Bicycle Chains
Contents
General Concept
Bicycle chains follow ISO 9633:2001 and JIS D 9417:1993 specifications for tolerances and specifications. US Tsubaki describes bicycle chains HERE. A quick reference to chain dimentions is HERE. Since a bicycle chain running in a derailure type configuration must allow for latteral movement, bushless chains are used. On single speed, or internally geared configurations, a bushing chain should be used.
Bushing Chains
Common sizes for bushing chains are 1/2x1/8 and 1/2x3/32. For all but abusive BMX riding, a 3/32 is the best choice.
Bushinless Chains
Connecting Chains
- Hyper glide pins
- Quick links
- Master links
- Riveted links
Offset Links
Commonly refered to as a 'half link', a misnomer since it is really a single link with offset plates.
The use of a offset link allows you to vary the chain length in 0.500" intervals, rather than one inch with a standard paired link.
Although it is possible to use an offset link in a variety of situations, their use is strongly discouraged. It is far better to plan a gearing that will produce the needed center to center distance for the application.
Available in 1/8 and 3/32 inch widths.
Common Cycle Chain Suppliers
Shimano
SRAM
Rohloff
Whipperman
ACS
KMC
Regina
See Also
External Links
http://www.damonrinard.com/chain_stiffness.htm
http://www.63xc.com/gregg/gregchai.htm
http://www.sheldonbrown.com/rinard/chain_stiffness.htm
Traditionally single speeders used 1/8 inch BMX chains, since most single speed (SS) bikes are just 26" wheel BMX bikes anyway. Other reasons include the fact that SS track bikes and old BMX bikes had 1/8 inch cogs and chainrings and since 1/8 inch chains looked bigger than 3/32 chains they must be stronger. Also 3/32 (7-8-9 speed) multi-speed rated (MSR) chains are designed to derail, something you don't want to happen on a SS bike. A second look however shows there had been a lot more R&D money thrown at MSR 3/32 chains by Shimano and SRAM, so most 3/32 chains meet or exceed the tensile or "pull" strength of 1/8 inch chains. Since most single speed components available today come in 3/32, it seems logical to use 3/32 chains. On the other hand, while some claim that 1/8 inch chains on 3/32 gears cause more noise and wear than 3/32 chains, the jury is still out on this matter as many more use prefer this set-up. In the real world, it would seem the use of 1/8 inch chains work fine on 3/32 components and some, such as the SRAM PC-7 and KMC Kool chains are stronger.
So do you need a single speed (non MSR) over a MSR chain? No, not really. Is there any advantage to a 1/8 inch chain? Yes, there can be if you have chainline and/or derailing problems a SS chain can help; and as I said before some are stronger. However if you are using a tensioner such as the early Surly Singleator a 1/8 chain may not work. Additionally if your are having a problem with your Singleator skipping, they work best with a 3/32 “ chain, in the push-up mode, without a 1/2 link, and with the addition of a zip-tie connecting the Singleator arm to the chainstay.
The tensile strength of a SRAM PC-7 is about 2500 ft lbs and only come in 1/8 inch (and pimp gold); all other MSR SRAM chains (including the PC-58) are around 2023 ft lbs. The KMC Kool chains rate at 2860 ft lbs and come in both 3/32 and 1/8inch. The KMC Z chains (with an H in the model number) also come in both sizes (i.e. the 3/32 Z610H; my choice of chain), rate at 2640 ft lbs and are a bit lighter than the Kool chains. KMC ranks most if their MSR chains at 2314 ft LBS; I have not seen and published data for Shimano chains.
So what chain should you buy? There is a plethora of 1/8 inch chains out there; one of the favorites is the SRAM PC-7 (on the other hand there has been considerable anecdotal information that the SRAM PC-1 (1/8) chain is of low grade and should be avoided). . KMC also makes a line of 1/8 inch (or 3/16 inch if you dare) and 3/32 SS chains. They come in various weights and strengths so you pay your money and make your choice. As far as MSR 3/32 chains go SRAM PC-58 seem to be popular with the anti-Shimano crowd as are the KMC chains. Shimano wise any of the better 7/8 speed HG or IG chains will work; The 9 speed and especially the new 10 speed chains may not work with some BMX cogs and SS chainrings.
