My girlfriend had reached the performance limits of her 27" wheeled Bianchi touring frame, and was getting the need for a faster/more efficient ride. She was really attached to the frame though as it had a lot of sentimental value, and there wasn't enough space in her apartment to keep two bikes.
While just switching to 700c wheels would have been relatively simple, the geometry of the frame would have remained early 80s touring style with seat and headtube angles in the 70/71 degree range, the wheelbase would be really long, and the rear frame spacing would be 130mm.
So this is where I come in. Itching for a little metalwork, I decided to weld, not braze, track ends onto her old frame to get her angles close to common road geometry, shorten her wheelbase, and respace her frame.
Here are some pics of the process.
Let me know what you guys and gals think:
Original ends after bending to 120mm. Notice that the slots are angled upwards above the chainstay.
Point of no return. Oh yea, this is my first attempt at frame work.
After grinding out slots and getting all the old braze out, the new ends were mocked up and ready to be tacked in.
Roughly aligned:
Commence to welding!
Closeup examples of my welds:
Shaping and contouring the dropouts:
End result:
She's now using flatbars with MTB grips.
New everything except seatpost, saddle, stem, and frame. I'd ride it.
It would have come out a little better but the first welder I used was too hot, and the second welder I ended up using ran out of gas in the middle of the project so I had to carry the welder to a different tank across the shop and use an extension cord. Big voltage drop. You fellow welders know what I'm talking about. Plus, due to time constraints, I only had about two and a half hours to do the work so I was a little rushed.
I only have a rough contour right now, but it could stand to take a little more material out to smooth out the curves. A little work with a flap disk and some metal polish and I think I'll be happy with it.
I don't have the numbers in front of me right now, but using a magnetic angle finder and a tape measure, the BB height was roughly the same (still taller than my fuji!), the wheelbase with the new fork was shortened about 1.25 inches, and the seattube angle steepened by about 2 degrees.
I didn't mess with the bridge because of the seatstay/seatube junction; I thought there would be too much angular preload on a brazed joint that already experiences a lot of shear. Plus this bike gets ridden in all conditions, so I didn't want to risk messing up the fender mount.
The GF likes the improved ride of 700c wheels quite a bit, and has found that her cruising speed is about the same as mine. She even passed me on some of the hills in the Upper East Side. For shame!