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Basics of Bicycle Wires
Generally speaking, a wire is a piece of steel that is wound into a string, and the common wire is called “inner wire (inner)” in bicycles.
On the other hand, the plastic cover to protect the wire is called “outer wire (outer). Keep in mind that they have different uses, so when replacing them, you can tell which wire to get by which one you are replacing.
Basics of inner wire types
There are two types of bicycle inner wires.
- brake wire
- shift wire
There is a difference between “the inner wire for pulling the brake lever to tighten the brake” and “the inner wire for pulling the shift lever to move the derailleur” respectively. Not only do they have different uses, but the thickness (diameter) of the inner wire is also different.
For example, Shimano’s inner wires have the following differences.
- Brake wire 1.6m diameter
- Shift wire 1.2mm diameter.
This size is the same whether it is for road bikes or MTB/cross bikes.
Since the inner wires are different in thickness, the corresponding outer wires must also be specially designed for each.
The main difference between those for road bikes and those for MTB and cross bikes is the “Wire drum.”
The difference between the wires for road bikes and those for MTB and cross bikes is the shape of the head of the wire that is fixed to the lever side, called the “Wire drum”.
The wire drum of the wire for road bikes and the wire drum of the wire for MTB and cross bikes have different shapes, so different wires cannot be fixed to the lever.
Also, the shape of the wire drum is different for brake wires and shift wires. The different shapes prevent them from being used together.
Decision points for choosing which wire to use
If you don’t know whether your bike uses wires for road or MTB/cross bike, you can determine whether it is an STI lever or not.
If the lever is an STI lever, then it is correct to use “wire for road”, and if the shift lever is attached to the same brake as a standard city bike, then it is correct to use “wire for MTB/cross bike”.
In fact, the wire is an important part that enhances the operability.
Wires don’t get much attention when it comes to upgrading road bikes, MTBs and cross bikes, but they are actually one of the most important parts of bicycle operation.
There are two ways to brake a bicycle, “mechanical” and “hydraulic”. The “mechanical” method, which is used in the overwhelming majority of bicycles, makes the resistance of the cable directly affect the weight of the brake pull. Quality outer and inner wires are designed and manufactured to have lower resistance, which makes braking and shifting lighter.
It’s just a wire, but brakes are a frequently used part of a bicycle, so if the pull is heavy, it will take away your grip strength on long rides.
People tend to think that the weight of the brake is determined by the brake itself and the lever, but actually the quality and routing of the wire is also quite important.
We have looked at the different types of wires for road bikes, MTB and cross bikes.
Even a single wire can make a big difference in your comfort while riding, so it’s a small customization that you should definitely try to stick to.