Unicorn search? Off-road fat step-through + internal hub?

CCroft

Member
Hello!

I’m looking for what might be unicorn, but wanted to see if anyone has ideas/suggestions. I’m a backcountry nature photographer/trail camera enthusiast and have been using a BBSHD-converted fat tire e-bike for several years now to get to rough/remote locations. I’ve spent enough time on that bike to realize that my ideal backcountry e-bike would have the following:
  1. Step-through frame (maybe a frame design like this) that is strong enough for 275-300lb rider+ gear weight over rough/bumpy terrain
  2. Mid-drive, at least 750w, not torque-sensing, and ability to add throttle (user-adjustable assist levels + throttle like BBSHD are perfect for me/my riding)
  3. Belt rather than chain drive (this is the least important of my criteria)
  4. Tubeless-optimized fat tire wheels
  5. Internal hub rather than a derailleur, since weeds/grass often clog my derailleur, and I replace hangers 2-3x a year with the leggy derailleur getting abused by rocks, logs, etc.
I’d need a quiet internal hub. I upgraded my current BBSHD conversion to an Onyx rear hub to eliminate that pawl clicking, which has been great for the kind of “in nature” riding I do. I’m guessing no internal hub is that quiet, but from video of the Rohlhoff, I can say that would definitely be too loud for what I want. If there are no reasonably quiet internal hub options, I’ll probably just scratch that idea and live with cleaning the weeds/grass out of the derailleur and the annual derailleur replacement.

If such a bike doesn’t exist, what would be the best strategy for assembling one? Perhaps finding a bike that meets 1.-4., then switch out the rear wheel for a custom rear wheel build with an internal hub (assuming a reasonably quiet one exists)?
 
Last edited:
Maybe a unicorn, but you can get close if you peruse the Biktrix line-up.


Swapping the standard derailleur with an Enviolo CVT hub would be the quietest option, but I'm not sure how they fare over rugged terrain, and a noisier option might be better from a durability POV.

Here's a good write-up about the Enviolo hubs...

Is there a reason you DON'T want torque sensing? From my experience, there's no downside to torque sensing, and all upside.
 
Thank you for your reply. You're right, I don't have a good reason to be against the torque sensing, particularly since I haven't ridden a bike/motor with it. I was just imagining that it might be an issue as far as loss of control over challenging terrain (where I current use mostly throttle-only since I've gotten to a point where I can subtly control that). But my concerns might be more imaginary than real--I sure can't recall reading many criticisms of torque-sensing. So we scratch that factor off my list ;)

That's a fantastic article on internal hubs! An Eviolo CVT seems like a better choice from a noise perspective, although as you say, there's likely a tradeoff as far as durability. I think for me, that's a tradeoff I'm willing to make to try to find a quieter overall setup. Folks are right when they point out that just tire noise is likely to drown out much noise from the motor, hub, and drivetrain when we're talking about riding on harder surfaces like pavement and gravel, particularly at higher speeds. But for my riding, I'm on softer surfaces at low speeds, so there's little if any tire noise to drown anything out.

The Shimano Alfine seems like a very good choice in terms of my noise concerns, particularly since they "have a robust set of roller-clutches instead of pawls, so…when coasting unpowered, these hubs are just about as silent as it is physically possible..." The problem is I can't find many bikes running the Alfine designed/built for my more demanding off-road riding, rather than comparatively less demanding commuting/pavement riding. Something like that Biktrix Juggernaut (although 265lb seems like a really low weight rating...even something like the Evelo Omega is rated to 350lb) but with the Alfine and a belt drive would seem about perfect for my needs. Or a step-through "hunting" ebike like this, but again with the belt drive and the Alfine rather than a Rohlhoff.
 
Yeah, I don't see any downside to torque sensing, and having it on a mid-drive is, IMHO, really the best way to go (just for the type of riding I primarily do).

Pedaling through rough stuff is always going to be more economical on battery usage than blasting the throttle, as well. :)

As for max load capacities, the hardtail version of the Juggernaut 4 is rated at 330lbs, so my guess is that the rear suspension and linkage may be a limiting factor.

How demanding are you on the bike? Since you're using it for backcountry photography, and bringing camera gear possibly worth as much as the bike (or maybe more, if you're serious?) my guess is that you're not riding aggressively like someone riding for the sport/thrill of blasting through singletrack, so maybe one of the IGHs mentioned above would do the trick.

