Which gear in a 3 speed hub is strongest?
- Thread starter gogo
- Start date
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.
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.
TylerDurden
100 GW
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.
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.
AussieJester
1 TW
TylerDurden said:
Actually 2...Safe snapped his axle clean in half.
KiM
TylerDurden
100 GW
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).AussieJester said:
Like mr_exon says: "Make'm to brake'm...then make them better!".
AussieJester
1 TW
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
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
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:
D
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:
D
1000w
1 kW
TylerDurden said:
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.
AussieJester
1 TW
deecanio said: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...
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"
KiM
AussieJester
1 TW
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)
KiM
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)
KiM
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.
Anyone want to buy a brand new 3-speed? It's very shiny and never been used.
spinningmagnets
100 TW
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...
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...
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).
TopCat
100 W
plebe said: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.
Regards
Tom
northernmike
10 kW
Hi folks.
Since I'm considering using one of these:
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!
Since I'm considering using one of these:
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!
jmygann
100 kW
- Joined
- May 30, 2008
- Messages
- 1,069
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 ?
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 ?
windtrader
1 kW
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?
Yes I know this is an old thread but I need a little help.
Trying to determine the relative backlash in a Sturmey Archer CS-RK3 hub...can someone roll their bike forwards while holding the chain, if it moves, and tell me the number of clicks in one revolution of the rear wheel? I believe it is around 10-12...but I have no way to verify.
Another option is to count the teeth that are machined into the shell i.e. the part of the assembly you see when looking at the hub from the exterior.
Thanks
Trying to determine the relative backlash in a Sturmey Archer CS-RK3 hub...can someone roll their bike forwards while holding the chain, if it moves, and tell me the number of clicks in one revolution of the rear wheel? I believe it is around 10-12...but I have no way to verify.
Another option is to count the teeth that are machined into the shell i.e. the part of the assembly you see when looking at the hub from the exterior.
Thanks
