Sturmey-Archer 5-speed hub, it's real!

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WoodlandHills   10 kW

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Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Feb 16 2016 5:23pm

I just received the new SA heavy-duty 5-speed hub in the mail. It is the functional equivalent of my current Shimano Nexus 3 with a 1st and 5th gear added on at the same 25% spacing. Both the SA and the Shimano have a direct drive middle gear: 3rd for the SA and 2nd for the Nexus so I plan on starting off with the same rear sprocket. I really wanted a lower crawling gear as well as more speed than the Nexus so this should be a good beginning.

The big problem, in my case, was finding an appropriate rim. The hub is only available in a 36 hole drilling and 36 hole Fatbike rims are like hens teeth. I almost bought a used Mongoose just for the 100mm rims, but a tip from mtbr.com led me to a Weinmann DHL80 double wall rim. It won't match the front, since it has no holes, but I really don't care as long as it works and it will be easier to go tubeless.

The rim is in transit and as soon as I get the new 5-speed hub on the bike I will post here with the result.

BTW, this is a new design than the old 5-speed model, that one was a closer ratio hub with a direct drive 1st gear, so it was ill suited to ebike usage. This new wide ratio rotary hub is built for heavy duty service and I hope will be suited for a BBSHD. Certainly the Nexus 3 was a great match: it just needed more gears and this Sturmey-Archer has them!

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Drunkskunk » Feb 16 2016 5:55pm

Cool. did you get the drum brake option?
I love mine. Been using it for years.

Not sure where you've been searching or what you plan to do with the bike, but 36 hole rims are common enough for fat bikes. here's a double walled like the one's I'm using. http://www.choppersus.com/store/product ... x-4-Black/
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Re: Sturmey-Archer 5-speed hub, it's real!

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WoodlandHills   10 kW

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Feb 16 2016 6:19pm

No, it's the RX-RK5:


http://www.sturmey-archer.com/en/products/detail/rx-rk5

I looked at those chopper rims, but I ride off-road and on trails and I didn't think they would hold up. Ditto with carbon fiber.... Anyway, the Weimann DHL80 was only $59.00 at NiagaraCycle and yours is $99.00 :o

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by bowhunter29 » Feb 16 2016 7:00pm

This may be my next option if/when my N360 blows up on my LR-Luna build.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Hillhater » Feb 17 2016 2:40am

There is an 8speed Nexus igh , or is that too weak ?
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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Chalo » Feb 17 2016 3:39am

Based on my experience, the Nexus 8 is on a par with the Sturmey 5 for robustness, and the N360 is stronger.

I haven't gotten my hands on the so-called "heavy duty" 5-speed Sturmey hub, but earlier Sturmey 5s were feeble, and Taiwanese hubs have proved less reliable, even though better made, than English ones. Both these things make me hesitant to assign any special qualities to the new model.
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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Feb 29 2016 9:13pm

I took my first test ride on the new 5-speed SA hub today. It shipped with an 18t sprocket that has a larger base than the ones that are interchangable with the Shimano Nexus 3 sprockets. This means that I have to start from scratch with my gearing: I have a wide selection of small base SA/Nexus cogs, but none of the large base. :cry: A bit of research turns up an 8-speed cog in 25t that might fit and it is under $5 so I took a chance and ordered it today.

Pairing the 25t cog with a LunaCycle Mighty Mini 30t chainwheel will give me almost the same (within .5 gear inches) direct drive middle gear as on my Nexus 3 with a 42t chainwheel and a 34t cog. Thus I will have the functional equivalent of my Nexus 3 plus a 25% lower 1st and a 25% higher top gear, which was my goal.

In my short test, the hub was dead silent with no discernible freewheel noise, although my tires are quite loud, and it shifted precisely and cleanly. The installation was very simple and so was the initial setup and cable adjustment. So far I am very pleased and I can only assume that as production ramps up it will become available in 32 hole as well as a black version. SA also list a 24t sprocket in their catalog that is not yet available: http://www.sturmey-archer.com/en/produc ... -sprockets

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by John in CR » Mar 01 2016 8:57am

Once you get tired of breaking down, start thinking in terms of replacing the 5kg BBSHD and 2kg SA with 7kg of motor with fixed gearing.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Mar 01 2016 10:44am

I would only replace the BBSHD if I could find another motor that was quieter..... And so far that does not exist......

And I would never spend my money on a motor that had a chain or belt reduction and most especially not if that reduction was not fully enclosed. No way would I buy a motor with an external controller either.

