If it's a 20-year-old 6-speed, it's a freewheel, and probably will fit a 7-speed freewheel. For 20 bucks he can get a 7-speed with a 28, which would lower his lowest gear about 11%; changing the 42 ring to a 39 (another $20 for a cheap ring) would lower it only about 7% (changing both would lower it about 17%). He might need a new (longer) chain, which he probably needs anyway. Front deralleur should work; the only issue might be the rear derailleur handling the extra wrap, but you can probably make it work with the 28. The megarange with the 34 is more iffy.OES said:Simple and cheap: They have these in both 6 and 7. Look at the Megarange if he REALLY needs a low gear.