What chainring and rear cog for Rohloff?

For discussions about bikes and equipment.
slowster
Posts: 1805
Joined: 7 Jul 2017, 10:37am

Re: What chainring and rear cog for Rohloff?

Postby slowster » 20 Dec 2020, 4:34pm

GrahamJ wrote: I would get a new bike, so it could be 26" wheels

GrahamJ wrote:My current bike, as bought, was a 3x9 MTB with 27.5" wheels and 2.25" tyres and a 17-110 gear inch range. It's currently 2x9 and 22-32T front, 11-40T rear, so a 15-80 range, with 22:40 as the lowest ratio. There's quite a few Rohloff options that are suitable, even with 29" wheels.

I would suggest you think very carefully before switching to 26". If you are riding off-road on even slightly bumpy tracks, bigger wheels will roll better over the terrain and are more comfortable. I think it would be a mistake to choose a new bike with 26" wheels mainly or solely in order to get the gearing range you want combined with a Chainglider. I use 29" wheels with a Chainglider, and the generally more efficient top seven gears - including the most efficient gear 11 - are higher than I would like, but that is a compromise which works for me because the bottom gears are neverthless low enough for my needs and the benefits of the Chainglider for my very particular use of that bike outweigh the advantages of lowering the gearing range. If I were using the bike for longer distances and tours, then I would remove the Chainglider and lower the gearing (and make other changes).

Whatever you choose is likely to be a compromise. The important thing is to choose the optimum compromise for you and your riding.

GrahamJ
Posts: 13
Joined: 18 Nov 2020, 8:15am

Re: What chainring and rear cog for Rohloff?

Postby GrahamJ » 20 Dec 2020, 5:16pm

slowster (and Brucey), I am not going to base a decision about a bike on a Chainglider. When I said "...16.2 (which I find irritating)", I think I was interpreted as meaning I found the numerical discepancy irritating. I meant the impossibility of a Chainglider with a 15 inch gear was irritating (but no worse than irritating). Low gears are more important to me.

I live in NW Scotland, and cycle locally and on tours mostly in the West of Scotland, maybe 3/4 on hilly roads, 1/4 offroad, mostly estate tracks. I'm 61 and not very fit. I've used an MTB for touring since the 1990s, and it has gradually dawned on me that MTBs have evolved in a way I don't like, and that I can now afford a more custom bike. As it happens, my current bike is the first one that didn't have 26" wheels.

Brucey
Posts: 42204
Joined: 4 Jan 2012, 6:25pm

Re: What chainring and rear cog for Rohloff?

Postby Brucey » 20 Dec 2020, 5:29pm

my point was that if you use 35mm tyres on 559 rims the actual wheel size is a touch smaller (closer to 25" than 26") and you can have your 15 and a bit inch gear + chainglider cake and eat it too. But if you need that extra 1/2" of gear ratio, or want bigger wheel diameter, or fatter tyres, some other kind of compromise is necessary.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

tommydog
Posts: 278
Joined: 11 Feb 2017, 6:48pm

Re: What chainring and rear cog for Rohloff?

Postby tommydog » 20 Dec 2020, 5:56pm

Billy007 wrote: think the 44T or 46T would give you the higher gearing you are seeking but still be stiff enough on your 104 BCD 4 arm crank. I feel a 48T front chain ring is too big.


For chain covers may be you could look at something else which maybe wider allowing you to use it with the Thorn chain ring such as a Pashley or a Raleigh cover or maybe go onto a few German websites as they produce a lot more very good utility bikes than we do in the UK? Just suggestions. Yes it does seem strange that the Hebie Chainglider is quite narrow.


Thanks for your reply. You have given me a lot to think about. I am very tempted to try the 48T thorn and pick up one of these BMX rings in 46T:

https://specialites-ta.com/bmx/330-1538 ... ure,46-dts

I have emailed them regarding the BMX ring to ask how thick it is, but I suspect it will be thinner than the Thorn. I have personally never seen anything as thick as the Thorn. Also, I think If I want stuff from Europe, it's probably a good time to buy in now, just in case they start charging import duty after Brexit.

