Fitting Rohloff to old bike?

[deejayen]

It's early stages, but I'm considering installing a Rohloff on an old recumbent bike.

The bike has a fairly standard rear triangle made from slender-ish steel tubes.  Vertical dropouts, and 135mm rear spacing (current hub has a quick release).  Rear wheel is 700c, and it has rim brakes.  It also has a rear derailleur hanger which could be used for a Rohloff chain tensioner.

There are no cable guides along the left hand (non-drive side) chainstay.

From what I see I'd need a 'regular' 135mm hub with either the disc brake cap (for any future changes) or smooth cap. 

Also, would either the QR or threaded axle work - is there any preference?

I'm not sure about the internal or external gear mech.  Which would work best on a bike which wasn't built with Rohloffs in mind?

I expect I'd also need the 'standard' hub which uses a separate torque arm.  Is this likely to cause any problems?

[PH]

I'll have a go at those:

There are no cable guides along the left hand (non-drive side) chainstay.
You can get purpose made fittings that stick and zip tie on, but standard zip ties are fine.  There's no indexing to worry about, but a smoother cable run gives a smoother shift.

From what I see I'd need a 'regular' 135mm hub with either the disc brake cap (for any future changes) or smooth cap.
If buying new there's no disadvantage to getting the disc hub, unless it's dearer.  If buying secondhand, non disc models fetch a good bit less.

Also, would either the QR or threaded axle work - is there any preference?
I have both, they work the same in a vertical dropout, the nutted axle is better in a horizontal.  Wheel in and out takes a bit more time with a nutted axle and of course you need a decent spanner.  By default I'd choose QR, but it's no big deal.

I'm not sure about the internal or external gear mech.  Which would work best on a bike which wasn't built with Rohloffs in mind?
Again both work fine, the internal is a bit crisper.  You have to have the external with discs, you can have either with rim brakes. The external is easier to detach, it's also easier when you replace cables.

I expect I'd also need the 'standard' hub which uses a separate torque arm.  Is this likely to cause any problems?
There's no issue.  The torque arm is a bit ugly, you have to detach it to remove the wheel, that's simple enough. You don't have to line anything up when refitting the wheel, which is an advantage over some methods.

There's various chain tensioners, chainline is easy to adjust on the Rohloff one, it's well built and parts replaceable. I have one on my folder, it isn't as big a disadvantage as some think.

[mickeg]

First of all, one topic you did not mention is spoke pattern.  Make sure that the wheel builder reads the Rohloff instructions for wheel builders.   I had my bike in a bike shop, a mechanic was looking at it and said that he was going to build up a Rohloff wheel for a customer.  Then he said he was going to use three cross, but was curious why mine was two cross.  I asked him if he had read the Rohloff instructions for the wheel builder, he said he had experience and did not have to read anything about building wheels.  I then told him if he built up the wheel the way he planned, his customer might have a lot of spoke breakage.  I have no clue what he did.  Point being, if your mechanic says he does not need to read the Rohloff instructions, find a different wheel builder.

I built up my wheel over a decade ago, I think now Rohloff specifies Sapim spokes where they did not when I built mine.  Sapim Polyax nipples, I would suggest them.

The Rohloff puts a lot of torque on the frame, so you probably need the hub with that long torque arm.

My bike uses the EX box.  It is easy for me to fit new cables.  I am clueless about the internal cable, so can't comment on that. 

I see no reason you can't use a couple zip ties for cable guides.  But if you had the kind of hub with internal cable, you would need some cable housing stops. 

Yes, 135mm.  I suspect that the nutted hub would work, but I would go with the quick release.  Hub does not come with a quick release, you would need to add the skewer to your shopping list.

I used 36 spoke for my bike, it is used for heavy touring.  For your purposes, you may prefer 32 as some rims are getting hard to find in 36.  But if your rim is readily available in both 32 and 36, use whichever you prefer.

You did not ask about gearing.  You need to figure out what gear range you want so you can chose the chainring size for your crankset.  I use a 44T chainring for riding near home on an unladen bike, but I change to a 36T for loaded heavy touring.  This is the Thorn forum.  Thorn uses 17T sprockets by default, but Rohloff comes with 16T. 

You did not mention chainline.  I think there is some info on that in the Rohloff printed materials, but I built my bike over a decade ago, I do not recall the details on how I picked bottom bracket spindle length.

I see PH just posted a response.  I agree with everything he said.

[Andre Jute]

The bottom bracket will have to be the last thing you order, because the Rohloff chainline is expected to be within one millimeter of true. (I know, several parties have skewed chain lines and claim no bad effects.) A straight chainlink helps reduce noise and increases chain/sprocket life.

If you're not planning to fit a Hebie Chainglider (it's a near-complete chain enclosure, the nearest thing to the mythical oil bath for the transmission), you could buy a secondhand Thorne chainring, a default fitment that is good and thick, very long-lasting, but for the same reason taken off by cyclists fitting the Chainglider because it requires a thinner chainring. You might be able to pick up the Thorn chainring at a good price on the forum.

