Some earlier cranks are definately unfriendly to narrow chains. In general, I find everything in the drivetrain tends to work best with the correct era chain. I'm not sure about your Stronglight but earlier Sugino Mighty Tour cranks for example will suck a narrow chain right between the rings.
Joe Bender-Zanoni
Great Notch, NJ
> I have a new bike ( Clean 1973 Raleigh Gransport, $75 shipped,
> whoo-hoo!) with a Stronglight 93 crankset. A previous owner chucked
> the outer chainguard, moved the middle ring to outer position, added a
> 48T middle ring, to get a triple (42 - 48 - 52)
>
> The chain looks like an early 1990's sedisport.
>
> Shifting from middle ring to large ring, the chain frequently jams
> between the chainrings. These are original 1970's stronglight rings
> which have a shoulder on one side only. The shoulder on the side
> where the countersunk hole for the chainring bolts is. In its current
> configuration, the shoulder from inner-middle-outer when looking down
> while riding in the saddle are on the left, left, right. This keeps
> the middle and outer rings as close as possible together, flat-side of
> these rings against the spider.
>
> When i shift onto the middle ring, the chain appears to be centered
> between the inner and outer rings.
>
> Is this crankset unfriendly to narrow chains ??
>
> - Don Gillies
> San Diego, CA