bhtooefr

I'd like to add an IGH of some sort to my Dahon Boardwalk 1, and am considering my options.

So, here's the options I have that I know of:

SRAM Automatix. 28h could be built into my existing rear wheel, but is hard to get in the US. (Or a 36h could maybe be laced for 28h?) And, no matter what I get, speed would need to be adjusted. Also, I'd need to spread the rear triangle from 110 mm to 120 mm. Upside is, automatic shifting and all, no worries about shifting during braking.
Sturmey-Archer S2C. No worries about adjusting the speed, but I hear these have horrendous reliability. And, kick-shift, so it'll be a little awkward to use. 116 mm OLD, so the rear triangle would need to be spread a little, but not as much as for the Automatix.
Find an old Sachs Duomatic. It would have to be disassembled and cleaned, which would be a pain, but could be worth it. Still kick-shift. And, I've read that they're designed to work with 110 mm rear triangles, although it's actually 112 mm OLD.
Find an old Sachs Automatic. Same issues as the Duomatic except automatic (and shift speed would need to be adjusted), and 114 mm OLD.
Go three-speed. Downside is the shifting mechanism is exposed to damage, on a folder, unless I get something with rotary shift. And, controls are less simple.

What's my best bet?

fietsbob

Sturmey Archer AW3.. Brompton has used them from the beginning , and currently..

28 hole hubshell , narrow axle options .. in spare parts, SJS, UK, has good stock ..

the steel trigger shifter is rugged and reliable. brompton placed it on top of the M bar ..

straight bar it can go underneath, to use index finger, up and down shift..

IDK what complexity you speak of .. I just read the service manuals ..

bhtooefr

I'm not saying the SA 3-speeds are complex, more that they'd complicate the user interface of the bike. (The idea is KISS - no shifter, no rear brake control, ideally.) And, actually, looks like an indicator chain setup wouldn't really be fragile... it's just the clickbox stuff that is.

Got my eye on a Duomatic, although I'd need to source a couple parts, and I'd need to disassemble, clean, and lube it, although that might actually not be as bad as I thought it would be.

SesameCrunch

I've had the Duomatic, S2C and am now using the SRAM Automatix.

Love the Automatix. Shifting is great, braking works great (I've even removed my front brakes because I am totally confident of the braking). I was initially tentative about the automatic shifting, thinking that I preferred the control over when I shifted. However, I find that I can just slow down and get the lower gearing whenever I wanted.

The S2C sucks. Believe everything you read about its reliability issues.

The Sachs Duomatic was great, reliable. They're expensive and hard to find. Other than nostalgic value, I don't think they offer any real benefit over the SRAM Automatix. If you do want to open one up and rebuild it, there are many reference materials online to help you. I was able to do it, and I'm no mechanical genius. You just have to be careful and make sure parts go back in the way the came out

Oh, and wait for BruceMetras to chime in. He is the master authority on all these IGH's....

loubapache

For 20" rim, Sun makes a 36 Hole version. That will make a very strong rear wheel.

https://www.amazon.com/Sun-Alloy-1-50...005309&sr=1-14

I am kind in a similar situation. I have many bikes but no folder so I am looking to find a single speed folder (or one with semi-vertical dropout) and then use a 3-speed IGH. Depending on the frame of the folder I get, I might even mount the shifter on the rear half of the bike behind the folding joints. I would have to make some mounting brackets and take one hand off the bar to shift but that is OK. I do not shift often with my full size 3-speed bikes anyway for the routes I normally take but the extra gears are nice for the occasional climbing.

bargainguy

If it were me, I like the 3-speed hub best of your listed choices. Automatix looks nice but 10mm OLD difference is pushing it IMHO, even with steel.

OK, going from memory here, but isn't there a SRAM S-RF5(W) with 111mm OLD? I seem to remember Brompton users going for this 5-speed hub because of the compatibility with existing Brommie rear triangles, which are 112mm OLD if I'm not mistaken.

