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Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 10:21am
by etard
While you guys have been busy trying to figure out what the hell the electrical engineers are talking about in the motor thread, I have been trying to figure a better solution than the 3 speed rear hubs. I am not sold on the ability of these to take anything above 1000 watts.

What I came up with is taking a planetary gearbox (one where the body is round) and adapting this into a rear hub. By process of welding or possibly screwing in two round discs to attach the spokes to on both sides of the body, one could have the speed reduction inside of the hub. You could also use a billet ring that uses the new push style spokes that are stronger than traditional spokes. The motor would turn the input shaft, the output side remain fixed and the body of the gearbox would turn. I also propose a much stouter rear assembly that rides on large inner diameter bearings that surround the gearbox and go inside large diameter rear dropout "cups" , for lack of a better term, that somehow clip onto the hub by way of retaining ring etc... Please tell me if there is an error in my thinking here, I am not too savvy on the theoretical modeling. Now this won't give us gears like we want, perhaps this can be taken care of by an auxilliary method, but it will give a fairly stealthy, very strong rear end if my thinking is correct. As for attaching gears for pedaling (who does that over 2kw :wink: ) you might be able to do this by attaching a cassette directly to the gearbox body. I am just throwing ideas out, any criticism and taunting is welcome.

If anything, this space can be used for processes of designing stronger rear dropouts better suited to our needs.

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 4:46pm
by Grinhill
Seems feasible, although I thought the different gear ratios was fairly high on a lot of people's priority list.

Any chance of a sketch, maybe a cross-sectional view to make this clearer?

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 5:50pm
by John in CR
Etard,

You can actually have a retro-direct 2 speed with that set up. Spin the sun gear in the opposite direction of wheel rotation for low gear. For high gear just drive a sprocket attached to the housing as if it were a normal hub.

John

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 7:42pm
by Thud
Etard,
I think the 3 speed hubs show some promise. Gary has that video of himself beating the puke out of a S-A with full power up shifts :twisted: I can't imagine anything tougher than that on one(on road anyway-off road there are all kinds of shock coming from all angles)

I have a old shimano 3 speed I am dying to lace into a 24"rim & pump 6k into it for the real acid test. (I loves me some E-bay) the only real addition I would like to see is something to take the shock out of the drive train.
A rubber "cush" mounted rear sprocket or some where in the drive line would releive a lot presure spikes on them li'l gears.

I have looked for the post where Safe grenaded a hub, But I have been told it was an 5 or 8 speed unit that had a failing record under human power also.

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 8:55pm
by mwkeefer
Safes grenade was the 5spd (can't remember which model)...

Though I don't have all my parts yet for my 3spd parallel drive (almost all here, just not quite yet) I can tell you that I have rigged up the best test I could:

Using 2x4s and Angle Iron I constructed a test stand which holds a Tower Pro 5330 in place (provides mount with tensioning swing plate) and used a 8mm 10t gear on the shaft - on the rear I mounted a 3spd SA and managed to attach only the 92t extron sprocket. 9.2:1 ratio.

My 5330 puts maximum of 2900w out but I haven't pushed past the 2100w mark and I'm using a disc brake to induce drag, raise the load on the chain drive #219.

Ive tried this both in delta (the default) and wye (reduction in speed of 1.73:1) and I ran this at 10S.

End result - no problems.

Granted this isn't a real world test as my butt + bike aren't there to provide resistance but Gary has done a good job of proofing the use of the SA3.

In a perfect world, we could get a SA8 with a better gearing range .5 - 2x across the 8 speeds (perfect for motor) but the ranges on most of the larger geared hubs are nearly useless for our purposes.

Thud has a wonderful new reduction system with a 2 spd gearing that looks marvelous (I want one) and I have a thought that we could use his design - not as a reduction unit but with smaller gears as a transmission between what would otherwise be a direct drive motor (RC style) and a SA3 providing many more gearing options and possibly lighter weight over the options.

I haven't mentioned this to thud in any thread yet as it's just dawning on me as I post this but... it would allow for smaller gearing within the thud transmission (hate that name) reducing it's size and weight and combined with the SA3 would provide any ranges we want!

I think this may be the perfect solution (at this time, unless we can talk SA into making us a highly efficient hub with more gears in a better ratio for eBike use - we can always change out the chainring for pedal cadence alignment.) until we have better technology to work with. Even an SA3 with wider spaced gears would work perfectly work in our application.

