Which gear in a 3 speed hub is strongest?

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deecanio   10 MW

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Re: Which gear in a 3 speed hub is strongest?

Post by deecanio » Jan 05 2010 11:54am

i call to the stand Mr G Goodrum.
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Re: Which gear in a 3 speed hub is strongest?

Post by amberwolf » Jan 05 2010 3:46pm

So...the obvious question is...how can we fix this problem?

The hubs are good except that the gears are too brittle. Are they too soft a metal, or is the hardening process used only hardening the tips of the teeth and not the whole gear? Or are they too brittle a metal, with no flex, and thus just shearing off when suddenly shifted under load? Or is it a problem with the shape of the teeth, with sharp valley edges leaving a shearable shoulder? Are they cast in this shape, or machined? Would doing the opposite fix the problem?

Are the problems only with those gears shown, or does the planetary or anything else in there also break?

In otherwords, is there something we can have made that would fix the problem, as a little "power users kit" that could be used to replace the parts that break?

I do have a feeling that as long as there are no hard starts on them, so that there is a gradual application of power, and shifting is never done while under load, they probalby don't break as easily. But they'd probably still break eventually, for one or more of the reasons listed above, unless the parts are actually changed out.

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Re: Which gear in a 3 speed hub is strongest?

Post by TylerDurden » Jan 05 2010 4:01pm

Like Thud says... "cush". Get those shock-loads reduced.

We only have the one example of the planetary lunching so far. It would take a lotta hubs/parts to do a Justin and bust em in each gear and see what fails most often and at what point.
Have a Nice Day,

TD

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AussieJester   100 GW

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Re: Which gear in a 3 speed hub is strongest?

Post by AussieJester » Jan 05 2010 7:38pm

TylerDurden wrote:
We only have the one example
Actually 2...Safe snapped his axle clean in half.

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Re: Which gear in a 3 speed hub is strongest?

Post by TylerDurden » Jan 05 2010 9:26pm

AussieJester wrote:Actually 2...Safe snapped his axle clean in half.
That could be kinda interesting, if it happened from torque. That might mean the gears are about as strong as the axle itself. 'Course, it wouldn't be surprising if Sturmey/Sachs developed the units such that the various bits could sustain up to similar limits. OTOH... two datapoints are meager; particularly in the field, amongst a myriad of variables (not the least of which is safe).

Like mr_exon says: "Make'm to brake'm...then make them better!".
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AussieJester   100 GW

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Re: Which gear in a 3 speed hub is strongest?

Post by AussieJester » Jan 05 2010 10:36pm

TBH TD i think our pal Safe did mention that the jackshaft setup he had the hub incorporated into put alot of sideways
load on the axle which would have contributed alot to the breakage...definitely did break though.

I seriously doubt (Nuvinci aside) that any of the multi speed internal hubs are going to be up to the task of hard riding on a
daily basis, and off road! come on Deec, the multi speed hubs aren't even recommended for hard off road riding in manual pedal form alet alone hooking you 6000watt motor to them.

What difference if any TD would rim/tire size have on the stress placed on the hub do you think?

KiM

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deecanio   10 MW

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Re: Which gear in a 3 speed hub is strongest?

Post by deecanio » Jan 05 2010 10:43pm

i am wary KIm but Gary's real world experience of the sram is convincing me she'll be alright ;)
gary has a pack and setup almost identical to my own and he is a much bigger guy than me, heed the warnings i will but if Gary tells me it'll be fine i'll try it.
i dont recall what sort of power he uses but i know it is at least equal to mine if not more.
My only fear with the sram is if i start to jump the crap out of it, however being as im still a very novice rider i dont see it getting too much abuse in the immediate future, if it turns out that i can trail quite happily with the sram and have the power i need i will be happy to give up on abusive riding and just enjoy some high speed singletrack.
Where the hell is Gary??? :lol:


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Re: Which gear in a 3 speed hub is strongest?

Post by 1000w » Jan 05 2010 10:52pm

TylerDurden wrote:In the SA, the planetary is always meshed and rotating during operation, but it has no load when 2nd gear is engaged.

