Author Topic: What's your Rohloff combo (chainring, cog)?  (Read 169511 times)

Matt2matt2002

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #285 on: May 01, 2017, 05:32:11 pm »
Very interesting insights to be gleaned here, reading all of these varied approaches to the problem of how best to get up and down hills.


Of course the gearing is crucial and very personal but while in Sri Lanka last year ( 37*17 on my Raven) I began to engage with the hills on a mental level.

Bear with me...

It was a case of embracing the slopes/hills. There were 3 of us in the equation.

My bike/weight/gearing.
The hill/headwind/slope.
And me/my physical condition/fitness.

I endeavoured to balance the three issues.
It was a mental thing as well as the physics.

Does anyone else talk to themselves while riding? Or talk to their bike? Or the hill?

Well, it got me up them in a happy mood.
 ;)
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Pavel

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #286 on: May 01, 2017, 06:32:43 pm »
Very interesting insights to be gleaned here, reading all of these varied approaches to the problem of how best to get up and down hills.




Of course the gearing is crucial and very personal but while in Sri Lanka last year ( 37*17 on my Raven) I began to engage with the hills on a mental level.

Bear with me...

It was a case of embracing the slopes/hills. There were 3 of us in the equation.

My bike/weight/gearing.
The hill/headwind/slope.
And me/my physical condition/fitness.

I endeavoured to balance the three issues.
It was a mental thing as well as the physics.

Does anyone else talk to themselves while riding? Or talk to their bike? Or the hill?

Well, it got me up them in a happy mood.
 ;)


Such an excellent point!  Yes, yes and yes.  I need to find ways of fooling myself into loving hills - where the reality is probably otherwise.  But much of the time making a game of it, or talking to myself, really does the trick.

I don't have a single thing I use, but sort of a range of several different mental activities, which when they work well really help both the climb as well as the enjoyment of the whole day.

long ago there used to be a Canadian commercial for a concept called participAction.  Funny now, I can't remember how it went, but I used to play that over and over and spin to the cadence of the song in my mind, the way they said the word over and over.  It was almost like a trick to get me slightly hypnotized. I sort of know I'm straining but the pain and in fact all of what I'm doing sort of disapears into the distance, as if I were in a slow moving memory.  Sounds odd to describe, but it worked for me.

I also sometimes used to focus and be aware of the muscles and how they were working, and working in tandem with the breathing.  It's almost as if I could slip into a slow moving world again, where I could feel the individual muscles pushing or not pushing.  That is one reason why I've always liked to be clipped-in.  It may be an illusion, but I can get into a zone where I can minutely change up how much I use the different muscles in slightly different ways, resulting in a bit of rest while I'm still full steam ahead, but mostly I think the benefit for me is purely mental, where it takes me out of the pain, and everything slows down.  It used to work a lot better when I used to run because a track is perfectly predictable, and not as well with cycling because I snap out of my trance at every odd thing in front of me - potholes, tree branches, cars etc all make it hard to stay "in the zone". But still.

and then of course there are a few other things, like pretending some announcer is commenting in a fast auctioneer sort of way on the details of my bicycling form - but now the rain has stopped, the sun is out, and Mexican food for lunch awaits at a nearby restaurant. :)

This is a great subject to bring up to touch on Matt ... I'd love to hear more on this if anyone else has any tips on the mental aspect of taming the less favored aspects of our hobby/sport.


Matt2matt2002

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #287 on: May 01, 2017, 07:29:27 pm »

This is a great subject to bring up to touch on Matt ... I'd love to hear more on this if anyone else has any tips on the mental aspect of taming the less favored aspects of our hobby/sport.

You summed up my thoughts exactly.
Should we start a new thread?
Never drink and drive. You may hit a bump  and spill your drink

Pavel

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #288 on: May 01, 2017, 09:31:08 pm »
Yup.  Pronto.

John Saxby

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #289 on: May 01, 2017, 10:38:58 pm »
Pavel, like you & Dave I find it easier to spin up hills at a higher RPM than I'd normally use on the flats.  To do so, though, I had to reduce my original 38 x 17 combination on my Raven to 36 x 17.  So far, that has been fine, the biggest test coming in the Rockies and Cascades last June/July.

I love the high places, and getting there by bike means climbing hills.  I don't especially like climbing and I'm not much into the Challenge Yerself thing, but I don't shy away from the hills, even the big 'uns, now that I have a good ratio.  It's possible that I'll change to a smaller chain ring (35T, or 34T) in the years ahead--that will depend on the places I go, and my reserves.

Going slowly up the climbs in the western mountains last year, Matt, I found myself doing a mix of talking/singing to myself; reminding myself to just keep the front wheel in line by looking a few yards ahead (and not getting distracted by motorists in the mirror); and on occasion, just stopping to eat, admire the view, watch the butterflies, etc. Lots of opportunities to pause on those looong western slopes.

