Thorn Cycles Forum
Community => Rohloff Internal Hub Gears => Topic started by: Andre Jute on August 15, 2021, 11:50:41 am
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JohnR wrote in another thread:
Perhaps the Rohloff hub is slightly less efficient than a derailleur system in optimum condition, but for how long does that condition continue unless the rider is a fanatic who diligently cleans the drivetrain after each ride?
I'm not so sure that even "a fanatic who diligently cleans the drivetrain after each ride" can reverse Time.
Take two bikes, a Rohloff and a derailleur, which are both new and factory spotless, and tuned by the finest mechanic. Put them on the street. Ride them.
The Rohloff may start out fractionally less efficient than the derailleur; we have laboratory evidence for that. Everyone can decide for themselves whether they want to consider the difference significant. I find it risible that serious people should waste their time on differences that on the road will disappear within a few miles.
But, when the bikes return from the ride, the Rohloff is in exactly the same condition as when it left, and the derailleur bike's efficiency starts to degrade the moment you ride it. The longer the ride, the more the more the derailleur bike's efficiency degrades.
In addition, you can fit a Hebie Chainglider to the Rohloff, which keeps the chain in its initial, most efficient condition, whereas you cannot fit a Chainglider to the derailleur bike, and dirt on the chain adds to the derailleur's relative inefficiency compared to the Rohloff, cumulatively as the miles mount up.
And, no matter how the owner cleans the derailleur bike, the damage done by the grinding paste of dust and oil accumulates and undermines its ride-on-ride efficiency, whereas the Rohloff, if properly serviced, merely runs in and becomes more efficient.
And that's on tarmac. Off the blacktop, the process of differentiation by grinding paste accelerates in favour of the Rohloff. And in mud, which the Rohloff was designed for (also for sand on the beach which ruined Bernd and Barbara Rolloff's derailleur bikes on their honeymoon), there's obviously zero comparison.
I fail to believe that there's a general case that derailleurs even in exceptional circumstances (a short ride when brand-new?) are more efficient than a Rohloff almost anywhere outside a laboratory. It's an argument about how many angels can dance on the head of a pin.
As for the foolish argument (reported by Moronic from the net) that the Rohloff seals are a drag curbing one's speed on the downhills, on the steep downhills of West Cork, members of the peloton who tried to race me arrived where I waited for them at the bottom of the hill with white lines of fear around their mouths while I laughed with the exhilaration of speed. Come again, boys!
Once you admit the inescapable logic above, you need a wholelotta faith to believe in the greater efficiency of derailleurs in any but the shortest term.
DISCLAIMERS: Rohloff hasn't paid me anything (yet). Since we're all so woke and bicyclesexual now: we respect your right to ride on derailleurs even if only to honour the history of the bike, or because you already paid for the derailleur bike, or because you like the precision of your gear changes, or because the bike belonged to your dad, or because you think it goes faster, or because you look cool on it. Any reason will do, as long as it is your reason. We also respect your right to practice scientism rather than science, but please don't do it near me as I'm allergic to the whiff of corruption.
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Though I am a convinced hub gear fan, I'm not quite so sure as André that derailleurs always quickly become less efficient than a Rohloff.
There is some evidence that even derailleur systems improve slightly after use, the difference is that this happens after a couple of hundred kilometers in clean, dry conditions, and declines fairly steadily afterwards with wear.
A Rohloff takes several hundred or several thousand kms of use to wear in and improve, and (AFAIK) stays at peak efficiency for a very long time if the oil change procedure is respected. A chain drive on a Rohloff is subject to similar wear to a derailleur chain, but this happens more slowly because the chain is (usually) always perfectly aligned and (again usually) doesn't have to bend around tensioner pulleys.
And, as André says, to keep the external parts of the system fairly clean, it is generally possible to fit a Chainglider to a hub-geared bike, thus significantly extending the useful life of chain/chainring and sprocket, at least in temperate European conditions.
What does seem clear to me is that a reliable hub gear system (some models aren't) requires much less maintenance than a derailleur system. This isn't much of an issue for a Sunday racer who only rides in clean, dry conditions, but is much more important for all-weather commuting, long-distance touring and other uses which involve bad weather, dusty tracks or suchlike.
My benchmark for comparing derailleur and hub gearing is my last long tour on a derailleur bike. 3,300 kms with an old mountain bike converted with pannier racks and drop bars. The first chain lasted about 900 kms on the original factory lube without any need for cleaning or lubrication - during this time the weather was dry, and I only did a few kms on stony tracks, there would have been no advantage using a hub gear for that part of the trip. Then the weather changed, with light to moderate rain washing sand and grit onto the minor roads I was using, 300 kms further on the chain was well worn, so to preserve the sprockets and chainrings I replaced it with a new one, cleaning the multiple sprockets, chainrings and derailleur pulleys as best I could. The new chain only lasted a few hundred kms before a combination of wet weather followed by riding on dry, dusty tracks caused excessive wear. Same for the third chain, a combination of wet weather and mild off-road riding had it skipping on the smallest sprocket after a few hundred kms. And the fourth one was completely worn out by riding on sandy cycle tracks in wet weather while riding home along the Atlantic coast of France.
With a hub gear, I might have used the same number of chains, though I somehow doubt it. In any event, it is much easier to wipe one chainring and one sprocket clean while on tour rather than trying to get the muck off a triple chainring and 7-speed cassette. From subsequent experience using a hub geared bike with a Chainglider for intensive winter survey work in wet and muddy conditions I reckon I could have probably done the same tour with a Rohloff and Chainglider and running one new chain on just the factory lube for the entire tour.
