Tom, I tend to think about the physician's maxim when dealing with rare bikes: "First, do no harm."
So, my instinct would be to use the bolt-on hanger approach, or an internal hub gear. I've done nice-looking jobs flush-mounting a hanger plate to a rear drop-out, even with reinforcements. I've replaced drop-outs. But not on rare bikes, because it is pretty close to irreversible.
And, I have the opposite, too: I love my Ephgrave, but the rear dropouts don't match. Someone sawed off the hanger before it was refinished, and didn't even think to grind the drop to match the left one. Far as I'm concerned, that's part of its history now, and I ride it as she is. With an internal hub now.
harvey sachs mcLean va.
Dear List:
?
I'm idly daydreaming on the new frame that's coming, a late 40s Hobbes
with 115 rear end and no provision for a rear derailleur.? What would be
the best way to fix the bike up for multi speeds?? Frame is probably
going to get resprayed after initial test riding.
?
Of course there are a range of?options, from riding it fixed (needs
someone fitter than me given the hilly terrain here), multi speed
internal hub (is there a modern hub that fits down this narrow?),
a?separate?hanger fitted between the derailleur and drop out, or trying
to replace the rear drop out with a modern one.? The last option is a
bit too far out for me, and might not be practicable with the skinny stays.
?
But I was wondering how common was it during the 60's and 70's for
someone when renovating a frame to have a derailleur hanger brazed onto
the existing drop out?? I had one frame so modified, and it seemed to
work fine.? Was this a common practice back in the 60's when derailleurs
were on the rise?? Any thoughts either pro or con, practical or
philosophical?? Would this be a?tricky bit of work for a modern frame
builder who maybe has never done this work before?? What says the list??
?
Option B is the separate hanger, of which I have several lying around
and which are reasonably available from several sources, so lack of
hardware isn't the problem.? In fact I've got two old frames (the Algurn
and the Holdsworth Sirroco) set up this way, so I've aready proved
whatever would be proved by preserving the original drops.? Just
wondering if I can do something different this time.??
?
Option C might be a multi speed internally geared rear hub, but most
modern ones are 130mm or bigger.? The 8 speed Sturney fits down this
narrow, but seems geared for smaller wheels, requiring a massive rear
cog and a teeny front ring to get some useful ratios on a 700c wheel.? I
am planning on spreading the rear to 120mm, but I don't want to go any
further than that.? A three speed rear probably isn't suitable, given
the hills here and my feeble fitness level.
?
What say you, list?
?
Tom Adams
Manhattan, KS, USA