invisiblehand

I thought about this too. I like the idea of an internal hub for a utility bike. However, I really have a hard time plunking $1000+ on just the hub.

According to https://hubstripping.wordpress.com/ neither the Shimano Alfine 8 nor the SRAM I-Motion 9 are rated for tandems or cargo. However, I have seen many references -- including the Nexus 8 on the bakfiets -- to these hubs successfully applied to utility cycling applications. For the price, setting up either hub with a double in the front -- according to the hubstripping website, one could pair up the i-Motion 9 with a typical compact crank in the front -- would achieve an excellent gear range for a lot less money.

Elkhound

Has anyone ever combined a Nexus 8 in the back with a Schlumpf in front?

invisiblehand

In the folding bikes section, I have seen this on a Downtube Full Suspension bike.

For the price, would you be better off with just a Rohloff?

Allen

https://www.kinetics.org.uk/
^^^
Ben Cooper is good for having bicycle esoterica. They are not listed on his site, but I've gotten some odd ball stuff from him in the past.

invisiblehand

In regards to the Schlumpf with an internal hub in the rear ...

https://www.bikeforums.net/showthread...pf#post5988263

Val

This may seem a bit redundant, but I would like to second the recommendation of the NuVinci for any cargo bike. I am a huge fan of internally geared hubs in general, and have ridden them on many bikes, and worked on many different hubs over the years. My impression of any of the "normal" geared hubs (Nexus, SRAM, or Sturmey) is that they work beautifully on normal bikes, but are not really durable enough for use with anything that will take a payload of more than 100 lbs. The SRAM hubs seem to be the most durable of them all, but even they can be destroyed by heavy loads, steep hills and agressive riding (it takes a while, but I've done it). The Rohloff, of course, is in a class by itself, and no one has been able to destroy one of them (that the maker knows of). If you can afford it, there is not much to be said against it; the only possible drawback is that it still has discrete shift points, and needs to disengage from one gear and engage the next before continuing to transmit torque - what we've always been used to, in other words. The NuVinci is particularly suited to heavy use like this, since it has no actual gears inside to wear down or lose teeth. The continuous nature of the shifting mechanism means that it is always in gear, and therefore can never be mis shifted. It is also extremely easy to downshift in overloaded situations; any time the pedal is unweighted a bit, the hub can shift, so you get just a bit of shift at every dead spot in your stroke, or a big shift, if you want, if you actually pause intentionally. I've been trying to overload mine, just to see, and so far the hub is much stronger than I am, which is how it should be. Just for reference, I am also using it with two chainrings, and it gives me a range of 20 gear inches to 90 gear inches - enough, in other words. For the price, nothing can touch it. For another perspective on a NuVinci Dummy, see: https://tinyurl.com/4743tl

invisiblehand

Interesting ... however, the manufacturer states that the minimum front chainring to rear sprocket ratio should be 2:1 ... i.e., 44/22 or 32/16.

Putzing with Sheldon's calculator, I calculate something like a 25-26 gear inch bottom with that combination and the fattest Big Apples. From touring, I can tell you that will not be low enough for my tired legs.

EDIT: Here is the document.

Val

invisiblehand: Indeed, according to Fallbrook's recommendation, the lowest gear ratio one can achieve will be a 1:1; that is, 26 gear inches for a 26" wheel, 28 inches (or so) for a 700c, etc. I have the advantage of having been able to question the engineers directly about this. In a face to face meeting, I asked them three times what the reason for this recommendation was, and what the consequences of exceeding these parameters would be. At first they seemed to be implying that they had just chosen those numbers as being the most useful range for most riders (they're new to the bicycle industry, and had no idea of cargo bikes), but when I pressed them, they did say that the hub was "more efficient" within this range. Not once did they mention any durability issues, which I found especially interesting, as every other manufacturer will state explicitly that exceeding the ratio limitations will cause damage to the internal mechanism of the hub. I decided that I could tolerate a bit of inefficiency, if it gave me the gears I needed, so I did not hesitate to ignore the manufacturer's specs. As mentioned, I have also been trying to break it, with no success (yay!). To date, the most extreme load has been a 140 lb log on the back of my 100 lb bike, going up about 110 yards of 11% grade. The hub was fine....my lungs and legs were less happy, but they survived. The experimentation continues.

cman

Question on the Nuvinci. How hard is it to remove the wheel for flat repair etc? I am familiar with the Nexus 3 and 7. Seems like a great option, if I could get used to the grip shift.

Allen

There is a small shifter box you have to un-click, other than that it is the same as removing any bolt on axel.

The grip shift is easy enough.

Allen

They have had failures. They have been due to over torquing from using the hub beyond the manufacturer's specs. They have as yet to have one fail due to manufacturer's defects, or one fail in normal use.

Val

Allen g: I had not heard of any failures due to overtorqueing Rohloffs; I had been under the impression that it couldn't be done. Do you have details? I'm seriously curious.

