Originally Posted by
RobbieTunes
I first noticed this with the DA7700 GS rear derailleur.
No doubt there’s math involved. A lot of pros are using larger aftermarket pulleys on the RDs, and the Wolftooth Roadlink is now being copied by Wheels Mfg and of course, the Chinese fabricators.
I like the Roadlink for the extra clearance.
I’m wondering if the larger pulleys increase chain wrap, and would the combination of both sort of equal a longer cage RD?
At my level, performance is not an issue, but it’s interesting.
Bunkie
I'm not an engineer but I have stayed in a Holiday Inn
I would say the chief reason larger pulleys are touted as "better" is that they reduce the angle/bend of the chain when it goes around the pulleys, thereby reducing friction. I'm sure they have some kind of fancy bearing in them that further reduces friction but I don't know that to be a fact. As far as increasing chain wrap, it would be the same as it was with smaller pulleys; only a greater distance between the pulleys (center to center) would do that.