Rohloff Speedhub

[JamesC]

I have been considering a few ideas for a new rear wheel build and come across a gear hub called a Rohlhoff (speedhub 500/14). These seem quite expensive, but have a wide range of gear ratios. Does anyone have experience of this type of gear? Durability, longevity, parts availability / support etc. I don’t know if they are suitable for ebikes such as the Pro Connect , so maybe they are aimed at the MTB market.
Just putting a few sprocket combinations into a crude spreadsheet that I have cobbled together, road speed (MPH) at a pedal cadence of 65 is as follows: (I’m assuming that 65 is the highest cadence at which the Panasonic motor provides assistance. Is this correct?) I have based this on the Pro Connect 700C wheel.

Gear......Nexus 18T Rear (mpH).....................Rohlhoff 13T Rear (mph)
1..........6.226881.......................................4.564501
2..........7.60932.........................................5.169829
3..........8.838154.......................................6.69133
5.........11.81571........................................7.591142
6.........14.45062........................................8.638196
7.........16.7665..........................................9.816132
8.........19.0823.........................................11.15767
9.............................................................12.66281
10...........................................................14.41335
11...........................................................16.36022
12...........................................................18.56885
13...........................................................21.1374
14...........................................................24.00044

The ratios of the Rohloff hub seem to sit nicely with the Nexus 8 speed providing additional ratios either side of first and eighth. Is this just expensive overkill or is there a worthwhile benefit to having these ratios available? I think the Nexus 8 speed hub suits my riding requirements well, but I am curious about the Rohlhoff hub. Any comments regarding its suitability on an ebike welcome. Finally will it fit into the wheel mounting lugs which are spaced for a Nexus hub?

Thanks
Tom

Tom
I have not yet fitted the Rohloff, but expect to play with it during the Summer.

A couple of points in comparison to the Nexus:
1. The standard 16T sprocket and the optional 15T sprocket put the chainline about 3 mm outboard of the standard Nexus hub.
The smaller Rohloff sprockets (14T and 13T) put the chainline well outboard in order to avoid the chain fouling on the gear case.

I have not looked at repositioning the chainwheel on the Panasonic drive. I think that the only easy way would be to remove the centre from a second chainwheel and bolt this ring on the outboard side of the existing chainwheel.See below - chainwheel must stay in line with motor sprocket and tensioner - sorry

2. The tidy installation of the Rohloff on the Flyer is probably down to the frame having specific dropout slots to accept the small Rohloff OEM non-rotation bracket.

The ProConnect has a couple of small threaded holes that might be useable to restrain a small, homemade, non-rotation arm, but the obvious choice is the large Rohloff arm along the chain stay (a bit ugly in my view).


Given that the Panasonic drive already has an adequate chain tensioner at the pedal end, it would have been excellent if Kalkhoff had designed a vertical drop out slot for the rear wheel, rather than horizontal and open at the pedal end.

The horizontal slot makes it difficult to tighten the wheel sufficiently against the chain tension of human + motor.

I would recommend that you use the TS "nutted" version of the Rohloff hub rather than the CC Quick Release in order to tighten the wheel sufficiently in the slots.


Parts for the Rohloff are very readily available, but very expensive with the present GBP/EUR exchange rate. In the UK, Kinetics and SJSCycles are likely suppliers.

James

PS A nice feature of the TS "nutted" version is the availability of an "extended" axle plate. This provides a long bolt for the attachment of trailers.

 

[flecc]

I have not looked at repositioning the chainwheel on the Panasonic drive. I think that the only easy way would be to remove the centre from a second chainwheel and bolt this ring on the outboard side of the existing chainwheel.

James, please forgive my interjection in your message to Tom. The chainwheel spline mounting with a circlip retainer already allows quite a lot of wobble once bedded in, and shifting the chain force laterally out of line would increase the pressure on the circlip and possibly worsen that.

More importantly, the chain alignment with the very close motor sprocket would be lost. As you know, the loss of efficiency due to minor chain misalignment over the whole chain run is tiny, so it would be best to leave the chainwheel as it is.

Given that the Panasonic drive already has an adequate chain tensioner at the pedal end, it would have been excellent if Kalkhoff had designed a vertical drop out slot for the rear wheel, rather than horizontal and open at the pedal end.

All bikes using the Panasonic system with hub gears use longitudinal adjustment wheel mount slots. This is because the "chain tensioner" isn't really that, but a chain wrapper for the motor sprocket. If you again examine the upside down view of the photo I linked to above, you'll see that as a chain stretched and the wrapper arm rotated out, the distance of the idler sprocket to the rear wheel shortens or stays roughly the same so it would not tension the chain length. To be a fully effective chain tensioner the arm geometry would have to be different.
.

