Abu Mahendra

you all know i am a big fan of SRAM's DualDrive hub. the reasons are primarily two. one, for the gearing range our affords. two, for the uber-smooth and nearly instantaneous shifts across the three gear bands. recent riding with Shimano 105 5800, however, has been quite surprising about how effortlessly and accurately shifts are between chainrings. no clunk, no grating sound of the chain against the FD. quite impressive, actually. not quite as quick and crisp as SRAM DD, but very, very good. i may have to rethink my predilection. for it in the future. Kudos to Shimano for dialing it in.

badmother

I am looking at the Sram dual drive these days for two bikes. I think the type of bike and use of the bike is a part of the desicion.

I am thinking about dual drive for my NWT that I bought in may this year. The bike is folded and unfolded often and it is not a "neat fold" as some other folders I find I am tinkering with it quite often. Put a new front der and still not sure if I am happy with it. Bought stuff to keep the chain on the chainrings in the front 3x9 so I am beginning to think about single chainring and dd. Sora and Deore stuff on it now.

Also with my trike that I just finished building I want a wide range but there is only space for one chainring at the froont and therer are restrictions with the chainline. I have to use hub gears or maybe a dual drive solution. I fear that to use dual drive (or any solution with cogs) I need to use two separate chains.

It is still good to know that the Shimano 105 works weell. I do not read as much as I used to in the other forums so I get most of my information from here.

Abu Mahendra

Sure, my comparo is apples and oranges. Closer to apples to apples would be a triple crank vs. SDD. But a triple crank will usually require an SGS RD which, on smaller wheels, will be a non starter due to ground clearance. Ergo SDD still has its place on small wheels.

SkunkWerX

Interesting comparison. I just recently diagnosed,fixed and dialed-in my SLX Shadow RD on the Trek DS.
Shifts like butter now, I don't hear the chain move a lot of time, just the 'click' of the shifter and the feel of a different gear.
It's better than brand new now....though it plagued me for a bit.

That said, smooth shifting can be had in an RD, no doubt. The Hub gears do make a lot of sense on the folders, though.
As badmother points out, for someone folding and unfolding a lot, the HGs do make a lot of sense! Compactness, cleanliness, and no RD hanging out there to be tweaked by an obstacle.

Q: SDD or Nexus hubs.... what is the frame/fork width they are designed to fit?
I "might" have an upcoming project where a HG would be a contender. 130mm?

Abu Mahendra

Yes, SLX rear derailleur shifting can be butta'. My Dash has SLX RD-M670 10-speed in the rear, and it's very good. But I was talking about Front Derailleur shifting performance vs. SDD.

badmother

All the older Nexus7 hubs I have is 130 old. Not sure about new ones.

badmother

If I stay with the 3x9 i have at present I am thinking of a new rear der. Was thinking this one https://www.sjscycles.co.uk/deraille...leur-sgs-cage/ since I think maybe it`ll go a bit forward, not just straight down plus it does not have that sharp curve on the cable before entering the rd.

Anybody using it for small wheels?

mconlonx

I had a Sachs DD on my Birdy; most of my other geared bikes have a traditional FD system. There's room in the world for both. For folders, it offers less complication when folding and features a built in cable quick disconnect, although retrofitting a Birdy 8sp bike with it was not as straightforward as one might think... I liked the system well enough, but front derailleur systems are also fine, and better than ever. So while I wouldn't hesitate to ride either, I probably would not convert a FD equipped bike over to DD... or vice versa.

fietsbob

Sturmey Archer (sun race) also has One
Sturmey-Archer | CS-RF3 Black

Optional on Bike Friday's Build lists..

SRAM also has a RD like that .

Abu Mahendra

That SGS job looks awfully long. GS is as long as i would use on 406 wheels. You may be a great candidate for SDD.

badmother

I fully understand what you are saying but GS is single and double chainset only. this is why I was thinking about the SGS https://www.sjscycles.co.uk/deraille...lleur-gs-cage/

At present there is 3 in the front and nine in the back. The small front is 30t and the big back is 32t . I`ll go for a ride today to see if the new chain can accept the old cog. If not I think I`ll go for a smaller "big" on the cog but not a real solution. Maybe big in the rear and down to two chainrings in the front..

