aka_finto wrote:
Ajax Bay wrote:
Here's Hambini's "analysis"Based on 1) zero test data, 2) never having ridden the system, 3) never having even seen (!) the system in person
Surely someone can get this setup onto a roller with a couple of power meters attached and confirm one way or the other. Either Classified are outright lying about their efficiency or so-called experts like Hambini are just sh!t stirring...
Please point us to where Classified state the system's efficiency. I guess here:
https://www.classified-cycling.cc/...iciency-measurements
They rely on size of chainring/sprocket (larger - better, so a 50-25 is better than a 34-17) and less cross chaining (losses actually small (<1%)). But in the 0.7 ratio (in hub) there will be losses. In the turbulent flow behind the shoe/crank the FD drag contribution is rather small ( but helps sell 1x).
Wiki: "The efficiency loss in a planetary gear train is typically about 3% per stage. This type of efficiency ensures that a high proportion (about 97%) of the energy being input is transmitted through the gearbox, rather than being wasted on mechanical losses inside the gearbox."
Hambini's analysis suggests how the epicyclic gearing works and makes the reasonable assumption of 96% efficiency (for the 0.7 ratio). Did you know/understand all this already?
In the FAQs:
"How efficient is the hub?
Very efficient!
More efficient than a 1x setup and as efficient as a 2x setup.
Compared to a 1x, less cross chaining is required, sprocket and chainring sizes are larger and thus chain tension, crank and hub bearing losses are lower.
Compared to a 2x; the fact that the 0.7 ratio of the hub still uses the large chainring in front, results in 30% less chain tension and thus lower chain, crank and hub bearing losses."