While this forum is great, you might want to see what kinds of experiences people over at the eMTBforums.com have had with some of the IGHs.

Also, if one of the major factors for an IGH is noise, and you don't mind maintaining a regular derailleur drivetrain, maybe a silent rear hub like the Onyx would be a good option.

You can get an idea on how quiet it is in this video.
 
The HD is not compatible with any internal hub I know of. Read the specifications of the hubs you are considering and pick a compatible motor from there. Even cargo hubs cannot take that kind off torque and are not designed for throttle surge from a dead stop. Shimano makes an eBike specific five speed IGH.
 
Mmm...good point on needing a safe match between the e-motor and the hub. It could be that there just isn't a quiet enough hub option that can handle the kind of motor torque I need for my off-road biking.

You're right antboy on my riding style. I'm pretty careful, both to protect my photo gear and my mid-50s body that doesn't quite bounce back as quickly as it once did ;) I'm moving at slow speeds (since I'm always scanning for wildlife), and for questionable sections I'm off the bike and walking it which I really don't mind doing...getting off the saddle a bit. My power needs are mainly for relatively short (and not crazy grades either...maybe 6-7% tops) runs combined with the weight of me + bike + gear. As far as stress on the bike/components, that's mostly from unexpected "drops" from weed/brush-hidden gopher holes etc., a feeling like when you hit an unexpected pothole while driving or a mogul skiing.

I'm currently running an Onyx rear hub; I splurged for a custom rear wheel build after a few months running a standard "clicking"/pawl freewheeling rear hub. Great setup! And my derailleur setup has worked well with the stress my BBSHD has put on it (I run a 40T single ring up front and very durable Shimano CS-M8000 11-46 cassette), it's only the occasional issues with derailleur-clogging and replacing hangers that had me thinking of derailleur alternatives. I'm attaching a picture of my current beast.

Going with a single-speed is another option, something available on some of the bikes marketed as "hunting ebikes." I'm not doing much hunting, but my needs/use case is pretty similar to some of these backcountry hunters. That would eliminate both the derailleur or IGH concerns. I've never ridden one so I have no idea what the riding experience is like. Apparently they climb well and handle loads great, but it looks like the top speed might be limited to 15mph. That would make for somewhat slower-going for trips where I have gravel road sections before/after my main backcountry riding, but would probably not be a deal-breaker for someone like me. And having to peddle it out if the batt or motor gives up would be no fun... Single-speeds for all-terrain/hunting seem to be pretty rare right now, and assuming there's a good reason for that, that might be a risky choice.
 

Attachments

  • 1.JPEG
    1.JPEG
    1,018.8 KB · Views: 33
If you do a mid-drive, you will want gears. That is the main advantage because the motor is then shiftable. You could do a 500 watt motor with a Shimano 5-speed. Here is a Specialized Fatboy with a torque sensor motor. It is 750w and we went with a 9 speed for durability. The chain can be thicker than 10,11,12.
 

Attachments

  • FatBoy4 (2).JPG
    FatBoy4 (2).JPG
    463.7 KB · Views: 33
If you do a mid-drive, you will want gears. That is the main advantage because the motor is then shiftable. You could do a 500 watt motor with a Shimano 5-speed. Here is a Specialized Fatboy with a torque sensor motor. It is 750w and we went with a 9 speed for durability. The chain can be thicker than 10,11,12.
Nice bike! So when you say "Shimano 5-speed," what exactly are you referring to? Thanks!
 
The e1 chain is about as strong as a belt and parts cost less. Belt cogs are brittle and prone.
1710709872115.jpeg
 
Well I’ve given this some more thought, as well as tried to research/inform myself more about what’s out there, and I’ve decided that all things considered, the advantages of a Rohloff setup outweigh the disadvantages. And importantly, after looking into the gearing issue in more detail, it seems there’s a good chance I can do most of my riding (keeping in mind the electric assist factor obviously) in the higher Rohloff gears (8 and above), which several people report as having much lower noise levels than gears 1-7.

So then the question becomes finding the best option for a step-through fat ebike with Rohloff and a belt drive. The closest I’ve found is this (I've included a pic since there are a couple of different models/iterations shown in the listing). Poking around and comparing pics/specs, I see that this model appears to be one imported by a couple of small US ebike sellers (mainly aimed at the hunting ebike market) who are charging ~ $2000 more for just repainting/throwing on some decals and perhaps changing out the headset; otherwise the specs and components appear to be identical.

