TomI 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
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.
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