1. Bike Type.
If you already know you want a mountain bike, or a road bike, or what have you, skip to #2. If you still don’t know what type of bike to buy here are some questions to ask yourself:
● Are you buying a bike to ride with your friends? Then buy the same type of bike. If your friends ride road, buy road, if they ride mountain, buy mountain. Don’t buy a hybrid to try to ride with friends on road bikes.
● Do you have access to mountain bike trails or great road riding? Do you prefer to be out in nature, or do you like to be on the road?
● Will you use your bike for errands and commuting? A road bike would be desirable. If all you will do is commute, you can look at hybrids and townies as well, especially if you prefer to ride in normal apparel.
● Are you planning on riding in a charity ride? Then a road bike is most likely the best choice (unless it’s a mountain bike ride of course!)
● “I want to do triathlons.” That is fine and good. Buy a road bike. A time trial bike will be useful in only a triathlon and you can’t go on group rides with one (the narrow bars and precarious brakes make it dangerous to ride in close proximity to others). Get a road bike first, TT bike later. that way you can ride with people and have options.
Fit should be the number one consideration. A bike too large will be too difficult to handle. A bike that does not fit you will cause myriad of issues from neck pain, knee pain, back pain and so on. A proper fit is the number one consideration.
No doubt, the more expensive the bike, the less it is going to weigh. When making your decision, be sure to consider your weight to bike weight ratio. If you weigh 125 pounds and your bike weighs 25 pounds, that is 25% of your body weight. If you are riding with a male who weighs 175 pounds and his bike weighs 20 pounds, his bike is 11% of his body weight. The weight of your bike is important. Parts are one component, wheels are a major component, however the frame is the thing. High end carbon frames for women are lighter than the men’s versions and a perfect choice. For road bikes, look for something around 17 pounds and definitely under 20. For mountain, 20 pounds is good, while under 23 for full suspension should be available to you. Of course, the lighter the better, and if budget is of no concern, you can always replace heavy parts (bottom brackets and cranks, stems, bars and wheels are usually big culprits on women’s bikes).
Titanium, aluminum, carbon, steel and so on. If you want Ti, choose a custom frame. When choosing a custom frame, be sure you have been riding long enough to know how the bike should fit. Many times clients dive right in to a custom frame before their bodies have adapted to cycling, and they outgrow the frame too soon.
Aluminum is light enough, and with today’s technology has become much smoother amongst the bumps. However, it is heavier than carbon. Will it outlast carbon? Probably. Value? High.
Carbon is the smoothest and the lightest frame material. I would choose a carbon bike any day of the week. The first carbon hardtail I had the chance to ride was light, stiff and faster on the downhills than most aluminum dual suspension bikes. I love carbon for its weight and handling.
Steel is of course a classic material. For a beautiful handmade one of a kind bike, steel is the ultimate material.
When it comes to choosing your material you have to decide: custom (ti, steel) or stock (carbon, aluminum)?; price is no issue (Ti, carbon, steel) or budget (aluminum, steel)? If price is not an issue, you obviously have free rein to decide which features you prefer in a bike frame.
source: MtbChick: Everything about Cycling.