Half link chains

[Philip Benstead]

I was doing my normal duties in the Royal Parks acting as Dr Bike.

I was asked to fit a new half link chain as in the link.

http://www.google.co.uk/products/catalo ... IsBEPMCMAQ


I found them difficult to fit I joined it by riveting it together instead of using the special link.

I thought the quality was agricultural

Are these chains stronger and it there any need for them it is just a fashion?

Views please

[Ugly]

you'r right, just a fashion. Nothing wrong with fashion, keeps the young and would be young interested and sometimes interisting and keeps the wheels of industry revolving

[PT1029]

Half link chains come into their own on single speeds with no so long traditional (not verticle) drop outs, you can get the chain lenght to with 1/2" (ie 1 link) rather than 1" (a pair of links) to get the chain tension right.
Same benefit if your chainring/sprocket combination puts your wheel axle with a new chain at the back of the drop out.
I use one on my hack, chain plates seemed a bit thin, chain tool pushed the rivit in/out with remarkably little resistance (to be fair, pins not fallen out yet!).
Most probably get something more sturdy next time, unless tension requirements mentioned above kick in.

[Brucey]

it is mostly fashion in many cases, but there is one practical benefit to such a chain which may (I've not participated myself, so I could be wrong BTW) be useful in BMX racing. It is certainly useful for some SS bikes to have at least one half-link.

The chain on singlespeed bikes like BMX, SS bikes etc often needs to be fiddled with when the gear is changed. If the dropout slots are short or you are fussy about wheelbase then very often the cure is to add /remove a chain half-link anyway. A normal chain only adjusts the wheelbase to the nearest half inch on any given gear.

A chain being no stronger than its weakest link, plus the difficulty in finding a single half link (possibly under time constraints) means a chain made of half links has some appeal. There is also the possibility that a single half-link, if installed and removed a few times, might become a bit loose and fail under duress.

In theory a half-link should be weaker than a standard link; there is a net force pulling the sideplates off the connecting bushing in the half link that isn't present in a standard chain link. For this reason I would not of choice install one on (say) a hillclimb or track bike, although having said this I have never seen a failure of this kind.

I have used half links when setting up singlespeed and hub gear bikes; it makes sense to install one with a new chain if it avoids having to shorten the chain half way through its life because you are going to run out of dropout length.

Sheldon Brown has (I think) noted that very stretched chains of conventional design do not wear evenly; the pitch of the inner plate half-links winds up different to the pitch of the outer plate half links. I suppose this does not happen with a half-link chain.

cheers

[hashtag]

I've found that half link chains 'stretch' (lets not get started on chain stretch but you all know what i mean) far worse than normal chains

i do however use a single half link in a normal chain in order to have the shortest wheelbase possible

[SilverBadge]

It's been discussed here before - IIRC the reason is to do with stunts involving grounding the ring and chain on obstacles as it provides a "smoother" surface than a "proper" chain. From an engineering viewpoint, it's not so good to have "tapering" links, there are fewer different component parts which presumably makes them a fraction cheaper for a given quality of manufacture.

[geocycle]

Awful things. I had one for a few hundred miles and it was always falling to bits. Brucey has it right above.

[Ribblehead]

They're rubbish!

I've heard stories of people using them on fixed wheel, and they just keep stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching, and stretching........................

and then when they're done with stretching, the side plates start snapping!

The design is fundamentally flawed. Any member expected to perform in tension must be either straight to begin with, or capable of straightening out under a very low load without damage (e.g. a flexible cable). The half link chain is neither of those!

[james-o]

Agree with ribbehead. They're junk in my experience - the plates bend a little resulting in massive stretch levels. I used one to try it out before potentially speccing them on a SS bike I worked on a while back and it lasted a few 100 miles max before I binned it. Simply a poor idea on any bike that has any amount of power applied to the cranks. A half-link on a single-speed can be useful but I try to avoid anything like that if possible.