Regarding singlespeed electric vehicles, I do not subscribe to the idea that electric torque negates the need for a gearbox of some sort. I have leased a BMW i3 for the past 15 months and despite being made of alloy and carbon and despite having 170hp it could benefit from a two speed city/highway transmission. Until you get up over 15hp or so a gearbox is essential for an off-road ebike given that one would want a speed range of 0 to around 60 mph or so with weight well under that of the lightest ICE MXers.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by John in CR » Mar 01 2016 1:03pm

Apples and oranges comparisons don't support your viewpoints in this regard. Your BMW is under-powered/over-geared for the weight, so your misconception about wanting to reduce torque with a shift to 2nd is understandable, since you haven't experienced a properly powered and geared electric. Making a motor housing to fit a controller is a matter of simplicity. Of course more quiet motors exist. You already have a chain drive, and I hope you're not trying to claim your 1000W drive does 60mph.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Mar 01 2016 1:46pm

Seriously, you should check your facts first: the i3 is not under geared for the weight. It's BMWs fastest acellerating car from 0 to 40 mph (faster than ALL the M-cars), it simply runs out of steam about 65 or so. How many miles have you driven an i3? I have about 15k so far and I suspect that I might have a better idea of what that particular vehicle feels like than you do. Would I be correct in thinking that you just read something somewhere as opposed to having actual experience in what you are posting about?

Perhaps you should actually read posts before commenting :roll: Its a short post, could you point me to where I led you to believe I am claiming that my ebike goes 60mph? I certainly mentioned "60 mph" and "ebike" in the same sentence, but there were also some other "words" as well that you may not have understood or have been unclear about. Sometimes these "words" can change the meaning of "sentences" or even whole "paragraphs", thus it often helps to read the complete post and then take the time to "understand" it before commenting. I hope this suggestion helps to avoid further embarrassment in future comments :)

Could you post a link to a quieter mid-drive motor than the BBSHD? It should be easy for you to find since you are so certain that they exist. Thanks in advance :D

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by John in CR » Mar 01 2016 4:58pm

WoodlandHills wrote:Seriously, you should check your facts first: the i3 is not under geared for the weight. It's BMWs fastest acellerating car from 0 to 40 mph (faster than ALL the M-cars), it simply runs out of steam about 65 or so. How many miles have you driven an i3? I have about 15k so far and I suspect that I might have a better idea of what that particular vehicle feels like than you do. Would I be correct in thinking that you just read something somewhere as opposed to having actual experience in what you are posting about?
3000lbs plus driver and passengers pushed by 170hp geared for 93mph with a 7+ second 0-60mph time is what I found with a quick search, an ice wagon AFAIC due to weight and gearing. Add field weakening to the equation and it's no wonder it's done at 65. You're the one who said it needed a 2 speed, which would hurt not help. If you added more motor with the extra weight of the tranny you want it would come out ahead. In all likelihood they've got the motor bridled back conservatively, since they don't want to embarrass their own gassers, so what you really need is a controller/computer hack and maybe a bit more voltage too.
WoodlandHills wrote: Perhaps you should actually read posts before commenting :roll: Its a short post, could you point me to where I led you to believe I am claiming that my ebike goes 60mph? I certainly mentioned "60 mph" and "ebike" in the same sentence, but there were also some other "words" as well that you may not have understood or have been unclear about. Sometimes these "words" can change the meaning of "sentences" or even whole "paragraphs", thus it often helps to read the complete post and then take the time to "understand" it before commenting. I hope this suggestion helps to avoid further embarrassment in future comments :)
You're the one who said "Until you get up over 15hp or so a gearbox is essential for an off-road ebike given that one would want a speed range of 0 to around 60 mph or so with weight well under that of the lightest ICE MXers." Why does a fixed gear ratio drive need to exceed what you have now if it's the same weight, more reliable, more efficient, etc.
WoodlandHills wrote:Could you post a link to a quieter mid-drive motor than the BBSHD? It should be easy for you to find since you are so certain that they exist. Thanks in advance :D
Any motor can be rigged up as a mid-drive motor. Multiple stages of reduction always add noise and cost efficiency. Higher rpm comes with more noise too, both in terms of the motor and the front sprocket or pulley. I'm not into 1-2kw drives and don't know all your requirements, but that's enough to get you started, since investing all that weight in motor instead of a bunch of gears and multiple planetary gearsets is the route to spinning the motor slow enough for near silence.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by windtrader » Mar 05 2016 4:14pm

WoodlandHills wrote:This new wide ratio rotary hub is built for heavy duty service and I hope will be suited for a BBSHD.
Is there any educated opinion on how many watts you can put thru this unit before blowing up? It seems all the previous Nexus and SA geared ups could not take much more than 1k reliably. Rohloff is supposed to take more but much more pricey.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Chalo » Mar 05 2016 5:54pm

The critical value probably isn't watts, but Newton-meters. Turn it faster, no problem. Twist it harder, things will break at some point.