I think the stock SA3 is .75, 1:1 and 1.36:1 - a better ratio for our use would be: .5, 1:1 and 1.75:1 or 2:1 - that would be a bit harder to pedal through (unless we had a 3 speed chainring front derailer, or atleast a 2 ring) but I hope my point is taken, this is the best solution (save for more gears in an efficient hub) available at this time.

-Mike

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 9:41pm
by John in CR
In addition to Gary using it, I remember someone doing custom small echoppers in Cali using Nexus 3's with Eteks without problem. Soon I'll have a big hubbie out of the wheel driving a Nexus3. I want to try to limit top speed to 40 instead of the 50mph I'm doing at 80V as a hub motor. It should be a billy goat.

John

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 9:56pm
by mwkeefer
One thing I forgot about....

There are guys out there building ICE type bikes using these geared rear hubs, there are also numerous accounts of other rears like the CVT nuvinci and so on handling 6000 + watts.

I'm fairly certain these things can be used to atleast 3000w without too much worry (the 3sp versions).

-Mike

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 10:37pm
by etard
Hey thanks for chiming in guys!!

So I guess Safe is the only real failure story told, SO FAR :twisted: .

That's good. I wasn't aware of any load tests put on these, so thanks for that Mike, you should work for Consumer Reports. :wink: But isn't Gary's system direct drive, so the torque load compared to say somebody using the Recumpence drive much less? And this guy down in San Diego, I havent seen or heard any other rport than Gary mentioning it in passing. I mean for all we know he could still have his sanity (think liability) and only be running 2kw through the Etek. I would definately be for thowing some money at somebody to destroy one of these (hint hint, nudge, nudge). So why don't we get a pot going to Mike or Thud to stomp these babys. I got $10 on it. Video would be requirement though. :wink:

So my argument has stood up thus far and the fact remains that we still lack an ebike gearbox, and only one shifting device has been constructed. I am waiting for an SA to show up as a jackshaft, but I think a major problem with that is the fact that the overall gear change would vary much more minutely (say that 3 times). Is that right? Like if it was 2:1 from motor to SA hub, then the end ratios would have only half the effect on speed.

Maybe this is the wrong section to bring this up, but wouldn't the most complete motor driven bicycle include both the motor, and a gearbox inside of it? If you could jam all this inside of the hub, and then make it strong enough to withstand a 10 foot drop with 200 #'s on it, you would have a world -beater. It would be the end all solution, the hub guys could finally say: "I knew they would come around eventually." :roll:

I think everybody is seeing it, but nobody is saying it. Make the damn thing huge out of billet aluminum, so what if it weighs 25 lbs, use the Axial Flux style motor sandwhiched between to different gear ratios, in however many layers as you wdeem necessary, the case will be expandable. You could even put two motors in there, they only weigh like 3 lbs each, the whole case is the sun gear, the annulus' (?) can be extron because they dont have to be tiny, have that motor screaming away at 8000 rpm, delta/wye switch for 4 speeds, which will be more than plenty for bursts to 100 mph. If you build this gentleman, I know a line of investors will form here to get on board. How much will people pay? Thats not the question, how many will be put in the crusher :cry: for street racing rice rockets? hahaha, yeah!!

People wonder what I see on here, and are like Electric Bike haha, cute. But what I see is a community, sharing, giving, expanding, and evolving. Evolving the form of tranportation that most people can't even imagine. Being here in this age, is like glimpsing for a second into the future. Truly I am blessed to be in the company of such a crowd. That was me giving Thanks, now lets eat some turkey!!! :lol:

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 11:03pm
by mwkeefer
etard,

I wouldnt' say safe had a failure - the hub failed but we all (including safe) have learned from it.. though to be actually scientific about it, somone should grab the same rear and reproduce the test (source the hub from a different vendor/supply batch) - it could have been just the unit he got... we don't have enough data to assess.

The torque may be higher coming off a dual reduction recumpence eDrive however... if I am not mistaken Gary is using a 3220 not a 3210, it produces nearly double the torque at a given RPM so I do think they are an equal torque match as opposed to apples and oranges (assuming not dual reduction unit behind the 3220) but in a 3220 direct drive it should be roughly the same torque output (someone correct me cause I'm sure this statement is wrong or inverted).

