Which geared hub for BBSHD in a full-fat tandem trike?

So, I've built this beast of a tandem trike based on all 26x4.0 wheels and currently the rear wheel is built with a 170mm fat bike hub and a 9 speed derailleur drivetrain. My BBSHD is up front at the captain's position and at the stoker's position I have an independent drive system (same one used on the e-assist DaVinci tandems - had them machine a separate unit for me). I don't know exactly what I did when I built the frame but for whatever reason I can't get the lowest gear on the cassette to effectively clear the sidewall of the rear tire without bending the chain outwards in what looks like "quickly destroyed" manner, especially with the BBSHD power output and two riders pumping human power into the equation as well. I've had internally geared hubs on cargo bikes in the past, and I even ran this BBSHD on a cargo bike with an early generation Shimano Alfine 8 speed hub. Anyway, to improve chain lines I'm seriously considering building up the rear wheel with a 135mm hub instead of the 170 and going with either an Alfine 8, or a NuVinci N171, or NuVinci N380.

It seems like any of these would likely be okay to use with the BBSHD but I'm also wondering since this is a tandem and the whole trike is a lot heavier than my cargo bike was, which IGH is likely to be the best option in terms of durability, and handling the BBSHD torque. A few key things - I prefer to the use the BBSHD as e-assist and rarely ever use the throttle, and if I do I'm almost always still pedaling and I'm only using the throttle to goose a little more assist out of the system momentarily for say getting quickly away from a stop in traffic, to when needing to pass several slower cyclists on a path or something in a quicker amount of time. Most of the rest of the time we'd prefer to use the assist at a very low setting so we're getting still getting our exercise. We're looking at the e-assist on the tandem as something for extending range and when the trike is in single-rider cargo hauling mode (rear seat is removable and there will be a cargo deck), then the motor would provide a little more assistance. In both use cases though, we're never riding throttle-only or otherwise "hot-rodding" the BBSHD.

Other factors would be WHERE we would intend to use the trike. Probably the greatest usage will be on streets and multi-user paths, but it should also be able to handle hills and some rough road riding (gravel/forest service roads), and some light off-road, but mostly gravel double-track type stuff and not necessarily bombing down gnarly singletrack downhills or anything. So, which hub do you think would be a good match for this trike? I'm kind of leaning towards Alfine 8, but only because I have a lot of experience with them on several bikes, but I don't know if it can handle the torque of tow riders AND whatever the BBSHD is putting out. It seems like the N171 hub is pretty strong for use with mid-drives and the BBSHD in particular. They are of course still available new, but from what I understand I bit more complicated to set up and I'm a little wary on buying a hub that's been out of production for a long time and for which there is no warranty support and dwindling spare parts available. I know I can always buy guts for Alfine 8 hubs to replace them and I even know there are tools to do more extensive rebuilds of those hubs. The N380 seems like a decent choice as well, but again - what is warranty like, especially since NuVinci specifically won't warranty usage on anything over 750w (BBSHD is 1000w, of course), again I wonder about replacement parts and such since NuVinci is now "Enviolo" and have changed their hubs in appearance. I have no idea whether the guts of the new Enviolo hubs are the same as the N380/N360 though. I do see there is an Enviolo specifically designed for cargo bikes or things like rickshaws/pedicabs though. Of course those are their latest models and more expensive than I'm looking to buy. Anyway, any suggestions for a suitable geared hub for this build, or should I just focus on figuring out how to improve my derailleur chainlines?

Why is Rohloff not in consideration?

Just too pricey?

Believe me, I'd LOVE a Rohloff but it's just WAY out of the price range. Also, Spinning Magnets did a write up a few years ago about IGHs and mid-drives and the gist of that article was that the Rohloff is a great, durable hub, but the ratios are so close, almost everyone who puts one on an e-bike ends up shifting so much they're only using half or less of the 14 available gears. I did something very similar with the the Alfine/BBSHD on my cargo bike. I used probably about 3 or 4 gears total. Although part of me wants a Rohloff just because there is SO much range when you're unpowered. I even envisioned that maybe riding this in tandem-mode would be largely unpowered, and the e-assist would be for those really windy days, or for helping dramatically extend the range of a ride. But, I can also see scenarios like doing a century ride (100 miles), and running out of juice in the battery and not having anywhere nearby to recharge. In that instance you'd WANT something like the Rohloff to help you get this heavy beast home or at least somewhere to recharge a bit.

