Mid Drive with Internally Geared Hubs

Does anyone have any experience using a mid drive with an internally geared hub? Does the extra torque lead to premature failure of the hub?

I'm getting tired of derailleur maintenance and am looking to switch.

General rule of thumb is anything below 500w can use most IGH on the market.

When you get to 750w and above, you risk serious damage. The real culprit, is accidentally being in a tall gear and the motor overpowers the internal drives beyond it's capability. Also, shifting with motor assisted loads is a general "no-no".

I've heard good things with a Nuvinci and Rohloff IGH's ability to handle the higher powered setups. I think someone has had good luck with the higher end Shimano alfine IGH's too.

There've been a number of discussions about this sort of thing--one of them within the last month or two, where doing something like a "cush drive" on the input of the hub was mentioned, IIRC. Sorry I don'thave a link to the thread.

Seems like the big problem based on some disassembly pics of an IGH after failure is shock loading, so anything you can do to bringpower up slowly and smoothly to the IGH's input, and prevent lash in the gears, will probably help prevent damage.

I don't have experience with it, but that's not stopping me from diving in head first.

My current build in progress is a middrive cargo bike using an IGH in the rear on a 20" wheel. The small wheel will somewhat limit the amount or propensity for torque induced damage, but I'm not exactly sure how it will pan out.

I'm hoping that with a decent technique, I can make the SRAM G8 last. They claim it can be shifted under torque, but I will have to check that out and report back. I just received tracking for an important part, so I will be commencing with the build again shortly:

Edgerunner Middrive - Crossbreak method

I have been running a BBS02 750w with an Alfine 8 now for nearly 2000km on a daily commuter.
Firstly with this hub shifting under anything but very modest load is a out it simply grinds the gears and will not change either up or down. Plus side is it is no issue simply to pause pedalling for an instant while you change, on the BBS02 you can use the dead band in the throttle to change or if you like you can even program the throttle to become a very effective "clutch".
I have had no issues with the hub no noise or any signs of wear so far however I am not a high watt user most of my time is at 300-400w and up to 600w for some of the larger hills plus my own input and the hub copes with this fine.
Having said that if I had the money I would go woth the NuVinci 360 as I think these are the perfect match with a mid drive.
Current I am runing my hub with the standard BBS02 48t front and a 20t rear this gearing spins me out at about 45-50 kph.

Have personal experience with 8 IGH installations on recumbent trikes, amongst our ride group:
1. I've got >4000km with Cyclone 480W/Lyen on Trisled recumbent trike with 20" wheels & Rohloff, over 9 month period.
2. Wife has >3000km on identical installation, over 6 months.
Recently had chains off for clean/lube & inspect sprockets/freewheel - all good (wife & I use 46t chainring to White Ind. ENO trials 18t freewheel, 18t Surly (motor-drive) sprocket, to 13t Rohloff sprocket). Climbs any hill & gets nearly 50km/hr. ENO & Surly are bulletproof (no wear); Rohloff sprocket shows some wear after 4000km (put that down to small 13t sprocket).
3. Regular ride-buddy has 200W Cyclone on Greenspeed trike (20" wheels), Rohloff. He runs 15t - 17t Rohloff sprocket, depending on his mood.
4. Another friend has Cyclone 1200W mid-drive on a Trisled trike that she recently upgraded from cluster to Rohloff, towing a trailer (large 36V battery pack & other stuff like her shopping in trailer). She does lots of km with that rig and no problems (she does know how to be gentle on power application, though). Loves the IGH upgrade.
5, 6, 7, 8. Other friends (4) have Cyclones (one 250W, two 360W, other 480W like mine) with NuVinci 360 hubs on various trikes (also 20" wheels).
I think they use 18t sprockets on their NuVincis. Top speed not great, but can still climb hills.
Agree with others re: gearchanging - have to be off the power slightly with Rohloff.
But if you're used to manual transmission cars/motorbikes, not a problem.
NuVinci not a problem with low-power motors & gear-changing (constantly variable transmission).
Don't know how it'd go with high power though.
Rohloff has much greater low-to-high gear ratio (>500%) than NuVinci (360%).
So Rohloff can climb hills and still go fast, using single chain-ring.
Multiple chain rings to increase gear-range is a problem with mid-drives, as matching cadence to motor-speed is only easy with one chainring/freewheel combo.
Over time, some of the others in our group who had multiple chain rings have gone to single to simplify chainline.
Summary - IGH's are great, as they simplify chain-line & sprocket/freewheel installation (esp. on trike).
Pay the money for a good one, though. Cheap IGH's are like cheap anything - wasted money & lotsa trouble.