pacificcyclist

I do have the Sachs Duomatic or known as the S2C and it is on my Speed Duo. It's true that while it does not seem all that reliable to begin with (mine works ok so far after thousands of miles riding in crappy weather), I think the S2C works better in the Low/Med gearing setup rather the typical Med/High setup that most people will be setting it up for. If you set it up for Med/High, you will be immensely disappointed with the S2C. For Med/High gearing, I would recommend that you go with the SRAM Automatix route. The reason I like the Duomatic setup is the control I have speed wise by varying my "cadence" when the gear is fixed. If I go pass a certain speed point, the gear will not shift like the Automatix does on the Tern Verge Duo which I disliked. When you have only 2 speeds, the only way to can fill that void is to vary your cadence to add more speeds to it. For slow speeds and low gearing, I found the Automatix shifting too soon and too often. However, in medium and higher gearing the Automatix works really great. My Duo is used as a coffee bike riding with my partner and her friends and sometimes, it's hard to ride slow with a high cadence on the Automatix. With the S2C, I can spin as fast as I want in low gear and still be on par with them.

Part of the issue with the Sachs Duomatic S2C is that it needs a certain speed for it to shift properly when it ages. Most problematic is when it is shifting from a high gear to 1:1 where it won't most of the time when the wheel spins lower than the speed it needs to shift and it seemed you need to fight the hub to get it to shift. This is its downside.
However, if you set the direct drive to low like around 35-40" gear and the high drive to 50-55" gearing, then the S2C works really well because if it's stuck at 55", just stand up and ride a bit faster to shift down. Whereas with a 70-80" high gear, it takes a bit more effort to reach the same speed to shift and this is when you're going to be fighting with the hub more.
I live in Vancouver where there are tons of hills so the Low-Medium gear setup is better for me, plus riding with my partner slowly helps to stay with her longer on the sea wall without the thing shifting too often and me braking all the time. Braking on the S2C is secure as well and I rarely use the front brake of my Speed Duo unless in heavy traffic.

So with my Speed Duo, I get the same benefit as the Shimano 3 speed coaster hub gearing without the high gearing. Btw, there are 2 folks here who converted their boardwalks to take the Shimano 3 speed hub with good experience. I almost went this route until Bruce Metras offered me the S2C at a really good price I couldn't refuse buying.

The other luxury option is the SRAM P5. It's a 5 speed coaster hub that has everything. Still needs a shifter to shift. I would love to have this, but it's not cheap compared to the S2C or the A2 Automatix.

Elvis Shumaker

The Nexus 3-speed is probably the cheapest option and not a bad choice if you can route the cable through the frame. The twist shift can be matched up with Nexus-specific grips (Ergon etc.) to make it blend in more. There's nothing much on the shifter to catch and break anyway I reckon. 80% of riding in 'high' gear, middle for starts and hills, low as as a rarely used granny gear is my pattern. So not much thinking about shifting, or even shifting full stop.

puchfinnland

I happen to have 3 old Sachs Duomatic S2C here in finland,
the one I have set up works fine, but the brake is very weak.
I found a guy who has NOS parts for it and will see him shortly.

is there some way to adjust the ratios between low and high?
there is not very large spread between mine.
mike

as for hub options a shimano nexus 3 is super reliable, I have nexus 7's and they are far better then nexus 8's or sram 7's

pacificcyclist

I bought mine from Bruce Metras so I don't know if he did something to it, but the brake itself is working fine like the stock Uno single coaster hub eventhough there's now some grease oozing out. When I got it, there was more drag then than it is now. But I know a shop here who can maintain it.

The Nexus 3 is the one I see as the common upgrade to a single speed bike because it is reliable and cheap to get. But with a 2 speed hub like ours, you can't really adjust low to high because of the limited gear ratio gain on both the SRAM A2 or the Sachs S2C. You have to choose either low to medium or medium to high gearing. If you live in Florida or Arizona, then the medium to high would be your best bet. But if you live in the Rockies, low to medium would be a better choice.

fietsbob

well some need regular dismantling and service .. in the wet season, and initial addition of more Lubrication,
which makes sense, since money is saved Minimizing the per hub amounts,
if making a million hubs/pedals or whatever..

from earlier link..
https://www.rideyourbike.com/internalgears.shtml

AW3 the Oil goes in the indicator chain , axle hole.. I took my last one apart and used grease on the axle bearings,
it also makes the oil on the inside not leak out easily.. Phil Tenacious Oil seems right.

dynaryder

Then you eliminated about 70% of your bike's braking capability. Fine if you're somewhere totally flat and riding at sedate speeds,completely nutter for a hilly urban region like DC. Oh,and hope you don't drop/break a chain.

