So, I'm upgrading my Trek 710 to 8-sp cogs (actually 7 of them, because I got a really swinging deal on an 8-sp corncob cassette, as well as on an 8-sp bar-end set). I THOUGHT the chain I bought last year was an 8-sp, but I guess it was really a 7-sp, because the pins measured 7.3mm, compared to the new KMC chain's 7.1mm. Slapped it on, but it still gave me a bit of "chatter", as well as not giving me really good up-and-down shifting on most gears (bike used to be friction).

Now, this chain was cheap, and I originally bought it for another bike, so replacing it wouldn't be a big deal. I might even go up to a 9 or 10 sp chain. But first, I was wondering if any of you mechanics knew of another 8-sp specific chain that would have just slightly shorter pins, or would just work better with NOS uniglide cogs?

Chain width of both 7.1mm and 7.3mm are claimed to be 8,7,6 speed specs. But .1mm (from center of the cog/chain fit up) is a very small dimension. I wonder if worn parts (pulley bushings, index detents, der pivots, cable route friction) are the larger issues at play. BTW Uniglide cogs are a bit wide, in function, as the Twist Tooth design takes up space and has sharp tooth tips at the edges of the cog width dimension. There's a reason that HG tooth profiles are narrowed at the tooth tops. Andy

I've used KMC Z51 chains on 8 speed with no issues. It is sold as a 6/7 speed chain, but it is 7.1mm so it works on 8 speed.

Brand new cogs, shifters, cables (jagwire teflon), etc. I can see the chain slightly catch the cog when it's set so that the indexing works perfectly going either up or down. Maybe I'm expecting too much from NOS components? I was hoping to make at least 1 bike never to need slight 'overshifting' when going to the larger cogs....

Well, maybe the 9-speed chain is the way to go....

The KMC x8.93, an 8-speed chain, is listed as 7.3 mm on KMC's European site.

The KMC Z72, sold as 6/7/8 speed if I remember correctly, is 7.1 mm.

Why the Zxx chains and the x8 chains are different widths, I have no idea.

i've installed dozens of KMC Z72's and Z51 chains... other than one certain rider that has BROKEN a Z72, i've had no issues at all with them... and at least two of those installs were onto uniglide cassettes.

you have some other issue causing the noise. Severely worn teeth will cause excess noise.

that "certain rider" also broke an X9.93 recently, too.... he's a BEAST.

According to Frank Berto and Shimano the HG cog tooth profiling (with chiseled outer tops and specific shift gating) was the shift (bad pun) to minimal over shift need and in some cases under shifting realities. For the alternatives the twist tooth (UG) design was far better a shift performance, SunTour and Campy (and Mailard/Huret/Simplex) were years behind. My experience bears this out, although I remained in the past with my SunTour then Mailard stuff... Andy

I have used a KMC Z chain, and it wore out, stretch if I can say that, in a year with all my 100 watts of power.... brand new cassette and crank too.
I use the KMC 8.93 chains, half nickel plated, and they last. Good price, best value.
Have also used 9 speed chain on 8 speed, put the front shifting was touchy, chain would skate on the smaller ring if I didn't shift it right.
SRAM seems good. But push a pin out of a SRAM chain and then do the same on a KMC mushroom pinned chain, and you will know which is better.

Functionally? yes.. the width is similar and all derailleur chains now use the bushingless design.