The issue with ultimate gear range is somewhat less important with motor assist compared to a bicycle, arranged so that top gear and max motor revs achieve your realistic chosen speed the lowest gear will climb anything without worrying that the Rohloff has an even lower bottom gear. Infact most geared mid drive setups using a set of ratios chosen for pedalling often feel like they have way too many gears with a mid drive and only a couple get used. I would imagine fewer gears could be a wiser choice if that option produces a stronger IGH.

Here's another link with a related discussion. Its about finding a way to get the bike to automatically let off the power when you shift (easy to forget in the middle of a ride). This is useful for a derailleur system, but...it is much more needed for an IGH, since they are more likely to break at a lower power level than a derailleur system.

"What a clever idea...so I thought" izeman
http://endless-sphere.com/forums/viewtopic.php?f=2&t=60651

Question: Are the 3 speed IGH as rubust as the top tier IGH? I'm thinking fewer mechanical parts equates to reliability

Under normal use, that might be true, but under high power (especially sudden surge like motors give) it probably isn't.

The main things that would make a difference to durability under these conditions would be the shape of hte roots of teh gear teeth, and how they are hardened, so they don't tend to shear off there under sudden stress, and how precisely they fit so there is no lash.

melodious said:

Question: Are the 3 speed IGH as rubust as the top tier IGH? I'm thinking fewer mechanical parts equates to reliability

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Some are and some aren't. Sturmey Archer AW (old style), SRAM T3, and Sachs Torpedo 3 are proven to be very rugged and reliable. Shimano Nexus 3 and new Sunrace/Sturmey Archer AW are looking that way, too. SRAM i-Motion 3 and Shimano 333 are weak junk.

Look at it this way: When Sachs, SRAM, and Sturmey Archer made versions of their 3-speed hubs with cassette gearing on the outside, they were opting into gearbox torques 2-3 times the typical values for a 3-speed bike. They would not have done that if there were not a big safety margin built in.

Keep in mind that the higher the primary gearing is (chain and sprockets), the lower the forces on the gears at any given input load. That's a reason to raise the gear ratio when you add motor assist.

For what it's worth, Shimano offers a version of the Nexus 3 hub with 135mm spacing and a disc brake interface. It's not the cheapest of the 3-speed hubs, but it's probably the easiest to use on a modern MTB.

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FWIW, my friends with NuVinci IGHs do like the ability to continuously adjust the "gear" to motor output (speed vs watts) & cadence so that pedalling is comfortable & power consumption is low. We do a lot of weekend rides on old "rail trails" (decommissioned train lines, turned into bike paths) & riverside trails. Conserving battery is a consideration, so using the CA & matching cadence to motor output is important to us. We also build/gear them so that if the battery pack goes flat, we can still pedal home (another argument for the wide-range gearing of a Rohloff, for me).
If you have a big enough battery, & your rides are shorter, not an issue for you. But it is for us.

Tench said:

The issue with ultimate gear range is somewhat less important with motor assist compared to a bicycle, arranged so that top gear and max motor revs achieve your realistic chosen speed the lowest gear will climb anything without worrying that the Rohloff has an even lower bottom gear. Infact most geared mid drive setups using a set of ratios chosen for pedalling often feel like they have way too many gears with a mid drive and only a couple get used. I would imagine fewer gears could be a wiser choice if that option produces a stronger IGH.

