Hybrid gears

[simongt]

Way back in the forties & fifties, Cyclo and Simplex marketed a hybrid gear system where a three speed derailleur was mated to a three / four speed hub gear, giving a nine / twelve speed combination, albeit with fairly closely spaced ratios. Although put that with a two speed chainset and you had eighteen / twenty four speeds with minimum chain crossover. Obviously, as these are no longer available, they can't have been overly popular for whatever the reason.
However, I was talking about this to a 'cycle bloke' - whose 'expertise' I don't altogether trust - and he said it's perfectly possible to fit a 'reverse' version of said gear by the following method.
- Fit a long reach rear mech to your hub geared bike, locked so it stays below the hub sprocket.
- Replace the front chainwheel with a two or three speed one and set up a front mech changer.
- Put on a new chain of suitable length and the rear mech will take up the necessary wrap and tension.

In theory, this SHOULD work, but theory and practise are of course, two VERY different things - !

 

[Rickshaw Phil]

What you've described would probably work but you'd need a thinner sprocket to take the narrower derailleur type chain...... or you could get yourself a SRAM Dual Drive: https://www.sram.com/sram/urban/products/sram-dd3-27 which is the modern version of the derailluer/hub-gear combination.

And Sturmey Archer also do something similar: http://www.sturmey-archer.com/en/products/detail/cs-rf3-silver

 

[Rickshaw Phil]

Oh, nearly forgot, another way to achieve this would be to have the hub gear of your choice at the rear and something like a Schlumph or a Patterson drive on the front.

 

[Pale Rider]

I wonder if you might end up with a heap of intermediate gears, rather than the extended range which presumably is what is being sought.

 

[Piemaster]

Sounds like something I'll be doing shortly As per this thread I'm looking at a nexus hub but retaining the mtb triple at the front, at least at first, then swapping to a single chainwheel later on. The rear mech is a recently fitted Acera, which should as you describe be capable of serving as a chain tensioner. A kink in the chain wrecked the previous mech.
However it doesn't really work. Far too easy to exceed maximum torque limits and as @Pale Rider suggests, keeping within limits you end up with more intermediate gears without really making much difference at top/bottom ends. You can try it out here.

 

[raleighnut]

Early SA hubs had a screw on freewheel, google the great sheldonbrown to see how many gears he managed to put on a bike

 

[TheDoctor]

6 speed Bromptons use a 3 speed hub and 2 speed derailleur, in a Cyclo style.
I'm sure it could be done, but why would you?

 

[simongt]

I wonder if you might end up with a heap of intermediate gears, rather than the extended range which presumably is what is being sought.

Indeed Pale Rider, if you crunch the numbers; three speed hub x nine speed cassette x triple chain wheel for good measure - yes, that's EIGHTY ONE gears you have at your disposal - ! Brag that to the die hard roadies out there - ! But of course, with just the hub / cassette arrangement alone, there's going to be a heap of gears which are so close ratio that they're not much use unless you are OBSESSED with ultra smooth cadence - !

 

[TheDoctor]

You'd need a spreadsheet to work out the shift patterns...
"OK, so if I go up one on the chainring, down seven on the cassette and up one on the hub, then my cadence drops by three rpm for the same speed." Or some such.

 

[TheDoctor]

Anyway, I'm sure I could cludge an 11 speed cassette onto a 14 speed hub, with a Schlumpf 2 speed BB and a quad chain set. Who wouldn't want 1232 gears?
Just need two pairs of bars to mount all the gear levers

 

[Piemaster]

Schlumpf 2 speed BB

Nah, not enough. Need to bodge fit one of these into the BB somehow too

 

[Tojo]

Eh, How many gear combos do you need, there's enough cassettes and chain ring combo's out there for what anyone needs......If you need that many.....Sorry, just get a wee bit fitter or hang your bike up on the wall sit and look at it while your watching day time TV....

 

[classic33]

Indeed Pale Rider, if you crunch the numbers; three speed hub x nine speed cassette x triple chain wheel for good measure - yes, that's EIGHTY ONE gears you have at your disposal - ! Brag that to the die hard roadies out there - ! But of course, with just the hub / cassette arrangement alone, there's going to be a heap of gears which are so close ratio that they're not much use unless you are OBSESSED with ultra smooth cadence - !

I've a 105 on one bike.
Even managed to twist the axle through 90°. Something Sturmey Archer said shouldn't be possible.
7-speed block on the rear, SA five speed hub and a triple on the front.

 

[Pale Rider]

A Pinion 18 speed bottom bracket gearbox, a triple chain ring, and SRAM Dual Drive at the back would give 1,458 gears.

Back in the real world, I like the look of the Pinion:

http://pinion.eu/p1-18-getriebe/

 

[tyred]

Simple fix - It should be possible to mount two standard dished sturmey sprockets "dish to dish" in the centre if you remove one of the spacers so you could have perhaps a 2 - 4 tooth jump by moving the wheel slightly in the dropouts and putting the chain on the other sprocket. The chainline will be slightly out but not enough to matter.