cassette lock ring - how many threads?

[mr_gumby]

Hello everyone,

The Sachs 6000 rear hub I have on my Cadex seems to have some compatibility issues.
Currently I am using it with a Shimano HG41 -7 Cassette.
I had to put a very thin spacer behind it in order to prevent the lock ring from pressing the dust cap against the bearings, and hence, seize the whole freewheel.

https://imgur.com/a/Q0YcZ

With the spacer, the lock ring turns 1 1/2 turns until it is fully engaged. We're talking steel lock ring and steel free wheel.
Should I worry that the thing comes loose?
Are there other lock rings with thinner side walls?

Thanks for your suggestions.

-Dan

 

[Retro JB]

Hi Dan, difficult balance here. You also need to make sure that the outer edge (without seeing it) doesn't fowl the frame when the wheel is bolted to the bike. Don't over tighten the lock ring either as with 1.5 turns you may strip the thread on either the free hub or the locking.
Re the 'comes loose', if the ring is tight, the 'lock ring' function should work, but this is dependent on how tight, which is now governed by the 1.5 turns.
Hope this helps and prevents a catastrophe! Stay safe!

 

[mr_gumby]

Re:

Thanks!

The outer edge doesn't touch the frame. There's enough clearance.
I'll post some pictures later!
Cheers

-Dan

 

[legrandefromage]

there are a few lockrings with different depths out there. Try a lock ring from a cassette with an 11t smallest cog, these are a bit smaller and may not be as deep

of course, there is also the chance that the Sachs freehub is expecting a Sachs lock ring...

 

[mr_gumby]

Re:

added pictures to main post.

 

[mr_gumby]

Re:

Eventually solved the problem by machining the dust cap (i.e. reducing its diameter) and using a SRAM lock ring (so @legrandefromage was right in suspecting that the darned thing needed something specific. The dust cap doesn't have a grooved edge anymore but grease and the second dust cap underneath as well as an additional rubber ring (pump seal) will keep out the dirt.

The lock ring now threads on completely (2 1/2 turns) and everything runs smoothly.
Enough bodging for today.

Good night.