If Rohloff is too spendy, then that leaves Nuvinci. N171 is rated 5kW and N3XX/Enviolo is rated 2.5kW (in both cases assuming compliance with input torque limits).

Under no circumstances would I use Alfine 8 to carry the power of BBSHD plus two people pedaling.

I visualize the Rohloff as a must-have for heavy tandem/cargo scenarios using mid-drives.

Especially if hills are in the picture, and **most** especially if human power is anything more than an afterthought.

As for the cost issue, just like spending thousands on excellent battery packs

my rationalization is that it will last through many iterations / instances of the bike around it

swapping controllers / motors / wheels even frames

in my pursuit of "perfection" or different use cases

The Rohloff being the one constant, likely lasting for decades.

Buying something weaker won't save you money when you need to replace / repair / upgrade / have spares handy.

Also check out Kindernay XIV from Norway, apparently a close copy of the Rohloff.

john61ct said:

I visualize the Rohloff as a must-have for heavy tandem/cargo scenarios using mid-drives.

Especially if hills are in the picture, and **most** especially if human power is anything more than an afterthought.

As for the cost issue, just like spending thousands on excellent battery packs

my rationalization is that it will last through many iterations / instances of the bike around it

swapping controllers / motors / wheels even frames

in my pursuit of "perfection" or different use cases

The Rohloff being the one constant, likely lasting for decades.

Buying something weaker won't save you money when you need to replace / repair / upgrade / have spares handy.

Click to expand...

Rohloff isn't as robust as NuVinci N171. Its rating for gross power is the same as the later, lighter Nuvinci/Enviolo hubs. All three have the additional advantage that they default to a fully engaged "in gear" state even when the shift cables are poorly adjusted or broken. This is especially important when you use power or torque in excess of what pedals alone can do.

Chalo said:

Rohloff isn't as robust as NuVinci N171. Its rating for gross power is the same as the later, lighter Nuvinci/Enviolo hubs.

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Wow yes 130Nm peak!

So despite both being rated the same, what makes the Rohloff "less robust"?

I've seen advice limiting Rohloff to 90Nm continuous

are you saying the CVTs can IRL be pushed closer to their peak rating? I'm seeing only 65Nm continuous from the mfg data sheet. . .

Do the CVTs also have protective shear pins?

john61ct said:

Chalo said:

Rohloff isn't as robust as NuVinci N171. Its rating for gross power is the same as the later, lighter Nuvinci/Enviolo hubs.

Click to expand...

Wow yes 130Nm peak!

So despite both being rated the same, what makes the Rohloff "less robust"?

Click to expand...

N171 is rated 5kW. Rohloff is rated 2500W, same as N360 and its siblings. These are separate specs from max input torque.

N171 is about 9 pounds, N360 about 5 pounds, and Rohloff about 4 pounds.

Nuvinci roller based hubs don't shear parts when they reach their torque limit-- they slip. They don't have any gear teeth inside to break, either.

Good stuff, don't care about a few pounds extra,

hoping to support a 500# tandem/cargo total

I guess for strength heavier is better!

I assume rating for kW is going to be more oriented toward load at speed, as opposed to standing starts pointed up a steep hill, where the peak Nm is more relevant?

My use case is prioritising the latter, not planning on a faster top speed than maybe 20-25mph

Man these seem to be (were?) so cheap!

Recommended sources with stock, service, accessories, spares?

Thanks for the all the input. I'd done some more reading since posting the other day and it seemed like the far-and-away best option was the N171 hub. I found a 32 spoke one on ebay and ordered it. The seller had some replacement parts and such, but Calfee has all the same stuff for half the price so I'll be heading over there shortly to order up some rebuild parts to have stuff on hand. The hub I've bought doesn't seem to include a disc brake adapter though and I'm having little luck finding any NOS adapters anywhere online right now. Just my random test rides on the trike the other day indicated there was little braking power on the rear, even with a 203mm rotor. I think it's mostly because with the back end of the trike empty it weighs practically nothing compared to the front. I'm planning on putting the battery (15 pounds), on top of a rack on the back, and with the N171 hub (another 8 pounds), I should have a total of about 23 pounds (probably more due to the weight of the rack itself), on the back wheel. I may just see about buying a roller brake for the rear wheel since most of the stopping power will be from the front brakes, and you can easily install one on the N171 with no extra adapters. Anyway, I'm glad I bought an N171 hub because it really seems like the absolute best hub for this build and should be way more durable (and CHEAPER) than any other geared hub option. Given that the renamed Enviolo hubs now have an option for cargo bikes and pedicabs, I wonder how that one compares to the torque resistance of the venerable N171. It's a pity they didn't keep making N171 hubs for people with more demanding e-vehicle projects.

john61ct said:

Also check out Kindernay XIV from Norway, apparently a close copy of the Rohloff.

