strumy archer rear

[woogie_man]

What do you guys think of these for the motorized bikes? I found an 8 gear one for a decent price and wouldn't mind picking it up for my build. Though want to make sure I wont destroy it while our riding.

 

[bluegoatwoods]

I've considered a multi-speed rear hub. I don't really think that a motor could harm it.

That is, as long as the motor has it's own drive chain. I'd be very reluctant to run a shift kit through that hub, for instance.

The other fear I'd have is finding out that the stock drive sprocket and rag joint wouldn't fit. That seems like a pretty good possibility.

 

[woogie_man]

Was thinking about doing a jack shaft so I would have to use the sprocket adapter. I currently have a manic mechanic adapter with a 36 tooth sprocket. When I took off the rag joint found I had 9 broken spokes.

 

[professor]

I have been using a 3 speed SA hub as a jackshaft for a few years and it has been good.
The thing is, the gears in them are tiny as is the selector mechanism.

I am getting away with it because the engine torque is at much less of a multiple at the jackshaft/hub than if it were out back.
So the thing spins fast but has low torque hitting it.
I keep it oiled.
A SA hub in the rear wheel would probably live if it were NEVER hit with an instant engine load.
Something I think would be unavoidable over time being that they freewheel until they are hit with power.

Suppose your engine had 3 foot pounds of torque, multiply that by the gear ratio, like 15 to one and you get 45 lbs/ft at the hub- it would live. But if you clobber it with momentum that 45 goes way up.

 

[woogie_man]

Thanks for the info.

Well take a look at a few other options. Thinking a standard cassette would function better?

 

[a_dam]

Hey Professor,
That's quite an idea about using that hub for a jackshaft. Somebody recently offered me an old 3-speed (60's?) Raleigh ladies bike with the SA hub for free. It has 26" wheels and I said I would feel bad taking it because about the only thing I would want is the hub. Someone else might use the whole bike.
But I keep thinking about how I might use that hub. They are supposed to be solid, and there is no long amount of unsupported axle on the drive side.

I never thought about jackshaft possibilities; maybe I should add that to my already-too-big collection of parts.

 

[curtisfox]

If you take a look at most of Worksman trikes they have a shifting jack shaft hub. Not sure how many speeds but they have had them for years.............Curt

Check out the video shows the hub at the rear of the bike

http://www.industrialbicycles.com/portotrike.htm

 

[professor]

On my first bike, which is still fine, the hub is driven by a HF79- no problems.

Bike 2 is a HF212 with the same general layout, but because of some belt slippage between the engine and hub- the full 9 lbs/ft of torque doesn't get applied to the hub.
I think it came close, but the hub does great.

Initially, it would jump out of one of the gears and taking it apart- there was wear on the cross shaped selector.
Parts are available, but I braised up the worn spots and filed them- problem gone.

If bike 2 had more gears it would go 50 mph- on the governor.
Maybe it's good it doesn't.

 

[KCvale]

Thanks for the info.

Well take a look at a few other options. Thinking a standard cassette would function better?

7-speed cassettes work fine other than the clatter and thin chain.

Personally I like the simple 3-speed Nexus best.
They have a couple band brake options as a coaster brake is useless on a shifter.

It has the same high to low gear ratio as a 5 or 7 speed, it just does it with 3 steps which unless you are climbing a lot of hills is perfect with engine power.

One thing to avoid with engine power is a NuVinci hub, they won't take anything more than a 48cc or electric without failing.

I have some details and pics of 30 or so shifters here.
http://kcsbikes.com/KCsBuilds.asp?motor=All&Drive=Yes

With an electric motor you don't need a jackshaft, just the bottom bracket freewheel for the pedals, for gas you need the whole thing.

I use the http://SickBikeParts.com shift kits.
Other than their custom mount piece it's a box of all the parts that play nice together.

You will need some skill and tools like a drill and files to put it all together, but if you read the instructions and take your time, geared power changes everything.

 

[woogie_man]

Awesome....

Will have to do some digging here in the next few weeks. Hoping to find a few donor bikes after the holidays! Hopefully getting material here in the next two weeks as well, so slowly things will come together.

Thinking a simple 3 speed would be better than a 7 or higher...just for the ease of things.

 

[bowljoman]

For jackshafts, bike tranny's are the way to go. Hold plenty of power, and after 20 miles of 30+ mph cruising, the device is lukewarm .

http://www.niagaracycle.com/categories/torker-tri-star-3-speed-coaster-brake-hub

I ride a powered dog scooter with that tranny. But if I was to do bike, I would use the 4 stroke kit, spin the engine 180 degrees, slap a 5 to 1 pocket bike tranny on it with a bmx chain sprocket, and run that power to the jackshaft, then rear wheel.

I hit 43+mph when going for that high-speed mark in 3rd gear on 1.5 hp.

