Ultra low gear with Alfine 11 spd hub?

General cycling advice ( NOT technical ! )
rand
Posts: 318
Joined: 5 Mar 2008, 6:38pm

Ultra low gear with Alfine 11 spd hub?

Postby rand » 1 Sep 2012, 8:49pm

Does anyone know the lowest ( I'm hoping for 12" 15") gear available with the latest Shimano Alfine 11 spd hub?

I'm aware of the advice given by Shimano, but I'm interested in hearing from someone who has ignored that advice, had a very low gear and experienced no hub problems as a result.

Would such a low gear be possible with a Rohloff?

I intend to use two chainrings.


Rand.

User avatar
Tigerbiten
Posts: 1919
Joined: 29 Jun 2009, 6:49am

Re: Ultra low gear with Alfine 11 spd hub?

Postby Tigerbiten » 1 Sep 2012, 9:04pm

I've geared my Rohloff down to either 10" or 12" on my ICE trike depending on the back sprocket.
Its feels fine with a full campload up to ~17% on hills.
But I don't like to take it steeper than that with the full load.
But I have done 20% hills with ease and only 25% hills are hard ....... :D
So far I'm just under 1 years and ~7k miles in that congfig.

It's matched up with a High Speed Drive on the front that gives me 7 more gears in overdrive.
Try 21 gears at 14% steps to give a range of 10" -> 130" in touring mode or 12" -> 156" in road mode.

YMMV ............. :D

rand
Posts: 318
Joined: 5 Mar 2008, 6:38pm

Re: Ultra low gear with Alfine 11 spd hub?

Postby rand » 1 Sep 2012, 10:54pm

Tigerbiten,
Thanks for that info, but is that gearing lower than recommended by Rohloff? I'm hoping that it is, as that would give me the courage to do the same with an Alfine 11 sp. Pity I can't afford a Rohloff!

Rand.

User avatar
Tigerbiten
Posts: 1919
Joined: 29 Jun 2009, 6:49am

Re: Ultra low gear with Alfine 11 spd hub?

Postby Tigerbiten » 1 Sep 2012, 11:24pm

rand wrote:Tigerbiten,
Thanks for that info, but is that gearing lower than recommended by Rohloff? I'm hoping that it is, as that would give me the courage to do the same with an Alfine 11 sp. Pity I can't afford a Rohloff!

Rand.

Rohloff recomend a minimum gear of 14" at a max weight of 100 Kg.
So I'm well below this and my all-up touring weight is probably around the 140 Kg, so I'm well over weight as well.
The only advantage I have is being on a trike means I can climb hills a lot slower than an upwrong.
So less force is needed on each pedal push on a given hill.

I thought about an Alfine 11 but as I was going for the maximum range thats easily possible I went the Rohloff-HSD combo for a max range of 1300% ........... :shock:

I would love to build the Rohloff into a lay shaft so it spins a 2x the back wheel.
The would probably lower the torque through the hub to back within spec.
Plus I could then put a motor in the back wheel for faster speed uphill.
Also I could open the range a little more by useing a 6-8 speed close ratio block in the back wheel ......... :twisted:

User avatar
Mick F
Spambuster
Posts: 46728
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Ultra low gear with Alfine 11 spd hub?

Postby Mick F » 2 Sep 2012, 7:28am

I would think that it's not the gear ratio particularly, but the torque that limits it.

Bradley Wiggins could wreck a Rohloff even if it was within gearing spec.
Mick F. Cornwall

fatboy
Posts: 3346
Joined: 5 Jan 2007, 1:32pm
Location: North Hertfordshire

Re: Ultra low gear with Alfine 11 spd hub?

Postby fatboy » 2 Sep 2012, 7:41am

I think it is worth noting that the hub will always experience high input torque. Personally it is so far away from their recommendatios (unless you have very small wheels) that I wouldn't risk it myself.
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

Fatou
Posts: 185
Joined: 5 Apr 2009, 3:27pm

Re: Ultra low gear with Alfine 11 spd hub?

Postby Fatou » 2 Sep 2012, 7:52am

I don't know what Shimano recommends, Rose bikes offer many Alfine 11 bikes with low gearing e.g....

http://www.rosebikes.co.uk/article/rose-black-water-ii-trekking-men-566032/aid:566055

this is a 28t front & 20t rear, giving ~20".

To get as low as you wish, what would the gearing be like for your bike? Using Sheldon's gear calculator I tried this combination, 20t front 24t rear, giving ~12".

I have no idea if it's possible to get those chain rings, it's just an example. It would look quite odd & the top gear would be ~50" for me this would mean the majority of those expensive gears are redundant. Perhaps run more than one chain ring and have a chain tensioner too, this would certainly increase your gear range but now money wise I would be getting a bit nervous.

I'd be interested to hear what your solution with the Alfine 11 was.
As good as Lance.

rand
Posts: 318
Joined: 5 Mar 2008, 6:38pm

Re: Ultra low gear with Alfine 11 spd hub?

Postby rand » 2 Sep 2012, 12:34pm

I feel I should let people know my current position.
My seventy five year old legs provide very little torque and my current lowest gear (I don't know what it is in terms of inches, but it's too high!) is 34t largest rear sprocket and 30t smallest chainring.
At the moment my rear mech is too near the ground for my liking and whilst mending front wheel punctures are easy (turn trike on side and no need to remove wheel, bliss) I dread having to repair puncture in rear wheel with all that rear mech dangling around while I'm holding the trike off the ground with one hand and trying to fiddle the wheel back with the other.
To make it easier for me to change rear wheel, I decided I should go down the hub geared route with two chainrings and I'm hoping that this arrangement could also give me a lower gear than I have at present.
I know nothing about gearing and ratios and have insufficient mental accuity to solve these problems myself and that is why I'm seeking advice from this forum.
I intend to contact Shimano with my problems, shortly and when I've collated sufficient relevant info I'll post it on to my local bike shop and ask them to make what they can of it.
If push comes to shove I might have to take the Rolhoff route but my wallet would scream in disbelief.