Allen

Val, I've looked and I can't find the specific article I had read. It has happened when combining the Rohloff with the Schlumpf Mountain and High Speed drives. The regular Schlumpf Speed drive is kosher, gives one an 868% gear range to boot.

https://www.rohloff.de/en/info/faq/fa...289/index.html

invisiblehand

Hey Val,

Thanks for the details. I am more likely to try the NuVinci.

BTW, I would figure that your head would be close to exploding too, but perhaps you would have passed out before the pressure would have blown the top off carrying a load like that!

Maxwell

So Val,

How much harder to shift under load does the nuvinci get when using the lowest gear?

If you're experimenting with trying to break it, some have speculated about putting a fixed cog on one, for a variable gear, fixed-wheel bike. I haven't read about anyone actually trying though. I guess a fixed gear bike that shifts without gears is a little esoteric.

penexpers

Once again thanks for everyone's input. This has been a very informative thread.

I've done some more digging and with the way the $ is at the moment, it might be cheaper to import it from the US even if I do end up paying import duty and taxes on it. I have asked staton-inc.com for a quote for shipping and I will also ask in mtnhighcyclery.com.

santiago

MtnHighCyclery will also make sure all customs papers are in order *nudge* *nudge* *wink* *wink*. Don't forget to ask.

Allen

If you have pressure on the pedals, the NuVinci is not going to shift. Take the pressure off and it shifts easily.

Of the hubs I've had, I prefer the shifting action of Rohloff best, followed very closely by NuVinci. Both shift equally easily.

Val

Maxwell: What Allen G said - pressure on the pedals equals resistance to shifting. In theory, you could force the mech to shift without internal damage, but derailleur cables and cable binders are only so strong; much better to let it shift easily when the pressure is off. The advantage here is that the pressure does not have to be relieved for long enough to allow engagement of the next gear, as on other hubs. Rather, any pressure relief allows some shifting, so in extreme situations, you can do many "micro shifts", sometimes two or three per pedal stroke, until the ratio is properly adjusted. As for the fixed gear dream, that would be fantastic, but, unfortunately, it is not possible with this version of the hub. The mechanism itself freewheels, and only engages fully when pedalling forward. The reason for the external freewheel is that the mechanism and the seals give enough resistance that the hub would be prone to "ghost pedalling" if the cog were attached directly to the hub driver. The folks at Fallbrook have admitted that a fixed version might be a possibility in the future. As with any major company, they need to be convinced that the market justifies the research and manufacturing expense. And as for big loads, don't try to tell me you don't have a collection of such stories yourself - or is that a different thread?

surfimp

And to confirm: the Nuvinci can be shifted while at a dead stop, too? Similar to the Rohloff, Nexus et al.

Despite its weight (which is arguably insignificant on a cargo bike), this may be the go. I'm liking what I'm reading, but one question to Val: in the three times you asked the Nuvinci folks about exceeding their stated limits, did you specifically prompt regarding durability issues? They might very well elide that discussion unless explicitly prompted...

Steve

Allen

Yes it can. Turn the knob and it shifts if the bike is in motion or not.

In my experience, I've on several occasions brought home 400 pounds of potting soil and or fertilizer on my Xtracycle. It's 7 miles from the nursery to my home, the largest hill is about a half a mile of 7%-8% grade, and between the electric assist and me standing on the cranks that's a lot of juice going through the hub. It's held up without sign of wear.

cman

You guys have me thinking Nuvinci now.

What do you think about this for prebuilt wheel?
https://www.niagaracycle.com/product_...ducts_id=19010

Val

surfimp: Indeed, since durability was my main concern, my questions were specifically about the consequences of exceeding the ratio recommendations, and whether such an application would lead to failure of the mechanism. They were understandably cagey; they did not state outright that the hub would be strong enough to withstand extreme torque, but they also did not warn me that it would not. It was my frustration with this approach that led me to repeat the question in various formats three times, thus giving them an opportunity to advise me of possible dire results. I also mentioned that I was very interested in putting one on a cargo bike, and they showed no trepidation. They pulled the "efficiency" card to get me off their case, I think. I have also sent pictures of my drive train, with a 22t freewheel and 46/34t chainrings, to one of their customer service reps, and have gotten no adverse comments in response. They have also seen pictures of the setup I put together for Bike Hugger (17t FW, 24/36t CRs), and they were impressed with the bike, but made no comment on the drivetrain. I think that the electric assist (Allen G, is that a StokeMonkey?) will do more to stress a hub than the extra torque from these drivetrains. The hub is solid. Good looking prebuilt, too, cman - hard to beat the price.

cman

Val, thanks for the response. Interesting that these hubs are being used for other applications. There is a race circuit call Greenpower where several team are using them.
https://www.greenpower.co.uk/about/

Here is one from Team Bentley hooked up to a 24v motor. https://www.bentleygreenpower.com/car/

moore.sean

This is a regular old xtracycle, not a big dummy? Impressive either way.