Last week I was riding in the Gatineau Hills across the river for the first time since early November last year (photos and notes to come in a day or two, especially if the rain continues.)  One of the days was April 25, ANZAC Day and Italian Liberation Day.  In tribute, I was singing (after a fashion) Eric Bogle's great anti-war song, "And The Band Played Waltzing Matilda". John McDermott gives a touching performance, here: https://www.youtube.com/watch?v=VktJNNKm3B0

PeteG

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #290 on: March 12, 2018, 09:51:24 pm »
Quote
While, like George (Mickeg), I would never advise anyone positively to breach the warranty conditions on such an expensive component, I'll tell you what I would do, in consideration of the above: First, I'd keep the supplied sprocket of 16T and run it with a cheap, probably steel, but permitted chainring until after the box is proven. By this I don't mean run in; as the great Chalo Colina said, a Rohloff box runs in at the kind of mileage where a Shimano hub gearbox lies down and dies (I trashed a couple before 5000m). What I mean is that you have to understand that there's quite a bit of hand-fitting in a Rohloff, so it rubs in the gears in the first couple of thousand miles (you'll see quite a bit of ground steel come out in the first oil change -- use a magnet in the dirty oil to see it, or rub the dirty oil between your fingers to feel it). This is also the time when, if it will break, it will break, so you may want it replaced under warranty. After a couple of thousand miles or after the first service at three thousand miles I'd buy the chainring I really wanted and fit it regardless because the chances are that, unless one abuses the box grotesquely, one won't ever require warranty service.

Well, it's been 22 months and one oil change ( another one not far off ) later and I think I'll try swapping from 42x17 to 38x17, as I'd much prefer an 18-95" range than the current 20-105". I simply never use gear 14 on my 29er mtb; not even on the road, going downhill. I climb some pretty steep hills, and while my lowest gear has worked ok, I like the idea of having one in reserve  :)

Of course, it doesn't hurt that I'm now 1kg under that cursed 100kg weight limit of Rohloff's.

Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #291 on: March 13, 2018, 12:30:41 am »
Great to hear from you, Pete.

38x17 is now permitted, but you could do even better than that within the current warranty terms, if you really want to go stump-pulling.

From https://www.rohloff.de/?id=1349&L=1:
"To prevent overstraining the hub, a minimum sprocket ratio of 1.9 must be used. With the available sprockets these minimum possible sprocket ratios are:
~32/17, ~30/16, ~28/15 and ~26/13. ... Larger chainrings can be used without exceptions."

In gear 1, the limit is the lowest speed at which you can keep your balance.

A consideration in the choice of chainrings and sprockets you now hear quite often is whether there is a Hebie Chainglider that fits the chainring/sprocket combo.
« Last Edit: March 13, 2018, 05:38:59 am by Andre Jute »

mickeg

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #292 on: March 13, 2018, 12:47:12 am »
Quote
While, like George (Mickeg), I would never advise anyone positively to breach the warranty conditions on such an expensive component, I'll tell you what I would do, in consideration of the above: First, I'd keep the supplied sprocket of 16T and run it with a cheap, probably steel, but permitted chainring until after the box is proven. By this I don't mean run in; as the great Chalo Colina said, a Rohloff box runs in at the kind of mileage where a Shimano hub gearbox lies down and dies (I trashed a couple before 5000m). What I mean is that you have to understand that there's quite a bit of hand-fitting in a Rohloff, so it rubs in the gears in the first couple of thousand miles (you'll see quite a bit of ground steel come out in the first oil change -- use a magnet in the dirty oil to see it, or rub the dirty oil between your fingers to feel it). This is also the time when, if it will break, it will break, so you may want it replaced under warranty. After a couple of thousand miles or after the first service at three thousand miles I'd buy the chainring I really wanted and fit it regardless because the chances are that, unless one abuses the box grotesquely, one won't ever require warranty service.

Well, it's been 22 months and one oil change ( another one not far off ) later and I think I'll try swapping from 42x17 to 38x17, as I'd much prefer an 18-95" range than the current 20-105". I simply never use gear 14 on my 29er mtb; not even on the road, going downhill. I climb some pretty steep hills, and while my lowest gear has worked ok, I like the idea of having one in reserve  :)

Of course, it doesn't hurt that I'm now 1kg under that cursed 100kg weight limit of Rohloff's.

For my Iceland trip I ran 36 and 16, that gave me 16.5 to 86.5 gear inch range.  The lowest gear was perfect, I wished I had higher gears a couple times when I spun out going down long shallow hills, but I would not have traded my lowest gear for any higher ones.  Thus, that was the closest to the perfect range that I could have gotten for that trip. 

If I had any gears that were lower, I would not have been able to sustain pedaling fast enough on any tall hills to go fast enough to maintain vertical and directional stability.  That is why I say the lowest gear was perfect, any lower would have been too low for me to use.

