aka: Dr. Cannondale
Join Date: Jul 2009
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If they are downtube shifters, those levers will work with any number of speeds on the rear wheel in friction mode your easiest solution if the number of speeds and number of index clicks are not the same. Turn the Dring on the right side shifter from SIS to Friction and you are done. If we are talking about a brake/shift lever combination (often called a brifter) then the number of indexed clicks and freewheel speeds need to match.
7 speeds will not give you any performance improvement, all things being equal. However, if your current freewheel is a corncob(like 1218) and you need more range, then a 1428 or 1326 6 or 7 speed will work with those shifters and derailleur again, if the number of index clicks are the same at both ends, in index mode, otherwise in friction mode. If the 8 speed RD is a 600 tricolor/640X series, then 28 is probably the largest rear cog that will wrap.
Stay away from 8 speed freewheels they are notorious for bearing failure.
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