1st and 3rd require the sun to be intact to operate; so with a stripped sun, 2nd can still work, but there might be some noise from the planetary.

If a broken tooth from the planets or sun gets into the ring, 2nd will jam.
Thanks TylerDurden.
This is exactly how the hub sounded and how the damage evolved.
As mentioned before, after the inital damage to the sun gears, 1st and 3rd sounded horrorable and 2nd operated fine except for the odd crunch.
However slowly but surely more and more noise started to occure while running in second gear until I had no confidence in the reliabilty of the unit.
The sun gears are very small in diameter and teeth have a very small cross section. I believe the gears are well under size and strength for anything other than human power.
I was running a max power of 2500w initially and then 3600w max with a modded controller and would suggest I personally have a good "mechanical feel" and wasn't abusive in my riding style, this particular hub isn't up for this power IMO.
Hope this give some perspective.
Cheers,
Matt.

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deecanio   10 MW

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Re: Which gear in a 3 speed hub is strongest?

Post by deecanio » Jan 05 2010 11:10pm

i think this info is invaluable, cheers Matt.
i guess there's only one way to find out if the sram is up to it :twisted:


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Re: Which gear in a 3 speed hub is strongest?

Post by AussieJester » Jan 05 2010 11:15pm

deecanio wrote:i am wary KIm but Gary's real world experience of the sram is convincing me she'll be alright ;)

I'll be waiting to say "I told you so" Deec you can be sure of that
I'm so nice to ain't i Deec LoL... :mrgreen: Seriously though mate as you know im just trying to save you ALOT of $$$

At least wait and see what the internals are like, Lukes on the job he'll have his stripped soon enough...Gary might not have blown his ...yet...doesn't mean its up to the job long term, how long has he been riding it? how hard does he ride it? Does he take it bush? does he jump it..? I hope they are alot stronger i just fail to see why they would be, they are designed for human power and dont need to withstand 6000watts of power pushed through them, I know from reading the Motoeredbike.com forums the guys have no issues with them on their 49cc setups but they have the torque capabilities of a sick fle and max out at 750watt (stock trim HT motor) So its not greatly above abilities of human leg power is it...

Either way, as Matt has just said above, he wasn't 'abusive' with his and it lasted what? 6-7 months under electric power Matt? What happens when your out 20miles from home in the bush and it shits itself Deec, you will be ringing for assistance as you wont be able to manually pedal it either buddy, will literally be a "push bike" :mrgreen:

KiM

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deecanio   10 MW

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Re: Which gear in a 3 speed hub is strongest?

Post by deecanio » Jan 05 2010 11:25pm

:cry: :cry: :cry: :cry: :cry: :cry: :cry:

i know, i know.
waiting is so painful though!!!!
right back to a triple up front and delta/wye :mrgreen:


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Re: Which gear in a 3 speed hub is strongest?

Post by AussieJester » Jan 05 2010 11:33pm

TBH im with Matt .S in terms of the need for gears on most e-bikes, not necassary.

You should be able to gear that Stinky of yours to suit the riding you wish to do with it, and yeah the delta/wye
setup would be advantageous too you i guess, electrically giving you a couple of speeds if needed..

It will all work out in the end Deec dont streess bud...and if it doesn't weeeeell...im liking them 3220 motors more and more,
so ill take it off your hands buddy, fit nicely on the reduction drive, togther there is NO WAY Matt.P could resist the offer to ise them on his MTB build (can you tellz i havent lost hope of convincing him to go RC over a frock motor yet Deec LOL) :mrgreen: :mrgreen: :mrgreen:

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Re: Which gear in a 3 speed hub is strongest?

Post by plebe » Jan 12 2010 12:44am

Aww crap. I just bought an extra-wide sturmey archer 3-speed for an extra wide rim/tire. Rats! Now I have to think of something else. Too bad I ordered this the day before this thread was posted! :(

Anyone want to buy a brand new 3-speed? It's very shiny and never been used. :)

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Re: Which gear in a 3 speed hub is strongest?

