Bicycle Mechanics - fixed gear chains
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11-07-10, 09:58 PM
i have always gone with kmc. i am going to throw a gold 8th inch chain on a fixed gear i am building..
MY QUESTION IS, what type of chain would you use? recomend? avoid?
im looking at a gold IZUMI chain for around 25, there are also a few gold KMC chains; the SuperLight, and D101.
Any good or bad exteriences with any of these chains
the D101 retails for like 50, any one know why that is? higher quality or longevity?
11-07-10, 10:29 PM
I like full busing chains when there is no shifting sideways, the roller rotates supported on a wide surface .. much longer wear ..
gold is so soft as to be meaningless, It's just decoration, jewelry.
now if you have a Titanium-Nitride process on steel, then there is surface durability improvement.
that is done for industrial gears, but don't recall seeing bike stuff nitrided.
I got a NOS 3/32 chain from Harris a year ago, one on my Brompton,
the other on my Rohloff Koga, been fine, they are Whipperman made .
and black steel. keeping adequate lubrication keeps them rust free..
11-07-10, 10:32 PM
Get the SRAM PC-7X or if you're on a budget, the PC-1.
as far as I recall, the gold on most cheaper chains are just some anodizing and not actual gold.
now the really expensive chains from KMC are ti-nitride coated steel chains.
KMC D101, I'm pretty sure, is just anodized.
K710SL, K810SL are Ti-Nitride
11-08-10, 03:19 AM
I like to use 1/8th BMX chains for the colour varieties:
With a straight chainline, regular cleaning & lubing, chains are all pretty comparable in durability and longevity.
For a fixed gear, forget about multi-speed chains (they are thinner, less durable, more wear just to be slim enough to fit the small gap between cogs, and also later weakness so it can flex to shift).
You need a solid "one speed" chain, like 1/8" chains, and I'd be looking into Yaban.. they make professional industrial chains, and bicycle chains also. So far Yaban chains are proven to be bulletproof in terms of stregth, and since FG chains are seriously abused, a snap of the chain should be avoided as much as possible, so for this go with a regular bushed strong chain (even if it is a bit heavier) from yaban for example.
11-08-10, 08:04 AM
There's no gold on gold chains. There's no anodizing either.
1/8" chains are not stronger than 3/32" chains.
11-08-10, 10:12 AM
KCM S10 is stainless, or so it says online. Seems like a logical choice if your bike is left outdoors.
And let's keep putting to rest the idea that 3/32" chain is somehow weaker.
11-08-10, 12:37 PM
Just to note the difference, 2 distinct camps of chain design, now a days.
a bushingless chain just makes part of the bushing the roller sits on, by punching it in
when the holes in the inner link are made .
the colored chains shown are bushingless. only the edges of the roller have support,
the pin supports the other side, of the edge bush, but the roller does not contact that.
a full bushing chain has a wee sleeve pressed in and so the whole roller is riding on the bushing,
so there is more surface to spread the wear over, and it will wear longer .
Bushingless chains came on when the side flexibility was desirable for derailler systems ,
that went past 6 speeds , but for a single speed drivetrain a Full Bush Chain is better.
Of course not needing to make all those little bushing tubes is a cost, and so those chains are disappearing ..
As once the punching machine is bought, it lowers manufacturers production costs.
11-08-10, 02:18 PM
I've never gotten more than 2000 miles out of a bushing chain. It's too hard to get lubrication and cleaners into the bushing. If oil drips down into both ends of a bushing, it traps an air-bubble in between them and no more flow occurs.
With bushingless chains, it's much easier for cleaners and lube to get into the parts that wear and I regularly see 4000-8000 miles out of bushingless chain.
Yet it's not all about durability, but of strength. A shock in the drivetrain (a kerb jumped, a hiccup in pedaling, a pothole hit during skid braking..etc) can snap a chain, in result of serious damage (the wheel still spinning grabs the chain around the frame and can and will bend the seatstays/chainstays, also that chain could have been the only brake on the bike an that is more problematic).
So for a fixed gear chain, strongest is best in my opinion (I do care of my life, even if riding FG in the city it's not so "healthy")
I'd love to test a batch of chains at a traction machine to determine the strength, but I'm not getting any sponsors on this area of material science/assembly organs, so otherwise than fun at my own expense I cannot run studies on bicycle chains.
11-08-10, 03:25 PM
The snapping chain you are referring to, where is the break? In the side-plates? Or in a pin? I've never seen a chain, either 3/32" or 1/8" that has been through so much force that it actually breaks. I've seen them badly mangled by chain-suck between the granny-ring and chainstay. Or twisted and chewed up when the RD goes into the spokes. But I seriously doubt a human riding a fixed-gear bike can break any chain.
Fixed gear chains don't need to be particularly strong. Shimano once made a 10mm pitch track chain that must have been 30% weaker than a standard chain, and it was used at a world championship. Derailer chains break because there can be a lot of sideways force when they engage 2 cogs at the same time during shifting, and because they are difficult to join. Fixed chains are never out of alignment, and there's less chain tension because you don't use low gears. If you use a wider chain designed for 7 or fewer cogs they are easy to join, and cheaper too. This is one of the few cases where cheaper actually works better.
On bike I have mostly seen chains dismantled by lateral forces, or if a pin is badly installed it will slip from one end and will bend out one sideplate with the pin attached. An interesting chain break that I have seen was a fracture in a sideplate (and bending out of the other sideplate still attached until it removed the pin from the plate).
As for fixed gear forces.. they are considerable higher than in any other bike, because of the stiff transmision. If the pedal hits something.. it's bad, if you hesitate pedaling a bit when coming of a kerb, if you frequently skid brake (and the skid is unsuccessful because of a high grip surface) . Inertia is a huge problem (inertia of the human that bounces on the pedals on various occasions), and the energy of the force impulse .. it's big. Plus all the forces go both ways on the chain in drive or brake mode
- Just my common sense, no numbers.
I do agree that chains are fairly safe on fixed configurations with no shifting and no lateral forces, but depends on the redundancy available on the bike (like braking.. on normal setup we have two brakes, in some odd setups we have no brakes and one chain.. how good that chain should be as the main component in braking? enough to ride without constant worries and fears.. or I'd better put some brakes, but it's another story)
In industrial chains, lots of chains break at the pins (some of the pins bend under the traction force and acts as a stiff link and in short term that pin will break) - but industrial chains are usually under constant load, constant speed, well lubricated being submerged in oil all the time.
Conclusion: for the peace in my mind I go with the full-bushed chains 1/8" made by yaban (yet the manufacturer is not so important)
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