Capacity of Rohloff tensioner for two chain rings
Capacity of Rohloff tensioner for two chain rings
Does anyone happen to know how to translate a capacity of 10 links into what two chainrings I could use with a Rohloff?
I have an ICE Sprint and have just moved to the Staffordshire Moorlands. The Peak District starts about 3 miles away and there are loads of rather steep hills such that the 526% range of the Rohloff is no longer sufficient. Yes I could gear it down but then I would spin out on the downhill sections. The easiest solution would be two chainrings up front. Hence the question as to what a 10 link capacity means. Is it as simple as, for example, a 34-44 set of rings?
Have a good evening, Lodge
I have an ICE Sprint and have just moved to the Staffordshire Moorlands. The Peak District starts about 3 miles away and there are loads of rather steep hills such that the 526% range of the Rohloff is no longer sufficient. Yes I could gear it down but then I would spin out on the downhill sections. The easiest solution would be two chainrings up front. Hence the question as to what a 10 link capacity means. Is it as simple as, for example, a 34-44 set of rings?
Have a good evening, Lodge
Re: Capacity of Rohloff tensioner for two chain rings
Not cheap, but my solution for the HP Velotechnik Gekko was a Schlumpf HSD paired with the Rohloff
It is a brilliant piece of kit.
I have a 32 T front chainring, and with a click of the heel it becomes an 85 T chainring
[youtube]z5auAfwWesc[/youtube]
NO change in chain tension or length, which makes it so simple
It is a brilliant piece of kit.
I have a 32 T front chainring, and with a click of the heel it becomes an 85 T chainring
[youtube]z5auAfwWesc[/youtube]
NO change in chain tension or length, which makes it so simple
- Tigerbiten
- Posts: 2503
- Joined: 29 Jun 2009, 6:49am
Re: Capacity of Rohloff tensioner for two chain rings
The 10 link limit is not the max capacity of the tensioner.
I run a 38-55 double with it on my Sprint without any troubles.
If your running a double then the large ring wants to be 1.466 times the small ring.
Starting from a 34 inner, I'd go for a 50 outer as this is exactly 3 gears difference between rings.
This will give you 17 unique gears.
I found this makes changing at the front better as all the steps are even.
Luck ........
I run a 38-55 double with it on my Sprint without any troubles.
If your running a double then the large ring wants to be 1.466 times the small ring.
Starting from a 34 inner, I'd go for a 50 outer as this is exactly 3 gears difference between rings.
This will give you 17 unique gears.
I found this makes changing at the front better as all the steps are even.
Luck ........
Re: Capacity of Rohloff tensioner for two chain rings
this
http://www.ritzelrechner.de/?GR=RLSH&KB=32,44&RZ=16&UF=2215&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=RLSH&KB2=30,44&RZ2=16&UF2=2215
compares 32-44 and 30-44 chainrings. The latter gives a 3 gear difference with a front shift and creates 17 ratios similar to Tigerbiten's suggestion. The former half-steps the 14% gears in the mid range, giving a slightly narrower range but more unique ratios, which you might prefer if you are fussy about cadence.
I think that a more extreme range of gears than that would be possible. It may be that '10 links' means up to a 20T difference in the chainrings.
cheers
http://www.ritzelrechner.de/?GR=RLSH&KB=32,44&RZ=16&UF=2215&TF=90&SL=2.6&UN=MPH&DV=gearInches&GR2=RLSH&KB2=30,44&RZ2=16&UF2=2215
compares 32-44 and 30-44 chainrings. The latter gives a 3 gear difference with a front shift and creates 17 ratios similar to Tigerbiten's suggestion. The former half-steps the 14% gears in the mid range, giving a slightly narrower range but more unique ratios, which you might prefer if you are fussy about cadence.