As for other Chain covers, I had a look at the Pashley, Hesling and a few for dutch bikes, but many of them look a real pain to fit, with no guarantees that they would fit my bike. The Hebie looks like the most straight forward option. One thing I meant to ask is, how much extra thickness to the chainring does the Hebie add after it is fitted? I ask this as I have a bottle holder on the downtube and need to measure up to see if everything still fits when the Hebie is fitted. I also like using Gopro mounts in strange places, so very interested to discover how much extra space the Hebie takes up?

slowster
Posts: 1805
Joined: 7 Jul 2017, 10:37am

Re: What chainring and rear cog for Rohloff?

Postby slowster » 20 Dec 2020, 6:41pm

GrahamJ wrote:I live in NW Scotland, and cycle locally and on tours mostly in the West of Scotland, maybe 3/4 on hilly roads, 1/4 offroad, mostly estate tracks. I'm 61 and not very fit. I've used an MTB for touring since the 1990s, and it has gradually dawned on me that MTBs have evolved in a way I don't like, and that I can now afford a more custom bike. As it happens, my current bike is the first one that didn't have 26" wheels.

My own approach was to determine first what my requirements were as regards geometry and tyre clearances, and then I trawled through the details of various frames which were suited to using a Rohloff without a chain tensioner and eliminated those which didn't meet the geometry and tyre clearance requirements. Maybe a similar methodology might work for you.

For the riding you describe, something like PH's Surly Ogre here might suit you.

GrahamJ
Posts: 13
Joined: 18 Nov 2020, 8:15am

Re: What chainring and rear cog for Rohloff?

Postby GrahamJ » 20 Dec 2020, 7:14pm

slowster wrote:My own approach was to determine first what my requirements were as regards geometry and tyre clearances, and then I trawled through the details of various frames which were suited to using a Rohloff without a chain tensioner and eliminated those which didn't meet the geometry and tyre clearance requirements. Maybe a similar methodology might work for you.


My methodology so far is to let Alee Denham do most of the trawling by buying his touring bicycle guide. I compare geometries at https://bikeinsights.com.

slowster wrote:For the riding you describe, something like PH's Surly Ogre here might suit you.

Surly Ogre vs my current bike:
https://bikeinsights.com/compare?geomet ... 0017726b66
Very similar, but in way, too similar: I want a longer chainstay, and the Ogre chainstay is only slightly longer. The Shand Tam Rohloff and the Thorn Nomad are better in this respect.

PH
Posts: 9786
Joined: 21 Jan 2007, 12:31am
Location: Derby
Contact:

Re: What chainring and rear cog for Rohloff?

Postby PH » 20 Dec 2020, 9:12pm

GrahamJ wrote:
slowster wrote:For the riding you describe, something like PH's Surly Ogre here might suit you.

Surly Ogre vs my current bike:
https://bikeinsights.com/compare?geomet ... 0017726b66
Very similar, but in way, too similar: I want a longer chainstay, and the Ogre chainstay is only slightly longer. The Shand Tam Rohloff and the Thorn Nomad are better in this respect.


I've been very pleased with the Ogre, I bought it with a fairly well defined idea of usage (Partly earning it's keep with Deliveroo) and it's fun enough to ride on a far wider range, I've even done a couple of Audax on it, though they haven't been my fastest. The Nomad was on the shortlist (I also have a Thorn Mercury) but I was swayed by being able to fit wider tyres to the Surly (it needed to be 700c so the wheels were interchangeable with the Merc) I have looked a couple of times at Shand, I like the look of them, but a lot of features and the geometry are not for me.
What other bikes are you looking at? If you're looking to treat yourself and the budget isn't too restricted, Tout Terrain have always looked a bit special to me.

colin54
Posts: 1486
Joined: 24 Sep 2013, 4:34pm

Re: What chainring and rear cog for Rohloff?

Postby colin54 » 20 Dec 2020, 9:24pm

tommydog wrote:
Billy007 wrote: think the 44T or 46T would give you the higher gearing you are seeking but still be stiff enough on your 104 BCD 4 arm crank. I feel a 48T front chain ring is too big.