Ive thought of using the SA as a jackshaft but haven't gotten past thinking and mentioning it in some other post / thread, in theory that would be lower levels of torque and may even survive longer (not that an SA3 has been blown out yet).

With regards to putting everything into a hub... yea it could be optimal but think weight of the motor and reduction unit + wheel and tire and now were heavier than traditional dd hubs. Additionally it would be a beast for maintainence and repair.

As you point out 2 speeds with Thuds box, add 3 for a SA rear for 15 speeds total. For RC style direct drive... the gearing in thuds box would need to reduce in larger factors so that od gear from the SA3 combined with maybe 1:1 from the thud would provide the top speed desired? - its getting late I may have this wrong.

Add to that teh delta wye and without checking for overlaps in ratios - and now it's 30 speed.

Which brings me back to the most important point... one I've missed previously - we don't need that many gears to have a fast and efficient eBike with RC drive - 2 or 3 is plenty its just where are those gears that matters (I mean how far apart covering what range of gear inches).

Another solution would be dual geared hub motors... using just one at a time each having different ratios and adding delta wye - remember geared hubs freewheel so yes it brings us to the weight of a single DD hub but... it does offer the total gearing you would want without needing to reinvent the wheel (once again I try to be funny and fail, shout have worn a helmet as it hurt my face).

-Mike

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 11:34pm
by TylerDurden
etard wrote: Maybe this is the wrong section to bring this up, but wouldn't the most complete motor driven bicycle include both the motor, and a gearbox inside of it?
No Hassle Motor.
Exterior+-+ray+traced.jpg
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NhM1.jpg
NhM1.jpg (97.18 KiB) Viewed 2018 times

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 23 2009 11:44pm
by TylerDurden
Regarding the gear range: Ebikes only need a couple of gears with little overlap.

Thud's little dogbox can do that; and if there is a 3spd at the end, those six variations should be enough for most finicky sweetspotters.

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 25 2009 9:06pm
by AussieJester
Put down another for a Sturmey Archer ...Matt.P (1000watt) Informed me week or two ago
his extra wide 3 speed sturmey archer has given up the ghost. Hes running Cyclone 1000watt motor.

Have you guys seen the inside of these 3 speeds? the match stick size pins that take all the load?
IMG_3929.jpg
IMG_3929.jpg (148.38 KiB) Viewed 568 times
Above pic is one of two pins that take ALL the load in a Shimano 3 speed hub, these pins
slide up and down through a elongated slot in the axle (soz i cut the axle up
and used it on the trike to screw footpegs onto so no pic of that
) This is what Safe broke
on his. Both pins and axle are weak points.

The ICE 49cc fellas use them successfully BUT they have pitiful performance compared to some here, their 49cc HT
motors stcok put out 750watt and dont have the torque to pull the skin off a custard BIG differnce from
whats found here...


Give me a couple of weeks etard then send me any 3 speed you like
and ill snap it, catch it all on video for you too :-)

KiM

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 25 2009 11:50pm
by mwkeefer
Kim,

Can you build a better Matchstick?

Seriously.. whats the pin made of, can we make a better part? Beef these up at the failure point?

-Mike
(couldn't fight my way out of a paper bag but... if it's damp enough I might be able to think outside of it)

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 26 2009 12:13am
by AussieJester
mwkeefer wrote:Kim,

Can you build a better Matchstick?
No i couldnt, it 's hardened steel PLUS...it has only so much room to pass through the elongated hole bored through the side of the axle, even if they did fit you would still have big mofo hole in the axle to weaken it (and no making a fatter axle isn't an alternative either.... Its just a weak setup period, great for human power and piss poor powered 49 & 66cc HT motors, and will work on electric to..I have one on my bike ! Sturmey Archer extra wide 3 speed same as Matt .P has broken, from the start though i have known it is a weak link and planned on 'back-up' wheel with standard freewheel hub with ENO freewheel mounted in a smaller pulley. I doubt ill have a need for gears with one low gear ratio & two 6500watt motors providing the mojo..if it doesn't go quick enough PUT MORE MOTORS ON TILL IT DOES!!!!11oneoneone :mrgreen: :mrgreen: :mrgreen:

KiM

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 26 2009 12:23am
by rguy56
Ummm...

Tyler Durden's post is the topper for ther rear end of things...now where do the batteries and controller go...

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 26 2009 2:05am
by mwkeefer
Kim,

Thank you for correcting me... and killing every other idea I had or would have had with a single post - seriously saved me hours of mulling it over !

