The type of bike...
Never ask "What bike should I buy?" or "What's the best
bike?" There are no simple answers to those questions. "Mountain
Bikes" come in many types ranging from gravel bikes (which look like road
bikes but with big tires) to fat bikes (which have huge tires to ride on snow).
Even among "standard" mountain bikes, there are many permutations of
frame type, wheel size, and components to make the bike more specific to a
particular type of riding. For example, a "downhill bike" is plush and
smooth on rough descents, but miserable for a new rider to pedal uphill.
Then within each category of bike, for example the "cross-country"
category, there are differences that affect how much you will enjoy riding that
bike. A "hardtail" mountain bike is considered a "cross-country
bike." It's light and responsive -- so it's often selected by mountain bike
racers -- but it's a rough ride on rocky trails. In bikes with full suspension,
the suspension design affects how well the bike absorbs bumps and how
efficiently it pedals. Even in same overall model of bike, the choice of frame
material affects the weight of the bike, and therefore how hard it is to pedal
uphill. In general, the lighter the bike, the more it's going to cost you.
Once you identify what type of frame and suspension design works best for the
type of riding you want to do, it's time to consider components. Components are
the shifters, brakes and stuff. The quality here can vary wildly. There are
department-store bikes with crappy components that may not survive even a single
rough bike ride without requiring service.
New versus used...
Bicycle components get better every year. A new bike will have the latest stuff.
Yes, you'll pay more. But the bike shop will help you get the right bike for
your riding style, and make sure it fits you.
If you want to save some bucks, buy a newer used bike. In general a one-year
old bike in good condition should sell for less than 1/2 of the new-bike price.
Evaluate the components carefully. If you have no idea what you're looking at,
get help from an expert rider. Go for famous-brand components -- so you know
what you're getting. Get the full names of each piece (for example,
"Shimano XTR rear derailleur") and go to the company website to see
where it falls within the spectrum of cheap to best quality. In general, one
step down from the "best" is still very very good and it's a lot
Most frames are either aluminum or carbon-fiber. Carbon is considered high-end.
These frames are expensive. They're very light, sometimes several pounds lighter
than aluminum frames. They absorb little bumps and vibrations well, yet resist
Aluminum frames vary widely in quality and in weight. The more
expensive aluminum frames use special alloys and fancy construction to
give a lighter frame with good strength. On the bottom end, cheap
department-store aluminum frames are heavy yet more brittle and/or
New bikes are delivered to the bike store without pedals. You pick the
type of pedal you want. "Flats" are the basic bike pedals we
rode on as kids. Trick riders love them, and you can get some pretty
pricey flats that hold your shoes well. "Clipless pedals" are
pedals that lock onto special cleats on bike shoes. Cross-country riders
will often switch to clipless pedals, because they increase the efficiency
of pedaling. More speed for your effort, an assurance that your foot won't
bounce off the pedal at a critical time, and the option of delivering
power to the pedal on the upstroke.
Sample of clipless pedal and cleats, with shoe designed to for clipless.
There are several different designs of
clipless pedals, meaning the cleat on your shoe must match the brand of
receiver on the pedal. If you're buying a used bike, there's a good chance
you'll be buying some new pedals. (If you're a clipless rider, you could
simply swap out the cleat on your bike shoes.)