Directional chains for road racing.
The latest chains from DURA-ACE, ULTEGRA, 105 and Tiagra feature a unique new asymmetric design. Therefore, the running direction must be observed when mounting. The specially shaped plates optimise the engagement on the pinion and lead to even smoother shifting processes even under load. To save weight, these chains have recesses on the inner plates and hollow rivet pins (the latter only with DURA-ACE).
Shimano HG (Hyperglide)
The chain transfers force from the chain ring to the sprocket of the rear hub. It is exposed to extreme loads and weather conditions. Chains vary in length depending on the conditions of use, but each must be replaced sooner or later. Replacing the chain in time is the only way to protect the chainrings and sprockets from excessive wear. To get the best possible performance from the Shimano Hyper-Drive system, it is important to use original Shimano HG chains.
HG cassette sprockets
In combination with Shimano HYPERGLIDE (HG) chains the HG cassette sprockets provide fast, precise indexing function. The special, computer-designed sprockets feature specific tooth profiles and specifically positioned climbing aids that optimise the chain guide during shifting. This results in fast, smooth and noiseless gear changes.