Recently I wanted to build up a bike with a slightly shorter top tube and a different head angle to test out a few fit ideas for myself - part of the joys of getting older and less flexible! Plus, if I could make the seat tube short enough then my 10 year old son could ride it as well - which would be his first true 700c road bike.
Since I had this old frame hanging in the shop that had a dented top tube I decided this particular frame would be a perfect candidate to do this conversion.
This frame was originally built in 1992 using a Tange Prestige Ultimate Superlight tube set - when this frame was built I had "upgraded" the down tube to use a slightly more robust "standard" Tange Prestige 28.6 O.D (.7mm x .4mm x .7mm) tube, and I also replaced the super thin 25.4mm top tube from the set with the original 28.6mm (.6mm x .3mm x .6mm) down tube as an upgraded and "oversized" top tube.
It is no wonder that the super thin top tube ended up with some dents and creases...This was, and is still, the only tube set I have ever seen with such a thin .3mm wall thickness - I think that is just a little too thin for a proper steel bike frame.
For this repair I decided to update the head tube to a simple 36.5mm O.D. 1-1/8" EC34 and also used a TrueTemper S3 teardrop shaped top tube that I had in stock. The existing seat tube was cut down a fair bit for the improved stand over clearance I wanted - this made for a very aggressively sloped top tube. I also removed the old above BB braze-ons and re-routed the cables under the BB.
I can ride it now with a long 330mm seat post, and my son can also ride it with the seat slammed close to the top tube...
He is pretty excited about it and can't believe how fast a real road bike - his first adult sized bike!