For chain covers may be you could look at something else which maybe wider allowing you to use it with the Thorn chain ring such as a Pashley or a Raleigh cover or maybe go onto a few German websites as they produce a lot more very good utility bikes than we do in the UK? Just suggestions. Yes it does seem strange that the Hebie Chainglider is quite narrow.


Thanks for your reply. You have given me a lot to think about. I am very tempted to try the 48T thorn and pick up one of these BMX rings in 46T:

https://specialites-ta.com/bmx/330-1538 ... ure,46-dts

I have emailed them regarding the BMX ring to ask how thick it is, but I suspect it will be thinner than the Thorn. I have personally never seen anything as thick as the Thorn. Also, I think If I want stuff from Europe, it's probably a good time to buy in now, just in case they start charging import duty after Brexit.

As for other Chain covers, I had a look at the Pashley, Hesling and a few for dutch bikes, but many of them look a real pain to fit, with no guarantees that they would fit my bike. The Hebie looks like the most straight forward option. One thing I meant to ask is, how much extra thickness to the chainring does the Hebie add after it is fitted? I ask this as I have a bottle holder on the downtube and need to measure up to see if everything still fits when the Hebie is fitted. I also like using Gopro mounts in strange places, so very interested to discover how much extra space the Hebie takes up?

Hi Tommy, I just measured the chainwheel I replaced my Thorn one with, the steel ebay one I mentioned earlier, it is 2.5mm thick all over. I originally ran my chainglider with the Thorn chainring and it was indeed a bit draggy, but not particularly noticeable once underway, the thicker part of the Thorn ring is 5mm where the glider rubs. I can't say it bothered me that much whilst pedalling, it does some other people from what I read.
https://www.ebay.co.uk/itm/PB-Single-Sp ... 3b53fbe725
One sided and available up to 46teeth.
I'd ordered the one from ebay anyway and when it arrived fitted it, it gives about 1.5mm clearance from the chainglider sides in total,
initially I was disappointed to find that the side of the chainwheel still rubs lightly on the chainglider, as it skates/floats across the top of the chain when pedalling, I can notice this turning the pedal by hand, not so much whilst riding. I still have the Thorn one as a spare and would probably fit it with chainglider when I wear this one out . I've pressed the chainglider from the rear to show the clearance with the replacement ring, it normally sits rubbing lightly against the outer face of the chain ring whilst pedalling.
P1120175.JPG


I think there may be a case to be made for using the Thorn ring with a chainglider as you can see the chain links in the gap between the thin replacement ring and the glider ( picture), the Thorn ring would effectively seal off that gap and keep a bit more weather out, but the drag business might bother you more than it did me. A long mudflap keeps a bit more at bay.It only rubs on about a 2mm deep strip, you can just see the witness mark here(picture).
P1120182.JPG

The chainglider is 14mm wide over the chain ring and a similar distance horizontally from the line of the bottle cage (picture), if that's the information you were after.
I bought this bike second hand and gave the the transmission a bit of a birthday whist I was still keen ! All this what fits with what stuff is a bit of a headache isn't it ? Worth putting the effort in to get it how it suits you though.
https://www.ebay.co.uk/itm/PB-Single-Sp ... 3b53fbe725
Image Attachments
P1120188.JPG
Last edited by colin54 on 20 Dec 2020, 9:47pm, edited 1 time in total.

GrahamJ
Posts: 13
Joined: 18 Nov 2020, 8:15am

Re: What chainring and rear cog for Rohloff?

Postby GrahamJ » 20 Dec 2020, 9:47pm

PH wrote:I've been very pleased with the Ogre, I bought it with a fairly well defined idea of usage (Partly earning it's keep with Deliveroo) and it's fun enough to ride on a far wider range, I've even done a couple of Audax on it, though they haven't been my fastest. The Nomad was on the shortlist (I also have a Thorn Mercury) but I was swayed by being able to fit wider tyres to the Surly (it needed to be 700c so the wheels were interchangeable with the Merc) I have looked a couple of times at Shand, I like the look of them, but a lot of features and the geometry are not for me.
What other bikes are you looking at? If you're looking to treat yourself and the budget isn't too restricted, Tout Terrain have always looked a bit special to me.