So basically it's a stainless hardened freaking sheer pin ? Crazy !

How do you estimate then that Gary's SA3 is holding up so well... I think he's near fresh water but... is he just taking it a bit easier on it so as to not pop up and therfore not hitting the "sheer pin" with enough torque to kaboom it?

I assume speed isn't the issue and only torque or instant force? So if you could curve the throttle advance you could (in theory) prevent the destruction (and yes remove 1/2 of the advantage of using this type of drive in the first place - killed my own idea) - nevermind, I give up. = )_

-Mike

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 26 2009 8:37am
by Thud
Don't give up so easily there Mckeefer.
cush cush cush.
you can't get away from the "shock" in any system that occurs from bumps, momentary wheel spin or even just shifting to the next gear. human legs & feet are great shock absorbers, A simple rubber mounted sprocket will go a long way to adding longevity to a drive system. Its why RC cars have a slipping differential & a slipper clutch. them tiny gears take a pounding.
It is the main reason I was so impressed with Garry' video. He is just Killing that poor lil gear hub & it lasted more that a few shifts! thats what makes me think there is real potential there. I don't know how hard you guys ride normaly, but Garry is JAMMING it on them power shifts.

I have seen the suprised look on guys faces when installing a Hinson clutch on their high end motocrossers. "Gee, I didn't know they put rubber in motorcycle clutches....looks kinda cheap".

Kim, that pin in the picture is the shifting pin.
It rides in the slot and slides back & forth. Properly adjusted, it should never see any force other than sliding the spider back & forth into gear & from the spring it rests against. As Mckeefer said, 1 fail is not a real test. This is the 1st recorded issue on that model gear hub. (that I am aware of) & if he was getting grinding noise, It may have been slightly out of position & mucked the 1st mm of engagment on the gears. once wear is introduced, the effect is exponetial.

If the axel pins in the spider fail it would be shock/tourque related & fixable (harder pins). I would expect to see a failure in the spider that holds the gear array or the gear teeth themselves from shock related damage.
Given the smooth power deivery of electrics, I would think the ICE crew would be destrying these with regularity. But again, I've never seen their set up.
When we just shred the teeth out of one, then maybe we put too much power into it, too fast!
I think you are going to like the shifting option & hope you have no issues other than ripping spokes out of the rim in a smoking burn out! :mrgreen:

Re: Posturing and Rants on the Rear End of Things

Posted: Nov 29 2009 8:40am
by AussieJester
Spoke to Matt .P today and asked how his 3 speed Sturmey was going
and was pleased to hear it is still going! It makes clunking noises in 1st and 3rd gear but is
fine in 2nd gear (2nd is 1:1) Matt has taken a few of these apart and advised that the 2nd gear is he strongest setup of the gears, seeing 2nd is the gear always used i might have more luck with the 3 speed than i anticipated! 1st will rarely be used same for 3rd. Matt has said in the past if he built again he wouldnt bother with the 3 speed go with gearing same as 2nd as performance is excellent ... Shall keep forum updated on the success of my 3 speed either wayz :: fingers crossed :: shall be leaving it in 2nd and caning it hard :mrgreen: If all holds up ill use this for the dual motor setup also as it is a lovely looking turned aluminium hub, with a smaller pulley the 2nd gear 1:1 ratio my top speed with 4in pulley will be 120km/hr 1st would also see more use for hill climbs.

KiM

Re: Posturing and Rants on the Rear End of Things

Posted: Jun 11 2016 2:23am
by windtrader
Very old thread but wondering what the current experiences are with durability of the SA 3 speed hubs and damping to reduce gear stress. Did anybody do any mods to the internal IGH parts to reduce weak failure points? What is the upper wattage/torque limits to keep from blowing it up? thx

Re: Posturing and Rants on the Rear End of Things

Posted: Jun 17 2016 1:24pm
by tahustvedt
There are harder materials than hardened steel. Carbide. Get a carbide endmill of the same diameter and cut to length (get lots of cutting wheels, it's hard!).

Re: Posturing and Rants on the Rear End of Things

Posted: Jun 18 2016 9:03am
by etard
Very old thread indeed!

Correct me if I am wrong, but I think the geared hubs are only reliable at less than 2000 watts. Aussie Jester had a failure early on and abandoned the geared hub.