On Thursday, July 18, 2019 at 10:10:03 AM UTC-4, Andre Jute wrote:
On Wednesday, July 17, 2019 at 12:57:46 AM UTC+1, Tom Kunich wrote:
It is kind of weird that you can do absolutely everything hydraulically that you can do with electronics. Just that it is so damned complicated and expensive that no one wants to do it that way.

Another thing is that you can use gear mechanisms to accomplish these things as well but with mechanical losses though of what amount I couldn't even guess.

Was it Andre or Joerg that was talking about a 14 speed internally geared rear hub. That would truly be interesting to ride and see how much losses it generated versus our normal chain and derailleurs.

I run a Rohloff Speed 14 hub gearbox on my everyday bike (the only one actually in use, the others being in the heated loft, once the servant quarters, three storeys up. The bike is from the German baukast (custom builder) Utopia-velo and is a 1935 crossframe-mixte design in modern times meticulously redeveloped from the ground up around Schwalbe's Big Apple balloons, the Rohloff gearbox (Utopia was the first OEM to fit Rohloff boxes, and basically established what was intended as a pretty agricultural mud-plugging box as a deluxe touring box), and whatever else will aid a customer's comfort and ease of operation, without considerations of cost or what roadies are likely to think. Load capacity is 170kg, and the bike is much proven in circumnavigations. Mine is used for recreational rides, utility rides, as a workhorse for carrying hefty painting gear to where I want to paint, and for light touring.

I've developed the bike to virtually zero-service, zero cleaning, zero attention. My chain, for instance, runs inside as near a fully sealed enclosure as you can imagine, and it is never opened, serviced, oiled, cleaned or even wiped down for its entire life; it runs for its entire life, about three times as far as I used to go on a chain before, on its factory lube. On the Thorn forum there are several essays by me describing the development procedure and the logic for each step. I didn't post those to RBT because I'm long since fed up with the tiresome clowns here wrecking every working thread in pursuit of their dumb vendettas.

Turning now to the so-called efficiency "loss" of the Rohloff, you have to be a quarterwit roadie or an ivory tower clown without any real world experience to believe in its occurrence anywhere outside a laboratory, and at that a laboratory with an airlock entry. Any old engineer with a bit of lab experience can design a set of tests to prove derailleurs are the most efficient drive form likely to be cost-efficient on a bike -- in the lab. The derailleur has survived so long for good reasons. The minute you take that Rohloff and that derailleur system out of the lab door, dirt starts accumulating on the derailleur and interfering with its efficiency, but not on the Rohloff, which is totally enclosed and running in an oil bath (which you can further tailor by operating it on the thinner winter oil to really trounce the derailleur in a very shot distance -- I run mine year-round on the all-seasons i.e. summer oil but put in only enough to coat all the gears, so there's nothing sloshing around). Of course someone will now argue that the Rohloff sprocket is as exposed as the derailleur cluster to dirt. But you can cover the Rohloff chain and gear wheelies very efficiently with a Chainglider (the supremacy of which I've also described on the Thorn forum, where with the other members who fitted it on my recommendation we have probably over a 100k miles of experience with it). There are photos on the Thorn forum of the inside of my Chainglider after I ran the chain in it for 4500km on the factory lube, zero extra oil, zero service, first time I opened it with serious intent -- and it is clean, and the chain looks new. As you can see, for a moment's worth of thought, this is a loaded deck against the derailleur, and was from the moment the two transmission systems rolled out of the lab.

We all know how fast the efficiency of a perfectly clean derailleur system falls off once it gets road dust on it. The only thing that is new here is that the efficiency of the Rohloff transmission does not fall at all, especially if the chain, sprocket and chainring are also competently enclosed. The Rohloff maintains its laboratory efficiency for the full 5000km or one year between oil services of the box (note that, Rolf -- your guarantee, which is effectively for your life unless you abuse the gearbox, depends on doing the oil changes on schedule). I would bet money that as little as few miles from home a Rohloff is routinely more efficient than the derailleur system that started clean.

I actually think the other argument, that the Rohloff weighs more than a derailleur system, is more logical, if by relative magnitude too petty to be convincing. The weight difference, if any, is so little that it could amount to a one-foot rise in several miles. So, while the argument on weight is more rational than the one on efficiency, it is not all that relevant, except perhaps in racing.

Steve Weeks says
in some applications the losses are tolerable.

I would say in virtually any everyday situation (possibly excluding racing) with the comparative measurement taken further than x miles from base, there are no losses for the Rohloff HGB compared to a derailleur.

The only questions remaining a

a) For any particular Rohloff owner's regularly ridden roads, at how many miles from base does the efficiency of an optimal derailleur system fall to that of the Rohloff? We know the mechanical efficiency differential is pretty small but I think it would be better grasped as a road distance. Call this distance x.

b) At which fraction or multiple of x beyond the first x does the efficiency of a derailleur system fall below the constant efficiency of the Rohloff by the same amount as the derailleur was superior in the laboratory? Call this likely imperceptible but measurable differential d1.

c) At what distance from base, expressed as multiples of d1, will the average cyclist notice that the derailleur system is less efficient than the Rohloff? Call this multiple d2.

My opinion, having used both systems, is that x, the distance of two perfectly tuned systems to equal efficiency, on my all-tarmac but rurally dusty lanes, could be 5-10 miles. Guesstimating (tm Jeff Liebermann), d1 might be the same.

Since in everyday use, starting on perfectly laboratory-grade clean derailleurs and Rohloff transmissions reveals no practical difference in efficiency to openminded riders, d2 seems to me likely to be quite a distance, at least under my relatively clean conditions, say several or many day rides, Perhaps even a couple of thousand miles: some of my riding companions never clean their bikes (they buy near-new aspirational bikes for fifty bucks out of the garages of onetime would-be bicyclists and ride them into the ground, then buy a new one) and their bikes definitely feel stiff to pedal.

Andre Jute
A little, a very little thought will suffice -- Maynard Keynes

PS: Y'all understand that a Rohloff is a handbuilt, handfitted gearbox, don't you? A Shimano machine-huilt HGB starts amazingly smooth and wears out from there; the MTBF is about 50,000km, at which point you throw it away because it isn't worth rebuilding. A Rohloff gearbox is run in, and then slowly reaches a plateau of service the extent of which no one knows, though we can guess by the experience of permanent tourers (to make Tom's point) that it is in excess of 250,000km, I repeat, nobody knows how far in excess. It takes somewhere between 3000 and 8000km (in my opinion) to run in a Rohloff, so for the discussion above we have to assume the box being tested is run in. Chalo once said something to the effect that a Rohloff gearbox is run in about the time a Shimano gearbox dies, so he might have a different view on how long a Rohloff box runs in; I bow to superior experience. I mention it though because we can't set the period of run-in of the Rohloff box longer than the entire service life of the competing derailleur system -- we'd be laughed out of the Double-Blind Testers' Club.

Apparently, Jute still gets paid by the word. Pity.

- Frank Krygowski