I recently bought a 2008 Dahon d7 vitesse. When pedalling there is noise coming from the rear derailleur/chain/freewheel. The gears engage properly, it rides OK and there's nothing wrong mechanically but I don't like the noise and the rough gear change. I've adjusted the gear cable and oiled the chain.
I want it to be like my hybrid mountain bike which is very smooth. The rear derailleur on the dahon is sram I think and it looks pretty basic. Is it normal for a folding bike to be noisier than a full size bike? Would it make any difference if I upgraded the rear derailleur/freewheel?