I think that a more extreme range of gears than that would be possible. It may be that '10 links' means up to a 20T difference in the chainrings.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
- Tigerbiten
- Posts: 2503
- Joined: 29 Jun 2009, 6:49am
Re: Capacity of Rohloff tensioner for two chain rings
I worked out the most extreme legal Rohloff range without a Schlumpf drive was using a 26/38/56 triple and a 13 sprocket.
Thats an extra 6 gears or a 1136% range, 10.4"-118" on a 20" wheel.
I went the Schlumpf HSD route for a 1900% range, 9.4"-179.4".
I tried a 38/53 double for a 2.5 gear step with my first set of chainrings, but didn't find the half step that useful.
Realistically only the gears above ~70" gain from being half stepped, but they're the gears not half stepped due to the offset overlap ......
I find the 38/55 almost setup feels a lot more natural as you get used to the size of the steps.
I'd run a 38/56 true 3 step setup, but the chain would foul the chainguard when shifted.
Thats an extra 6 gears or a 1136% range, 10.4"-118" on a 20" wheel.
I went the Schlumpf HSD route for a 1900% range, 9.4"-179.4".
I tried a 38/53 double for a 2.5 gear step with my first set of chainrings, but didn't find the half step that useful.
Realistically only the gears above ~70" gain from being half stepped, but they're the gears not half stepped due to the offset overlap ......
I find the 38/55 almost setup feels a lot more natural as you get used to the size of the steps.
I'd run a 38/56 true 3 step setup, but the chain would foul the chainguard when shifted.
Re: Capacity of Rohloff tensioner for two chain rings
Many thanks for the replies. Much appreciated.
I've currently run a 16 rear to 34 front but have a 44 in stock so could give this a try for no cost. Then get a front derailleur if it works. This would give me two more gears. If the tensioner would stretch to a 50 this gives three more as suggested earlier by Tigerbiten.
Next question then is whether I can increase to 18 teeth at the rear with a new-design Rohloff splined carrier. I'd have to move the tensioner out slightly with the longer bolt but that's doable. 34-18 is just about on the 1.9 minimum ratio limit specified by Rohloff. Mind you, being recumbent and in my 60's I'm unlikely to stress the hub too much so could go to illegal ratios if need be. It's all down to whether the tensioner can take larger sprockets.
The Ritzelrechner gear calculator is really nice - many thanks Brucey!
I've currently run a 16 rear to 34 front but have a 44 in stock so could give this a try for no cost. Then get a front derailleur if it works. This would give me two more gears. If the tensioner would stretch to a 50 this gives three more as suggested earlier by Tigerbiten.
Next question then is whether I can increase to 18 teeth at the rear with a new-design Rohloff splined carrier. I'd have to move the tensioner out slightly with the longer bolt but that's doable. 34-18 is just about on the 1.9 minimum ratio limit specified by Rohloff. Mind you, being recumbent and in my 60's I'm unlikely to stress the hub too much so could go to illegal ratios if need be. It's all down to whether the tensioner can take larger sprockets.
The Ritzelrechner gear calculator is really nice - many thanks Brucey!
- Tigerbiten
- Posts: 2503
- Joined: 29 Jun 2009, 6:49am
Re: Capacity of Rohloff tensioner for two chain rings
I assume you have a 110mm BCD crank as a 44/30 double would be ideal with the 16 sprocket.
A 34/18 combo is fine.
But I've run a 38/21 combo, 1.8 ratio, for the last 7 years due to the Schlumpf HSD spider being 130mm.
So a 34/19 combo is also probably ok, but at your own minimal risk ......
The 19 sprocket is really the max size for the chain tensioner as I find the 21 sprocket is a fraction big because the sprocket teeth just touches the top jockey wheel teeth.
Ps:- I've found that "SJS Cycles" is the place for Rohloff spares.
A 34/18 combo is fine.
But I've run a 38/21 combo, 1.8 ratio, for the last 7 years due to the Schlumpf HSD spider being 130mm.
So a 34/19 combo is also probably ok, but at your own minimal risk ......