Very thorough reviews of the SRAM Automatix and SA S2C. Was surprised to read that nether hub was totally sealed. Esp with SA originally being from Jolly 'Ol.

bhtooefr

10 mm going too far? Damn.

That restricts the options CONSIDERABLY.

(Also, the coaster brake 5-speed Sturmeys are 127 mm OLD. If I come up with a rear rim brake, the non-brake 5-speed one is available in 111, but my goal is to minimize the amount of rim brakes on this bike as it is - front at most, and I wouldn't mind replacing that with a drum eventually.)

So...

Sachs Duomatic: Rare, but apparently it's 112 mm OLD, and doesn't blow up like the modern kickback Sturmeys.
Sachs Automatic: Rare, but essentially an ancient 114 mm OLD version of the SRAM Automatix (1.36 high gear instead of 1.37, and more compact)
Sturmey-Archer S-RC3 or AWC: More common, current production, 116 mm OLD. Downside is added controls.

There may be other options (older Sturmey hubs, older Sachs 3-speeds, and the like), that I'm not aware of.

The Nexus 3 is 120 mm, the SRAM i-Motion 3 is 130.

Edit: And looks like I'd have to drill holes in the frame to internally route a shifter cable.

Edit 2: Sachs 515 is 115 mm OLD, it seems.

Edit 3: And the original Duomatic 101/102 is 110 mm.

bargainguy

I'm sure there are folks here who don't think spreading a steel rear triangle by 10mm is any concern. Me personally, I wouldn't go that far. It's not just a matter of whether the steel will bend that far, it's also a matter of keeping the dropouts aligned.

Good point about the SRAM 5-speed not being available 111OLD in a built-in brake version. I knew I was forgetting something.

I can see why you'd be so stoked on the Automatix hub. The bikes I've seen with them have a very clean, uncluttered look, as they have no cables or housings whatsoever.

There is perhaps one more point to make in discussing the various multi-speed hubs. Their efficiency is all over the place depending on design. You might get around 90-92% efficiency in the middle gears, but that might drop off considerably to as low as 80% in the highest and lowest gears. It might not be a big deal to some folks, but you'd be surprised how many people think hub gears are as efficient as a derailleur drivetrain. In a small folding bike, those losses add up considerably. YMMV.

bhtooefr

Oh, and SRAM doesn't have a 5-speed any more, but the old Spectro P5 is 122 mm OLD for the coaster brake version (and the freewheel version is WIDER, at 123 mm). (The S-RF5(W) you refer to is a Sturmey-Archer product, not SRAM).

I'm leaning towards a vintage Duomatic 102 now for frame reasons - no spreading needed at all. The Duomatic R 2110 would need barely any spreading (2 mm), and the Automatic A 2110 would only need 4 mm of spreading (but it'd still need to be modified - stock, the 28h version shifts at 16 km/h. Better than the 14.9 km/h or whatever it is of the Automatix 28h, but not anywhere near where I want the shift point to be).

Also, with the riding I plan on doing with this bike, I really don't see the point to going past 3 speeds. If I want a wide range, I've got my (X-RF8(W)-equipped) recumbent trike.

bargainguy

See what happens when I go from memory? Touche!

Dahon.Steve

The Nexus 3 speed is the hub I have on my non-folding bike. I've used Sturmey AW-3, Sram-3 and Nexus 3 and I have to say the Nexus is the best. I feel less friction in third gear than my prior Sturmey or Sram. Things might have changed but who knows.

I think the OP's fear of breaking parts of a three speed hub should not be an issue. I've broken the chain on a three speed and purchased a new one in no time. It's rare to break parts unless your careless with a folder.

What's more important when creating a hub gear bike from scratch is establishing a sweet gear that you can ride 95% of the time. If the OP does now know what gear he likes riding most of the time, the bike will be constructed and hardly ridden. There's nothing worse than riding a hub gear bike where none of the gears feels comfortable. This is even more important on a 2 or 3 speed where your gear selection is very limited. In a three speed, if second gear does not feel great and allows you to ride the bike all day, you'll rarely use it.

bhtooefr

Actually, that's the strong downside to the automatic hubs - difficult to adjust the shift point, whereas if I decide the gearing on a kickback or a 3-speed is wrong... I change it.

tcs

Including Mr. Berto and Dr. Kyle after their instrumented tests: see report beginning on page three of this IHPVA bulletin.

