sram dual drives? why are they not popular?

[Cheesewheel]

This thread arises from my contemplation of options to get more gears out of the 1 x 10 krampus range.

for the uninitiated, sticking a double chain ring on the front poses tyre rub issues in the lower gears. The sram dual drive is a 3 speed internal gear hub that can fit 9 spd cassettes ... and seems like the easiest solution

A web search shows that the only bikes that seem to be equipped with them are dubious ones from China .... and there doesn't seem to be much out there on retrofitting them.

Anyone got any experience or thoughts on the subject?

[RonK]

They are quite popular for recumbents and bikes with small diameter wheels where a long cage derailleur is vulnerable to damage. They have been around for years, originally from Sachs Germany before they became SRAM. See Sheldon Brown.

Another option you could consider is a Schlumpf Mountain Drive.

[lobstermash]

Yep, I had (and have seller's regret) a BikeE with a 3-speed hub and 7sp freewheel. I guess the disadvantages of using this setup are the same as with any IGH; weight and serviceability (including both faults with the hub itself and with the wheel in general).

[il padrone]

Greenspeed (Ian Sims) has used them for many years on his recumbent trikes to get a much wider range for climbing and fast riding. Most of the trikes have 63 gears I think, including tall high gears and walking speed lows.

[il padrone]

I guess the disadvantages of using this setup are the same as with any IGH; weight and serviceability

*cough* (Rohloff)

While I can agree that weight is not light for the Rohloff, it is not that much greater than a conventional touring or MTB derailleur drivetrain, and the weight is central on the wheel. But servicability for a Rohloff is outstanding - far bettter than any derailleur drivetrain.

[Baalzamon]

John Lewis has repaired quite a few of them due to them breaking. That put me off getting one for my Ice Trike which you got cheesewheel

[Aushiker]

SRAM have an nine-speed IGH coming out, the SRAM G9 (disc and belt drive compatible). Maybe another option to consider?

Andrew

[petie]

I acquired a Schlumpf mountain drive recently (fitted to my recumbent). Not sure if that is an option if you airway have the rear wheel? Certainly get good spread with the 2.5:1 and 1:1!

[mikedufty]

My parents just got a dahon folding bike with the dual drive and are very impressed with it, much better shifting than a front derailleur. Haven't had it long enough to say anything about durability.

[find_bruce]

My guess is that the dual drive is a bit betwixt and between, with no clear "this is why you want it" feature

[rifraf]

I'm a fan of the SRAM dual drive and have a new one sitting in my parts bin should I ever have to build up a spare wheel to get my Ogre back on the road due to Rohloff failure. The Dualdrive is often set up beyond the manufacturers warranty spec which makes it obvious as to the reason some have experienced failures. Even Rohloff has a manufacturer spec gear ratio to keep within to maintain warranty

[Cheesewheel]

I'm a fan of the SRAM dual drive and have a new one sitting in my parts bin should I ever have to build up a spare wheel to get my Ogre back on the road due to Rohloff failure. The Dualdrive is often set up beyond the manufacturers warranty spec which makes it obvious as to the reason some have experienced failures. Even Rohloff has a manufacturer spec gear ratio to keep within to maintain warranty

How do the dual gear cables rig up on the frame? Are there any special work arounds required to get two gear cables connected to the rear hub or can it all pretty much be done with a few cable ties?

[il padrone]

I'm a fan of the SRAM dual drive and have a new one sitting in my parts bin should I ever have to build up a spare wheel to get my Ogre back on the road due to Rohloff failure. The Dualdrive is often set up beyond the manufacturers warranty spec which makes it obvious as to the reason some have experienced failures. Even Rohloff has a manufacturer spec gear ratio to keep within to maintain warranty

How do the dual gear cables rig up on the frame? Are there any special work arounds required to get two gear cables connected to the rear hub or can it all pretty much be done with a few cable ties?

Rohloff you mean? It all depends on what your frame has. If you have the good sense to buy a Rohloff-dedicated frame there may be a nice set of dual cable-guides already fitted.




Otherwise you can just use the existing rear derailleur cable guides on the top/down tube for one cable, and cable tie the second cable housing alongside (what I did with my wife's Rohloff on her Giant Sedona MTB frame). Rohloff do make special dual cable housing cable-ties to secure the housings.

[rifraf]

I'm a fan of the SRAM dual drive and have a new one sitting in my parts bin should I ever have to build up a spare wheel to get my Ogre back on the road due to Rohloff failure. The Dualdrive is often set up beyond the manufacturers warranty spec which makes it obvious as to the reason some have experienced failures. Even Rohloff has a manufacturer spec gear ratio to keep within to maintain warranty

How do the dual gear cables rig up on the frame? Are there any special work arounds required to get two gear cables connected to the rear hub or can it all pretty much be done with a few cable ties?

Sorry for the late reply,
I'd missed your post.
Assuming your talking generally and not specific, a cable tie is all that would been needed for the second cable.
I'm sure there are other fitment options available if you look hard enough, in the way of frame cable attachments.
My Moulton had previously utilised the Sachs 3x7 so already had factory brazed fittings for two rear cables running along the drive side chain stay.
I think when I swapped to the dual drive I used a cable tie due to a difference in length of cable.
Yip - here tis:

[rifraf]

This thread arises from my contemplation of options to get more gears out of the 1 x 10 krampus range.

for the uninitiated, sticking a double chain ring on the front poses tyre rub issues in the lower gears. The sram dual drive is a 3 speed internal gear hub that can fit 9 spd cassettes ... and seems like the easiest solution

A web search shows that the only bikes that seem to be equipped with them are dubious ones from China .... and there doesn't seem to be much out there on retrofitting them.

Anyone got any experience or thoughts on the subject?

Like many IGH's, the Dualdrive has a manufacturer specified gear ratio to keep within warranty.
I've read of failures with regards Srams non Dualdrive, basic 3 speed IGH's not being up to 29er duty due to a lack of robustness.
I'd personally equate this to the Dualdrive which is the same basic unit with the addition of a cassette.
Whilst I've happily toured utilising the Dualdrive on mixed surface conditions, its not marketed as a pure off road hub suitable for hell for leather treatment.
I think to get the gear inches you'd find useful, you'd see the Dualdrive out of warranty spec on your Krampus.
Easyist solution? - Yes
Best solution? - Perhaps not
You web search perhaps needs some work as there is a lot of bikes with Dualdrive, though with perhaps a bias toward small wheel bikes and folders.
Some of them including Moultons, Bike Fridays, Terns and Dahons hardly in the ilk of dubious Chinese bikes.

The earlier incarnation which was the Sachs 3x7, utilised no click box, but the same sort of set up as the Sturmey Archer IGH inner gear change.
Apologies for the dreadfully ill focused pic:



Sturmey Archer also makes its own version of a Dualdrive (3 speed internal with cassette)

Having a click box like the Dualdrive means wanting a Bob Trailer attaching to the axle nuts impossible.
I'd just bought a Bob before upgrading to the Dualdrive in anticipation of moving to WA by riding my Moulton there.
I had to rethink my trailer ownership which saw me sell the Bob (at a loss) and buy a Carry Freedom Y-frame Trailer.
Probably not an issue on the Krampus due to dropout mounted trailer nuts rather than axle mounted ones.