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Transmission maintenance (and general bike cleaning) for my Mercury during my recent LEJOG (~1070 miles) was zero. I had checked the chain for stretch before I set out and it was fine. I'll check it again soon now that it has accumulated 5000 miles. I had also scraped off a bit of muck (I think it gets into the Chainglider around the rear sprocket) and added a bit of dry lube as part of the pre-ride preparation. While none of the other bikes, all with derailleurs, suffered ride-stopping problems, there was a significant amount of cleaning and maintenance. The last derailleur bike I had was ridden through a winter on my local roads during which time the transmission got extremely filthy and very hard work to clean (I bigger issue for me than cumulative worsening efficiency). That's when I resolved that hub gears were a good idea with the brief use of a s/h bike with the Alfine 11 (not enough range for some of my local hills) before deciding to ignore the price tag and get a bike with a Rohloff hub.
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martins wrote:
Though I am a convinced hub gear fan, I'm not quite so sure as André that derailleurs always quickly become less efficient than a Rohloff.
There is some evidence that even derailleur systems improve slightly after use, the difference is that this happens after a couple of hundred kilometers in clean, dry conditions, and declines fairly steadily afterwards with wear.
I'll take this point as read from experience, Martin. But I can't help noticing that 200km of derailleur improvement before an expected decline is pretty marginal.
I used to be disgusted with chains, and even cranksets (Nexus ali, with the chainring attached to the crank), which lasted less than a thousand miles in far, far more favorable conditions than you last derailleur tour, but I'm just stunned by chains that give up the ghost in 300km even in the conditions you describe.
Transmission maintenance (and general bike cleaning) for my Mercury during my recent LEJOG (~1070 miles) was zero.
One of the reasons I splashed out on a Rohloff despite having several other good bikes was in preparation for being old and not wanting to bend over the bike for routine maintenance: I was, in the most literal sense, developing a near-zero maintenance bike, partly as an intellectual exercise and partly as future-proofing. The only service items left on it are chain (I run it in the factory lube for its entire life inside a Chainglide) brake block, and cable replacement when required, hub oil replacement and, at the same time, a shot of grease to the EXT box. Every second year I wipe the dust off my bike whether it needs it or not. I have a towel near the bike for wiping it down when it comes in wet, but that's not as common as you might think when you hear "Ireland", because I can choose my short rides to suit the weather. Also, the country lanes I ride are all crowned, and none of them are on the flat for long, so they wash clean and, except in the harvest season, there is amazingly little dust on the roads, certainly nothing like the bike-hostile roads Martin describes.
If seems that with your and Martin's input we've achieved an equilibrium opinion:
"that even derailleur systems improve slightly after use, the difference is that this happens after a couple of hundred kilometers in clean, dry conditions, and declines fairly steadily afterwards with wear" whereas a Rohloff improves perceptibly over about a popular guess of 6000km or miles (it makes little difference with such large numbers) and given manual-compliant servicing then remains there for an unknown distance, but we hope for at least outlier experience of 200,000+km.
I'll take that.
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Horses for courses. Just how do you measure efficiency? The tapping along gear on my derailleur and Rohloff Mercury are almost identical, good chainline on the dangler, perfect on the hub, quite similar bikes in other ways, particularly position and tyres (The two biggest variables when considering cycling efficiency) The derailleur bike is noticeably easier to pedal, so much so that I'm likely to be up a gear and 2kph faster for a similar effort.
Even on an easy flat ride I'm unlikely to spend more than 60% of the time riding like that, how far away and how much time and the calculation becomes impossible. Even if you could come up with a number to demonstrate that, it would only be your number and would likely vary day to day and ride to ride. it's then largely down to personal preference, there's a lovely Mercury in the for sale boards, a rider has decided they prefer their derailleur bikes, I feel the opposite, in fact I haven't ridden my derailleur bike this year! That doesn't mean one of us is wrong.
For me, the big efficiency gain would be really hard to measure, with a IGH I'm always in the right gear. I was on a club ride yesterday that included the appropriately named Long Hill out of Buxton and the classic Holme Moss (390mtrs over 7km) On the Mercury of course, I guarantee I changed gear more often than I would have on a derailleur bike and being in the right gear is always more biomechanically efficient than not. Try measuring that!
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Horses for courses. Just how do you measure efficiency?
Not very scientific, but I just ride the bike several times over the same circuit before and after changing the gear system (or other component) and compare the average time taken.
That's how I arrived at no significant difference speed difference between a moderately used but clean and well-lubricated 3x7 derailleur system and a new (i.e. not run in) Nexus 8 Premium hub over a moderately hilly circuit of about 50 kms. I did replace the grease originally in the hub with a synthetic gear oil before building the wheel. This result was not what I expected, I thought there would be a noticeable drop in efficiency when changing to the hub gear. Perhaps the ease of gear changing on the hub gear compensated for the lower mechanical efficiency demonstrated in the (few) laboratory tests accessible on the Internet?
I used the same method to convince myself that a Chainglider wasn't an energy hog - 4 times round a 25 km circuit before fitting and 4 times after fitting over a period of about 10 days. Again, no significant difference in average speed, and again not the result I was expecting, I thought there would be at least a small efficiency penalty with a chaincase that just sits on the chain.
Comparing my two lightweight day bikes over the 50 km circuit, my old derailleur bike is consistently faster than my "new" Rohloff equipped Raven Sport Tour by a margin of about 1 km/h. But the overall gear range on the derailleur bike is set higher, which means I must push harder on the steepest uphills. So I feel less tired after doing this circuit when I use the Raven Sport Tour. Riding positions are about the same on the two bikes, but the derailleur bike is about 1 Kg lighter (probably not a factor) and has 28 mm Schwalbe One tyres, which are, according to tyre rolling resistance tests, supposed to be significantly more efficient than the 35 mm Kojaks I had at the time on the Raven Sport Tour. But the fatter tyres make the Raven Sport Tour more comfortable to ride over long distances, and I find I don't choose the derailleur bike very often nowadays, the Raven Sport Tour is simply more fun to ride. This would probably be different if I was into time trials, racing or Audax riding.