Post by spinningmagnets » Jan 13 2010 7:50pm

I have a standard width Sturmey-Archer 3-speed that is available to anyone who wants to experiment with one. However mine is free (you must pay for your shipping of choice). I am in zip code 66441, Central Kansas, USA.

I began looking for one to play with and found two. One is a hub only and the other is on a 700c road bike rim, you can have either one, I will use the remaining one as a transmission this summer. Condition?, both dirty, old, and worn (like me).

Edit: enoob wants it. Anyone else want one? I find stuff like this on a fairly regular basis...

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Re: Which gear in a 3 speed hub is strongest?

Post by amberwolf » Jan 14 2010 2:54am

If you ever find a couple of them cheaply enough, I could really use a pair for the front wheels of the trike I'm working on. It would incredibly simplify having a couple of ratios on the wheelchair motors (one to each wheel).

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Re: Which gear in a 3 speed hub is strongest?

Post by TopCat » Aug 15 2010 7:25am

plebe wrote:Aww crap. I just bought an extra-wide sturmey archer 3-speed for an extra wide rim/tire. Rats! Now I have to think of something else. Too bad I ordered this the day before this thread was posted! :(

Anyone want to buy a brand new 3-speed? It's very shiny and never been used. :)
Im on the lookout for a 3 speed hub for my Schwinn Spoiler. A few questions about your hub...

1. Do you still have it.
2. Is it the Sturmey Archer 3 Speed Aluminium Freewheel Cruiser Hub for Disc Brake SX-RK3 - 36 Hole.
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Re: Which gear in a 3 speed hub is strongest?

Post by northernmike » Sep 12 2010 10:16am

Hi folks.

Since I'm considering using one of these:

Image

I thought I should chime in with a thought...

Miles' bike's use of the SRAM dualdrive has probably been reliable, in large part, because he's using a 20" wheel.

I remember reading up on my broken (now replaced under warranty with an updated model) Sturmey Archer XRD-5 ball-locking hub - their predecessors, the Sprints, were OK under the torque loads presented by folding bikes and their small wheels... but prone to failure under heavier loads.

Anyone who's ridden a bike with small tires knows how much easier they are to accelerate, and of course this is the greatest stress for everything - getting off the line.

And, there are some AWESOME 20" tires around!

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jmygann   100 kW

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Re: Which gear in a 3 speed hub is strongest?

Post by jmygann » Sep 12 2010 11:26am

I thought the SRAM DD was the strongest of the 3 speed internal hubs.

any reports or experiences with the SRAM DD ?

previous thread about the SRAM DD .... but no conclusion

http://endless-sphere.com/forums/viewto ... 28&t=15216
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Miles   100 GW

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Re: Which gear in a 3 speed hub is strongest?

Post by Miles » Sep 12 2010 1:01pm

northernmike wrote: Miles' bike's use of the SRAM dualdrive has probably been reliable, in large part, because he's using a 20" wheel.
Sure. It was one of the reasons for choosing the Moulton.

20" wheels also mean that there's less reduction from motor speed :D

I believe Shimano also make a 'dual-drive' but, you never hear much about it....

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Re: Which gear in a 3 speed hub is strongest?

Post by Miles » Sep 12 2010 1:03pm

jmygann wrote:I thought the SRAM DD was the strongest of the 3 speed internal hubs.

any reports or experiences with the SRAM DD ?

previous thread about the SRAM DD .... but no conclusion

http://endless-sphere.com/forums/viewto ... 28&t=15216
Jmy. Stop agonising and just do it :)

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Re: Which gear in a 3 speed hub is strongest?

Post by jmygann » Sep 12 2010 2:00pm

Okay .... which quiet, efficient, legal, (1000 watt) motor ?

which motor do you use ? what is the Kv ? sprocket reduction ?

which motor is anyone else using ?

I thought the SRAM DD internal hub with the double broached freewheel was going to be used ... what happened ??

Looking for a street legal 3 wheel bicycle (tadpole) for the boomer car replacement ?
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Re: Which gear in a 3 speed hub is strongest?

Post by windtrader » Jun 11 2016 2:35am

Since the sun gear on the shaft was identified as a failure point, did anyone source a gear that had more strength? Any other mods that resulted in improved strength?

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