Bicycles of the 1970-1990 era had what are termed as "downtube shifters". These shifters were index style gear levers that were located on either side of the downtube of the bicycle. To change gears you simply moved one of the shifters forward or to the rear to loosen or add tension to the shifter cables. Converting an older bicycle from this era to a newer shifting system is actually quite simple and can be accomplished by even novice bicycle mechanics.
- Skill level:
- Moderately Easy
Things you need
- Allen keys
Use the Allen wrenches to loosen the cable nuts on the derailleurs and pull the old cables and housings off of the bike. Use the screwdriver to loosen and remove the downtube shifters mounting bolts.
Pull the downtube shifters off of the frame. Unpack the new shifters and slide them onto the handlebars. The rear shifter will be on the right handlebar and the front shifter on the left handlebar. Position them within easy reach while you hands are on the top portion of the handlebars and then use the Allen wrenches to tighten down the mounting bolts on the bottom portion of the shifter to lock them in place.
Slide a new cable through the shifter and then route it and its housing back along the downtube and chainstays of the bicycle, securing in place with the zip-ties. Slide the end of the new cable into the derailleur and secure it with the Allen wrench. Make sure there is a 3 inch loop in the cable from the end of where it is secured to the bicycle and the derailleur as this ensures the proper cable tension for accurate shifting.
Tune your derailleurs according to your owner's manual.
Tips and warnings
- Converting from downtube shifters to other shifters (Shimano Flight Deck for instance) really only entails longer cables as the shifting mechanism will be similar in both sets of shifters.
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