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On the Mercury of course, I guarantee I changed gear more often than I would have on a derailleur bike and being in the right gear is always more biomechanically efficient than not. Try measuring that!
Been there, done that, got bored and moved on to something more exciting before the T-shirts arrived. In the 90s and the noughties, I rode a fixed, measured circuit every weekday and sometimes on weekends too. My bikes were consecutively derailleur, Shimano Nexus, Shimano Di2 "Smover" -- the full automatic not the cutdown one they now sell as DuraAce, and Rohloff. The automatic gear changing bike was fastest of all precisely because it was always in the right gear relative to the effort I put in and the road, the Rohloff came second, the Nexus HGB third and the derailleur bike last of all. Measured!
If you haven't seen its description and photos yet, the fully automatic bike (with electronic active suspension as well, oy vey!) is at
http://coolmainpress.com/BICYCLINGsmover.html
and journeys on it are at
http://coolmainpress.com/BICYCLEKilmacsimon1.html
and
http://coolmainpress.com/BICYCLEKilmacsimon2.html
I'm very surprised to hear that anything at all is unmeasurable. I've certainly never found anything that I couldn't somehow measure, including the ghostly lovers in my family's house.
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I find that the weather (particularly the wind) affects the time I take to get round one of my circuits such that the effects of changes in equipment are difficult to discern. While I initially felt that my Birdy Rohloff was almost as fast as the Mercury I'm now thinking the first ride on the Birdy was helped by favourable weather. The Birdy has a dynamo so I thought that was causing some extra drag so I disconnected the lights to reduce that, without obvious improvement. I now wonder if the poor chainline and chain tensioner on the Birdy is creating unwanted drag while the Rohloff hub has only accumulated a few hundred miles so far. Comparing two Rohloff bikes is almost going off-topic except it highlights the difference of making comparisons in other than laboratory conditions.
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Comparing two Rohloff bikes is almost going off-topic except it highlights the difference of making comparisons in other than laboratory conditions.
Yes this. AJ's testing has so many variables that isolating one element isn't possible, it becomes anecdote not data.
I used to have a fast road bike, I have the data to prove the rides I did on it were always the fastest. Except - I didn't like getting it dirty so it never (Intentionally) went out in the rain, the tyres were a bit narrow and delicate so it stayed off bridleways and cycle paths, I always wore cycling gear rather than my customary casuals, it had no fitted lights or rack or guards, it had a steep ST and low bars so uncomfortable for more than 100 km, and I'd only take it out if intending to do a fast ride...
I'm also faster on my Alfine Mercury than the Rohloff, but it hasn't got low enough gears to take it anywhere seriously hilly. My urban Rohloff is the slowest bike I own, you can probably guess why.
We have to put such things in perspective, we're talking in gearing systems differences of a few watts, that isn't insignificant but neither is it likely to be the determining factor for anyone contemplating one.
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Wow I'm glad Andre started a new thread for this - lots of enthusiasm and helpful info for people researching Rohloff user experience.
As someone new to Rohloff I'm close enough to my purchase decision to remember what was mainly on my mind as I pondered. The fear I had was not whether my derailleur riding friends would gain an extra 20 metres on me every kilometre just from my choice of gearing system.
What worried me was that I might find the hub frustratingly draggy or indirect. So that when I was pedalling it felt as though I was putting a fair bit of effort into just spinning Rohloff planetary gears, or overcoming seal drag.
Google commentary on the Rohloff, and track down every stray thread, as I did even while waiting for my ordered Mercury to arrive, and you'll find bits and pieces to that effect. Much of it possibly coming from early hubs, which it seems were noisier.
What has surprised me - and obviously pleased me - since I started to get out on the Rohloff is that none of those fears has had any justification from my experience. I experience the Rohloff transmission as feeling freer and more slippery than I remember of my derailleur transmission.
I rode recently with a friend who had a derailleur equipped bike, which is old but reasonably well maintained. He is about my size and we swapped steeds for a while. Not for an instant did I think: wow this thing is so easy to propel, or, wow it's great how free this derailleur drivetrain feels when I pedal.
It might be argued that a factory fresh set of derailleurs might have felt a bit better. Um, yes, and that's part of the point.
Move from feel to measured drag and we have ways to discover that, under specified conditions, one system or the other is marginally less efficient.
That's dandy, but it doesn't matter much for non-racers if the less efficient system doesn't feel less efficient.
For the rest of us I'd argue that how it feels to ride is the important bit here. The bike that feels better to ride tends to get ridden more. And the more you ride, the stronger you get, and the faster you'll go on either geartrain.
Those of you who ride both systems frequently are obviously well placed to comment on how each feels for efficiency - as opposed to how you think or know it is from measurement. Has your experience matched mine? Or do you indeed think Oh, not this old grinder whenever you step back onto your Rohloff steeds?
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Comparing two Rohloff bikes is almost going off-topic except it highlights the difference of making comparisons in other than laboratory conditions.
Yes this. AJ's testing has so many variables that isolating one element isn't possible, it becomes anecdote not data.
That may be comforting but it is nonsense, as I shall explain shortly.
Martin has the right idea:
Horses for courses. Just how do you measure efficiency?
Not very scientific, but I just ride the bike several times over the same circuit before and after changing the gear system (or other component) and compare the average time taken.
