I'm trying to start mountain biking, I already have a bike, but I'm ready to upgrade. I'm looking for a bike that can take on weather, dirt, mud and about everything I throw at it.
Why won't you ride with your current bike for few thousand km at least, and come here back with detailed explanations with what you don't like with your current bike? Because we don't know what features your current bike has and how they fit to your riding style, it is impossible to recommend a better bicycle.
Before buying your current bike I would at least recommend:
- Switch to the tires best for your riding style. If you purchase a new bike, it rarely comes with the most optimal tires. Thus, you will get to use the most optimal separately purchased tires even if you decide to purchase a new bike -- tires are easy to change and most people don't select bikes based on their factory-installed tires. If you don't know how to mount tires, learn! You'll need the skill anyway the first time you get a flat in the middle of nowhere.
- Switch to the best brake pads. For rim brakes, the best pads are generally agreed to be Kool Stop Salmon, although in some cases the Salmon pads can squeal.
- Adjust the fit of your bike to be best possible you can achieve. If you are unable to have a good handlebar distance and height with your current bike, you at least know which direction (longer/shorter top tube) to go to. Even a very cheap bicycle is an excellent fitting aid when the time comes to upgrade, assuming the style of handlebars is your preferred one.
You also need to consider straight vs drop bars. Most people do mountain biking with straight bars, but evidence from cyclocross bikes actually suggests that in some cases a drop bar bike can too accept weather, dirt and mud.
I'm about 5 feet and 50 kg. Specifically, I would like a bike with a single ring chainring.
Don't choose single chainring! While 50 kg is not much weight and thus you don't necessarily need uber-small chainring for climbing hills and uber-large chainring for fast speeds as much as someone with 100 kg weight might need, a single chainring is inherently unreliable. If it fails, you have no chainring.
Whereas, if you have two chainrings, failure of one doesn't ruin your ride. I wouldn't be satisfied 30 km away from civilization with a broken single chainring in a terrain where cars cannot drive.
Also, a properly adjusted front derailleur reduces likelihood of dropping chain from the chainring and increases your ability to raise the chain to a chainring without getting your hands stained in chain lube.