Unanswered Zee on 42t cassette?

[Blebo19]

How to adapt a zee rear derailleur on a 10v 42t cassette ?

 

[Gary]

Don't.

The Zee FR mech has a slightly longer link plate adapter than the DH Zee/Saint to allow it to work on 111-36 cassettes. the DH version is only rated to 28t
it has a super short cage for this reason. And was never intended to run a larger cassette than 36T or larger capacity difference than 25T
If you make it work with a 42T cassette by bodging it or adding a longer aftermarket link it'll still have poor tension in the 11T.. especially taking FS chaingrowth into account.
RD-M640-SS

Run the 11-36 as it's meant to... you have a motor

I'm running a ZeeFR mech with an 11-25 cassette on my commuting wheelset and 11-36T on my off road wheelset. Both with a 36T chainring... neither are lacking on the hills even in Eco

If you really need a 42T sprocket run a 10 speed M7000 SLX or M6000 Deore mech

 

[Jackware]

Or if you really have to have a Zee for the slightly better ground clearance, settle on a 11-40T cassette. I ran this this combo on a previous hardtail bike and it does work but as Gary highlighted the limit of the Zee's capacity (28T) is less than the cassettes range (40-11=29) so not sure if a FS bike will allow this.

 

[Gary]

Hardtails don't have chaingrowth.
Depending on the bike (suspension kinematics and travel) an FS mtb can have as much as 6 links of chain growth throughout it's full travel.
The Zee won't cover that plus your preferred 11-42 cassette and stay in tension on the smallest sprocket.

As for ground clearance, Just look where you're going and stop smashing your rear mech into stuff

 

[outerlimits]

I used to run a Zee short cage mech on a hardtail with 11- 42. It worked, but it’s not a combination that works on all frames. Depends a lot on the hanger ect. Won’t work on a full suspension bike.

And when I say it worked, there was way accelerated wear of the chain and cassette especially because of a lot less chain wrap.
It can be done and ridden, but it’s not great ?‍

 

[DrStupid]

Or if you really have to have a Zee for the slightly better ground clearance, settle on a 11-40T cassette. I ran this this combo on a previous hardtail bike and it does work but as Gary highlighted the limit of the Zee's capacity (28T) is less than the cassettes range (40-11=29) so not sure if a FS bike will allow this.

Zee FR wouldn't work on my Full suspension (trance e+) with the 11-40. Not only was shifting less than steller on the stand (too much free chain length with the B screw adjusted to make the stretch to the 40t cog), with the suspension compressed the chain take-up wasnt sufficient. I didn't bother with trying a goat link, just swapped back to 11-36 until I tore the zee off on a stick or something that lodged in the cage while climbing.

I'm now running the xt medium cage 11 speed derailleur with an 11-40 10 speed cassette, and 10 speed xt shifter. Its held up better than I thought it would.