On the contrary, perfectly scientific, the more tests you take, the more scientific.
All the four bikes I cited went over the same 7.5m circuit in the same direction more than 440 times, year-round. Thus every bike partook of all the offered weather conditions, all of my conditions that may influence speed, etc. Two of those bikes were Dutch vakansiefietse with Shimano Nexus boxes, the only difference being that one had a fully automatic gearbox and adaptive suspension aiding efficiency; if any upset in the results were likely, it would have shown in these two. The other two, derailleur and Rohloff, were steel, another layer of indicators in case there was something wrong with the count. I wrote down the order I expected before extracting the data, as a hypothesis, if you like, and the result was precisely as I expected. You're arguing against a huge, huge statistical probability for my result being rock-solidly unimpeachable.
1760-plus rides over the same piece of road on four bikes is a long way up the ladder of certainty from an anecdote, laboratory or none. That large a sample smoothes out the small daily fluctuations until hardly a ripple disturbs the result.
You're the one trying to hold up anecdotes of single rides as contrary evidence, Paul, as in your post above, not me.
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In any event, by the evidence of the net, the average Rohloff tourer isn't a kid wet behind ears and possibly a fashion victim but a mature party of judgement and means. He can, if he wishes, scour the net for Rohloff information, and form his own judgement; if he is serious he is likely sooner or later to land either here or, if he speaks German or has discovered Google Translator, on the good German board, where the various opinions eventually combine to form a singular opinion, which is then his initial opinion. We're just privileged to be on board not too far after the beginning of Moronic's journey. We won't mislead anyone by a variety of pretty much mainstream opinions.
As for a laboratory, back when I took these rides, I financed a prototype lab to build and test the high tension (up to 2000V) thermionic tube (valve) audio amplifiers I designed for a Japanese maker. My engineering partner had spent his life at the cutting edge of instrumentation. He was no faculty common room talker: he'd done it daily all his life. When I suggested to him that we should test my new Rohloff, he pointed to the tarmac on the parking lot outside and said, "The best test is the one you already performed on your earlier bikes. Match it." So that's what I did. When I caught up, a bit late, on Kyle and Berto's Rohloff v. derailleur tests, I saw instantly what he meant: those tests were pie in the sky, useless for real life decisions. A one or a two per cent efficiency difference when the power source is outside the equipment being measured, linked by a chain, will just disappear into any number of variables, like the fact that their Rohloff wasn't run in but brand new. Ouch!
And I repeat: in real life the Rohloff's efficiency is the average over the ride, which is very likely to be a constant over many rides on the same course, whereas the derailleur's efficiency is not fixed when it leaves but should be measured and calculated upon its return, dirty and degraded. The Rohloff average efficiency will be the next best thing to a flat line, the derailleur efficiency line will always, except for a brief honeymoon early in its life, point downwards.
By the way, Bernd Rohloff's reply
https://www.hupi.org/HParchive/PDF/hp55/hp55p11-15.pdf
to Kyle & Berto gives a whole bunch of considerations, including ones from sports medicine that I picked up on immediately I read the K&B article, of the type that my own tests would subsume under straightforward statistical weight of number of tests.
But for my money the best thing that Rohloff and Greb do in their reply is "Figure 6: SPEEDHUB 500/14 efficiency comparison. Gears 8-14 shifted to the left to compare with gears 1-7." It shows why I'm so keen on Gear 11 that my whole transmission is planned around it and the overdrive gears come into use here in the Rome of West Cork (very hilly!) only on the downhills.
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Comparing two Rohloff bikes is almost going off-topic except it highlights the difference of making comparisons in other than laboratory conditions.
Yes this. AJ's testing has so many variables that isolating one element isn't possible, it becomes anecdote not data.
That may be comforting but it is nonsense, as I shall explain shortly.
I look forward to that explanation.
Happy to peer review it.
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Comparing two Rohloff bikes is almost going off-topic except it highlights the difference of making comparisons in other than laboratory conditions.
Yes this. AJ's testing has so many variables that isolating one element isn't possible, it becomes anecdote not data.
That may be comforting but it is nonsense, as I shall explain shortly.
I look forward to that explanation.
Happy to peer review it
Heh-heh! You should consider a career in stand-up comedy, Paul. The clubs are crying out for you.
So as not to confuse those who come after us, the promised explanation followed immediately upon the promise in the same post in this thread at:
http://thorncyclesforum.co.uk/index.php?topic=14325.msg106935#msg106935 (http://thorncyclesforum.co.uk/index.php?topic=14325.msg106935#msg106935)
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Heh-heh! You should consider a career in stand-up comedy, Paul. The clubs are crying out for you.
I tried to get booked but you've cornered the market, This one
All the four bikes I cited went over the same 7.5m circuit in the same direction more than 440 times, year-round. Thus every bike partook of all the offered weather conditions, all of my conditions that may influence speed, etc. Two of those bikes were Dutch vakansiefietse with Shimano Nexus boxes, the only difference being that one had a fully automatic gearbox and adaptive suspension aiding efficiency; if any upset in the results were likely, it would have shown in these two. The other two, derailleur and Rohloff, were steel, another layer of indicators in case there was something wrong with the count. I wrote down the order I expected before extracting the data, as a hypothesis, if you like, and the result was precisely as I expected. You're arguing against a huge, huge statistical probability for my result being rock-solidly unimpeachable.
is guaranteed to have them rolling around the aisle in any first year science class.
I know you enjoy writing fiction, but you really ought to be able to tell the difference.
This is a forum, if you wish to put forward opinions as undisputed facts, then you need to do a lot better than offer a series of anecdotes, otherwise they're no more or less nonsense than anyone else's opinion.