Remember that the same problems we face with flatted motor axles are much more critical with a 10.5 x 9mm axle that has to transmit reaction torque.
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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Mar 05 2016 8:03pm

My Nexus 3 uses the same type flattened axle to prevent reaction torque and I haven't had any issues. There is a steel washer with a oblong hole that locks to the axle and a tab that fits into the dropout. Irregardless of whether the torque is magnified or minimized it has not been an issue with 3-speeds of torque and a BBSHD. Perhaps the extra two gears will create a problem, time will tell.
I am awaiting delivery of a 25t sprocket as well as a new suspension fork to soften up the ride so I haven't done any more than tool around the neighborhood a few times to make sure it was all installed correctly. Having the correct gearing/sprocket is critical to the performance of an IGH.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Chalo » Mar 05 2016 8:28pm

WoodlandHills wrote:My Nexus 3 uses the same type flattened axle to prevent reaction torque and I haven't had any issues.
The reaction torque transmitted through a gearhub axle is a function of the difference between the input and output ratios. A 3-speed hub stepping down to 75% isn't nearly as challenging a case as a multi-speed hub reducing to 50% or less.

I have spun 7-speed gearhub axles right through their non-turn washers with pedal power only.
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Re: Sturmey-Archer 5-speed hub, it's real!

Post by bobc » Mar 06 2016 3:59am

Regarding the torque reaction capabilities of a flattened axle in a wide ratio IGH, I've put about 10k miles on an alfine 11 over the last 5 years, and I have to say it's hard on the NTWs. The rohloff has an extra external torque reaction arm, and frankly I think the Alfine11 would be better with one. In reality the issue with the A11 is that it gears both up and down by a significant amount and this puts both negative and positive torques on the axle. Unless you tighten the axle nuts really tight they eventually come loose due to the constant axle torque reversals. Axle torques are not insignificant, I have calculated that when I stand on the pedals that's +80Nm on the axle in bottom and -40Nm in top

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Ronan-Carter » Mar 20 2016 12:55am

Hello, I'm incredibly interested to know how the new sturmey rk-whatsit is holding up to the bbshd as I'm looking into an igh for a bbshd build and there seems to be precious little information out there on it, hows it holding up? Did you use a gear sensor? Was it the igh specific one? What gear ratio did you settle on? I know its allot of questions but I'm one of those people who plans and prototypes (read obsesses) a big costly project before spending a penny. Hope it went well!

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Mar 20 2016 12:45pm

I had about 70 miles or so on it when I broke my collarbone on another bike. No problems at all with the hub in such a short time, but the complete lack of gearing options is frustrating. IIRC it ships with a 22t cog and that's that. David Prosser at Strurmey Archer/Sun Race says that eventually alternate cogs will be available, but only sizes ordered by their big OEM clients have been supplied to date. There is an offset 25t cog in their catalog that would be perfect for my needs, but it may be a year or more before it is available: it was listed when an OEM was considering it, but later cancelled.

The real issue is that the C-50 hubs use a different size cog than any other SA or Shimano hub, so one has to start all over again from scratch......... Maybe by the time I heal up SA will have an actual selection of cogs!

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Ronan-Carter » Mar 20 2016 4:27pm

Really sorry to hear about the collar bone! So the cog drives it is a different size than standard sturmey 3 speeds, I can take that into account, possibly machine an adapter for tiny raceface narrow wide chainrings. I hope things he's up soon! Might want to go with a more flexible handlebar and some chunky foam grips for the first few rides so as not to put too much vibration through the healing bone, best of luck dude!

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by WoodlandHills » Mar 20 2016 5:11pm

There is very little material to this cog to create an adapter (see the SA pics), I was thinking of machining the teeth off and welding it to a steel cog of the correct teeth count. They would both need to be altered to fit together and to be concentric, it would also be an opportunity to correct any offset issues in my specific installation.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Ronan-Carter » Mar 20 2016 5:17pm

Hadn't thought of that, one thing I've found is there is an rf5 as well, does the rk5 freewheel when backpedaled? (I know the bbshd won't allow backpedaling but I'm worried that coasting downhill ona fixed hub could damage the motor forcing it to turn unpowered) or am I missing an obvious difference between the two models?

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by Ronan-Carter » Mar 20 2016 5:36pm

Ignore the freewheel question, I goofed and forgot that by freewheel in the rf5 description it means rim brake only, same internals as the rk5 while the rk5 has a disc mount. I was wandering how it shifted under load, or if you used a shift sensor? I thought about making a clutch using the magnetic brake sensor part for the bbshd and a brake lever suicide shifter arrangement, ad a pin to the downtube style shifter that has to be lifted by pulling the brake lever, cutting the motor, then the pin snaps into place on the next index, just by bolting a bit of handlebar to the shift lever it becomes a cool little gearstick with clutch and indexing, my build is inspired by the juicer bikes for its style so I think it would fit quite nicely.

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Re: Sturmey-Archer 5-speed hub, it's real!

Post by waynebergman » Mar 20 2016 11:19pm

I also noticed in regards to lack of cog sizes for this 5 speed we can add the Over Locknut Dimension of 135mm only. I don't see a 170mm version for fat bikes.

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