Edit: I added a chainguard to the front yesterday so four rings in the front totally. I am not happy with the situation.

Sorry for hacking your thread.

Tourist in MSN

I put the Dual Drive on my Airnimal Joey. I wanted a wider range than I got from just a rear derailleur, can't fit a front derailleur on the bike so an IGH was the only option.

I eventually learned that I could use a Sturmey Archer 3 speed bar end shifter on the Dual
Drive, which I use because I am running bar end shifter on drop bars for the rear derailleur so a bar end shifter for both front and rear is preferred. For several years I tried to use a friction front bar end shifter for teh Dual Drive which was far from ideal.

For reference, I am using a 11/32 eight speed cassette.

Advantages of Dual Drive:

1. An IGH allows me to down shift once I came to a stop at the stop light so starting out is easier.
2. If you have a Dual Drive and rear cassette, you can change all of your gears up or down with a single chainring change (and maybe new chain). A conventional derailleur bike with a triple would need more parts to raise or lower your entire range of gears. If I ever tried to tour on my Airnimal, I would put a smaller chainring on it for the tour for steep uphills, then go back to what I have when I get home.
3. On a small wheel bike like most folders, you likely will have lower gears than you really want unless you have a huge (and expensive?) chainring. The Dual Drive has an "overdrive" for the higher gear, so you get higher gears, I bought a smaller chainring when I switched to the Dual Drive because I wanted more lower gears but not as many higher gears. I knew one Bike Friday owner that wanted to put a dual drive on his wife's Bike Friday for this reason alone, she was spinning out because she did not have high enough gears.

Disadvantages:

1. The hub does not have a very strong spring in it, sometimes the hub will not downshift due to cable friction. My bike uses full length outer housing, there are lots of bends in the housing, and it is long enough that I need a tandem cable. So, this disadvantage may be unique to me due to my bike design and cable issues.
2. I would prefer a quick release. Dual Drive has a solid axle that is pretty long, I would guess an inch longer per end. I have been trying to figure out how to make this a travel bike for airline transport and the longer axle is pertinent.
3. There is a constant chirp out of the hub from pawls clicking, not silent like a derailleur bike when you are pedaling. I get used to it, but on a silent windless day out in the country where there is no traffic noise, it certainly is noticeable.
4. Without a quick release, you need a 15mm wrench packed with your spare tube to remove the wheel.
5. On my bikes with triples, I change chainrings to change the gearing for the purpose. (I use older square taper cranksets and vintage front derailleurs, thus have a lot of flexibility unlike some of newer drive trains.) My stock crank was 52/42/30, but I have also toured with 52/42/24 and with 46/42/24. Dual Drive has fixed gear ratios that a user can not change.

I left cost off the list, it all depends on the individual. Weight, same thing.

If you switch to a Dual Drive from a derailleur system, think about how you will shift it. Dual Drive was not made with drop bars in mind. I think some have run a Shimano brifter but since I have not done that, I can't comment on that option. I think the Sturmy Archer 3 speed bar end it the only other option.

osco53

I hated my stock Derailleur and shifter on my Dahon speed P8, It was total junk IMO.
So was that overbuilt extra heavy chain.

Replaced with a low cost low end Shimano Alivio derailleur and a shifter that Indexes accurately, That and a good chain fixed things.
Total cost was $69

My shifts are accurate, quiet and smooth.

fietsbob

even tidier is 2 speed Planetary cranks and an IGH

Patterson Metro* cable shifts a 1.6 overdrive. chainring turns that many times More than the crankarms.

Swiss Designed Schlumpf has a Mechanical Button shift, another 1.6x over drive but from 130 or 110 chainrings.
and a 2.5X overdrive (unique 27t chainring and larger

* is similar that it uses a spline fitted chainring but not interchangable ..