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Pfffft.
I can understand that you're embarrassed to be caught out rushing to judgement without asking me a single question about what I based my conclusion on:
http://thorncyclesforum.co.uk/index.php?topic=14325.msg106933#msg106933 (http://thorncyclesforum.co.uk/index.php?topic=14325.msg106933#msg106933)
If you had asked me, I would have told you about the 1760 data points underpinning my conclusions. Next time I'm going too fast for you, do ask. You'll find me charming and helpful.
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It shows why I'm so keen on Gear 11 that my whole transmission is planned around it and the overdrive gears come into use here in the Rome of West Cork (very hilly!) only on the downhills.
I had previously read (probably here) that 11th gear is the most efficient as it's direct drive so I targeted my gearing to be 11th when on the level as this should be the average terrain. That leaves 3 higher gears for downhill after which it's a matter of pedalling faster. However, depending on what the wind is doing I can be in any gear between 9th and 13th on the level. Is 4th the most efficient gear when in low range?
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Is 4th the most efficient gear when in low range?
Yes.
Having looked at the gear efficiency charts I decided that I probably wouldn't be able to notice the efficiency difference between the top 7 ratios.
So I haven't bothered to try and get 11th gear as my most-used level-road gear. I just went for the lowest "permitted" combination that would also fit a Chainglider at the time I bought my Raven Tour in 2012, which was 38x16. I hardly use the top two gears and the lowest "permitted" combination is much lower now, so I may go to 38x19 at some time in the future.
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A useful graphic comparison of the efficiency of the two gear trains inside the Rolloff box is Figure 6 on the original's p14 bottom left of
https://www.hupi.org/HParchive/PDF/hp55/hp55p11-15.pdf
Figure 6: SPEEDHUB 500/14 efficiency comparison. Gears 8-14 shifted to the left to compare with gears 1-7.
It looks like the upper seven gears make pretty much a higher stack of the lower seven with 2, 4, 6, 8, 9, 11, 13 as the outstanding (sorry!) gears, if all you want to consider is efficiency. I also had mechanical silence in mind in choosing my transmission, and it is likely that direct drive, by simply not wearing the other gears, aids longevity (a bit irrelevant with a Rohloff).
Also notable: Herr Rohloff confirms, on top of the middle column on the first page of the link above, that dragging seals need running in, and that they will make a difference under 200W. I can't say I remember it ever bothering me, and not because I pull over 200W all the time.
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I've finally got round to reading the paper (I had previously incorrectly thought it might be in German) and all is revealed. Actually, almost all, as they didn't test the scenario of a well-used and filthy drivetrain.
In real life I don't think it's possible to tell the efficiency difference between 4th (one set of gears) and either 3rd or 5th (3 sets of gears). I just use whatever feels best for the conditions and that's one of the joys of the Rohloff hub - being able to easily shift a gear when going up a hill without lots of gnashing of teeth or loss of momentum.
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Yes. that's why I qualified the observation with "if all you're interested in is efficiency".
In practice I can tell you when I'm in gear 11 because I change up to 14 and then back three notches, but for the rest I have no idea.
That paper also contains another table, perhaps more useful than the efficiency table, which lists the distance travelled for one revolution of the pedals in each of the gears.
https://www.hupi.org/HParchive/PDF/hp55/hp55p11-15.pdf (https://www.hupi.org/HParchive/PDF/hp55/hp55p11-15.pdf)
Figure 4 on p14 of the original
If you're the kind of scientific cyclist who had a laminated table of half steps on your handlebars in derailleur days, I should think that table would be your bible, because on the Rohloff, with its even gearing steps, the fact that there are not even steps in forward motion per pedals-revolution for different gears subsumes both utility and efficiency into a single number, very handy once you put your head around it or make a laminated table to go on your handlebars.
Of course, a Rohloff makes it easy to change into only the gears that are the most efficient, 2, 4, 6, 8, 9, 11, 13. I tried it once for a 22km ride but it reminded me too much of a wedding march in 7/11 time I once heard an organist with a sense of humor play in concert (no bride will stand still for being made to look handicapped on her wedding day -- excepting reportedly the composer's bride, "a jolly gal game for anything"). By the time I returned home, it was a very old joke.
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I just use whatever feels best for the conditions
Yep. I bought the Rohloff eight years ago 'cos I'd had it with derailleurs & haven't regretted it for a moment. I rarely bother looking at the gear-number indicator, either--half the time, shadows prevent me from seeing it anyway.
In the lower register, I find 4 is the quietest, so take that as a proxy for efficiency, with 3 being a close second (as it were).
in the high register, 8th always feels/sounds nice, after the hill relents. Then, I suppose 11th is quietest, but again, it doesn't really matter: I just choose whatever I need to maintain a decent cadence.
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In practice I can tell you when I'm in gear 11 because I change up to 14 and then back three notches, but for the rest I have no idea.
Is your hub so well run in that you can't hear the difference in sound when shifting between 8th and 7th (or vice versa)?
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A useful graphic comparison of the efficiency of the two gear trains inside the Rolloff box is Figure 6 on the original's p14 bottom left of
https://www.hupi.org/HParchive/PDF/hp55/hp55p11-15.pdf
Figure 6: SPEEDHUB 500/14 efficiency comparison. Gears 8-14 shifted to the left to compare with gears 1-7.
I took the opportunity to have another look at that discussion, having read it quite a few years ago. I see more meaning in it now that I have a Rohloff to ride.
I think part of the burden of the Rohloff response was that efficiency is complex enough that simple tests are likely to mislead.