Gotta go cook.

[Tigerbiten]

With a recumbent you'll have a lot more freedom about the chain line simply due to the 2.5x chain length.
On my bent trike I use twin chainrings (38/56) to give 3x more gears at the top end.
The pully/chain tubes keeps the chain line correct at the hub even when shifting chainrings.

[deejayen]

Thanks, everyone.  That's really helpful.

I've watched a video on changing the cables for the internal mech - it doesn't look too bad if you change them at home as part of routine maintenance.

I did notice that they had a 2-cable stop which bolted into the canti brake studs.  I'll look at my bike, but that might simplify cable routing.  It's an underseat steering longwheelbase bike, so the cables could be run from the handlebars under the seat to the 'seat stay' where the brake posts are, and from there the inners would run down to the hub, so I don't think I'd need anything along the chainstay.  I think it would be a relatively short cable run, too. EDIT - I've just had a look at the bike, and the rear brake (an old Magura HS hydraulic rim brake of some sort) is on the underside of the chainstays.

As Tigerbiten says, chainline probably won't be too much of an issue due to the long chain on this bike.  I'm not sure if it would need any sort of chain tube or idler, or if it would need some sort of chain retention at the chainring (eg a derailleur cage or a narrow-wide chainring).  Perhaps the chain tensioner and a correctly sized chain would keep things under control.

Gearing might take a couple of goes to get right, but I'd probably try a larger rear sprocket, say 19T, with a larger chainring of around 48T, 50T or 52T.  I suppose the thing is to gear it such that the majority of your riding is in the most efficient gears.

As I said, it's early days, but if I decide to give it a go and bought a new hub I'd get it from SJS Cycles and have them build it into a wheel so that the build would meet Rohloff's recommendations.  Speaking from experience with other recumbent wheels, broken flanges, snapped spokes and split rims are bad!

[PH]

A couple of other thoughts, if the cable run is low and likely to attract dirt, I'd either choose the external mech, or come up with a way to protect the connectors.  The bayonets can be a little awkward to detach, keeping them clean would be an advantage.  The brake boss is the more usual place to put the stopper on the int mech, but Rohloff do a fitting so you can add it to any tube. 
If using the external mech, there are clips that allow you to attach cable to cable, both bike specific and those intended for electrical cables. it would be straightforward to have the gear cables attached to the brake cable until their routes diverge, I did this when I had a Surly frame. 

I've watched a video on changing the cables for the internal mech - it doesn't look too bad if you change them at home as part of routine maintenance.

I wouldn't consider either to be difficult, but both are awkward enough that I wouldn't want to do them roadside, not that I'd be carrying the parts anyway.  It's such an infrequent task, that I wouldn't choose hubs on this basis, but the external is easier in all regards.

[mickeg]

Decades ago most bikes did not have much in the way of brazed on cable stops or cable guides.  Even water bottle cages came with straps to strap around the frame.  Back then, bolt on cable housing stops were made that would strap around the chainstay for the rear derailleur cable.  My point is that this could be another option if you can find such cable stops for the shifter cables if the canti brake mount bracket does not work out.  Attached photo shows an example, this is on a 1960s vintage bike I have not ridden in years that I have in storage.

On gearing, if you could figure out what the lowest gear that you would need for the steepest of hills and pick sprockets and chainring to match that for first gear, that might be the way to go.  I knew before I bought my Rohloff bike and hub that I would want two sets of gears, one that was ideal for around town riding near my home on an unladen bike.  And a different set of gears for heavy touring where my lowest gear was my priority.

On my other bikes, I noted what derailleur gears I used for the extremes of uphill and downhill, picked my chainring size based on that for my riding around home.  I decided to stick with the standard sprocket size of 16.  I am a retired engineer, so I did this with a spreadsheet.  But now there are gear calculators on line that would make that easy.  These are the gears I use around home.
https://gear-calculator.com/?GR=RLSH&KB=44&RZ=16&UF=2120&TF=72&SL=2.6&UN=MPH&DV=teeth

For comparison, these are the gears on my Thorn Sherpa touring bike which has a 3X8 half step plus granny drive train, I wanted my Rohloff gears to be similar to these gears for unladen riding.  I try to avoid using the two most cross chained gears on each chainring, so I set it so that those two gears are in light gray instead of black on the graphic.  But you with a recumbent, not sure if cross chaining is a thing or not.  A friend of mine had a recumbent trike with a 3X10 drivetrain, cross chaining was not an issue.
https://gear-calculator.com/?GR=DERS&KB=24,42,46&RZ=11,12,14,16,18,21,26,32&UF=2200&TF=72&SL=2.2&UN=MPH&DV=teeth

And for heavy touring, I wanted a first gear that would give me a cadence of 72 at 3.5 miles per hour, which is about the slowest speed I can pedal without a lot of over-steering to maintain vertical and directional stability.  And I picked a chainring that would give me that for my lowest gear.  I swap chainrings and add or subtract four chain links when I change chainrings.

You could play around with options at that website.

