Hello,

I'm thinking of installing a CS-RK3 on a folding bike that I retrofitted where the front derailleur works but the chain slightly rubs against the fork, even after filing it down as much as I could. No biggie, but I like silent bikes.

Some users find that hybrid hub a bit draggy or heavy, but could it be worse than the (1,155g vs. 940g) BWR that powers the six (now also twelve) speed Brompton that I find OK?

Before ordering, do I need other parts than the hub, a compatible shifter (eg. Shimano SL-M310 or Sturmey-Archer SLS30), and possibly a "Fulcrum Lever Full Cover" to keep the crud away?

Thank you.

The Sturmey archer 3 speed shifter is not compatible with that hub. it requires a Shimano MTB compatible 3 speed front derailleur shifter.

Yes, it's in the message.

Some sites include that important info: "This hub gear can only be operated with 3-speed Schimano or Shimano compatible switches (ratio 1: 2) with indexing. The Sturmey Archer's own twist grip and other switches do not work here and can destroy the hub!!!" (source)

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Edit: Do I need a "Axle Fulcrum Lever with Washer - HSJ905"?

The fulcrum lever is one option, but but not vital. A fulcrum clip mounted to the chainstay will work as well. I have used both,

What's the use of the fulcrum lever/clip? As a housing stop?

Do I need one, considering the S-A hub has an indicator chain/spindle to set the cable's length?

https://www.sturmey-archer.com/en/pr...ke-and-fulcrum
https://www.sheldonbrown.com/indicators.html

In the case of the photos above, it appears that bike does not have conventional chainstays where a cable stop (fulcrum clip) could be mounted, so the fulcrum lever is the best option.

Makes sense.

So it's just used to hold the cable, and a housing stop isn"t needed, just nice to have.

I know nothing about derailleurs, cassettes, and their compatibilies.

Since the CS-RK3 hub is "compatible with standard MTB/ATB 9 and 8-speed cassettes", I tried installing a Shimano CS-HG41-8 11-32T AW cassette I had handy, but it stops halfway-through.

What eight-speed cassette should I get instead that's sure to work?
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Edit The box and the sticker on the cassette itself say 11-32T and "CS-HG41-8 aw", but it turns out it only has seven cogs, and it's 13-32T :-/ I guess that explains why it won't fit that hub.
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Edit Turns out the 11T cog was in the baglet in the box, along with the locking. And you first have to push hard enough for the cassette to slide down the hub axle. Hub + 8s cassette = 1,440g.

After taking it for a ride, I notice one odd thing, though: According to calculations, with a a 40T chainring and in third gear on the hub, the two smallest sprockets (13/11T) should provide a ~6m and ~7m developments respectively, but experience shows they're much bigger to the point of being totally useless — I ordered a 36T chainring instead. Any idea what it could be?

Normally, 6m is a breeze on the flat with an empty bike, and even 7m is no biggie.


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Edit: The 36T is much better, although, on a loaded touring bike, the biggest gear could only be used on the flat once the bike's at full speed. Just for comparison, I ordered a 34T

The mystery remains.