Alee Denham likes the Tout Terrain (https://www.cyclingabout.com/2021-tout- ... to-detail/) but says the maximum tyre size is 2.1″ which seems a little bit limiting. I've looked at lots, including https://planetary14bikes.co.uk/ who build Rohloffs with cheaper frames.

tommydog
Posts: 278
Joined: 11 Feb 2017, 6:48pm

Re: What chainring and rear cog for Rohloff?

Postby tommydog » 21 Dec 2020, 12:13am

colin54 wrote: I replaced my Thorn one with, the steel ebay one I mentioned earlier, it is 2.5mm thick all over. I originally ran my chainglider with the Thorn chainring and it was indeed a bit draggy, but not particularly noticeable once underway, the thicker part of the Thorn ring is 5mm where the glider rubs.
I'd ordered the one from ebay anyway and when it arrived fitted it, it gives about 1.5mm clearance from the chainglider sides in total,
initially I was disappointed to find that the side of the chainwheel still rubs lightly on the chainglider, as it skates/floats across the top of the chain when pedalling, I can notice this turning the pedal by hand, not so much whilst riding.

I think there may be a case to be made for using the Thorn ring with a chainglider as you can see the chain links in the gap between the thin replacement ring and the glider ( picture), the Thorn ring would effectively seal off that gap and keep a bit more weather out, but the drag business might bother you more than it did me. A long mudflap keeps a bit more at bay.It only rubs on about a 2mm deep strip, you can just see the witness mark here(picture).
P1120182.JPG
The chainglider is 14mm wide over the chain ring and a similar distance horizontally from the line of the bottle cage (picture), if that's the information you were after.
https://www.ebay.co.uk/itm/PB-Single-Sp ... 3b53fbe725


Thank you vey much, this is all very useful information. I am starting to think there is no perfect solution when using the Chainglider and see what you mean about the gap, but then a thicker chainring will cause more drag. Out of interest, if you did not already have the Thorn as a spare and were starting from scratch - would the Ebay one be your first choice for use with the Chainglider? Secondly what sort of quality is the Ebay one? How is the wear? Would you trust it for a long tour?

I have to say, I am very tempted to pick up a 46T chainring from that Ebay listing. Or maybe the TA BMX one is a better bet below?
https://specialites-ta.com/bmx/330-1533 ... ure,41-dts
Last edited by tommydog on 21 Dec 2020, 9:58am, edited 1 time in total.

colin54
Posts: 1486
Joined: 24 Sep 2013, 4:34pm

Re: What chainring and rear cog for Rohloff?

Postby colin54 » 21 Dec 2020, 1:18am

tommydog wrote:
Thank you vey much, this is all very useful information. I am starting to think there is no perfect solution when suing the Chainglider and see what you mean about the gap, but then a thicker chainring will cause more drag. Out of interest, if you did not already have the Thorn as a spare and were starting from scratch - would the Ebay one be your first choice for use with the Chainglider? Secondly what sort of quality is the Ebay one? How is the wear? Would you trust it for a long tour?

I have to say, I am very tempted to pick up a 46T chainring from that Ebay listing. Or maybe the TA BMX one is a better bet below?
https://specialites-ta.com/bmx/330-1533 ... ure,41-dts

I think I would go with the Thorn one for it's reversability, and potential better weatherproofing, I think the total interference between guard and ring is only about one mm in width by a couple of mm depth how much actual drag
can that be ?
It's hard to say the quality of the ebay steel one , if you scroll all the way through the description it mentions it's suitability for Rohloff and electric drive & 'long life steel' ! . I've done about 500 miles with the new chainring, it still looked like new about a 100 miles ago when I put some wider tyres on for the winter, too early to tell really.
Billy 007's high mileage advice makes sense to me regarding the Thorn one. Eventually the two will wear together,
Good luck !

tommydog
Posts: 278
Joined: 11 Feb 2017, 6:48pm

Re: What chainring and rear cog for Rohloff?

