Wife and I have DualDrives on our Dahon Speed TRs. Sweet spots:
* Hub gears make big ratio jumps (36%) while 8-speed derailleur makes smaller ratio jumps (13%). There are sweet spots to each. While riding when I want a big gear ratio jump, I use the hub gear -- it's on a thumb switch (not a trigger, it's a 3-position linear shifter) and it shifts FAST. Smaller gear jumps go to the twist shift derailleur (which I prefer over triggers because I can jump multiple gears with simple motions). I use the big gear ratio jumps on the hub when starting from a dead stop and the smaller jumps when topping out my speed. The large gear ratio changes in the hub make good sense at lower speeds because my cadence range is wider at the lower power required of lower speeds. But once the bike speed gets high, power input just to maintain speed is high so I need closer gear spacing and that's where the derailleur is good. When near top speed if I can afford a big burst of speed I'll drop the hub down one gear and overspin for a few seconds, the switch back up to third. Easy to poop out if doing that too much, but if one needs a speed burst, this transmission responds.
* The DualDrive allows upshifting while under full power. One doesn't have to ease off full power when taking off and shifting until it's time to use the derailleur gears. It saves energy and makes for faster overall acceleration not to have to ease off power during gear changes.
* The DualDrive allows downshifting when dead stopped. Except when bursting for speed, I don't need to apply power when downshifting the hub, so I commend SRAM on choosing a bias toward using power input to assist upshifts rather than no bias or bias toward assisting downshifts.

Not so sweet, but worth it to me:
* I dunked my DualDrive at 2500 miles and it started squealing a while later, story here. I disassembled it, found watery rust inside, cleaned, re-grease and re-oiled it. Found the exploded diagram from SRAM which gives disassembly, lubrication and reassembly directions. Doesn't have to be de-spoked to be disassembled, fortunately. Pay attention to the pawls on the planet carrier, they're easy to inadvertently flip backwards. All bearings are in holders or bearing assemblies so not to worry about balls spilling out. I found rusty scale on the chrome plated pins for the chrome plated planet gears; I think that's where the squeal was coming from. I cleaned the scale off the bearing pins with a brass wire brush (brass is softer than chrome). The pins have a very nice fit in the planet carrier; no perceptible slop yet the fit in both both the planet carrier and planet gears is smooth, not an interference fit on gear or carrier. Reassembly takes a bit of faith that it'll all work if one just follows the directions exactly. I could not figure out the shifting mechanics, but I don't need to know that to do this job. And yes you do have to set cone bearings as one of the last steps of reassembly. Anyway, it's back on the road and has stayed 100% like new for 200 miles since. I'm happy with the component quality of this hub gear and very happy with its design and performance bias toward quick upshifting under power.
* I think it could use an oil port, but I thought the oil ports on the old SA 3-speed hubs of my youth were ugly. Suggestions?

We also have Bike Fridays with Dual Drives (NWT and Pocket Crusoe). Took delivery of them 8 months ago - not an ounce of trouble. Love the "shift-down while stopped" feature, especially at traffic lights when I have forgotten to shift down the derailleur gears before coming to a stop.

Only downside might be the weight the hub adds to the rear of the bike.

Several Sturmey AW's and clones.
Sturmey S5 dual chain
Sram S7 Drum
Shimano Nexus 8

Hubs I'd like to try: Sturmey 8 speed, Sram I-Motion 9, Sturmey 7.

I'm just about fed up with the SA 8sp on my R20:

* planet gear broke
* re-lubing has been problematic
* water-resistance seems rudimentary
* shifting is too sensitive to adjustment tolerance - I have had problems with 6th gear from the beginning, and it seems to be getting worse. Right now, 6th gear can't be used without heavy skipping before proper engagement, so I can't trust it at all any more.

On the one one the MIni, 3rd and 5th seem sensitive. (3rd and 5th use same set of planetary gears.)

:(

"shifting is too sensitive to adjustment tolerance - I have had problems with 6th gear from the beginning, and it seems to be getting worse. Right now, 6th gear can't be used without heavy skipping before proper engagement, so I can't trust it at all any more."

I've had trouble with 6th also when things aren't perfectly adjusted. What I have found to be the adjustment sweet spot for my bike isn't with the yellow arrows lined up but aligned to the top of the upper red mark even though I've checked and rechecked the 145mm spacing from the adjustment barrel to the the cable anchor unit. The bike seems to hold 6th gear and shift well adjusted outside the recommended range.

I have tried the same thing on both sides. I know what the innards look like and I know what the problem is. I just don't know if I can attempt to solve it without completely wrecking 6th.

Sturmey claims to have solved adjustment sensitivity with the new 8 speed. I wonder when we'll see the new wide range Sturmey 8 shipping on Downtube's bikes.

