Best internal gear hub?

[greenspark]

Do you find that the three speed is enough for your riding? I'm thinking if im not climbing major hills then a wide 3 speed might be enough paired with the BBS02. It will definitely save some weight. Id does rule out doing some steeper singletrack on my bad boy though which i've enjoyed in the past.

. I find the Sturmey Archer AB to be adequate with a 0.75 (Low) 1.0 1.33 (High) ratio.

 

[Supertux1]

I did some calculations... according to the N360 tech manual the diameter of the shifting interface at the hub is 52.5mm (Page 13 "6. Technical Data")

That makes the circumference the wire travels along 164.93mm (pi*d)

On page 7 ("Rear Wheel Installation/Removal") It shows a diagram with hash marks showing 90 degrees of movement pull for shifting high and another 90 degrees of movement for shifting to low. (Maybe a little bit more for complete range.) That would require pulling the cable 1/4 of the circumference in either direction so 41.235mm of travel each way.

This is completely doable with a dual servo arm length with each side approximately the same diameter as the cable circle, 52.5mm, (super fast shifting) or perhaps a smaller diameter on a servo capable of turning more than 180 degrees (slower, more torque). Winch servos with cable spools and the like.

I'll dig around in the toybox to see what I got, maybe wire a resistive thumb throttle with springs removed to an arduino to a servo to see what happens.

I'll start another thread and post results rather than hijack this one, but thanks for the info!

 

[greenspark]

This is completely doable with a dual servo arm length with each side approximately the same diameter as the cable circle, 52.5mm, (super fast shifting) or perhaps a smaller diameter on a servo capable of turning more than 180 degrees (slower, more torque). Winch servos with cable spools and the like.

Not sure I quite understand the reason for the analysis. I have a N360 on another Raleigh DL-1 with a Bafang BBS-01 and find that it works just fine. The amount of twisting to move from uphill low to downhill high is ergonomic, which is a fancy way of saying it feels right. Going up a 15 degree hill, I don't need it in full low, and then riding downhill, I find that I still can pedal at the maximum speed that I feel safe riding (it has a SA front drum brake and a NuVinci roller brake on the rear).

 

[Supertux1]

My intent is to develop a motor control and shifting system that requires little to no human intervention -- like the CVT's in motor vehicles.
A micro-controller in charge of the servo, pulling the wires for you based on inputs like speed, acceleration, RPM and watts consumed by the motor etc... (yeah maybe even PAS!)
Programs to optimize efficiency or acceleration or anywhere in between at the push of a button, twist of a dial.
If I can get a feel for the mechanics of it and the basic control algorithms it shouldn't be too hard to code and wire up.

 

[tahustvedt]

An internal gear hub like this would be cool: http://www.bitraptor.com/en_andeguro_bike.html

I'd like to try making one.

 

[kenkad]

Supertux1,
I have considered using a Hayden-Kerk size 8 stepper motor/lead screw linear actuator as the control for an IGH. You would need to couple that with a linear magnetic sensor like from AMS. Then you do not have to worry so much about loosing position because your stepper drive software/electronics missed steps. That is not a trivial issue. I personally believe that is better than an RC servo approach. Just a suggestion.
kenkad

 

[Supertux1]

Supertux1,
I have considered using a Hayden-Kerk size 8 stepper motor/lead screw linear actuator as the control for an IGH. You would need to couple that with a linear magnetic sensor like from AMS. Then you do not have to worry so much about loosing position because your stepper drive software/electronics missed steps. That is not a trivial issue. I personally believe that is better than an RC servo approach. Just a suggestion.
kenkad

Disclaimer: I don't own a N360 hub yet so my opinions on it are from what I see in its tech manuals, videos online and anecdotal sources of how it works.

The Nuvinci N360 IGH shifting disc 'floats' and requires pulling both clockwise and counterclockwise to change ratios.
It doesn't have a spring to return it to a low/high ratio in absence of cable tension like some other hubs and the typical derailleur.
You have to manage TWO rear shifting cables running the length of the bike, (lots of zip ties I guess) and any slop or misconfiguration
is going to manifest as sloppy/unresponsive/dead zone shifting control.
I don't have a good feel for how much force is applied to those cables so I can't say if they're going have issues stretching and what not.

I like stepper motors but servos positions are easily controlled with microcontroller PWM and require no external positioning sensors.
Although it is good engineering to have switches trigger on each end of the mechanical stop to prevent overdriving it and also aids in calibration.
Compression springs can also be used to prevent a high torque motor from breaking something that really doesn't want to move or is sticking.
(I read somewhere that the N360 hub won't allow full range shifting at a dead stop so this could be an issue.)

Perhaps a single one of these things would do it, pulling/pushing on a center pivoting bar that has each end attached to the N360 cables... http://www.servocity.com/html/heavy_duty_linear_servo__25__l.html#.U72Bdo1dUgo

(These are $300 though, so perhaps something else...)