I'm reminded of the rolling resistance conversation promoted by Jan Heine at Rene Herse. He has argued that measuring the resistance of a tyre to rolling on a steel drum misses a big part of the resistance experienced in real riding, and also it ignores contributions a tyre's suspension performance might make to rider fatigue. His conclusion is that 50mm tyres with supple walls are best for most of us most of the time, and more and more people are finding that conclusion compelling.
When I've been out on my Rohloff Mercury, I've been observing to myself that it feels fast, which is what matters most to me, even though I might well be slower on it than, say, a similar Club Tour with derailleurs. The thought that I might be slower has been founded entirely on my prior reading of efficiency testing.
Rereading he Rohloff piece reminds me that I missed a lot last time. To put it another way, it helps me reconcile the narrow-dimension test results with my experience. I feel like I'm significantly faster point to point on the Rohloff Merc than on my prior bike, which has derailleurs. I don't time myself, so have relied for that on my sense of ease, and have acknowledged that might mislead. I'm thinking now that it doesn't mislead. Of course efficiency isn't just about friction under load. Stress-generated fatigue is relevant, as is capacity to match load to cadence. And it will vary enormously with conditions. What is most efficient in a group on a smooth, open and mainly flat road might be least efficient solo on my cycle path network.
Rohloff is right to point broadly to such considerations in his article.
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In practice I can tell you when I'm in gear 11 because I change up to 14 and then back three notches, but for the rest I have no idea.
Is your hub so well run in that you can't hear the difference in sound when shifting between 8th and 7th (or vice versa)?
It's raining cats and dogs here, John, so I can't take my bike out to discover the answer to your question. Short answer: I don't know. I'll have to ride the bike on some quiet piece of level road and pay attention to know for sure.
When my Rohloff was new, I put Tippex (white typewriter corrector fluid) on gears 8 and 11, but it has long since worn away. In fact, in 10K kilometers and change, some part of the numbers have worn from the rotary control. I hardly ever look at it, and find gear 11 by going to 14 and stepping back three notches, burp.
You should also understand that when I say a Rohloff is silent, or mine is anyway, I'm referring to gear 11. Theoretically all other gears should be somewhat louder or in the lower gears at least more audible because you aren't riding as fast and generating as much wind. But I've long since ceased listening to the gearbox because all the gears require a) a special arrangement of riding on the most dangerous and fastest piece of road around here, because it is smooth and has well-defined white and yellow lines to kill the noise of my 60mm Big Apples, which are the loudest thing about my bike, including the Rohloff, but is so busy it can only be done in the middle of the night, and b) I have to listen carefully because there isn't much in it.
On the other hand, I've been a classical music critic all my life, so I'm very aware of noises off, and I design and build my own single-ended tube hi-fi to be played through electrostatic loudspeakers, so extraneous noise is the second-greatest obsession with me, next to micro-vibrations in my hands (a writer is a manual laborer: he operates a keyboard). So, if there was something to hear in the last several thousand kilometers, I would have heard it, and stopped to investigate.
Also, see above what John Saxon says about "feels/sounds" -- yeah, I know, Herr Rohloff, an upright German engineer, is cringing! -- but it happens to be an exact description: You just know when your Rohloff HGB is in a happy place and you stop turning the control.
By the way, I haven't adjusted the rotary control on my bike in the slightest in over 10K. People who get a ride on my bike are amazed at how loose I leave it. I don't see the point in adjusting it when the transmission appears happy. It's just a different paradigm to a derailleur whose efficiency and even operation depends on fine adjustments.
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I don't think we know for sure when a Rohloff is run in. There'll be a natural variation because it is a piece of hand-assembled intricate engineering built light for what it offers in convenience and longevity, with the assembler having some leeway for judgement calls. So different Rohloff HGBs will run in at different rates, possibly significantly different rates because the service life is so long.
I felt that mine was a bit looser at 2K and there was another bigger step at about 5-6K, that's kilometers, where it felt looser again and some tiny noises that I knew to listen for in gears other than 11 had gone away. I'd originally thought that the Rohloff would never have the smooth gearchange of a Shimano Nexus, which is a thing of wonder if it is set up right; but about there I changed my mind. The next significant thing that happened was that at 8500km I replaced half-worn Big Apple Lites with new ones, and I noticed in the middle of listening to the rougher ride of the minimal tread on the Big Apples that of gears 7 and 8, eight appeared to have gone silent. As I say above, about 2K further on, I can't tell you anything about gear 7 without riding the bike under ideal testing conditions. Maybe I can tell a difference, maybe I can't.
Sorry to be so longwinded about telling you I can't tell you, but you'll arrive at the same place with your Rohloff eventually.
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Stress-generated fatigue is relevant, as is capacity to match load to cadence.
I'm big on the biggest balloons your bike can take, and with the softest sidewalls available, which is where the comfort comes from even with stiff anti-puncture bands. My favorite bike doesn't even have a suspended fork, nor a suspension seat post, just the Big Apples and the sprung Brooks saddle.
I also think that if I had a decent cadence (I don't, I'm a masher), and concentrated on being in the right gear in the Rohloff HGB, as my automatic Trek Smover is always in precisely the right gear, the Rohloff could have come out on top in my longterm tests described above in this thread.
The greatest advance on the present Rohloff box would not be a lighter version but an electronic stepper motor and control for it, plus a torque and speed sensor, to replace the Rohloff EXT box (or work with it) and handlebar rotary control, turning it into an automatic gear change; it's irrelevant whether the connection is by cable or radio or Bluetooth. With a gear range of over 500% and 14 effective gears (near enough the same number of effective gears on a derailleur bike), the Rohloff would own the hills.
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I think part of the burden of the Rohloff response was that efficiency is complex enough that simple tests are likely to mislead.