Click to expand...

Kindernay was briefly on the radar as well, but I knew they were as expensive (actually MORE expensive), than the Rohloff. Originally I was looking at what I could put in the rear of this frame that would fit the 170mm spacing that I initially chose. I'd originally intended to have two sets of wheels - a full-fat (like pictured), and a smaller volume set (probably 26x2.50 - likely Surly Extraterrestrials), however the chainline issues got me thinking about geared hubs. If you go geared hub though, AND you want a second set of wheels, that means a second geared hub. If I could find another N171 32 hole that *might* be an option but frankly I think I'd rather just buy different tires and go through the trouble of swapping tires. I figure the most I'd want to change would be maybe to smoother "street tread." Anyway, digressions aside, the nice thing about the Kindernay hub is you can swap it in and out of shells, so you could theoretically swap it between different bikes even, because the shell is laced to the wheel and the actual IGH is a modular unit that slides in and out. It's a really cool concept, but so far doesn't have longevity of the Rohloff and I just don't read enough bike related stuff to hear more about how the Kindernay is working out longterm. I also agree with your comments about the Rohloff and it being a quality part that can be moved around to different builds for years. Only problem is, if there are maintenance needs beyond oil changes - say a repair - you have to pack and ship the hub off to Germany so count on being without it for potentially months. They're tough, but I just don't think it's up to the task in something like this trike/vehicle. The N171 is the clear winner, made only problematic by the dwindling lack of repair parts. If you want to get your hands on an N171 there is a seller on Ebay who has some (that's who I just bought from), and for spare parts go to the Calfee Designs website and buy from them. Calfee's prices on the spares are HALF what the Ebay seller is charging for their stock of the identical components.

Good stuff thanks!

kiltedcelt said:

If I could find another N171 32 hole that *might* be an option

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I've heard rumours Chalo might have an old one just sitting around [emoji6]

Turns out I ended up buying a Rohloff after all. I was having problems with the shifter itself not wanting to effectively pull both cables equally. I'm betting NuVinci never expected someone to use their hub on a recumbent tandem and for it to have to pull cables that were nearly 4 meters long. The shifter just isn't designed well enough for that to work properly. So, I watched some videos, looked at specs and determined that the Rohloff shifter is WAY better built and I know for a fact that it has been used on some recumbent tandem trikes without issue. I do believe the N171 would probably be the more durable hub, but ultimately I know the Rohloff will outlive every trike project I choose to install it on, so I figured it was worth the investment. I'm currently waiting on a different left side axle plate to interface with my horizontal, rear-facing dropouts as the torque arm connection hardware that came with my hub just won't work with my frame. The other thing I hadn't known was that I should've bought the tandem version because it not only has longer cables (albeit not long enough for my frame), but they have aluminum sheer pins inside the hub versus the nylon ones in the basic version of their hub. Peter White Cycles is seeing if they can get some of the pins in stock for me, and if so swapping those pins is something they can do and it will only cost $25. It'll actually cost more to ship the hub back and forth to them than swapping the pins. It's more delays in my build which is aggravating, but I want to do it right so I guess I gotta wait.

Just a follow up to @kiltedcelt comment about shifting problems. I have a couple recommendations to help. 1. Use Jagwire LEX 4mm (non compressible) cable housing. 2. Lightly grease the cables before install. 3. Make sure there is a little slack in the cable after tightening up the adjusters on the shifter.
4. I use a shift cable sensor to cut motor power to my BBSHD while shifting.
Even when doing all that I have found that downshifting is impossible unless you reduce pedal pressure to zero. Upshifting works fine while pedaling with light pressure. I can even upshift when taking off with the throttle assist, I just let off the throttle momentarily when up shifting. After riding with the N171 for a few hundred miles you get used to it’s quirks.
The n171 hub also pedals easier then pedaling thru an e-bike hub motor. I can pedal about 16mph without power on my 70 pound e-bike. Overall I’m pretty happy with it on my custom fat tire e-bike.

john61ct said:

Good stuff thanks!



I've heard rumours Chalo might have an old one just sitting around [emoji6]

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No doubt he has his stash of good stuff hidden somewhere, under his fat bike parts no doubt.