I read allot of threads discussing the value of triple cranks in climbing, but doesn't triple offer better gear ratios for flats as well?

For example, I am running right now a compact crank (50,34) and 11 speed cassette (11,28). If I swap out the crank to a triple (52,39,30) the middle chain ring (39) will give me a better speed range for flat riding than the compact's small chain ring (34).

The picture below illustrates this. At 95 cadence I can reach 36kph with the triple's middle chain ring (39), where as the compacts smaller chain ring (34) can't go faster than 29kph. This is a big difference in maximum speed and its partially due to the bigger size of the middle gear but also its position relative to the cassette.

It seems the triple crank positions the middle chain ring in a sweet spot that allows it to work with one more small sprocket (13t) versus (14t) which is the the smallest sprocket the compact's (34) ring can work with. So with a triple (39) ring I can shift to 13t without over stretching the chain or rubbing on the front derailleur, is that right?

I really have no experience with this but the charts seem to suggest that. I hope to learn from experienced riders about this.



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