Originally Posted by
noobinsf
I think the length of the derailleur hanger is a factor, because once you jump to the GT cage, the max cog is rated at 34 teeth. There is probably a catalog page on the interwebs that would shed some light.
EDIT: Aha!
https://www.disraeligears.co.uk/site...-_page_14.html
It's not clear to me why the largest rear cog is different between the two. I always thought max cog was determined by the distance from the axle to the top of the upper pulley. As far as I know, the Cyclone and Cyclone GT derailleurs are identical except for the GT's longer cage (which increases total capacity). How do you get from 26/28t to 34t max just by extending the cage? I would think you'd need to either change the geometry of the derailleur body or move it down, either with a longer dropout hanger or a hanger extension.
Also, what is a "Superbe rear end?"