I think that's in in a nutshell, as the thorough Rohloff testing showed the conclusions are restricted to a narrow set of parameters. I haven't re-read the results for at least ten years, they were not universally accepted, several well respected cycling engineers criticised the mythology and conclusions.
The idea that anyone can come up with something more conclusive is.. well laughable, if they could I'm sure Rohloff would be happy to review and publish, but I'm not holding my breath.
As I said earlier
Even if you could come up with a number to demonstrate that, it would only be your number and would likely vary day to day and ride to ride. it's then largely down to personal preference
martinf's testing is closer to reality, it provides everything he needs to know, it's interesting to hear about it, but they're right to acknowledge it isn't scientific, or at least what the parameters are. They can come up with the conclusions they're looking for, any claim that it applies to anything outside that testing is conjecture.
If someone's hub feels like riding through treacle then a zillion data points don't prove otherwise.
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martinf's testing is closer to reality, it provides everything he needs to know, it's interesting to hear about it, but they're right to acknowledge it isn't scientific, or at least what the parameters are. They can come up with the conclusions they're looking for, any claim that it applies to anything outside that testing is conjecture.
If someone's hub feels like riding through treacle then a zillion data points don't prove otherwise.
In 2004 I had a commute of about 44 km for the round trip. To make things interesting, I used all the bikes I owned and compared the average times, eliminating days with strong winds that would introduce a lot of bias.
Conclusions over a total of 3391 km:
Position is very important, drop bar bikes performed consistently better than flat bar or roadster bar bikes (expected). 2.5 km/h difference for the same Moulton bike fitted with drops or roadster bars.
Tyres are important. Huge difference for (on-road) speed between knobbly mountain bike tyres and slicks. Significant differences for some brands/models of tyres (expected). Later on I was surprised by the small drop in efficiency between my Nokian studded tyres and my more usual Marathon Supreme slicks, I was expecting a much more important efficiency hit, especially as the studs make a lot of noise.
Gears seem not be particularly important, with one exception. Very little difference between two bikes with similar (flat) bar positions, similar tyres, one with 21 speed derailleur and the other with 5 speed hub gears (not expected). Later tests on my old mountain bike when I replaced the 21 speed derailleur with an 8-speed Nexus Premium hub confirmed this, again contrary to my expectations.
My Nexus 7 hub gear was, however, significantly less efficient than other gearing systems. (not expected, especially as the hub feels smooth). This Nexus 7-speed improved significantly after I cleaned out the original grease and replaced it with a less viscous lubricant (invalidating the guarantee in the process), but was still significantly slower than the S5/2 it replaced.
Fastest bike was my 700C derailleur geared lightweight (expected). Second fastest was a Moulton Stowaway with drop bars and 7-speed derailleur gears. IMO slower because of the tyres (not so good as the ones on the 700C bike) and the less efficient small sprockets needed with small wheels. Maybe also the small wheels, in real-life conditions small wheels deal less well with road imperfections (potholes, etc.).
Slowest bike was my old ATB with knobbly tyres. Same bike with flat bars and slicks was much faster, equal third with my old utility bike, also with flat bars and (reasonably efficient) Marathon Tour tyres but with an S5/2 hub gear.
But, if I add the time spent on maintenance, the hub gear systems come out as clear winners, as I spend far less time cleaning and lubricating the transmission. Note that this is only true if the hub gear is reliable - I had an unfortunate experience with unreliable Sturmey Archer Sprinter 5-speed hubs that were more hassle than they were worth. One of the selling points of the Rohloff is it's supposed reliability (I haven't yet done enough kilometers to validate or invalidate this claim). Where wide range isn't important, Nexus 8 Premium hubs seem a reasonable compromise between price and longevity, not yet had any problems with any of mine, despite abuse on the 2 visitor bikes.
At that time, I didn't have a Rohloff, so for touring in really hilly areas a derailleur system was mandatory. I have since got a couple of Rohloffs for my large wheel bikes. Even if they are a couple of percent les efficient than the derailleur systems they replace, when I factor in the maintanance time I will still be ahead. Especially after fitting Chaingliders.
I was very sceptical about the Chainglider chaincase, reckoning that something that justs sits on the chain with no other support must generate a lot of friction. So I bashed my old utility bike 4 times round a 25 km circuit before fitting a Chainglider, then another four times after fitting the thing. I was surprised to find no significant speed difference, despite the non-optimal setup with a relatively thick 1/8" chainring. I am now a Chainglider convert, all but one of the large-wheel bikes I maintain have Chaingliders, the exceptions are a visitor bike with verical dropouts and the 3 family Bromptons.
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In 2004 I had a commute of about 44 km for the round trip. To make things interesting, I used all the bikes I owned and compared the average times, eliminating days with strong winds that would introduce a lot of bias.
Interesting reading. Some universal truths like position and tyres and a demonstration of just how many variables there are.
We should also note how speed is only one indication of efficiency. We could make it the primary one, but only with a measured input. I've tried a HR monitor as a poor man's alternative, but it's too influenced by other factors so not accurate enough. We also have to consider that such data only applies to that testing, OK we can speculate how much wider we consider it relevant, and within reason we'd probably be right, but it would be far from conclusive. Acceleration often doesn't get adequately taken into account, people who don't do a lot of urban riding don't always grasp how much energy is used pulling away from a stop. It's the reason so many cyclists don't stop at red lights if they can avoid it, there's very little time advantage, it's a big saving in effort (No I'm not endorsing it!). This consumption shouldn't surprise anyone, just compare car MPG between urban and motorway driving.
