>my mind, however, it is important to have someone do it that has the
>:>and the experience. There have be some in r.b.t. that have suggested
>:>a foot on one drop and you hand on the other and yank..."hey it worked
>:>me"...this is potentially very bad news. It is important that each drop
>:>maintain the same distance from the imaginary center plain of the main
>:>triangle and that the faces of these drop are parallel. Anything less
>:>that and you can end up with a poor handling or poor shifting (or both)
>What kind of spreading tools are used to ensure that the
>spreading is symmetrical? I'm aware of the simple method
>using a pair of nuts on a threaded rod which is claimed to
>do a reasonable job.
Actually, this is not the best method, because it leaves the dropout
not parallel, the bending occurs at the bridge (which may or may not
be a problem) and it doesn't assure symmetry in any case (yielding is
not that predictable). The tools I'd use for a job like this is a
lever bar with a hook in it. A 2x4 works fine. The hook is the
lag-threaded hardware-store variety, with several layers of duct tape
to prevent scratching. The hook is about 45 cm from one end of the
2x4. I hook the hook around the dropout, and then insert a fulcrum
between the 2x4 and the spot where I want the bend to occur. I use a
2x2 of the softest white pine as a fulcrum, and tack it to the 2x4
with a***(from the side so that the***head doesn't dig into
the frame. The softness of the wood has been enough in my case to
prevent dents, though I suppose you can put a thick piece of felt on
it for insurance.
My 2x4 is about four feet long. I put the bike in a stand, and get a
couple of buddies to hole the frame by the seat tube and the head
tube. I hook the lever around the dropout, press the fulcrum at the
bend spot, and apply force. I work both sides, with an alignment
string to maintain symmetry. I work carefully, and so far, I haven't
overshot and had to back up, though I want to overshoot by a mm or two
because realigning the dropouts will soak up some of the new width. I
use a ruler to check spacing.
If the location of the bend is not right at the brake bridge, then you
minimize the risk of popping the bridge's solder joint, which was a
problem mentioned by another poster.
I then realign the dropouts using standard dropout alignment tools.
I don't worry about what the seat stays are doing. I figure they don't
really have to even yield--they are pretty thin, and can just go along
for the ride.
I used to think this was a problem (about 25 years ago, that is). When
I saw Bill Moore bending my fork stays in a form, cold, I realized it
wasn't a problem.
I've widened the rear triangle on three frames using this method,
without even marring the paint.
I'm sure Troy has a more officially acceptable method, but I like
methods that I can do in my ba***t. In general, though, look at the
tools that any good shop will have, and use them as models for your
own homemade tools.
Rick "Forks are harder, just because they are harder to hold onto, but
I've done them, too" Denney