on my old hardrock I changed the rear derailler to deore and got a new shifter and cable, new chain and tires and spent about $125-$150. Now it rides like a new bike. It's worth fixing if you like the bike. I found that I wouldnt get enough money for it to make it worth selling. And a new cheap bike wasnt really as much of an upgrade as I thought. I am still putting together a new bike while I ride this one but Am doing it slowly and with the components I want, not what comes on the thing good luck