Or, plan B.  Contact some recumbant bike builders that have fitted their bikes with Rohloff hubs and ask what sprocket and chainring they used.

I assume your knowledge of Rohloff is not very high.  So, you may not know about cable tension.  You want a lot of slack in the shifter cables, this is the opposite of derailleur systems.  If I am in gear 10, my shifter can turn from 9.5 to 10.5 by just taking up the slack in one cable or the other.  If your cables are too tight, that can lead to gear shifting problems.  That can be a hard thing to get used to when you are used to derailleur systems that have no slack in the cables.

You will have to figure out where to put your shifter.  I am clueless about the controls on your recumbent bike.  The Rohloff shifter is sized for the end on a mountain bike handlebar.  There are lots of other options.
https://www.cyclingabout.com/rohloff-hubs-with-drop-handlebars

Second attached photo, I use the Hubbub adapter to put the Rohloff shifter on my drop bar handlebar end.

I see once again PH posted a reply while I was typing.  Nothing I wrote conflicts with his comments.

[Andyb1]

If you are buying a secondhand hub be aware that early hubs which are heavily used can occasionally crack at the spoke holes.  Rohloff supply alloy rings to stop this problem but it means rebuilding the wheel to fit them.

[deejayen]

Thanks again for all the great info.

I checked with ICE Recumbent Trikes (here in the UK) because they sell a modified Rohloff shifter which is extended so that the entire grip rotates.  HP Velotechnik also supply similar (it could be the same product).  On a recumbent a normal twist shifter would end up being positioned so that you'd have to grip it with your little finger and heel of your hand, which I imagine could be awkward and tiring.  The extended shifter allows you to grip and rotate the shifter with thumb and all fingers.  I think it's over £200, though. 

I always thought that buying a used bike with a 'run-in' Rohloff would be a good option, but I think in this case it would make more sense to buy new. 

I'll check out the various Rohloff fittings.  Although the internal mech might be fine for this bike, I suppose it could be wiser to buy a hub which has the disc brake option and external mech, as there'd be more chance of it being compatible with a modern frame if I upgraded the bike.

[mickeg]

If the trike dealer used the Hubbub adapter, that is what I have on my bike that I showed the photo of in a previous post.
https://www.sjscycles.co.uk/gear-spares/hubbub-drop-bar-adaptor-mount-for-rohloff-63-mm/

That adapter sticks inside the end of the handlebar and gives me a place to put my Rohloff shifter.  The Rohloff can slide on either way, little fingers or big fingers.  The key point is the outside diameter of the tubing that the Rohloff shifter slides onto is the old mountain bike handlebar diameter, I think it is 22.2mm, but I could have that wrong.

If that adapter is what you use, you have to tighten it really good.  I have read that some people did not crank down on it when they installed it, and the torque from shifting loosened it up over time.  So, I cranked mine down really tight and it has been trouble free for the past 12 years.

I am quite happy with the external shift mechanism.  My bike frame came with cable guides for that version, so that is what I bought.  To remove the wheel, you unthread a thumb screw and remove the part that the cables are attached to slides right off.  If you get the external gear version, you should be careful when the wheel is removed that you do not move the shifter.  OR, the smart way to do it is put it in gear 1 or gear 14 before you remove the wheel, then make sure that the shifter is set in that gear when you replace the wheel.  I usually forget to do that, so sometimes I have to spend a couple minutes getting it right.

[martinf]

If the trike dealer used the Hubbub adapter, that is what I have on my bike that I showed the photo of in a previous post.

The Hubbub adapter works well when you want the Rohloff shifter as a prolongation of an existing handlebar. I have Hubbub on the ends of the drop handlebars on my two Rohloff equipped full-sized bikes.

I have used 4 other methods to fit a Rohloff twistgrip or similar twistgrips.

1 a crude but no-cost copy of the Hubbub made from a short bit of MTB handlebaradded to the end of drop handlebars. I used a bit of smaller diameter tubing from an old camping chair, with epoxy resin glue to hold the whole lot together.

2 the Thorn accessory bar that fits to the steerer tube to put the twistgrip under the handlebars.

3 a sawn-off bar end extension that happened to have 22.2 mm outside diameter. I fitted this to an old-style handlebar stem, which was also 22.2 mm outside diameter, so the clamp on the bar end extension fitted. More or less the same position under the handlebars as method 2.

4 on one of my Bromptons, I used a Brompton accessory bracket to put the Rohloff shifter under the Brompton handlebar (photo below). It would work for other riser bars with 22.2 mm outside diameter.

[mickeg]

...
3 a sawn-off bar end extension that happened to have 22.2 mm outside diameter. I fitted this to an old-style handlebar stem, which was also 22.2 mm outside diameter, so the clamp on the bar end extension fitted. More or less the same position under the handlebars as method 2.
....

I also did that for a year or two before I settled on the Hubbub.  That extension worked well, I just wanted the shifter to be on the handlebar so I could have both hands on the bars for steering when I also needed to shift.

Now that you mention it, this might be a great option on a recumbent.