Affix hub; specifications and internal details

[mattsccm]

I would have happily had guard mounts but as I have a couple of pairs of SKS clip on ones kicking about it was no big deal. I can always get another bike out if it gets too muddy. Weight wise it isn't too bad although I suspect that the 725 tubing isn't featured on all tubing and the forks are made of railway irons as expected.

[mtwils]

A bit of thread revival with possible alternatives to the Affix hub:

Sram Torpedo fixed & Free about 2009, not expensive on ebay, switches using a screwdriver on the left axle end, which engages or disengages a back drive ratchet. I have one which I have never used, the lash seems comparable to an ASC or S3x.

BSA DP 2 speed fixed or free hub, old, not common, expensive when you find one (1000 or 2000 pounds for the only one I have seen on ebay), cable shift between fixed and free, also cable shift between the two gears, I do not know much about these.

If you can accept fixed and noDriveEitherDirection as your two "gears", then either ASC or S3X with the gears removed should work. My bichain fixed/free with 2x10 on the right and fixed on the left shifted with Campagnolo brifters uses an S3X clutch internally. TF probably can be made to work by grinding off whatever locks the sun pinion to the axle (I forget what that is as I write this) but most people are not going to modify a TF part like that.

If you want cable shift between fixed and free, possibly use an ASC shell and planet cage, and an AW axle and gear ring with high gear pawls. The gear ring probably needs support over the planet cage or against a replacement steel hub shell; it could be tried without support to determine experimentally. Grinding the teeth off the sun pinion will have planet pinion speeds 2x the hub rotation speed when coasting downhill so is probably not ideal as support. You will want some stop to keep the clutch from disengaging the pawls in what would have been 1st gear, either a cable clamp thing against the shift cable stop on the frame or some internal machined spacer. Shifter options abound because only 2 positions are used. Do not use modern spoke tensions on an actual aluminum ASC hub shell, and use all 36 or 40 holes. I do not know if an S3X can be converted this way. FG left ball cups show a place to drill the 3 holes to allow pinning to the FG planet cage but I have never tried that, nor do I know what is needed to drill the presumably hardened plate.

If you want 3 fixed gears and a positive neutral position, an ASC with 4 speed shifter and shift indicator and the clutch dogs on the gear ring ground back to not engage in the 4 speed shifter 3rd gear position will work. But I do not think I would want to have that shift pattern, nor do I want to modify ASC-specific parts. Bruce Ingle had a similar shift pattern on his bichain:
https://www.sheldonbrown.com/bichain-fixed-free.html

I have not yet figured out how to have the freewheel gear be lower than the fixed gear without an external freewheel and 2 chains. With 2 chains multiple freewheel speeds are possible, as noted above, but any 2 chain hub construction work is non-trivial, BTDT. It might be easier if one can source a freewheel that mounts to a disk brake mount and then use a Sturmey Archer disk brake hub converted to fixed use. Or find a Sturmey Archer band brake hub shell (CS-RB3? TS-RB3? RS-RB3?) and convert that; they did offer them at one point and I have read about at least one person having one (stock, not converted).

My knowledge of Sturmey Archer after ~1984 and all other IGH brands is limited.

[mattsccm]

Oh my goodness. What paths to follow!

[mattsccm]

A couple of pics. The daft rack may well come off and I have yet to check the suitability of the gear dues to a knee replacement 6 weeks ago today.

[mig]

A couple of pics. The daft rack may well come off and I have yet to check the suitability of the gear dues to a knee replacement 6 weeks ago today.

i quite like that..! the brake levers look some distance away and i'd want 'guards especially at the back but that's just me.

technically/legally do you need a rear brake on it?

[Brucey]

FWIW I have outline designs for an AW conversion to 2s fixed as well as a cable-operated fix-free drive. The former should be almost lash-free, high gear fixed (but 'low normal') as well as highly efficient, owing to a roller bearing conversion. This hub features a steel RH flange and an Al LH flange; with approx. 90mm flange spacing it is expected to build into a super-strong wheel, designed to accept a disc brake if required. The f/f drive is designed to be lash-free, and is designed to default into fixed gear mode, in which it will be drag-free. A small (sub-1W) parasitic drag is anticipated in 'freewheel' mode.

[mattsccm]

As long as I keep it in fixed mode I don't need any other brake on the road. It is really only a summer fun toy for the gravel. It was built primarily to use something unusual although it would work well on my commute which has a long downhill on the way home where the freewheel will be handy. As this is not on the road those laws don't apply and I have yet to see a Forestry England limitation! The original plan was to use both a disc and canti brake but my only front wheel with a disc hub and rim braking surfaces looks awful and is only 15mm wide . Bit narrow for the 40mm tyre.

Edit. Just been for a spin. There is a minute amount of backlash in fixed mode which of course in free wheel mode and the smallest amount of side to side movement at the hub. Not noticeable when riding but when you "drop" the bike there is a tiny rattle. I'll investigate.

[fastpedaller]

As long as I keep it in fixed mode I don't need any other brake on the road. It is really only a summer fun toy for the gravel. It was built primarily to use something unusual although it would work well on my commute which has a long downhill on the way home where the freewheel will be handy. As this is not on the road those laws don't apply and I have yet to see a Forestry England limitation!

Your choice in the circumstances, but I'd want a brake just in case of emergency eg a bear jumping out of the forest

[mattsccm]

Got one brake and the boar give me plenty of warning.

[mtwils]

It seems to me that the intent of an Affix hub bike is to be able to freewheel down hills, in which case I would add a rear brake.

[Dr H Tool]

One of the only reasons I sourced the Affix was because of the downhills like Holme Moss and the Snake, hardly ever change otherwise. It is a nice bit of kit and uniquely stylish.

[mattsccm]

I acquired mine because it was cheap, unusual and puts one over on a mate.. Quite possibly in a different order.

[Dr H Tool]

When I sourced mine from a bike shop in the Philippines also got one for my mate Phil who built it into the specified wheel for me.

[mig]

One of the only reasons I sourced the Affix was because of the downhills like Holme Moss and the Snake, hardly ever change otherwise. It is a nice bit of kit and uniquely stylish.

which side of Holme Moss do you climb on singlespeed?

[Dr H Tool]

Both when I’m on form. My preferred gear over years of cycling is 40/16 and whilst it can be a bit of a thrutch it keeps the leg strength up, especially seated. Mind you not breaking any records although a friend of mine and training partner back in the day held the Snake Hill climb record for 8 years and did that on a fixed gear. Most shallow climbs are a breeze on fixed and much better than on a freewheel.