Postby tommydog » 21 Dec 2020, 10:45am

colin54 wrote: I think I would go with the Thorn one for it's reversability, and potential better weatherproofing, I think the total interference between guard and ring is only about one mm in width by a couple of mm depth how much actual drag can that be ?


I am going to make a decision soon. Just waiting to hear back from Specialites TA what the thickness of the below chainrings are (although it's like banging your head against the wall, they just keep quoting me the chain size every time I ask what the thickness of the chainring material is!)
https://specialites-ta.com/bmx/330-1533 ... ure,41-dts

It seems from what you report, an optimum thickness for the chainring with the Hebie, may be around 3-4mm. It seems at 5mm, the Thorn maybe a little too thick.

colin54
Posts: 1486
Joined: 24 Sep 2013, 4:34pm

Re: What chainring and rear cog for Rohloff?

Postby colin54 » 21 Dec 2020, 11:30am

Brucey wrote:
I have not seen the inside of the latest type of chainglider, so I don't know if there is a lip which can be dressed easily or not. I suspect there is, but I don't know for sure.

cheers

Here's a picture I found of the interior, opened out like a leaf and a close up of one side in case it helps (new this year).
P1140398.JPG

P1140397.JPG

Billy007
Posts: 57
Joined: 15 Apr 2020, 8:56am

Re: What chainring and rear cog for Rohloff?

Postby Billy007 » 21 Dec 2020, 3:24pm

tommydog wrote:
colin54 wrote: I think I would go with the Thorn one for it's reversability, and potential better weatherproofing, I think the total interference between guard and ring is only about one mm in width by a couple of mm depth how much actual drag can that be ?


I am going to make a decision soon. Just waiting to hear back from Specialites TA what the thickness of the below chainrings are (although it's like banging your head against the wall, they just keep quoting me the chain size every time I ask what the thickness of the chainring material is!)
https://specialites-ta.com/bmx/330-1533 ... ure,41-dts

It seems from what you report, an optimum thickness for the chainring with the Hebie, may be around 3-4mm. It seems at 5mm, the Thorn maybe a little too thick.


Here is the information you need about Hebie Chainglider specs. It's fairly easy to find .................

https://www.hebie.de/en/protection/chai ... lider/350/

I think if I were buying again I would still buy a Thorn chain ring again, to go with the Chainglider. Reading with interest other contributors' valuable experiences on this thread, I think I would rather have as little gap as possible between the chain glider casing and the chain ring to keep crud out. When I remove the glider from my bike the chain is very clean. The reason I bought the Chainglider was to keep the chain clean and minimise maintenance which it has done. A little drag at the start was a little irritating, but once I put a few miles on the bike it gradually disappeared. I suppose if you were that bothered you could take the ring to a machine shop and they could take 0.5 - 1mm off the thickness of the Thorn chain ring where the Chainglider casing sits. Possibly.

tommydog
Posts: 278
Joined: 11 Feb 2017, 6:48pm

Re: What chainring and rear cog for Rohloff?

Postby tommydog » 21 Dec 2020, 4:59pm

Billy007 wrote:
Reading with interest other contributors' valuable experiences on this thread, I think I would rather have as little gap as possible between the chain glider casing and the chain ring to keep crud out. When I remove the glider from my bike the chain is very clean. The reason I bought the Chainglider was to keep the chain clean and minimise maintenance which it has done. A little drag at the start was a little irritating, but once I put a few miles on the bike it gradually disappeared. I suppose if you were that bothered you could take the ring to a machine shop and they could take 0.5 - 1mm off the thickness of the Thorn chain ring where the Chainglider casing sits. Possibly.


You may be interested to hear that I heard back about Specialities TA BMX Chain ring, and they confirmed that it is 4mm thick. Therefore this may work very nicely with the Chainglider for a relatively tight fit. It's thicker than the Surly and the Ebay listing, but 1mm thinner than the Thorn. I am very tempted to get it:

https://specialites-ta.com/bmx/330-1536 ... ure,44-dts

I have no experience of Specialties stuff, but have read a few positive things about them. Do you think it's worth a punt, as on paper it looks like it may work quite well with the Chainglider?