3 Speed Hub As Jackshaft Question.

I believe it will SB!
Getting ready to order some split locking collars to make the hub mount. I ordered pull start as the hub will freewheel when the bike rolls forward. Will make it easier on the hubs gears too. This hub is a mid 70s Shimano looks well made. Most folks run a SA, they are known to be pretty tough. If this one trashes will just get an SA.

The idea of not having 3 separate chain lines with the associated back lash/complexity is appealing. The Bikes pedal system is left totally alone.
 
Subbing, with great interest.

I too would like to see it work. I just don't have enough bicycle mechanical knowledge/experience to blaze that trail, first.

It certainly would be a more refined solution than a jack-shaft.
 
Same here... I'd like to see this setup work too... I just bought a 3 speed hub to do some of my own experimenting with so maybe we can trade some ideas once mine comes in. I've read the other thread on this and don't see why you can't make it work the way you planned. It may take some refinements etc, but it should work once all the bugs are worked out.
 
I would like to see a feasible left side shifter too!
Heck, I'm all about gears.

I can see this working with a thin enough back wheel and the sprocket cupped way in to compensate.

The thing is, no matter how you look at it, single speed chain needs a straight line of travel, heck even 10mm or a small sprocket wobble will cause a chain jump.

Maybe if you used good 7-speed chain, sprockets, and some sort of derailleur type sprocket guide on the bottom return path to 'bend' the chain to hit the sprocket teeth it could work?

I wish the best of luck and success with this bud, I truly do, just keep the dynamics in mind is my last apparently unwanted advice.

*bows out*
 
I have been watching to find one of these 3 speed fixie hubs for the right price.

I would like to mount the hub in the bike so the fixie drive is on the left side and is driven by the motor only.

Then machine a fixture to mount a free wheel on the right side for a freewheel sprocket.

Make a split coupler clamp similar to a sprocket adapter and clamp it on the fixie hub's center spool.

Then machine a plate to bolt onto the adapter with freewheel threads in the center of the plate to instal a freewheel sprocket.

If it would work work as I envision it, you could bump start it. Have no Jack shafts. 3 motor drive speeds. Still have pedals and a pedal chain.

Then I think you would have something worth having. I have to have one in my hands to get started. If someone knows of one where the price seem right let me know. Or feel free to run with it yourself.
 
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Thanks for the well wishes KC! I know you have built many fine shifter bikes both gas and electric and I respect your opinion. Just trying something different. I agree on the slight difference in the chain line. Im hoping reversing the sprockets dish will come close to handling it.

Sad thing is my Shimano only has 2 operating speeds. normal(1:1) and overdrive, low is trashed, by a broken shift key, which is NLA. Seems these are pretty fragile. I will go ahead as its what I have, and plan on an SA conversion later. The advantage is I can shuffle the ratios several ways with sprockets to get the range where I want it. If I run a 1:1 through the hub(same size sprockets) I will have the same top speed I have now(28)in mid range and around 32 in OD. Or I can shuffle the hub sprockets ratios to raise or lower as needed as well at the final drive sprockets.

Brown trying to envision what you are thinking. I know why you don't have the fixie hub in hand I bet. Its close to $200 isn't it?

Stay tuned, this project is right behind the CG wet clutch development.
 
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There are usually quite a few shimano hubs and internals onnebay for a reasonable price and I'm pretty sure you can buy the internal assembly off ebay for yours as long as the actual shell isn't messed up.
I've also seen quite a few new and used SA hubs on ebay with used ones as low as $24.99... Id get a new one if budget allows, but there are plenty of internal parts available sonit might be possible to fix the one you got.

I just recently bought a shimano 3 speed hub to play with for $10 that's complete with the bellcrank assembly and saw there are a lot of parts available for both the shimano and Sturmey hubs...

As far as the wet clutch you mentioned, I'm also interested in that project... hopefully that one will go good for you too...
 
I know why you don't have the fixie hub in hand I bet. Its close to $200 isn't it?

Pulled the trigger today and ordered the 3 speed fixie in the 36h and 120mm rear spacing configuration. $150 delivered. It is Sturmey-Archer S3x 3-speed Fixie Hub w/shifter.
 
It has a direct and then 2 lower gears.

This might help.

https://www.youtube.com/watch?v=AJmUds2YQ74

Plan is to mount the hub in the frame so the drive sprocket is left hand drive from the motor. Since it is a fixie hub it doesn't care which way it is in the frame.

