There are 3 common dimensions of steerer: 1 1/8” fork steerer (Image 2), 1/5’’ fork steerer and tapered is a hybrid of the 1 1/8’’ and 1.5’’ system.
Tapered headset is a technique which increases a size and the stiffness. The frame is applied tapper headset which just assembles to the fork having the same technique. It is used by many large bike brands.
The symbol of tappered headset on Asama Bikes:
A tapered headset must refer to the same dimension of fork. This type of tube is very easy to distinguish from others. The diameter of the upper race is smaller than the low race. When assembling, it is important to consider the diameter of the race of headtube to use the right fork
City bikes usually set 1 1/8’’ steerer because they are used to exercise. Bikes setting tappered headset and 1/5" steerers are sport bikes that under high pressure. So the tube is made larger in order to bear all big forces. Tapered fork has lightweight, so it is used widely on sport bikes. The 1/5’’ steerer is likely to be the highest load – bearing, so it is applied on downhill bike.
For use for tapered head ribs, the diameter of the upper diameter is 1 1/8 ", the diameter is less than 1.5", the conical neck is conical. Often found on specialized sports cars, especially the road vehicles. This cone shape increases the impact resistance of the road surface and the driver's load, but the weight is lighter than other tubes. Prices of tapered forks are also higher than nomal types.
The traditional headsets are made to fit standard frames and 1 1/8’’ fork steerers. It is equipped on normal bikes to exercise. It has the low price that suits to newbie.
Some modern gravity bikes or speciality down-hill bikes use 1.5” fork steerers and correspondingly larger head tubes for extra strength and front-end stiffness. The price is quite high.
The tappered headset technology is applied to sporty bikes of Asama brand so you can be comfortable when riding.