The 19 sprocket is really the max size for the chain tensioner as I find the 21 sprocket is a fraction big because the sprocket teeth just touches the top jockey wheel teeth.
Ps:- I've found that "SJS Cycles" is the place for Rohloff spares.
Re: Capacity of Rohloff tensioner for two chain rings
SJS have good stocks and good knowledge too. However Rohloff spares are distributed in the UK by Ison distribution, so if you know what you want, any convenient LBS with an Ison account can order in the bits you need.
cheers
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Re: Capacity of Rohloff tensioner for two chain rings
Sorry if it's stating the obvious, there are other tensioners available. I ran a Rohloff hub with an Alfine* tensioner for a while, though only with a single ring, worked fine and the front capacity is stated as 16 T.
* There's more than one version, I think it was this one
https://www.bike-discount.de/en/buy/shi ... DIEALw_wcB
EDIT - I assumed you needed to buy the tensioner, then realised on the ICE you probably already have it... if you do change there's a ready market for s/h Rohloff tensioners.
* There's more than one version, I think it was this one
https://www.bike-discount.de/en/buy/shi ... DIEALw_wcB
EDIT - I assumed you needed to buy the tensioner, then realised on the ICE you probably already have it... if you do change there's a ready market for s/h Rohloff tensioners.
- Tigerbiten
- Posts: 2503
- Joined: 29 Jun 2009, 6:49am
Re: Capacity of Rohloff tensioner for two chain rings
I found the Alfine tensioner had the wrong chain line.
It's easier just to use a rear derailleur because you can match the cage length to your chainrings, ie: long cage with a 56/38/26 triple.
Just replace the top/bottom limit screws with longer ones and screw them both in until the cage becomes locked on the correct chain line.
It's easier just to use a rear derailleur because you can match the cage length to your chainrings, ie: long cage with a 56/38/26 triple.
Just replace the top/bottom limit screws with longer ones and screw them both in until the cage becomes locked on the correct chain line.
Re: Capacity of Rohloff tensioner for two chain rings
An update...
The proof of concept worked so I've obtained a 50 tooth 104 mm BCD Middleburn chainring to go with my existing 34 tooth Surly on the Hope crankset. Also managed to get a 19 tooth Thorn threaded Rohloff sprocket so no need to adjust the alignment of the tensioner. Added in a Shimano derailleur and a SRAM twist shifter with long grip similar to that of the Hase Rohloff on the other side and it all works well. I now have the options of 19/34 and 19/50 i.e. two gears lower than I used to have for (relatively) easy climbing of gradients greater than 10%, plus one gear higher for downhill use. The Rohloff tensioner handles the 16 tooth difference easily.
A Schlumpf would have been nice in theory but at over £500 plus the need to machine the bottom bracket and junk the rather nice 165 mm Hope crankset I wasn't going there. At least not for the foreseeable; opinions can change of course. Perhaps the Hope could be transferred to one of the other machines...
Anyway - many thanks to you all for the advice and help. It is very much appreciated. Now if it would only stop raining...
The proof of concept worked so I've obtained a 50 tooth 104 mm BCD Middleburn chainring to go with my existing 34 tooth Surly on the Hope crankset. Also managed to get a 19 tooth Thorn threaded Rohloff sprocket so no need to adjust the alignment of the tensioner. Added in a Shimano derailleur and a SRAM twist shifter with long grip similar to that of the Hase Rohloff on the other side and it all works well. I now have the options of 19/34 and 19/50 i.e. two gears lower than I used to have for (relatively) easy climbing of gradients greater than 10%, plus one gear higher for downhill use. The Rohloff tensioner handles the 16 tooth difference easily.
A Schlumpf would have been nice in theory but at over £500 plus the need to machine the bottom bracket and junk the rather nice 165 mm Hope crankset I wasn't going there. At least not for the foreseeable; opinions can change of course. Perhaps the Hope could be transferred to one of the other machines...
Anyway - many thanks to you all for the advice and help. It is very much appreciated. Now if it would only stop raining...