1991 Cannondale SM700

I just acquired this from my brother who got it from a collector a few years back. It's a 1991 Cannondale SM700 18". I always wanted a Cannondale of this era but was only 12 years old at the time and Cannondale's were a bit out of my price range. It's really a bit small for me but with a 140mm stem I will be able to get my riding position correct, and a 140mm is still borderline acceptable for this size bike of this era.

It's all in quite good condition and very close to catalog spec. I've just fitted an LX rear derailleur to bring that back to original spec. Plus I put on a new Turbo saddle which while not catalog correct is fitting for this vintage. The Ritchey post was cracked so I put on a Kalloy copy.

Other parts to be replaced are:
-Remove Smoke and Dart tires for suitable Ritchey model
-Remove 560mm Zoom bar for 580mm Ritchey (or similar)
-Remove new style Ritchey grips for old style WCS foam or ODI Attack
-Remove 120mm stem and make a new one in 140mm length
-Remove the seat skewer and replace with a bolt

This should be enough, along with a general service and re-grease of all bearings.

Then time to give it some throttle on the local trails...

The stem will be made from some 4130 tube. Normal diameter and wall thickness for a 1" stem would be 22.2mm x .065" (1.6mm) wall for the quill tube but as the stem needs to be extended a bit I'm going to go to .083" (2.1mm) wall to keep it stiff. The extension tube will be 25.4mm x 1.2mm wall. The clamp tube will be 28.6mm x 1.6mm. First the extension tube will be mitred at both ends in the drill press with hole saws. Then the tubes will be jigged up, tacked, and welded. Next I will turn up on the lathe some solid rod for the pinch bolt. This will be tacked and welded on to the clamp tube. The clamp tube will then be reamed with a hand reamer to an exact 25.4mm internal diameter then slotted using a cut-off saw. The angle on the bottom of the quill tube will also be cut in the cut-off saw. I will just use the quill wedge and bolt off an old stem. The quill cap will be turned up on the lathe. Then all edges de-burred with file and emery paper. I won't weld on the cable roller as I'm not a fan of those. Maybe a cable running through the stem or just use a headset mounted hanger. If you are interested I can post build pics of the stem, it won't be for a few weeks yet.

Re:

Will you ovalize the extension tube to match the width of the quill tube? I brazed a couple stems but found it difficult to ovalize the chromoly tube evenly.

I was thinking maybe doing it like the old Salsa stems and just welding the gap on a non-ovalised tube. The gap between the 22.2mm tube and 25.4mm tube will only be 0.4mm on each side for a small part of the radius. But I'm not sure, will see what it looks like, an ovalised tube at the quill end will give the slight illusion that the stem is not extended as high as a non-ovalised tube, which on this bike will look better.

When ovalising tubes such as top, seat, down tubes, or the end of the stays at the dropout end I've normally used some firm wood in the vice and it's come out nice and even providing each piece of wood has similar grain and running in the same direction. Or I've used some MDF with G-Clamps.

Re:

Cool, thanks for the tips.