I've been using the Mountain drive , 2.5 reduction gear + a 3 speed Hub.
1,2,3 in low range , 4th is a switch to Hub low gear + direct gear in the crank
which is a double shift from High gear in Low range , but both can happen at once

at any speed .. the Downshift is really useful when Bogged down climbing a Hill .

You are not pushing the chain anywhere , (unlike derailing schemes)
just hesitating with the pedals for a moment to let the Planetary gear combinations change.

randomwon

I have a dual drive 27 speed system and if I could do it all over again, I would probably opt for a bigger chaining/derailed setup. on paper the dual drive setup sounds good but there is a noted efficiency loss in the hill riding and fast riding gears, this loss isn't present in the direct drive mode. This makes pedaling feel a little gummy or in other words adds a little resistance to your pedaling. I also rarely use any of the other two modes. It all depends on what you hope to accomplish with one of these , is it bigger gear inches in the top end? or extremely low hill climbing gear inches? Also the bike gets alot more added weight to the rear wheel which you might want to consider if you use your folder in alot of multimodal situations.

Amt0571

The SRAM DualDrive has one huge advantage over conventional transmissions for small wheeled bikes: it gives you a higher final gear that you can't match with a conventional transmission. Not even with a Capreo. Unless you like 70t chainrings, of course.

Obviously, if you're not interested in going faster than 30 or 35km/h, then it's a non issue. I don't like to spin out on descents, and I have a couple of "interesting" ones in my daily commute, so I couldn't live without it.

Abu Mahendra

never noticed any 'gumnyness' on any of the three SDD gear bands. on paper it's there I the low and high bands, but I can't personally say it's palpable on my rig.

if a double chairing gets you the gearing range you need, there's little reason to go with SDD. i myself am considering that. SDD competes against a triple, not a double or single ring crankset.

Tourist in MSN

I do not notice any efficiency loss in those two gear ranges.

onbike 1939

I have the Sram dual drive with a 9 speed derailleur on my Moulton TSR27 and wish I had had this when I was touring as it give me a huge gear range and the ability to change gear while stopped. I really can't fault this set-up and mated with the Moulton's suspension and comfort it's a dream.

Amt0571

i notice a *really slight* efficiency loss in both low and high gear compared to middle. For me, it's most noticeable when going fast on flat (or almost flat) terrain in high gear.

Also there's noticeable vibration that transmits to the cranks in low gear when using the smaller sprockets, but this is a gear combination that makes no sense, as you can simply use middle gear with a bigger sprocket.

Anyway, I feel that for small wheeled bicycles it's the ideal drivetrain and the advantages it provides are worth it.

bhkyte

I agree with that.
But the ideal depends.
Ihg work better on birdies for several reasons, due to chain clearence and folding issue with chain.
Sometimes lighter weight may be proitity. I may finish my Mezzo cespro sometime to compair to my dual drive version.
Also sometimes I don't need lots of complication and I like my relieble 8 speed rear mech on one of mybasics bir set ups r this reason.

I agree all things being equal I would dual drive most bike most of the time.

invisiblehand

You can use a triple with a road cassette with a GS rear derailer. At least that's what Shimano supplies in its road triple group sets.

invisiblehand

Although you can switch cassettes and the single chainring.

Older Shimano STI shifters only had three front derailer positions. The cable pull happens to be close enough to work the SRAM DD. Newer STI shifters have four positions.

randomwon

For those wondering how to place dual drive shifters on dropbars. The solution is very simple. All you need is an accessory bar with a 31.8 mm clamp such as the evo spacebar pictured here. This allows you to slide the 27 speed grip shifter over the bar with plenty of space to spare with your handlebars. Ive had no problems with the shifter using this setup

fietsbob

Bar End shifters would work too , Cassette/derailleur on the right, internal 3 speed on the left.

Microshift makes Both..