Bicycle shifter, brake cable, and housing standards

Updated: 17/02/2021.

This post’s topic are shifter and brake cable and housing standards. From my experience, many problems with poor shifting, or braking, come from using incorrect components. Separate post explains brake and shifter cable routing.

Contents:

1. Shifter (derailleur) cable standards – differences
2. Brake cable standards – differences
3. Shifter housing standards
4. Brake housing standards
5. IMPORTANT: difference between brake and shifter housing
6. “Exotic” models
7. My shopping recommendations

1. Shifter (derailleur) cable standards – differences

Shifter cables have a barrel on one end, that is used for shifter to pull (and release) the cable, while the other end is soldered, so that wires don’t get unwinded and so that the cable can more easily be routed (and cut to the appropriate length after routing).

Shifter (derailleur) cables come in two standards, main difference being the end barrel, though cable thickness also tends to differ:

• Campagnolo standard – 1.1 to 1.2 mm cable diameter, with a bit smaller diameter barrel at the end
• Others (Shimano, SRAM…) – around 1.2 to 1.3 mm cable diameter – with end barrel a bit larger than Campagnolo one

Apart from the diameter, Campagnolo and Shimano shifter cables are visually almost identical, so pay attention to specifications when shopping (especially if you have Campagnolo shiters, since Shimano cables won’t fit Campagnolo shifters).

2. Brake cable standards – differences

To avoid/prevent any confusion, I’ll explain brake cables (and housing) as well in this post.

Brake cables come in three standards, with the main difference being the size and shape of the end barrel:

• MTB – with a large barrel on one end
• Road Shimano compatible – for Shimano and SRAM shifters
• Road Campagnolo

With road cables, Shimano ones have a bit larger barrel, though very similarly shaped. In fact, some manufacturers (like Jagwire, for all I know) make road bike brake cable ends such that barrels are a bit on the smaller side, hence the same model fits both Shimano and Campagnolo brake levers.

3. Shifter housing standards

For shifter housing there are two standards:

• Shifter housing with 4 mm outer diameter.
• Shifter housing with 5 mm outer diameter (the same diameter, but not the same type, as brake housing).

All the shifter cables will run with no problems through housing by any of the above noted standards. Some MTB riders prefer 5 mm housing, since it leaves more room, so they don’t get stuck with mud that easily. Though, for 4 mm shifter housing, Shimano makes seals that prevent the entrance of dirt:

For 5 mm shifter housing ends, the same (metal) ends can be used as for brake housing (even though those are two different housing types!).

Important note: Shimano seels (at least here, in Serbia) two shifter housing models:

• Shimano SP40 SIS. This one doesn’t work very well and I don’t know what it is good for. On the outside, it looks like the proper shifter housing: is only 4 mm wide (brake housing is usually 5 mm wide), and has SIS (Shimano Indexing System) written on it. But, it has a spiral steel “skeleton,” like the one used in brake housing – stronger, but more flexible.
• Shimano OT-SP41 SIS. This is the proper shifter housing. It is also 4 mm wide (outer diameter), but has the longitudinally lined steel wires, making it stiff in terms of shifter cable for-aft movement, resulting in more precise shifting. See picture 8 below for the difference between this, and brake housing “skeleton.”

SP40 does work a bit better with shifters, compared to brake housing (low-end bicycles sold locally often come with brake housing used for both brakes, and shifters). But it is still inferior to OT-SP41 in terms of shifter precision.

4. Brake housing standards

With bicycle brake housing standards there aren’t any differnces – they are all 5 mm outer diameter with steel end caps. Apart from hydraulic brake hoses, of course, but that’s a different matter.

5. IMPORTANT: difference between brake and shifter housing

Too often I see brake and shifter housing mixed. But this is not good, and can even be dangerous!

• Shifter housing is constructed to compress and elongate as little as possible with shifter cable tension change (while shifting up and down). But it can not take large force – pull cable strong enough and it will split!
• Brake housing is made to sustain very high cable tension forces without splitting, but slight compression is not as detrimental.

6. “Exotic” models

There are special, braided brake housings that compress a lot less than “ordinary” brake housing, which is good – leaves more lever play and allows for more precise brake modulation. They are usually constructed using a layered combination of longitudinal steel wires and spiral steel, or kevlar lining to give more strength, so the housing doesn’t split when high braking force is exerted.

Such housing, due to less compression, can also be used for shifters. Though, for shifters, it is still a bit better to use shifter housing.

Their main downsides are somewhat higher weight and a lot higher price.

This sums it up. In case I’ve forgotten to mention something, or you have any corrections, or additions, use the comment section below.

7. My shopping recommendations

On-line shopping (Amazon affiliate links):