Originally Posted by
dddd
If you're running a Nuovo Record rear derailer with a 28t freewheel, the chainring difference should not exceed 10t or it may be impossible to get full use of both rings with the larger cogs.
Never run a chain too short to shift onto the large cog and large chainring, or an inadvertent shift can damage quite a few parts with relatively little pedal force!!!
My chainrings are 42/52, so I'm good there.
I did run a too-short chain so that the squashing noise didn't occur. I never shifted into big-big inadvertently, but then I realized I was playing with fire, so I lengthened the chain, just for safety. I don't use bottom gear often, and when I do, I can tolerate the noise.