Sweat and thirst are unavoidable part of cycling. For sweat, we can wear a sweatband and to quench the thirst we need a bottle of water. But wait, where would you store them while riding? You would need a bottle cage to do that. Bottle cage usually fits above the down tube of the bike, but sometimes it finds its place in other parts of the bike.
When out in the market to buy a bottle few things to keep in mind are as follows.
Bottle cages are generally made up of alloy, carbon fiber or plastic. The basic type is made by bending the alloy tube into a loop to give it a cage-like structure. Cages made up of an alloy are very strong and safe but are on the heavier side when compared to the carbon fiber and plastic. The alloy cage is cheaper when compared to the plastic and the carbon fiber is on the higher side. Bottle cage of any material serves the same purpose but thing that varies is the weight of it. If you are a leisure rider, alloy cage would be sufficient but if you see yourself on a TT bike where each gram matters then you may opt for the carbon fiber cage.
The purpose of the bottle cage holder is to retain the bottle, hence it should wrap around the collar or the body of the bottle securely. Plastic or the carbon fiber cage adopts a wraparound structure to retain the bottle securely; it grips on the body of the bottle instead of the collar. But many modern-day bottle cages come with an extra grip around the collar which helps in retention of the bottle during extreme vibrations caused due to bad roads.
You would want your bottle to be easily accessible whenever required and it should also be convenient to put it back when not in use, so the grip cannot be too strong to make it difficult to access. There has to be a proper balance between security and accessibility. The cages which are road race specific are more towards accessibility and mountain bike cages are towards the security.
The weight of the cage would matter if you are looking at performance segment. But, if we look at the bigger picture the weight saved is negligible, because of the additional weight added by the bottle. Lightweight cages would provide ease of access but would fall short of secured grip. One needs to find a proper balance between weight, security, and ease of access according to his riding style.
Majority of the bottle cages are sized to fit both small and big size of bottle which has the collar at the same position. The advantage of alloy cage is that it can be shaped back to its position if it loses its shape over time because of constant use.
One of the final things to consider is the mounting options, mostly the bottle cages are mounted on the down tube of the bike buy it can also be mounted under the saddle with an additional mount.
Bottle cages can make your riding comfortable, but it has to be chosen keeping the above points in mind. One has to filter his choice based on the bike and bottle.