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In my considerable PERSONAL experience, I disagree.

Re lows: There are times for me when pedaling isnt an option, yet i want it to climb a cliff~. my 24 speed 300w mid-drive does that. awkward loads, mono up stairs, wiggling, standing upright thru gridlock for maximum balance & vision

much of my riding is at a relative crawl (long story - dog), and it suits me to choose a very low gearing and power setting - maybe 100 watts. easy on me and the motor.

re highs, i hear complaints they are not high enough, even of 3 front ring 24 speeds. This can be true also if you are keen to pedal going down hill etc. It has to be good to have choice and know if the maker didnt guess your needs right, you still have fine control to choose to suit you.

and anyway, no such thing as too many gear options for eking the most out of limited power and watt hrs, as we do.

On steady terrain, you have a better chance of settling on the perfect gearing blend of pedal assist cadence and motor rpm

the rohloff sounds magic, bar price and weight &, for me, a daunting retrofit. for much less, stealth aside, maybe a; freewheeling light, cheap front hub as a second motor, and gear it to take the bulk of the chores up to 15kph, and let the mid-drive kick in smoothly with its own brand of extra power. No chain and cog stress and 2wd for rough stuff.

briefly, a killer factor if touring rough, i have it on very good authority, is w/ an igh, you can have a sealed off chain, and perfect daily chain maintenance is as simple as squirting oil thru a hole while you spin the pedals. my mate swears by rohloff for its durability. He says they wear in, not out.

cycleops612 said:

briefly, a killer factor if touring rough, i have it on very good authority, is w/ an igh, you can have a sealed off chain, and perfect daily chain maintenance is as simple as squirting oil thru a hole while you spin the pedals.

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Ordinary Dutch bikes have had chain cases for more than a century. It doesn't take very many flat tires before you use up a lot more time on them than you save on cleaning and replacing chains. Chain cases and drum brakes gave us Dutch style flat repair, where you find and patch the puncture without ever removing the wheel from the bike.

How long does it take to wear out a singlespeed ebike chain on an IGH with a mid-drive anyway? Keep it clean and use a decent wax on it and your alloy sprockets/chainwheel will wear out first.....

In my experience, I started with a Lightning Rod small block with the Nuvinci N360. I bought the older grey version (The modern N360 is black). I switched a month later to a BBS02 and the IGH worked like a charm. The only problem I was having was, I ride a cargo bike (Kona Ute) and was getting alot of flats in the middle of Winter( I had cheap tires). There are two cables that come out of the N360 that need to be placed correctly in the hub. The position of the hub has to be memorized because the cables have to fit perfectly or you will be taking off your gloves (due to chain grease) and freezing your hands guessing the different positions in putting back your rim and lining up the hub to put the cables back. This problem can be solved by practicing at home (in warm weather) the positioning of the wheel when you put it back on the bike.

I ordered a BBSHD and have installed it on the bike. The Nuvinci N360 has not given me any problems once I learned how to deal with the putting back of the rim. There are many Youtube videos that teach you how to change the cables in the shifter. I've done this twice with no problems. I ordered and tried the Bling Ring, I have tried the crank with 52 teeth, 46 teeth.

Through all this I have no problems with the N360. The chain lined up perfectly in all motor changes.

The best thing about the N360 is when I come to a complete stop I can shift to the easiest pedal position while at a complete stop. When I take off I start pedaling to get some motion. I stop pedaling (PAS) or let go of the throttle and the easiness of getting into a harder gear with the N360 is a breeze. The trick is to practice letting go of the throttle, change the gear and hit the throttle again or pedal, whichever you are doing.

All this while on a cargo bike with all my equipment (400 lbs). All on flat terrain in NYC.

WoodlandHills said:

How long does it take to wear out a singlespeed ebike chain on an IGH with a mid-drive anyway? Keep it clean and use a decent wax on it and your alloy sprockets/chainwheel will wear out first.....

