Wow. OP is sorta' reacting to like ****** to people. Thin skin or something? Dude, no one is proclaiming themselves experts, but... the way the bike looks setup in your pic? You'll get more benefit from better seat, bar, and control setup and angles than lighter weight. I say that as someone who isn't an expert, but has been riding bikes of all sorts for a long time. The way you have your seat and bars angled looks...painful and very, very poor for decent pedaling and riding, unless you're just stylin' out on the paved MUT.


Seriously though: Cranks, seat/post, bar and stem. What's on there appear to be rather boat anchor-ish, and you can find light and cheap options.

As others have pointed out, wheels and tires, but you seem to have that already in hand.

Go single ring up front. Get rid of the extraneous crap attached to your handlebar and seatpost.

Depending on your budget, and how light you want to get the thing, it may just be more cost effective in the long run to save, save, save and buy a newer/nicer/lighter ride down the road.