Then I have to come with a good way to mount a freewheel for a right side of the hub. I have a great machine shop that may be able to cut treads into the cover flange on the other side of drive sprocket. I will need to get a freewheel mount for the right hand pedal chain drive.

The last question is how with the internals hold up to the power the motor delivers.
 
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So if I understand correctly you are driving on the left directly from the engine. The fixie bidirectional? Will drive the hub in either rotation? If this is what you are doing how are you getting the secondary reduction?
 
Did you watch the You tubevideo I posted with my response? I think it is pretty clear how the hub uses a planetary system of gears for 2 reduction and one direct. There is no freewheel in this fixie hub.

That is what makes it so cool. That way you can but bump start it. Also you can use the engine compression to slow it down. And it has 3 speeds. One direct and 2 reduction. Just think if it as any other 3 speed hub but it doesn't freewheel.

Yes the hub is bi-direction in all three grears. That is what a fixie is. That is why a lot of fixie bikes don't have brakes. You stop them by stopping the pedals.

Basically a motorized bike has a fixie drive on the left/ motor drive side with a manual clutch.

It stands to reason since the hub does not have synchronizers in the hub that shifting from on speed to the next is going to have to done carefully I think.

All that said it will be worthless until I get a right hand freewheel mounted on the side opposite of the existing drive sprocket on the hub.
 
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I watched the vid. What I am asking is you will need( I think) a secondary reduction to get the ratio low enough for the engine to be able to operate, I don't believe the hub will provide a low enough range.
I have something in the range of 18:1 overall between the engines reduction and the 10/44t sprocket. My 3speed hub will work with this ratio to provide different ratios with in it(actually on either side, a lower, and a higher). If you run the engine sprocket directly to the fixie hub say with a 20t sprocket(a 1:2) I don't believe the hub can achieve a low enough ratio to make that work. Right/wrong?

Also I would figure bump starting to be as hard on it as shifting ever would be, though the clutches did look pretty substantial.
 
I fully intend to have a custom sprocket made for what will be the motor driven side of the fixie hub. Likely a 44 tooth to be exact.

That will be like a standard MB ratio with two lower gears. I have wanted to take a ride is Missouri where the are some major hills. All my bikes already will run over 30 mph. Don't need anything taller for what I am doing. Others might but that is fast enough for me.
 
Just thought I'd throw this into the mix as an option. I don't know if anyone is looking to use a multi speed coaster brake hub, but Bendix made some sturdy hubs in the past and a lot were sold. I'm most familiar with the single speed hub and being robust and common it is my usual choice when building a rear wheel. They are easy to take apart and reassemble and I have never had one fail on me.

Although I have a salvaged 2 speed cable type Bendix, it sits on a shelf waiting for something to happen. It occurred to me that the two speed might answer most needs for a lower gear and a normal one, especially if it is robust.

Bendix also sold an automatic which was operated by kicking back on the pedal. It was commonly called a "kickback Bendix) Every kid wanted one, but only the rich kids got them.

Anyway, here's a page giving schematics on all of the Bendix models. The 2 speed looks a lot more complicated inside to me.

http://www.trfindley.com/pgbndxhbs.html

SB
 
Thanks for the link SB. Very interesting. The 3sp Shimano is not so mysterious once its taken apart, but cant imagine the newer multispeed hubs with so many speeds!

Brown, your idea makes perfect sense now that I understand you will use a large rear sprocket directly on the hub at the rear wheel. Its a great idea!
If the custom sprocket get to be to$$ you can use the hub as in intermediary as Im intending, just keep the 2 sprockets the same size on the hub.
I actually had as I remember(maybe wrongly) a 9 hole sprocket bolt to the teeth of a coaster type sprocket on a build I did.
 
cannonball2 said:
Thanks for the link SB. Very interesting. The 3sp Shimano is not so mysterious once its taken apart, but cant imagine the newer multispeed hubs with so many speeds!

Brown, your idea makes perfect sense now that I understand you will use a large rear sprocket directly on the hub at the rear wheel. Its a great idea!
If the custom sprocket get to be to$$ you can use the hub as in intermediary as Im intending, just keep the 2 sprockets the same size on the hub.
I actually had as I remember(maybe wrongly) a 9 hole sprocket bolt to the teeth of a coaster type sprocket on a build I did.
Click to expand...

I figured I could always center up a steel sprocket from a engine kit onto a fixie sprocket and weld the two together. Then just install it as intended onto the 3 peed fixie hub.
 
I look forward to seeing you guys' ideas on builds so that we can see them working. Thanks for sharing your thoughts. Pictures will be much appreciated.
SB
 
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