Originally Posted by
chagzuki
Resurrecting an old thread here as I'd like to know the answer to this question also.
It seems to me that Sprinter S5 internals ought to fit the S-RF3 shell.
Were the X-RF5 internals and S-RF3 shell proven to be compatible?
I unsubscribed from the thread a while ago so i must have missed your post. Anyway to your question; I found out that the 5 speed internals will not fit into the SRF-3 shell. I did consult quite some technical documents and I did come to the conclusion that the HSX 140 internal unit that I bought is the same you find in the Sprinter hub. The 5 speed internals that they sell on SJS Cycles seems to have the same dimensions. Unfortunately they do not fit in the SRF-3 shell. They screw in, however, the low gear pawls cannot engage the ratchet inside. So I went ahead and did the AM conversion. Gear steps are very nice , however I do miss the low end of the AW. So I have been thinking that I will get the 2 speed derailleur (SRAM 6 speed conversion kit). The driver of old SA hubs is wider so you can fit 2 cogs and a spacer. 13/15 combination in the back would give only 4 unique gears out of the 6, however, as I have said before I see it as a low and high range AM. If I ever need more range I will get old AW internals; it is an easy enough swap.
Good luck with the search for the perfect gearing and let me know if you have more Brompton/Sturmey Archer related questions=P
-Carcinogent
P.S. You can build a new wheel with a hub of choice, however, this might take some more mixing and matching of parts.