 

[eMax]

I have used the 'simpler is better' ethos and ordered a Sturmey-Archer S3K from Universal Cycles for use with my Cannandale Bad Boy and BBS02. Don't plan on shifting under load at this stage, and based on my calculations the 3 gears with correct cog should be enough range (177% paired with 16t cog).

Product is here http://www.universalcycles.com/shopping/product_details.php?id=56897

Price is good at $84 at least if I fail it will be a cheap one. Will keep updating my progress on this thread. Anyone have a suggestion for a chain tensioner?

 

[melodious]

Anyone have a suggestion for a chain tensioner?

http://surlybikes.com/parts/drivetrain/singleator
I looked at it more and they have different springs for tensioning the chain up or down.

50 bones though.

 

[eMax]

http://surlybikes.com/parts/drivetrain/singleator
I looked at it more and they have different springs for tensioning the chain up or down.

50 bones though.

Looks great, thanks. Hard to source where I am though without expensive shipping from overseas :?

 

[Avitt]

I have used the 'simpler is better' ethos and ordered a Sturmey-Archer S3K from Universal Cycles for use with my Cannandale Bad Boy and BBS02. Don't plan on shifting under load at this stage, and based on my calculations the 3 gears with correct cog should be enough range (177% paired with 16t cog).

Product is here http://www.universalcycles.com/shopping/product_details.php?id=56897

Price is good at $84 at least if I fail it will be a cheap one. Will keep updating my progress on this thread. Anyone have a suggestion for a chain tensioner?

Be careful to never shift under power...

I believe that all Sturmey Archer 3 speeds use a gear selector key in the axle. These seem to have a tendency to sheer away, when shifted under load.

I purchased a used S3X (SA's fixed 3 speed hub) last year. It wasn't long before it started slipping, and missing shifts. I disassembled it, and found that the shifter key was starting to wear. You can see pictures (not mine) in this thread: http://forums.mtbr.com/internal-gear-hubs/sturmey-s3x-any-long-term-users-757484.html

On the plus side, SA sent me completely new internals to fix the problem...

 

[eMax]

Be careful to never shift under power...

Won't be. I figure whatever hub i went for i would be apprehensive to shift under power. Even if it were the Nuvinci. Thankyou for providing a link to your thread in the mtbr forum. If this hub lasts as long as the BBS02 then happy days!

 

[jdaniel226]

I have a Trek Soho that is about 7 years old with the Shimano Nexus 8 speed and a belt drive. Over the summer, a bungee cord got wrapped up between the hub and belt, causing the hub to crack open. I have had it serviced, but the issues with it keep getting worse. The shop has taken it apart and lubed it as well as fixed the drop outs which must have also gotten bent in the bungee episode.

When free-wheeling there is a noticeable vibration through the frame and pedals and the when on a stand, the back wheel slows down quickly after setting it in motion. Also, the shifting is clunky at best. I feel like I have a few options. 1. Replace the guts of the internal hub keeping the old shell2. Build a new wheel around a new hub or 3. sell the bike and go for a newer model. Option 1+ replacing cogs and belt is going to be around $650 (about half of that is parts/labor for hub and half is parts/ labor for belt/cogs)- Option 2 will probably be a few hundred more unless I can find a deal on a wheel already built. Any advice? I do love the Soho – it is such a great workhorse as a commuter bike.

 

[cycleops612]

Many posts here seem focused on torque/strength.

For some, perhaps another way of addressing your transmission durability related issues, is, what about 2 motors, of types with different properties.

I have a 24 speed mid drive. To take off some of the strain, i have considered a suitable hub motor that got me rolling at the lights and helped on hills, so it was smooth for shifts and starts always.

it would also weigh less?

 

[spinningmagnets]

Just did some research for an article, the strongest gear for an IGH is the second gear of either the Nexus Inter-3 or the Sturmey-Archer 3-speed. Both of these lock the input driver to the hub shell at the rim. The power doesn't even go through any of the gears.

I'm sure that with enough power, even these can be broken, but...if you like IGHs and E-power, make a note of this.

 

[cjh]

Spinningmagnets, did you also test the Sturmey-Archer 5-speed RX-RK5?

 

[cycleops612]

Just did some research for an article, the strongest gear for an IGH is the second gear of either the Nexus Inter-3 or the Sturmey-Archer 3-speed. Both of these lock the input driver to the hub shell at the rim. The power doesn't even go through any of the gears.

I'm sure that with enough power, even these can be broken, but...if you like IGHs and E-power, make a note of this.

If this happens with some IGHs, it would be highly relevant to many owners to know they have a ~bulletproof ~locked gear.

makers should shout this feature from the rooftops.

