Could it be that the extra width of the 1-8" chain allows for thicker, less-pointed sprocket teeth, better able to keep the chain from derailing?
David Snyder Eating grape juice ice cubes in 100-degree Auburn, CA
> Mark Stonich wrote <but I snip to leave only one of his interesting
> points>:
>
> [relative to 3/32 and/or 1/8" chains] There must be some cost in strength
> though as 3/16" is coming back in vogue for BMX and modern Single Speed.
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> May I suggest that this might be a fashion, not driven by serious
> analysis? In 4+ decades, I've rarely broken a 3/32 chain (and one of
> those times was riding an on-topic triplet with a pretty strong team, and
> required missing a shift, too). Besides, one wonders if the side plates
> are thicker or stronger on the new 3/16" chains. Or do they claim that
> better bearing surfaces give enough advantage to overcome the certain
> increase in weight? My sense is that these are chosen primarily for
> visual impact, but I'd be happy to be proven wrong - off-list, of course,
> unless the argument is on-topic. :-)