Bicycle drive chain standard dimensions

This post will give an overview of bicycle driving chains standard dimensions. Each chain has three important dimensions: pitch, inner width and outer width.

Table Of Contents (T.O.C.):

TL/DR

1. Bicycle driving chain pitch
2. Chain inner width
3. Chain outer width
   3.1. Bicycle chain width standards table
4. Bicycle “chain construction and standards” video

TL/DR

If you read this, you will know:

• How long is a bicycle chain link (this is called “chain pitch“)?
• How do chain inner widths differ depending on the number of speeds (why do the high-speed narrow chains get stuck on single speed wide chainrings)?
• How do chain outer widths differ (why do low-speed wide chains get stuck between high-speed narrowly spaced cassette sprockets)?

I’ve also added a chain width table.

– T.O.C. –

1. Bicycle driving chain pitch

Chain pitch is the distance at which the pins are placed. It is measured by measuring the distance between 3 links, then dividing it by two.

For detailed explanation of chain pitch, and why measuring three pins gives a more accurate result read the post Chain wear (“stretching”). For this post it suffices to say that bicycle chain pitch is exactly 1/2 inch (12.7 mm). This goes for all the bicycle chains, regardless of the speed number.

– T.O.C. –

2. Chain inner width

Inner chain width is the spacing between a pair of inner plates. It is marked in the picture 2.

For inner chain width there are the following standard dimensions:

• Single speed chains have inner width of 1/8″ (3.175 mm).
• Multi speed chains, from 5 to 8 have inner width of 3/32″ (2.38 mm).
• Multi speed chains from 9 to 12 speeds have inner width of 11/128″ (2.18 mm).
• “Exotic” standard for freight bicycles is 5/32″ (4 mm).

– T.O.C. –

3. Chain outer width

Chains for one and multiple speeds differ from each other by the outer width. The more “speeds” a chain is designed for, the thinner the outer plates and shorter the pins are (and they protrude less) – so the outer chain width is smaller (i.e. chain is narrower). Inner width of all the multi speed chains is almost the same – with only single speed chains having a significantly larger inner width.

Note how rollers of all the multispeed chains are of almost the same width, only single speed chain being significantly wider on the inside.

Pitch is the same for all the chains – they are aligned by length.

As can be seen from the picture 3, the outer width differs mostly. This is important for bikes with multiple sprockets, so the chain doesn’t get stuck (too wide), or drop between the sprockets (too narrow – this latter case is practically never a problem in practice).

See this great post by “Graeme_FK” on the Cycle Chat forum for an in-detail explanation of the “fine print” in terms of Campagnolo vs Shimano vs SRAM vs 1x chain compatibility and size differences.

– T.O.C. –

3.1. Bicycle chain width standards table

Table 1 gives an overview of chain outer dimensions, by number of speeds.

– T.O.C. –

4. Bicycle “chain construction and standards” video

My video explaining bicycle chain construction and dimension standards:

For an overview of which chains can be combined with which sprockets, read this post: Bicycle chains compatibility:

The existing comments posted under this article (questions and answers) have been moved to this BikeGremlin forum thread:
https://www.bikegremlin.net/threads/bicycle-drive-chain-standard-dimensions-article-comments.122/

– T.O.C. –

Author

Relja Novović

Relja is an avid cyclist, a pretty good bike mechanic, and a professional computer systems administrator – with decades of experience in both those fields (computers and bikes 🙂 ). Relja Novović’s credentials and a short biography