PeteG

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #293 on: March 13, 2018, 10:38:46 am »
I don't believe I'd ever want more than 90" on this bike, so a spread of 17-90" is very appealing ( either 34x16 or 32x15 ), and more ground-to-chainring clearance would also be nice.

Despite those gears still giving me a ratio of about 2.12/3, I guess I'm still cautious, due to my 99kg being so close to that warranty limit. I do wish Rohloff could be more clear, as I wouldn't suddenly generate tandem-level amounts of torque, simply by gaining 2kg :)

mickeg

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #294 on: March 13, 2018, 05:10:00 pm »
I don't believe I'd ever want more than 90" on this bike, so a spread of 17-90" is very appealing ( either 34x16 or 32x15 ), and more ground-to-chainring clearance would also be nice.
...

What kind of crankset would you use that has a 32?  A 34 is pretty easy to set up on a five arm 110 mm BCD crank, but I don't know what kind of crank would work with a 32?

I run chainrings and sprockets that have even numbers of teeth.  I cut a small notch in one tooth on each and I always put my chains on so that a link with outer plates is on that notched tooth.
https://www.sheldonbrown.com/chain-life.html

After a while, dirt fills in the notch, I later used a bit of nail polish to mark that tooth too so it is easier to find.

PeteG

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #295 on: March 13, 2018, 05:51:16 pm »

What kind of crankset would you use that has a 32?  A 34 is pretty easy to set up on a five arm 110 mm BCD crank, but I don't know what kind of crank would work with a 32?


It's a 4 arm 104bcd crankset.

AndrewJ

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #296 on: August 22, 2021, 09:03:01 pm »
I'm bumping this thread to stay relevant to the previous discussions... which appeared to be suggested practice.

As a heavier rider, and still new Speedhub owner, I'm wondering specifically about the admonition of not dropping below a 2.5 sprocket ratio (still posted on Rohloff site). I'm at 105 Kg, and think I want to move from a 46:17 (2.706) to a 46:19 (2.421) for good touring gearing range. That's a bit below the 2.5 warranty limit for a heavy rider... but in practical riding, what do you long-term owners think? The jump from lowest recommended ratio of 1.9 for a 99 Kg rider to 2.5 ratio for a 101 Kg rider tells me there's got to be some middle ground in there.

Yes, I prefer larger chainrings and cogs, and want to stick with an odd cog. Also, am running fat/tall 700x45 tires.
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mickeg

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #297 on: August 22, 2021, 10:10:13 pm »
I am not going to try to justify the specific numbers that Rohloff set, but the broad concept applies that if you push too hard on mechanical components like spur gearing, too much torque can damage the innards.  Rohloff chose to base it on the weight of the rider, which makes some sense.

I am sure that they could have come up with a more appropriate equation that also takes into account wheel diameter and crank arm lengths.  Or maybe also factor in the steepest uphill grade and total weight on the bike?  But there is merit to setting a criteria that is based solely on a binary criteria that does not involve using a calculator, that is a hard one for the user to get wrong.


Andre Jute

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #298 on: August 22, 2021, 10:27:45 pm »
How new a Speedhub owner, Andrew, in time and distance both, if you please? It makes a difference to sensible advice.

The assumption is that, absent abuse, a Rohloff that hasn't broken in a few thousand kilometers probably won't break soon or maybe even at all. Probably. Herr Rohloff has also been known to extend the warranty almost indefinitely for those who keep up the service schedule (though there have been recent rumblings from Rohloff HQ about that liberal warranty policy}, and that's a value if you plan on heavy touring in distant places.

So, if your Rohloff is out of warranty, and you've done a few thousand kilometers, and you aren't planning to do loaded touring in places where a horse-shoeing smithy is cutting edge tech, you may be glad to hear that there is a suspicion abroad that Herr Rolloff is covering his backside with an overly safe permitted gear ratio, that operation a small bit lower won't harm the gearbox.

It's your money, so you must make the final decision, or postpone it until you the parameters I outlined.

AndrewJ

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Re: What's your Rohloff combo (chainring, cog)?
« Reply #299 on: August 22, 2021, 10:57:14 pm »
How new a Speedhub owner, Andrew, in time and distance both, if you please? It makes a difference to sensible advice.
Ah, the Speedhub itself is probably five or six years old (a tale of woe wherein a builder procured it for a friend, took money for a frame, never delivered, and said friend had to hire Doug & Dinsdale to fetch the hub). It came to me with a threaded 16T cog, and I am the first one riding it, after building up the frame last month. So, it has still less than 500 km on it.

I appreciate your comments, and with an Engineering background, I understand well the factors or torque and materials fatigue on a complex & precise system like this IGH. I feel that being 5% over the weight tier I am probably within an acceptable safety factor to go with a ratio that is 3.2% under the tiered ratio, as long as I treat the unit with due respect while climbing. But as I'm new to it all, appreciate comments from those who know it the best.
« Last Edit: August 22, 2021, 11:05:36 pm by AndrewJ »
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