SesameCrunch

Yes, I agree. The bike on which I use the Automatix is just for pootling around, and the Automatix is supremely suited for that purpose. I have other bikes for more serious riding.

SesameCrunch

That's why I was initially reluctant to get the Automatix. However, after getting one, I find that when I need the lower gear, I just have to slow down, then it shifts into the lower gear. One advantage of the Automatix is that you don't automatically shift gears when you engage the coaster brake. Different strokes....

pacificcyclist

First try a Tern Verge Duo from a Tern dealer and see how you like it. You may or may not. I didn't like it, but that's probably due to the shift point being too soon. It wasn't customized to my taste. The downside of the automatic hub is that, you don't truly have a single speed bike because you can not pedal at any cadence without shifting to the next higher gear. If it shifts, then it disrupts your cadence unless you're going downhill which is why this 2 speed hub is suited for. I think you're trying to get a low and medium gear with the A2 is when your concern is justified. Again, it truly depends on your riding style and terrain you'll be riding in. I personally like the S2C more than the A2 because I like to control when I shift and at what cadence I pedal without being restricted by the hub's shift point. The downside to the S2C is that kickback shifting is not so reliable and when you stop you shift which the Automatix solves, but then it emits a sound which is distinctive which gear you are in with the S2C. At least mine does.

The easiest way to choose a hub is to determine if your current Boardwalk gearing is either too high or too low. If it's too low for you, then the Automatix is for you. If it's too high for you and you need to stand a lot to start, then you may want to consider more gearing like the Nexus 3 which is great for the Boardwalk. Last year, someone almost sold me a Boardwalk with a Nexus 3 for like $75 Canadian. Darn I didn't buy it or I would have stripped the rear hub and place it on my Speed Uno. I didn't have a S2C then. The Nexus 3 is a good compromise as it has a low,medium and high gearing and you shift when you like. It's only 1 cable to the rear hub you know.

bhtooefr

I think the Boardwalk gearing is about right, maybe a bit too short for level ground, but I'd like a lower gear for up hills, really. It's definitely a short-distance pootle bike, so I don't need a hammer gear for max speed. A low and a medium gear is what I'm after, yes.

Annoyingly, didn't win the NOS Duomatic 102 that was on eBay.

Sixty Fiver

Spreading a steel frame by 10mm is generally considered to be very safe and once the frame has been cold set the dropouts have to re-aligned.

Internal gear hubs demonstrate high levels of efficiency and like derailleur gears, this varies according to model and the gear selection used and there are a few other factors to consider in that internal hub gears maintain their efficiency far better than derailleur gears. With modern folding bicycles and better technology the gap between these and conventional bicycles in the performance department as very small and in some cases, smaller wheeled bicycles demonstrate many advantages.

The efficiency of the SA AW is the same as a 27 speed Shimano drivetrain but this is only part of the equation... wider ranging gear hubs and derailleur gears allow the rider to maximize their efforts more efficiently as the engine is small and underpowered and has a fairly narrow power band.

My Moulton has very small wheels and a 7 speed Shimano IGH... the slightly lower efficiency of the Shimano 7 gets made up with what is a highly efficient bicycle.

My 21 speed P20 custom uses a derailleur gear and is like riding any other 21 speed touring bicycle save for the fact it is a little quicker and faster due to it having better aerodynamics and this is where most losses come from.

bhtooefr

Alright, having gone on a hillier ride, screw 2 speeds (OK, 2 would be enough of an improvement for most of the riding I'd actually do on this bike, although I think I do want manual shift-point control, so it'd be an old Sachs if I go for 2), I want 3, and who cares about routing a shifter cable. (Medium, low, and granny, in my case, instead of just a medium, or with a 2-speed, a medium and a low.)

So, the options:

Sturmey-Archer S-RC3: 116 mm OLD, 177% range, 1290 g
Sturmey-Archer AWC: 116 mm OLD, 177% range, 1350 g
Shimano Nexus SG-3C41: 120 mm OLD, 186% range, 1220 g
SRAM i-Motion 3 Coaster: 130 mm OLD, 186% range, 1390 g

So, if those are the options, it's a choice between Sturmey and Shimano, and if I go Sturmey, whether I go steel or aluminum hub shell.

How's the durability and maintenance requirements of each? I know the Sturmeys have an indicator chain, and the Shimanos have a bellcrank, as far as the shifter goes... on a folder where it may get banged around a bit, how does each hold up?