Originally Posted by
Jonesandrew
Yes, the XX1 crankset will fit, it's the crankset supplied for ultralight models, but be warned there are several constraints to be aware of when choosing a crankset. One of these is that the chain runs very close to the swing arm tube. Consequently there are limits to the largest sprocket and chain ring combinations that can be fitted without the chain starting to saw through the swing arm. The rear changer should also fit but you should contact Helix directly for detailed clarifications. It may take several days to get a response. You can see some of the ultralight derailleur component details if you go to Helix.ca and click on "Order" then "compare".
Yup, understand for the crankset. What about the cassette and rear derailleur? I also have been checking other Helix bike forum / social media.
Different rider different answer. So I myself also a little bit confused. These were their respond.
Changeable:
Rider A: Using a XDR Driver.
Rider B: Quoted from Helix Upgrade Guide - You can upgrade the cassette to any configuration. Everything from a 9 tooth sprocket up to a 51t will work. The limiting factor is the front chainring. Anything above 36t will a need a smaller front chainring.
Not Changeable:
Rider C:
XX1 Rear derailleur cannot mount to the hanger. Only fit rear derailleur with direct mount.