Single Speed Chain Compatability Checklist
Most contemporary bicycles and all contemporary single speed bicycles use chains which conform to an identical 'link length' standard of 1⁄2" so fortunately we can almost ignore that factor.
Chain Gauge - 1/8" or 3/32"
However these same bicycles usually make use of one of two 'guages.' These are described slightly confusingly as 3/32” and 1/8 ” (we think 3⁄32" and 4⁄32" would be easier to work with). In the usual lingo these two chains are simply known as 'wide' and 'narrow' chains. (Well, actually, ‘wide’, or ‘BMX’, or ‘track’... and ‘narrow’, or ‘skinny’, or ‘road’)
Here's a photo to show this:
The brown chain to the left is a 1/8" Gauge, wide chain
The silver on the right is a 3/32" skinny chain
The discs on the insides of the plates are noticeably different widths
It is not just chains which vary in size, chainrings and sprockets also are of these two corresponding widths.
This is where the potential issue is, because a narrow chain can not run along a wide sprocket as it will not fit over the teeth.
To avoid this problem, here are two rules to adhere to when purchasing chains, chainsets and sprockets:
- Do not buy a chain which is narrower than your chainset or your sprocket – that is to say if you have a wide chainset or sprocket don't get a narrow, 3/32” chain, get a 1/8” one. If in doubt just buy a wide chain - it will run okay over narrow cogs.
- Do not buy a chainset or sprocket which is wider than your chain– and if you already have a narrow chain, don't get wide sprockets unless you wanted to change the chain anyway. If in doubt buy a narrow chainset and sprocket– as above, even if you have a wide chain this will run fine.
Because of this basic situation, when we are selling a single chain and cog to someone we will sell wide items by default, in case they have a second cog which is wide gauge.
Should I buy a 1/2 Link Chain?
A half link chain has links which are half the length of those on a standard chain.This means that you can select the total chain length to double the precision.
In general we'd only suggest you buy a half link chain if you have either very short dropouts or vertical dropouts. With short dropouts the half link chain can really help as the extra detail in what length you shorten the length of the chain to means you have more likelihood of getting the chain to be at adequate tension in the frame.
Vertical dropout frames, are kind of an extreme case of short dropouts! So with them if you want to try to avoid using a chain tensioner - either for aesthetic reasons or because you want to ride fixed gear - then a half link chain gives you more chance of finding a 'golden combination' of front and rear cogs which will allow you to get decent tension.
Outside of these two situations the extra weight of a half link chain I'd suggest makes it not worth using.