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It's the worn-out chain that wears out sprockets and chainrings. As long as the chain isn't elongated, sprockets hold up just fine. The most worn part of the system tends to bring the other parts down to its level. But it all starts with an elongated chain.

No amount of maintenance can prevent the chain from becoming elongated within a few thousand miles. I've heard of fastidious cleaning and lubrication allowing chain life exceeding 10,000 miles-- but unless your time is worth nothing, that's more expensive than just replacing your chain every so often.

On my mid-drive, I use CA to limit current to 10A @24V so less torque load on rear chain from Cyclone motor.
I use Wippermann Connex 808, which gives me ~4000km life on rear chain, 8000km on front (highest load on rear, motor + pedalling, front chain only gets pedalling load).
Measure stretch regularly, & mid-drive Surly sprocket/Eno freewheel never need changing.
Rohloff 15T sprocket gets replaced every 8000km or so.

I am with you chalo. The least work and grief is to be fastidious about making them and sprockets last.

but thats my mates point. a quick squirt & a spin & baba bim...

the guy is a legend. 65 now & heart of a horse. sydney pilbarra (NW Oz) via perth, back blocks of agentina, india many times...

its grit thats the killer. NB the guard seals the chain also.

NB also, bigger sprockets & chain are doable with an igh.

To share, i was chuffed at a vignette of his about solo riding in remote india. as he rode, folk would sidle alongside on a bike or motobike & chat. by far, their prime motive was "hospitality"?

They were dieing to just have him come to their house for tea with his family. Nice.

shifting while stationary does sound cool.

avoiding mechanics too.

most of my need for them on my factory ebike has been for derailleur glitches over time- so if igh is more ride & forget, sounds good

I am sure you hate it, but would a 3 ring at the front work ok on an IGH?

just saying, i also have a cheap chinese work bike mid-drive, with 2 separate chains and rear freewheel sprockets for motor and pedals

naturally, without the delicate derailleur and cog swapping requirement, an igh chain can be very heavy duty, like a motorbike

cycleops612 said:

most of my need for [mechanics] on my factory ebike has been for derailleur glitches over time- so if igh is more ride & forget, sounds good

I am sure you hate it, but would a 3 ring at the front work ok on an IGH?

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Gearhubs are lower maintenance than derailleurs, with a caveat: if you keep riding them when there's a problem, you can easily break them in a way that's much more expensive and difficult to fix than derailleur troubles. (The exception is the NuVinci, which is always fully in gear even when it's being shifted.)

You can use front shifting with a gearhub in the rear, but you'll have to have a rear derailleur there just to take up the slack in the chain.

Chalo said:

cycleops612 said:

most of my need for [mechanics] on my factory ebike has been for derailleur glitches over time- so if igh is more ride & forget, sounds good

I am sure you hate it, but would a 3 ring at the front work ok on an IGH?

Click to expand...

Gearhubs are lower maintenance than derailleurs, with a caveat: if you keep riding them when there's a problem, you can easily break them in a way that's much more expensive and difficult to fix than derailleur troubles. (The exception is the NuVinci, which is always fully in gear even when it's being shifted.)

You can use front shifting with a gearhub in the rear, but you'll have to have a rear derailleur there just to take up the slack in the chain.

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thanks. Interesting concept, a 42 speed direct drive gearbox?

cycleops612 said:

Chalo said:

You can use front shifting with a gearhub in the rear, but you'll have to have a rear derailleur there just to take up the slack in the chain.

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Interesting concept, a 42 speed direct drive gearbox?

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Gearhubs usually have a maximum input torque rating or an input ratio limit. In the case of the Rohloff, the manufacturer specifies 38:16 as the lowest allowable input ratio for single rider use. So 38-48-58 front gearing with 16 rear would be OK, but the more common 28-38-48 would be contrary to specification.

There's a higher minimum ratio specified for tandem use.

I'm very heavy, and I use unusually long cranks on my Rohloff hub bike, so I chose 44/16 for my chain drive ratio.