 

[spinningmagnets]

There are youtube videos of IGH teardowns. I watched many of them and looked at pics of the internal parts that broke, plus where they broke.

I am about to publish an article on this with pics. The 5-speed has a driver-to-hub locked 3rd gear, very strong. However...I am very concerned about how the other four gears are actuated. The axle-dogs are a "ball pin" arrangement. Not horrible for human leg power, also simple and cheap to make. Once you upgrade the design to using the modern style of axle-dogs, it's easy to add a few more gears than having 5, and most customers seem to like the 8-speeds...

The Shimano Nexus Inter-3 and the Sturmey-Archer SX-RK3 (SeXy-RocKet 3-speed?) Both use the same internal configuration. Hub-locked 2nd gear, and very strong under-driven planetary first gear. Both use four planets, 33% stronger than a 3-planet reduction. Third gear is a somewhat weaker 33% overdrive (using those same four planets). Not horribly weak, but...a prudent rider will not try to pop wheelies in 3rd.

 

[Marin]

There are youtube videos of IGH teardowns. I watched many of them and looked at pics of the internal parts that broke, plus where they broke.

I am about to publish an article on this with pics. The 5-speed has a driver-to-hub locked 3rd gear, very strong. However...I am very concerned about how the other four gears are actuated. The axle-dogs are a "ball pin" arrangement. Not horrible for human leg power, also simple and cheap to make. Once you upgrade the design to using the modern style of axle-dogs, it's easy to add a few more gears than having 5, and most customers seem to like the 8-speeds...

The Shimano Nexus Inter-3 and the Sturmey-Archer SX-RK3 (SeXy-RocKet 3-speed?) Both use the same internal configuration. Hub-locked 2nd gear, and very strong under-driven planetary first gear. Both use four planets, 33% stronger than a 3-planet reduction. Third gear is a somewhat weaker 33% overdrive (using those same four planets). Not horribly weak, but...a prudent rider will not try to pop wheelies in 3rd.

I was hoping this sx-rk3 was going to be a good choice, mine is a 170mm version laced to a 65mm rim, it's going on my Luna frame. 3.5" vee rubber tire so far.

Looking forward to your article.

 

[spinningmagnets]

What a sexy beast!

Here it is. Will add more stuff later today

http://www.electricbike.com/mid-drive-kit-igh/

 

[cjh]

What a sexy beast!

Here it is. Will add more stuff later today

http://www.electricbike.com/mid-drive-kit-igh/

Good article. How about the Nexus 3 as a jackshaft with the Cyclone? What do you see as its power limit?

 

[cycleops612]

a very sage sounding, very recent, comment, on spinningmagnets igh piece, may relieve much anxiety for prospective IGH users.

"Karl Gesslein • 3 hours ago
Great article. The best place I've found to get information on IGH robustness is forums where the gas powered bicycle crowd hang out. Although putting a gas motor on a bike feels almost sacrilegious to me, they have a pretty good idea of how much power will make what fail. 1hp is equal to about 750watts and they always talk in HP not watts. The 3 speed IGH seem to work well up to about 4hp (3000W) as long as you don't shift them under load and take it easy on the throttle. I've been running a 2500W mid drive with a SA 3 speed fatty for hundreds of miles without any issues at all. The N171 is generally accepted to be fine up to about 4hp or 3000W as well as long as the acceleration is smooth. I've had good luck with the N380 up to 1300W and have ridden mine very aggressively off road for well over a year now even though it is only rated for 250W....."

 

[WoodlandHills]

I tried to post this over at the comments section following the article, but was unable. Any comments on the suitability of the new rotary C-50 5-speed from SA? I've less than 200mi on mine, paired with a BBSHD, but I like it so far. Supposedly it was designed from the start as an ebike hub, or so I have read and is intended to be far more robust than previous designs by Shimano or SA.

 

[cycleops612]

Its not exactly the issue, but very relevant, yet no mention of it?

An IGH allows a much more robust chain and sprocket to be used.

Derailleurs require a fine chain.

And vitally, according to my legendary ~circumnavigating touring mate (evangelical about rohloff - durability, they get better with age some say) , allows a sealed chain guard.

Makes lubing the chain daily a snack. Just quoting him. Few on the planet would tax an IGH & bike like he does in a year, or pump watts into pedals like him. Big super fit guy. (thinks ebikers are sissys, but polite enuff not to say it to me in actual words)

If you think about it, a mid drives weak point vs hub motors is the chain drive. An igh allows a stronger, straight chain.

 

[spinningmagnets]

Cjh, that's a tough call (Cyclone with a 2:1 jackshaft IGH). If it does break, it's only about $100 for another 3-speed (you don't have to re-lace the rim, just slide out the broken guts and slide in the new )

You would be the first to do it if you try it out. Karl said the second gear was a taking four HP (2800W), before the shell broke. Like sending a rod through the side of a Chevy small block?