I believe this bike has a 60T chainring + 34T cog combination. I haven’t found much info on whether that is a recommended combination for the Bafang Ultra being used for the off-road fat biking, etc. I'm doing. On my current fat ebike, I’m running a BBSHD + 40T Lekkie chainring + Sunrace CSMS8 11-46 cassette. That setup actually gives me more high and low than I really need; 95% of the time I’m between 32T and 15T using the electric motor assist levels and throttle. Using some online gear calculators and charting that out against the Rohloff + 60T chainring + 26T cog, it looks like a corresponding range (in gear inches) would be 6-12 or so on the Rohloff. This makes me think I'd be able to to stay 8 or above most of the time and avoid the worst of the noise--my only real concern with the Rohloff--but get all those other Rohloff benefits/advantages.

Thoughts?
 

Attachments

  • a.png
    a.png
    239.6 KB · Views: 35
Only has 265% range eg 11

Only has 263% gear range compared to 11-46t cassette which 418% and only rated for 65nm of torque. Can't lower the overall range by using large rear sprocket either as this will exceed make torque rating. These IGHs were designed for commuter bikes not offroading.

Its either Rohloff or derailleur anything is likely to break.

In regards to cadence vs torque, for fine power delivery in rough can't beat torque sensing. The likes of Bosch CX in eMTB mode (google it) has excellent controlled power delivery. Cheaper motors don't necessary have equivalent eMTB mode which make all difference in rough.
 
Hello!

I’m looking for what might be unicorn, but wanted to see if anyone has ideas/suggestions. I’m a backcountry nature photographer/trail camera enthusiast and have been using a BBSHD-converted fat tire e-bike for several years now to get to rough/remote locations. I’ve spent enough time on that bike to realize that my ideal backcountry e-bike would have the following:
  1. Step-through frame (maybe a frame design like this) that is strong enough for 275-300lb rider+ gear weight over rough/bumpy terrain
  2. Mid-drive, at least 750w, not torque-sensing, and ability to add throttle (user-adjustable assist levels + throttle like BBSHD are perfect for me/my riding)
  3. Belt rather than chain drive (this is the least important of my criteria)
  4. Tubeless-optimized fat tire wheels
  5. Internal hub rather than a derailleur, since weeds/grass often clog my derailleur, and I replace hangers 2-3x a year with the leggy derailleur getting abused by rocks, logs, etc.
I’d need a quiet internal hub. I upgraded my current BBSHD conversion to an Onyx rear hub to eliminate that pawl clicking, which has been great for the kind of “in nature” riding I do. I’m guessing no internal hub is that quiet, but from video of the Rohlhoff, I can say that would definitely be too loud for what I want. If there are no reasonably quiet internal hub options, I’ll probably just scratch that idea and live with cleaning the weeds/grass out of the derailleur and the annual derailleur replacement.

If such a bike doesn’t exist, what would be the best strategy for assembling one? Perhaps finding a bike that meets 1.-4., then switch out the rear wheel for a custom rear wheel build with an internal hub (assuming a reasonably quiet one exists)?
The Nexus 7 hub on my Ariel Rider C Class (w/ Tongsheng motor) seems quiet. Also, I find it reliable and maintenance free. There is a Nexus 8 too.
 
CCroft
I have a XL program of over 55+ Step Thru hunting Ebikes with over 25+ different spec's listed for each of these bikes listed.
If you want a copy drop me a PM and I can email it to you,
You can compared spec's etc, should save you some time looking around etc.
This is for STEP THRU bikes only, with Hub and Mid drive motors.
 
Hound Supercharged by Watt Wagons?
Motor: Bafang Ultra boosted to 2300W Peak, Throttle incl.
Transmission: Shimano Cassette OR Gates One Speed with Belt Drive
 
I've been gone for awhile. I don't know if Watt Wagons ever sold any Hounds, and it looks like the owner started a new company called Zen bikes.
Zen offers the Photon, which is much cheaper than the Hound.
Motor: Zen 500W, 900W peak
Transmission: Enviolo Heavy Duty CVT internal geared hub, Gates Carbon Belt Drive

It looks like there is also a Zen Photon Ultra with the Bafang Ultra motor, Rohloff hub, and Gates Belt Drive
 
Last edited:
FLX Blade 2.0 also with the Bafang Ultra motor, Rohloff hub, and Gates Belt Drive:
 
Back