Originally Posted by
bikemig
Sure, I know it's an old crank designed to work with 5 or 6 on the back. I'm not arguing with you but I'm a little surprised that shifting is so poor with a 10 tooth jump.
Back in the day — 1976 IIRC — I built up a touring bike with TA chainrings (on a Stronglight 49D) with 50–30t chainrings. This was with one of those Simplex Delrin front shifters that moved in and out, but not up and down. To everyone's surprise, it worked just fine.
The "secret" was using a long-arm
rear derailleur that could take-up the excess chain. I used a Regina 13–29t block.
Much to my regret, I sold that crankset along with some spare rings and the stronglight extractor tool on eBay.