 

[JamesC]

Absoloutely right, Flecc - brain fade on my part in suggesting that the chainwheel line can be altered.

James

 

[JamesC]

All bikes using the Panasonic system with hub gears use longitudinal adjustment wheel mount slots. This is because the "chain tensioner" isn't really that, but a chain wrapper for the motor sprocket. If you again examine the upside down view of the photo I linked to above, you'll see that as a chain stretched and the wrapper arm rotated out, the distance of the idler sprocket to the rear wheel shortens or stays roughly the same so it would not tension the chain length. To be a fully effective chain tensioner the arm geometry would have to be different.
.

I don't know whether the newer Panasonic drive does have the spring loaded arm in a slightly better position to effect some chain tensioning, but it feels as though there is enough tensioning to deal with a half link of stretch without any compromise to the motor sprocket wrap.

Standing on the pedals + the motor assist pulls the wheel strongly towards the pedals, and needs very tight wheel nuts on less smooth road surfaces.

I wonder whether others have experienced any movement in the dropout on the sprocket side on rare occasions.

With the number of bike models that couple the Panasonic drive to a hub gear (no derailleur tensioner), it would remove a slight worry if the hub could pull against a vertical slot in the frame, rather than rely wholly on the wheel nut to stay in place.

James

 

[tillson]

I wonder whether others have experienced any movement in the dropout on the sprocket side on rare occasions.

I have had this happen, but it was my fault for not tightening the nuts to the correct torque. I gave them what I thought was plenty of pressure on the socket wrench, but the sprocket side moved forwards whilst going up an incline.

After tightening the nuts to the recommended 45 NM, I have had no problems.

 

[flecc]

I don't know whether the newer Panasonic drive does have the spring loaded arm in a slightly better position to effect some chain tensioning, but it feels as though there is enough tensioning to deal with a half link of stretch without any compromise to the motor sprocket wrap.

It's actually much worse than the old unit James, because of it's 9 tooth motor sprocket. That had a 14 tooth sprocket much less inclined to allow the chain to jump the motor sprocket teeth. You may have seen some members have suffered this jumping on the new unit when the chain adjustment hasn't been correct.

Old unit . 7 teeth engage . . . New unit . 4 teeth engage motor chain sprockets

Standing on the pedals + the motor assist pulls the wheel strongly towards the pedals, and needs very tight wheel nuts on less smooth road surfaces.

I wonder whether others have experienced any movement in the dropout on the sprocket side on rare occasions.

This was a problem on the Lafree, partly through the frame softness, David Henshaw of A to B magazine suffered it as you'll see on my website here.

With the number of bike models that couple the Panasonic drive to a hub gear (no derailleur tensioner), it would remove a slight worry if the hub could pull against a vertical slot in the frame, rather than rely wholly on the wheel nut to stay in place.

There are two problems with using the chain wrapper as a tensioner:

The first is that it would increase the chain path length from motor sprocket to idler with the spring tension reducing at the same time, and this would allow the chain to have some trailing slack to allow the jumping mentioned above which it's so prone to, this lower chain run not under drive tension of course.

The second is that there isn't enough travel on the wrapper arm without seriously compounding the above problem. The rear frame slots allowing up to 15 mm or so of adjustments acts on both upper and lower chain runs to allow a total about 30 mm/1.25" of adjustment for chain and sprocket stretch/wear and chainlink/half-link variations. The wrapper arm only acts on the lower run and would need to arc through 30 mm circumferentially to do the same. The chain would definitely jump the motor sprocket well short of that, the wrapping function being essential.

I'm sure the existence of the frame slots on all hub motor Panasonic unit equipped bikes results from Panasonic's own guidance on it's use.
.

 

[Beanie101]

Hi Beanie
Thanks for the review of your Flyer T14 HS.
I have gradually been accumulating the bits to try the Rohloff hub on my ProConnect.

Does the Flyer use the 41T chainwheel on the Panasonic drive, and the 16T sprocket on the Rohloff hub ? I am planning to use 41/15, as the low end gears seem to go towards a very low first gear which might be too slow to retain balance.

James

Hi James

Sorry, I don't know. The only trouble that I've had with balance using the low first gear is tipping over backwards because of the incline! Or having to zig-zag because I couldn't get traction going straight up on loose shale

 

[JamesC]

Hi James

Sorry, I don't know. The only trouble that I've had with balance using the low first gear is tipping over backwards because of the incline! Or having to zig-zag because I couldn't get traction going straight up on loose shale

Thanks Beanie - nice and low then.

James