Rand.

Gearoidmuar
Posts: 2170
Joined: 29 Sep 2007, 7:35pm
Location: Cork, Ireland. Corcaigh, Éire má tá Gaeilge agat.

Re: Ultra low gear with Alfine 11 spd hub?

Postby Gearoidmuar » 2 Sep 2012, 2:05pm

Mick F wrote:I would think that it's not the gear ratio particularly, but the torque that limits it.

Bradley Wiggins could wreck a Rohloff even if it was within gearing spec.


From Sheldon Browne's site..
"We had more conversations about how low you could gear the hub, Rohloff have calculated that the maximum torque, that the hub will reliably withstand, is slightly more than could be produced by two world class athletes on a tandem using a 38 tooth chainring and a 16 tooth sprocket"

If B Wiggins twice a strong as world class athletes?

Doubt it..

User avatar
Mick F
Spambuster
Posts: 46728
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Ultra low gear with Alfine 11 spd hub?

Postby Mick F » 2 Sep 2012, 3:39pm

What about the other way round?
What about a 28t chainring and a 34t sprocket?
Mick F. Cornwall

User avatar
Tigerbiten
Posts: 1919
Joined: 29 Jun 2009, 6:49am

Re: Ultra low gear with Alfine 11 spd hub?

Postby Tigerbiten » 2 Sep 2012, 4:23pm

I hate to say this but fixing a punture with a hub gear can be more fiddly than with deraileur gears.
It just depends on how the gear cables attach to the hub.

I've the quick release fitting on my Rohloff, so its just undo one screw to remove the cables and then remove the wheel.
It still a little fiddly to get it back in as I have to line up the disk brake and reaction arm as the wheel slides back in.
Then reattach the gear quick release.
I find that easier than derailer gears as there not so much tension in the chain, so its easier to line the back wheel up as it slips into place.

I don't know how the Alfine hub fits so I don't know if its easier or harder than that.

Also the chain tensioner will still rest on the ground like a rear mech does.

From the sound of it you have a recumbent trike with a 20" back wheel ?????
If so then an Alfine 11 with a 20 tooth matched up with a compact double 38-24 or better still a triple 48-36-24 will give you the range you want.

Fatou
Posts: 185
Joined: 5 Apr 2009, 3:27pm

Re: Ultra low gear with Alfine 11 spd hub?

Postby Fatou » 2 Sep 2012, 4:54pm

rand wrote:I feel I should let people know my current position.
My seventy five year old legs provide very little torque and my current lowest gear (I don't know what it is in terms of inches, but it's too high!) is 34t largest rear sprocket and 30t smallest chainring.
At the moment my rear mech is too near the ground for my liking and whilst mending front wheel punctures are easy (turn trike on side and no need to remove wheel, bliss) I dread having to repair puncture in rear wheel with all that rear mech dangling around while I'm holding the trike off the ground with one hand and trying to fiddle the wheel back with the other.
To make it easier for me to change rear wheel, I decided I should go down the hub geared route with two chainrings and I'm hoping that this arrangement could also give me a lower gear than I have at present.
I know nothing about gearing and ratios and have insufficient mental accuity to solve these problems myself and that is why I'm seeking advice from this forum.
I intend to contact Shimano with my problems, shortly and when I've collated sufficient relevant info I'll post it on to my local bike shop and ask them to make what they can of it.
If push comes to shove I might have to take the Rolhoff route but my wallet would scream in disbelief.

Rand.


Perhaps an electric motorised hub or bike? Entry price £600 - £1000. If this is of some use then I'd suggest the pedelec forum.

I'd really like one for the commute.
As good as Lance.

Edwards
Posts: 5978
Joined: 16 Mar 2007, 10:09pm
Location: Birmingham

Re: Ultra low gear with Alfine 11 spd hub?

Postby Edwards » 2 Sep 2012, 5:21pm

I now wish I had shown you the setup on Mrs E's trike yesterday.

She has the Alfine 8 at the back and a triple at the front. I am not sure about the gear inches but it is possible to lower the bottom gear by using smaller MTB chain rings. If you do not have much leg strength and do not stamp on the pedals you should be alright.
I have used a rear derailleur as a chain tensioner as it was cheaper, a proper sprung tensioner would probably not be as low or as delicate.

I do dread a rear puncture and would think that a cycle helmet* could be used to hold up the rear in the event of removing the rear wheel. :wink: :lol:

Or anything else high enough (cooking pan)
Keith Edwards
I do not care about spelling and grammar

User avatar
Cunobelin
Posts: 9527
Joined: 6 Feb 2007, 7:22pm

Re: Ultra low gear with Alfine 11 spd hub?

Postby Cunobelin » 2 Sep 2012, 5:43pm

MY answer was a Schlumpf high speed drive.

With a 34 tooth on the front and a 13 on the back it is within the specs of the Rohloff.

I tend to do most of my town riding on the 34 and the top of the Rohloff, and the bigger 85t ring equivalent when the Schlumpf is changed gives me a range of high gears that allow me to accelerate on the flat.

User avatar
[XAP]Bob
Posts: 16917
Joined: 26 Sep 2008, 4:12pm

Re: Ultra low gear with Alfine 11 spd hub?

Postby [XAP]Bob » 2 Sep 2012, 5:46pm

I have thought about fitting a chainstay kickstand...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.