I recently got a State 4130 Road Bike with 1x8 gearing using a Suntour R80 and indexed friction shifter. I took it out for my first ride on it and everything felt great until I tried shifting down to some smaller gears for a hill. I got most of the way up the hill and I feel the chain jump between cogs. I shift back up to a higher gear at the top of the hill and everything seems fine. When I got home, I tried adjusting the high and low screws and the barrel adjuster for the cable. I followed a park tool guide I found on YouTube to try to get it shifting smoothly. I got it so that the bike will shift from the highest gear (smallest tooth rear cog) to the lowest gear (largest rear cog) smoothly. The problem is when I try to shift the other direction the chain is skipping over cogs and jumping back and forth between them. I went through the process of trying to readjust the screws and barrel adjuster multiple times and I can only get it to shift smoothly one direction and only ever going down. I checked another guide for other problems and it mentioned checking worn parts, bent derailleur hangers, etc. but the bike is band new so I don't think that's the issue. While i was tinkering around on it, I noticed that if I shift to a higher gear and it's skipping around, I can apply some pressure on the shifter towards shifting back down a gear and it seems to fixed the jumping around of the gears. I can put it in any gear and just apply some pressure make the other direction and it makes them all smooth. Is there a way I can fix it so I can just shift smoothly both directions without having to fiddle with it? It's like the spring in the rear derailleur isn't pulling back on the shift cable hard enough is my guess, but I have no idea how to deal with this.