Then, we can only use what we have. We tend to have a preferred cadence, particularly on an uninterrupted segment, such as a long flat road or hill with steady gradient. You could raise or lower the gearing by some amount and you'd still naturally fall into the same cadence at a slightly higher or lower speed. I don't know the extent of this and it undoubtedly varies between riders, I know I can change tyres equivalent to a 1.5% gearing difference and the result on the flat is a corresponding change of speed. There is a cost of course, though the energy difference is probably lost in the other factors. Any comparative efficiency testing would require identical ratios. it's the reason I'm not a huge fan of the Shimano 8's, those big gaps in the middle often means maintaining my preferred cadence requires more effort or accepting a lower speed, this is likely to happen without realising it. Strava says my fastest times over a segment that includes a short steep bridge are on my 3spd Brompton! It's nothing to do with the bikes efficiency, I don't have much choice - push hard or get of and walk...
...variables, so many of them, which I think is where I came in, it isn't possible to isolate them outside of a laboratory and inside one doesn't reflect the riding experience... make your own mind up.
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it's the reason I'm not a huge fan of the Shimano 8's, those big gaps in the middle often means maintaining my preferred cadence requires more effort or accepting a lower speed, this is likely to happen without realising it.
For my own use, I don't mind gear systems with big gaps when doing short rides. I used Sturmey Archer and SRAM 3-speed hubs for urban trips for quite a long time, these have a gap of about 33% between gears. Pushing this to extremes, I used a wide range 2-speed derailleur system on my "light" Brompton for quite a while with 12/19 sprockets and 58% gap, used like a single-speed but with a bail-out gear for hills. Quite usable for short urban trips, and the minimal gearing made this Brompton significantly easier to carry.
It is different for me on longer rides. With a 3-speed hub I often wanted a gear in between the 2nd gear and 3rd gear. The gaps on an S5/2 five-speed are slightly closer at 18%, 27 %, 27 %, and 18 %, this made a significant difference for me and I have done a lot of distance rides with this system.
I experimented with close ratio derailleur cassettes, 5 sprockets 13 to 17 with one-tooth increments, then 2 bigger sprockets. On the close range part of the sprocket spread the gaps were between 6 and 8 %, but I generally jumped 2 or 3 sprockets, so concluded I didn't really need such fine tuning.
The Rohloff with it's approximately 14% gaps is OK for me, on the upper part of the range I never find myself looking for in-between gears and on the lower part of the range I could happily live with much bigger gaps.
Now that I have been spoilt by the Rohloff, I do notice the 27% gap between 3rd and 4th on my S5/2 equipped bikes.
And with the Nexus 8 premium hubs I notice the 22% gap between 4th and 5th, but not the identical gap between 1st and 2nd.
In both cases, it is only on longer rides, and is only a minor nuisance. For me the important advantage of the Rohloff is the very wide range, which has enabled me to get rid of derailleurs for rides in very hilly areas.
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In practice I can tell you when I'm in gear 11 because I change up to 14 and then back three notches, but for the rest I have no idea.
Is your hub so well run in that you can't hear the difference in sound when shifting between 8th and 7th (or vice versa)?
Okay. The main road I billed as being smooth enough to conduct listening tests in the middle of the night, is no longer smooth, and a piece of smooth newly made road only a few hundred yards from my house carries heavy and loud traffic. So I improvised.
My house is old, with very thick walls, so not a lot of sound gets past multiple glazes and heavy drapes. I turned the bike upside down and changed the gears while turning the motor. The whir of the motor was the loudest thing, not very loud. I also tried turning the pedals by hand but the rustle of my clothes was drowning out the effects I was trying to listen for.
At something over 10,000 kilometers, my Rohloff is silent for all practical purposes in all gears, but it is less silent in gears 7 and 8, and between those two, I would say 7 is less silent than 8. There's not much in it, and certainly nothing you will hear over the sound of tires on the road and the rush of air through the spokes.
There's really not much to say about the sound of silence unless you're a neurotic; I've spent my life in silent rooms and I rather like the sound of silence; if I were ever unlucky enough to lose my bike with the Rohloff, I'd just order the same again, and break the Rohloff in, because it does run in -- it's just a more extended process than someone new to the Rohloff perfectly reasonably expects.
Sorry I can't give you a precise number for your gearbox running in, John. But, if you read carefully, you'll discover that people with new Rohloffs are a lot more confident in their claims of their Rohloffs running in than the older hands, whose predictions one after the other required to be extended. The one verity is that your Rohloff will become smoother with time and miles. Ride more often, ride further.
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It would be interesting to learn whether a new NuVinci, which is a CVT, a continuously (stepless) variable transmission, is more silent than the Rohloff, or whether the NuVinci too breaks in and thereby becomes more silent.
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My Nuvinci N380 is definitely quieter than my Rohloffs and it's not noticeable above the whirring of the Bosch electric motor and the sound of Heavy Mental in my headphones.
[I was joking about the H M ;)]
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Well I test rode a Nuvinci a few years ago. Utterly silent. Small ratio range. I think Ive read they have a wider range version which would be good where it's mainly flat or for people who like to work hard on climbs.
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I've noticed that on a moderately windy day I can't hear any noise from the hub on my Mercury (just over 6k miles) due to the wind interacting with the helmet or its straps. I've also just changed the very quiet Marathon Almotion tyres to the slightly noiser G-One Speeds but I can still notice the sound difference between 8th and 7th gears. So far there's been no noticeable wear to the numbering on the shifter.
My Birdy Rohloff is a much noisier bike. In addition to the hub having only closed up a few hundred miles I suspect that the chain tensioner and poor chainline will always create some unwanted noise although they have got quieter with use. However, the extra noise in low range is very audible. As it's the number two bike it will take some time to get everything bedded in.