OK, So I'm building a SS bike for the first time and thought I knew everything until it was time to pick out a chain and then I realized there was this whole area I knew very little about.

I want to use a Sram S300 Single speed crank with a Surly Cassette cog. But when picking a chain I couldn't make sense of all the options.

From Surly: Our cogs will work with 6-9-speed 3/32" chains

Srams website doesn't list the S300 Courier crank but another website said: for 3/32" chains. (Sram's website lists the S300 double as a 10 speed Hard Anodized)

I know that chain links are 1/2" in length and I have heard that 3/32" and 1/8" refer to the width of the chain for geared or track bikes. But I don't know where the 9 sp, 10 sp etc. comes into play.

I am building a single speed bike so 9 or 10 speed doesn't matter to me but I want to know what chain will fit the Sram S300 courier AND a Surly cassette cog.

Anybody know what I'm talking about?
Thanks.

The inside link inner width of any 3/32 chain meant for multi-speed systems in nominally 3/32" but the total outer width varies between 6-8, 9 and 10 speed chains, because the freehub cogs are spaced differently depending on the number of sprockets. So a 10 speed chain is narrower overall than a 6-8 speed chain. None of this really matters on a single speed setup with a 3/32 chainring and cog. You can always use a 1/8 chain, regardless. I have never tried to use a 10 speed chain on a SS/FG, but I have used a 6-8 speed chain without any problems.

Ahhh, so whether it is 6-10 speed only refers to the metal gage of the link's side wall? ( maintaining 3/32" inside clearance) OK that makes sense, Thank You.
So for a single speed setup any of them will work, but the higher the speed, the lighter the chain will be (I assume.)

I am wondering why the surly cog only said 6-9 sp. Is a 10 speed chain too thin? AND.. Would you get less (or slower) chain stretch on a 6 sp chain because there is more metal to wear through?

I don't know about the 10 speed, since I've never tried to use one, but perhaps they run tighter clearances or the chainrings/cogs are slightly thinner. In any event, wear will be the same, because the plates do not stretch, instead the pins and bushings wear over time.

Thanks TT,
I learned something new today.

Actually, it's got more to do with the way the pins are riveted and the design of the side plates. I'd avoid 9 and 10 speed chains unless you have an application that specifically requires one. They require special pins to re-join the chain (or masterlinks) and are a lot more demanding about how they are assembled. They are also more money.

the chainring teeth are spaced a bit closer to each other. everything, including chain, cogs and derailer are all narrower.
10sp chain costs more than 9sp chains of similar quality.



I use a 9sp sram chain with the quicklink for my fixed gear.
the chain wore out over winter, but it never exploded into a million pieces during it's life span.
all things equal, I'd use the better 8sp chains from KMC or that other maker which I can't remember the name of because they last longer than cheaper chains or similarly priced 10 and 9sp chains.