jzsoup

I'm paralyzed and on a handcycle that came with 3x10 drivetrain. The front shifting didn't work well (mostly due to my hand) so I converted it to 1x10 (bike came with SRAM GX). Then I needed a lower gear so I put on a 10 speed cassette from ebay with a 50 tooth low gear & added a Wolf Tooth to handle it. I've since stipped out the treads on the derailleur where the B screw goes through. A kind stranger helped me out by cutting new threads and used a larger screw so I could get home, but it's only a matter of time before this goes badly and I have to call my wife to bring my wheelchair to pick me up; and I'm sure it will be on the busiest traffic section.....

I am willing to go 1x12 but not sure about: A. my frame & wheel are old school style spline & QR. Converting to thru axle is not a possibility; but can I update the hub if I need to?
B. chainring is 36 tooth 110 bcd with 5 arms & custom crankarm attachment. I don't know if it can handle a 12 speed chain & I haven't been able to find a replacement that says it can handle the crankarms (I pedal with my arms).

In my head, the easiest solution would be to install a 12 speed NX or GX rear derail that can handle 50 tooth. Then I can get rid of the Wolf Tooth & my current 10 speed GX rear derail is gonna die anyway.

Would this ungodly set-up work???? Can a 12 speed rear derail work with a 10 speed cassette, shifter, and chain??? Thanks for any help and sorry for the long story.

dsbrantjr

Why don't you simply replace the existing derailleur and put the Wolf Tooth on it? Having said that, why do you think that the new, larger B screw will fail? It is not a high-stress part and should not need to be readjusted unless you install different parts and even then probably not if you change like for like.

jzsoup

The b-screw doesn’t push on the hanger now. I had to add a nut to the end of the screw so it will push against the wolf tooth at all. I’m thinking that eventually that nut is gonna vibrate out of place and the derailleur will end up jamming against the cassette & I’ll be stuck. Breakdowns weren’t a big deal when I could walk; now I’m paranoid about it.

So my thought is a 12 speed derailleur that doesn’t need a wolf tooth will eliminate an extra point that could go wrong. That’s my theory anyway.

JonathanGennick 

What are those nuts called that have plastic in them to help lock them into place? One of those might give you some added security.

Going to your original question, Sunrace makes a 12-speed cassette that fits a standard Shimano hub:

https://www.jensonusa.com/Sunrace-MZ...SPEED-Cassette

Sunrace also makes an 11-speed 11-50 cassette that is claimed to work with a specific list of Shimano 11-speed derailleurs:

https://www.jensonusa.com/Sunrace-CS...Speed-Cassette

Drivetrain compatibility gives me headaches to think about, but it does like the Sunrace cassette provides a way to go 12 speed without having to change out your hub.

CycleryNorth81

Nylock nut.

jzsoup

The nylock nut is a good idea! Now I need to get to home depot...….