Super tough unit has 2000 miles and works as good as new behind that gas power...

 

[KCvale]

if I was to do a bike, I would use the 4 stroke kit,
spin the engine 180 degrees,
slap a 5 to 1 pocket bike tranny on it with a bmx chain sprocket,
and run that power to the jackshaft,
then rear wheel.

I am confused as to why you would turn the engine around, is that pocket bike output a pair of meshed gears to reverse the rotation?

That sounds cool...
Then all you would need is the BB freewheel, 2 sprockets, and crank arms.
No special mount or even a shaft, bearings, etc.

5:1 is same ratio as the 7G (20T/100T), do you have a link to this 'pocket bike tranny'?

I can't find any technical info on that Torker 3-speed.
What's with the dual sprockets?

 

[bowljoman]

Heck yea!

Here is the power output for 1.5 hp on my setup

The tranny

http://www.partsforscooters.com/transmission?sc=32&category=132677

This goes on the tranny.

http://www.fancyscooters.com/item00298-scooter-part-sprocket-type-i-55-12-mm-12-tooth.html

Why two sprockets on the hub? To go FAST of course! Because it is easier to swap in/out change input sprocket sizes, and allows the BMX cassette on the rear wheel to be large enough for my 10 inch tire.

Another incarnation

Foot scooters are legal in my town.

 

[woogie_man]

Now that is bad a$$!!

What about using the hub in the jackshaft and then just have a single best in the tire? To keep everything nice and clean looking?

 

[bowljoman]

The 12 inch tire is required to handle BMX sprockets at 18-22 tooth. I could not find a satisfactory rear hub at 12 inches that would lace.
A larger rear hub requires a larger rear sprocket. The largest available for a IGH is an sram 24 tooth. Maybe you could lace an IGH to a 16" hub with the 24 tooth and chain directly to the tranny.

a 26" tire would need a 32 to 44 tooth input to achieve direct coupling to the tranny.

So, if you were to run a 49cc foot scooter/utility motor with the 5-to-1 tranny output on the right hand side (opposite of a china girl engine) , Install a 32 tooth rag joint or manic mechanic style clamp on precision preferred, purchase THIS
http://www.niagaracycle.com/categories/torker-tristar-sturmey-archer-3-speed-coaster-brake-hub
..And move the output sprocket to the other hub-flange to drive the 32-tooth sprocket on the LEFT side of the bike. In other words, use the sturmey version to cross over the drive-train/rim. use the nexus version to drive the same side of the rim.

For pure china girl implementations, with BUMP START and manual CLUTCH, purchase this

http://www.niagaracycle.com/categories/sturmey-archer-s3x-3-speed-fixie-hub-kit-36h-120mm-silver

Install the bolt mounted sprocket on the S3X hub and orient the sprockets to the LEFT side of the bike. Yes the S3X is a fixed gear 3 speed, and can both bump start and drive. 3rd gear is 1 to 1 so use a 22 tooth sprocket on the rear wheel, or 32 tooth in hill country

Specialty kit , install stronger springs in this unit and utilize as an auto-shifting jack shaft.
http://www.niagaracycle.com/categories/sram-automatic-2-speed-hub-freewheel-no-brake-36-hole-130-0mm

My next experiment is with the I-motion hub. wider range three-speed and my goal is better response for shifting when the centrifugal clutch wont let go at mid rpm's.
http://www.niagaracycle.com/categories/sram-i-motion-3spd-coaster-brake-36h-hub

The king of the jack shaft IGH is the Spectro P5 , 'Cargo' version if you can get one. You need to provide the second sprocket for the spoke flange to use it and 49cc will get action in all 5 gears.

Modern IGH hubs provide thousands of trouble free miles when properly matched to the engine with the right gearing. My nexus jack shaft spins 1200 RPM at max engine torque 2 40+mph.

Thats all I know. I get off on slamming gears more than anything else.

 

[mike_ric]

I use a Sturmey archer five speed on a Felt Slater with the Honda 49cc 4-stroke and a jackshaft. You can find photos of my setup here in the forum by searching for "Slater." I also use a DID 50cc race chain because the stock bike chain constantly stretched. I just replaced the SA 5 speed with another SA 5 speed, both are of the "wide ratio" variety. My first hub was having issues staying in first and second gear after about 200 miles on the bike. It was adjusted correctly. I chalk up this problem to me testing the bike as I was building it, as well as having others ride it that didn't really know how to shift. So I risked replacing it with the same model hub. So far so good, first and second gears work fine and so is the overall performance. I also replaced the original 18t rear sprocked with a 22 (or 23?) tooth for better low-end performance. With this setup I can cruise at 35mph all day in 4th gear. 5th is more of an overdrive, and 1st is super low, good for steep hill climbing or starting from a dead stop.