Hi, newbie here. I just bought my first real bike (non-walmart). I got a Diamondback Sorrento...after some shopping around for an entry level bike. I live in Columbia, MD where we have miles of paved bike paths that I'm riding it on, but there's also a lot of hills! I really like it so far except for one problem. I'm having trouble shifting the front from 2 to 1...unless I'm going like downhill. If I'm going up even a slight incline it won't shift into first gear...and will sometimes throw the chain. I'm a big guy, 6'1'' and about 260lbs. Am I asking too much out of it? Do I need a better front Derailer (sp?)?

Here's a link to the bike specs if that helps: https://www.diamondback.com/bikes/mtn...l/sorrento-11/

Thanks for any advice!

Probably a cable adjustment. Use the park tool website to learn a how to adjust it or go back where you bought it and have it looked at. There is some technique involved too though. You shouldn't be hammering hard when shifting, especially up front.