Rohloff Hub drag - what is normal?

[AlexRa]

So I know Rohloff hubs have some drag. But is mine normal? I’ve got my bike on a stand. I hand crank the pedals to get the wheel spinning. Then I hold the pedal still. The wheel seems to stop fairly quickly. Is that normal? Here’s a video of me doing it so you can see how quickly it stops and the kind of speed I’ve cranked it to.

https://youtube.com/shorts/fJe6HjUAtMY?feature=share

If this is normal then that’s totally fine. But if not, I’d like to know.

I know they wear in over time. Mine is second hand - and I have no idea how far it’s been!

[il padrone]

I am not sure what my hub drag is like as I have never placed it on a stand to spin it like that. The drag that matters is the drag you can feel as you ride. I know that I can happily ride and roll at the same speeds as I used to do on my derailleur bike, and pace it with my fellow riders.

One comparable thing could be the drag from the SON28 dynohub. When I first got mine I tried to spin the axle and was horrified at how hard that was. It does not spin at all like a normal hub. But once in the wheel and rolling I cannot notice any drag. In fact my old SON28 was cited by Peter White Cycles as like riding a climb of 1m per kilometre when the light is switched on, and about 30cm per kilometre when switched off. These sorts of gradients are what most people would describe as a flat road, and the new SON28 has even lower drag.

Others may know more and have some data.

[spoof]

Hi Alex,

I no longer have my Rohloff hub bicycle so cannot do a comparison to the freewheel action what was of mine to yours in your recent demonstration video.

... but ...

I do remember the freewheel action that was of mine well. Even though the wheels were 26", ex-box and oem anti-torque bracket differs slightly to your setup, I remember the freewheel action of mine consisted of a lot more rotations of the hub wheel than yours exhibits in the video. Maybe some other folk with an actual hub and bike stand could cross reference to help narrow things down for you but upon looking at your video, I would think there is some internal resistance going on inside the hub slowing it down prematurely.

edit: I watched your video on repeat about 20 times and is hard to say so take what I said with a pinch of salt. Hopefully someone here will give their hub bicycle a similar test reconstruction for you with maybe a set gear 7 for example, similar teeth chainring/cog and fixed number crank revolutions to see if the freewheel performance is similar.

[JohnR]

This might be relevant http://thorncyclesforum.co.uk/index.php?topic=12490.0 .

[Dunroving]

So I know Rohloff hubs have some drag. But is mine normal? I’ve got my bike on a stand. I hand crank the pedals to get the wheel spinning. Then I hold the pedal still. The wheel seems to stop fairly quickly. Is that normal? Here’s a video of me doing it so you can see how quickly it stops and the kind of speed I’ve cranked it to.

https://youtube.com/shorts/fJe6HjUAtMY?feature=share

If this is normal then that’s totally fine. But if not, I’d like to know.

I know they wear in over time. Mine is second hand - and I have no idea how far it’s been!

I did something like this just last week. I had fitted a set of SKS mudguards and wanted to check there was no friction anywhere. I repeated the test in your video several times - before and after removing and replacing the rear wheel. I wanted to do this as a check I hadn't mucked anything up (first time removing my Rohloff rear wheel).

I do distinctly remember the wheel coming to a stop much sooner than my derailleur-equipped bikes, whose wheels seem to rotate forever before stopping. However, I'm pretty sure mine didn't stop rotating as quickly as yours. Unfortunately, I can't replicate the experiment for you as I'm leaving for a LEJOG trip in the morning and things are a bit chaotic here!

[geocycle]

Rohloff have of course counted the number of revolutions to expect after cranking the bike up to speed in a stand. The answer is 15 when in gear 14.
https://www.rohloff.de/en/service/handbook/faqs#c9471

[GamblerGORD649]

Have you re-lubed it? You are not getting it spinning very fast is what's happening. The bike is only hanging on a rope. WTH. Turn it upside down and REALLY get it going properly. Mine goes around about 30 secs, nut and bolt axle version. Actually, my Nexus 7i with a roller brake is worse. LOL.
The Rohloff is also coasting way better now after 18,600 miles.
Another thing to try is going to a hill and noting the max speed for various bikes. I finally got it up to 43 mph.
My SA XL-RD5w has gone 46 mph on the same bike and 44.6+ on 2 others.

As for a SA XL-FDD dyno drum hub, it's been my front hub for 30,000 miles. It sure as hell doesn't slow me a bit, lights always on.

[mickeg]

My Nomad Mk II Rohloff, if I was off the bike and pushed it forwards, the crank always turned.  I think my bottom bracket is a UN55.  But now nine years later, sometimes it does and sometimes it does not.  Perhaps my seals have loosened up some.  It also varies on which gear I am in as some gears do not turn the crank and some do but I do not not recall which.  I am not going to go out and verify this, but I think if it is in high range (gears 8 to 14) it is less likely to turn the crank when I push the bike than if in low range (gears 1-7).

Since most of the time you are turning the crank with your feet, that extra drag when coasting really does not matter much on a long ride as you likely did not coast much.

[PH]

it's a pity the OP hasn't been back with an update, either here or on the CTC forum where they posed the same question.  Maybe they found the answer somewhere else. I hope they haven't concluded there's a problem.
Has anyone ever measured the wattage of a spinning unloaded wheel? It must be tiny.  I have spun one with and without a tyre on, there's a considerable difference, flywheel effect? By the time the wheel's being ridden, I suspect that added drag in the hub, which must exist, will be too small to notice.
I've played around with freewheeling down a hill on various bikes, not enough examples or consistency to be conclusive, but anecdotally, wheel size made the biggest difference, followed by tyre size and pressure.  There was no measurable difference between my Rohloff and derailleur touring bikes at a similar weight and the same tyres. Yet spinning those wheels on a stand is completely different.

[mickeg]

it's a pity the OP hasn't been back with an update, either here or on the CTC forum where they posed the same question.  Maybe they found the answer somewhere else. I hope they haven't concluded there's a problem.
Has anyone ever measured the wattage of a spinning unloaded wheel? It must be tiny.  I have spun one with and without a tyre on, there's a considerable difference, flywheel effect? By the time the wheel's being ridden, I suspect that added drag in the hub, which must exist, will be too small to notice.
I've played around with freewheeling down a hill on various bikes, not enough examples or consistency to be conclusive, but anecdotally, wheel size made the biggest difference, followed by tyre size and pressure.  There was no measurable difference between my Rohloff and derailleur touring bikes at a similar weight and the same tyres. Yet spinning those wheels on a stand is completely different.

I have never tried to estimate wattage, but I would not be surprised if the drag on a Rohloff when the wheel is turning but the crank is not might be about double the drag from a dynohub powering lights.  This is just a wild guess on my part.

I can't feel the extra drag when my dynohub lights are on compared to off when I am riding the bike.  But if I am off the bike and spin the wheel by hand the wheel will spin much longer if the light is turned off than if the light is turned on.  Thus, I know that the drag is there.

Almost a decade ago I saw an article that had a graph of dynohub drag at different speeds with lights on or off, but that is off topic so I will only search for it if someone asks.