My Downtube came with a Sturmey Archers 8 speed hub and a single 50 tooth chain ring giving me a 37 to 114 inch gear range. I decided to get a Metropolis internal crank giving me 16 gears with a more reasonable 21 to 103 inch range. It is the first internal gear system I have had on a bike since I was in grade school. So far it works great and I love it. Love it enough to consider going internal on my full size touring bike.

I converted a 6-speed derailer to a Nexus 7-speed internal with coaster brake.

Primarily because I wanted a cleaner look. I wanted less exposed chain to dirty up anything it contacts. And, I wanted to eliminate one handbrake, cable, v-brake.

Secondarily because it seemed like a fun project to build my own wheel.

If I remember our german Brompton Guru, (Stomatash), had the same problem?

I am using 3X7 sash dualdrive on a back up Mezzo bike, and a 3x9 Sram on my road bike converted Mezzo. The 3X9 dual drive is like silk and faultless after 3 years daily use. Matched to ultegera brifter its wounderful !
I avoid using this bike in rain where I can.

The sash is less good, mainly because I used grease, rather than oil to lubricate internals, and I guess its an old hub. I might convert this to a a Nexus or something someday.
Might fit an cheaply available internal on a Diblasi folder soon. Dahon D3 Curve wheel cheap??
My Brompton 5 speed sometimes slips in 1st and 2nd, not sure if adjustment.

I have 2 .. there is a 3 speed and a 2 speed crank on my Brompton,
both are planetary gears so chain does not shift off the chainwheel.
advantage: the double shift is able to be done simultaneously
at any speed, like bogging down on a hill in low gear in high range
next gear is high gear in low range.. 3<>4


I use the Bike Friday Pocket Llama as my Daily commuter, with it's Rohloff Hub.
front Dynohub, disc brakes.. year round, [except on black ice]

[actually similar, though instead of a 2 speed crankset,
the range shift is inside the hub, 7<>8 ..


Early 60's I had a 3 cubed bike drivetrain, AW3 + 3 Cog Cluster + Triple Crank
so 27 'speeds' 3x3x3 3 levers..

When I've test ridden bikes with internal hubs, I've been surprised by how much the weight imbalance--the feeling of pulling something behind me--has bothered me. I wouldn't have considered these bikes heavy if the weight had been evenly distributed, I don't think.

Is that simply something one gets used to?

I had a BF NWT with a Nexus 8:

- low cost
- low maintenance
- strong rear wheel

No downside really.

I've never noticed it.

Our Origami Fox uses a Shimano Nexus 3-speed IGH. On the positive side, it is silky smooth and never misses a shift. On the negative side, it is a bit heavier and a lot more expensive than a derailleur.

I did not like the gearing on my Airnimal with only an 8 speed rear so I built up a wheel with a dual drive to give me 24 gears. My point is that I have ridden that same bike with both regular and IGH wheels. Have not noticed feeling any weight imbalance at all.

Did anyone else notice that most of this thread is over four years old?

I have several hub only & hub/derailleur folders. Something no one has mentioned yet: Hub shifting from a Shimano STI brifter.

AFAIK, Shimano does not recommend using an STI brifter with any hub due to the slighly different cable pull (someone please correct me if I'm wrong). My Speed Pro TT is particularly bothered by this. After a bunch of shifting, tends to go out of alignment & sometimes I get caught between hub gears = no power. Nothing I can't realign, just annoying, and esp so if I gear down while approaching a hill, suddenly finding myself in no gear.

Don

You're right that Shimano has never recommended it. But that's all going to change when they release their Alfine Di2 setup with brifters.

I've shifted a SRAM T3 hub with a Shimano LH (front) triple brifter for four+ years with zero issues.

My Moulton has a Dualdrive. This is a three speed internal hub with a cassette. I've read of people using nine or ten speed cassettes with the hub but as mine was an upgrade from an earlier Sachs 3x7, I stuck with a seven speed cassette so I didnt have to bother buying new shifters. I just added a 4.5mm spacer behind the cassette and was off. Its a strong enough hub as it towed a well loaded cycle trailer (Carry Freedom) across Australia, East to West. I love the fact theres no front derailleur to worry about and enjoy the ability to shift to low range when stopped. I sent to the USA to build up my current wheels which was the Dualdrive and a SonDelux hub dynamo for the front. Wheelbuilder appeared to be the only one who would make the CX-Ray spokes I wanted short enough for the Velocity Aeroheat build. I've just bought a Rohloff 14 speed which may end up in the Moulton.

I have a Sachs 3sp rear in place of a FD on my old BF Pocket Rocket. Hasn't bothered me though it's a bit weird with my Campy shifters (two-three clicks per step). Only real perceptable downside has been that I can't easily mount my kid trailer. No biggie.

There is a 3rd party made brifter for Shimano's hubs..