Sturmey-Archer 3-speed tranny

[trackfodder]

I learned something from a bike-shop guy. I had not been getting all 3 speeds out of the rear wheel tranny I am using for a jackshaft. I broke the little shifter chain and lost it's adjustment sleeve. The guy told me the shift is 1/4" movement for 3 gears, or 1/2 " total. I inserted the new chain and found I was only getting 3./8", which left it in 2nd, or direct drive. Turns out is was a matter of how much axle stuck out on each side. I moved it over and SHAZAM ! It will now obtain 3rd. It is already a long-stepping gearing, so should be interesting. I may need a bigger rear sprocket to get it within reason, but the 6-1/2 HP is quite adequate in 2nd with GOBS of acceleration. Far from lugging. It is really amazing to get rid of the squawking with the rear bike caliper. All it took was little ell things on the shoes that bear against the frame so they can't cycle back and forth.
On another note, I am still thinking Lawnboy for a friction drive. Wonder if a hard-rubber boat trailer roller might make a good drivewheel. A swiveling motormount on the rear rack would allow clutching to start or peddle and swinging it would bring the driver in contact with the sidewall and also the back-up idler roller on the other side. I don't know if a sidewall would stand up to it. I do have some 2.75 motorcycle tires that might serve. The Chinagirl clutch lock button method might be good to keep it disengaged against a pretty stout spring. They are really light, start easily, last forever,. and with around 6 HP could be awesome.

 

[maniac57]

I would not drive a wheel from the sidewall. It will not hold up long, even with a back up idler. The rubber is simply too thin.
I always loved those little lawn boys! So simple and reliable...we had one that ran perfectly for better than a decade before my Dad replaced it. (with another lawn boy)

 

[trackfodder]

My Lawnboy is an ancient Scamp model that I run on 32:1. It sits with fuel in it under my sailboat all winter and starts right up in the spring. However, I now use an electric drill with a socket to start it, I just don't want to over/under prime it. I just turn the tap on and spin it without priming.

 

[dodge dude94]

What engine are you using currently? I'm really curious, as I have a (never to be motorized) 68 Flyer 3-speed with a similar Sturmney-Archer hub.

 

[silverbear]

Tackfodder said, "I learned something from a bike-shop guy. I had not been getting all 3 speeds out of the rear wheel tranny I am using for a jackshaft."

I gather from your statement that you are using a rear hub Sturmey Archer as a jackshaft. And you are running a 6.5 hsp engine driveline through it. I've been toying with this idea for some time... wondering if I could salvage an old English bike 3 speed hub to use as an external transmission. Is this what you're doing? Could you please post pictures showing your setup? Thank you...
SB

 

[msrfan]

Tackfodder said, "I learned something from a bike-shop guy. I had not been getting all 3 speeds out of the rear wheel tranny I am using for a jackshaft."

I gather from your statement that you are using a rear hub Sturmey Archer as a jackshaft. And you are running a 6.5 hsp engine driveline through it. I've been toying with this idea for some time... wondering if I could salvage an old English bike 3 speed hub to use as an external transmission. Is this what you're doing? Could you please post pictures showing your setup? Thank you...
SB

HI SB. trackfodder's drive train sounds interesting. I have a couple of 3 speed hubs for trikes if you want one to fool around with one. I think they're Shimano. Just a regular 3-speed hub for a bicycle with a sprocket welded onto one of the spoke flanges. Let me know if you're interested and I'll post a photo. You can have it for the cost of shipping.

 

[chainmaker]

Wonder how the hubs would hold up under higher hp

 

[msrfan]

Wonder how the hubs would hold up under higher hp

Shimano is usually pretty heavy duty, but maybe someone will test it before me. I think some other forum members are using hub transmissions already, I'll have to search the threads.

 

[chainmaker]

Damn this forum...... Now I'm thinking!! Hmmmmmmmmmmmmmm

 

[silverbear]

HI SB. trackfodder's drive train sounds interesting. I have a couple of 3 speed hubs for trikes if you want one to fool around with one. I think they're Shimano. Just a regular 3-speed hub for a bicycle with a sprocket welded onto one of the spoke flanges. Let me know if you're interested and I'll post a photo. You can have it for the cost of shipping.

You are kind and generous, sir! Yes I'm interested both in the hub and in seeing a photo. I believe it was camlifter for one who was experimenting with a three speed hub as an independent transmission. I can see how it would be an especially nice setup for a trike since you could set up the driven sprocket on the trike axle wherever it lined up. Not so easy with a two wheeler, maybe. I do have in mind to put together a hybrid trike using one of the first pancake motors from Golden Motor which is the front wheel. I have a 63 Schwinn American Deluxe girl's bike with a HT motor with pull start on it. Recently found an Italian light motorcycle fork that fits just right, both the frame & headset length and is heavy enough for the pancake motored wheel. With a trike rear end it would be a good candidate for the three speed transmission I would think. Electric for stealth mode and gas for the long haul outside of town.
SB

 

[silverbear]

Wonder how the hubs would hold up under higher hp

Just thinking out loud, but I'm guessing that hub longevity would be better if treated gently while shifting gears, letting off on the RPMs and maybe not under any load during the shift... with a HT pull in the clutch and let off the gas ... let out the clutch in the new gear and give it gas. Probably would last a long time that way as a kind of cruiser road bike... not subject to the stress of racing.

A long time ago I had a couple of 3 speed English bikes with a little thumb shifter on the handle bar. Never had any trouble with them and as I recall I wasn't real gentle about standing on the pedals. I think that treated with respect it might handle motor power nicely. And part of the whole idea of gears, for me at least, is to make life easier for the engine.

I'd like to see what some of you smart natural born engineer types (not me) could come up with in making a simple 3 speed jackshaft. The simpler the better.
SB

 

[RicksRides]

pictures, Please!!
Rick

 

[trackfodder]

The freewheel direction made it necessary to use a 2nd. jackshaft. Not a big deal as it is readily accessable in the fork it mounts in. I am going to try to install the pix but may not get to as they have been run before. (see "did a springer") If not, send me your email address to [email protected]. Alternatively I can do it in Motoredbikes.com. Sounds like you had a Cerriani fork like I used. I am toying with setting up a back-up tranny from a Shimano just in case. Once when my 55 yr old son was about 6 I built a crotch-rocket looking thing with a very modified Power Products from an Otasco lawnmower. It origionally had the smallest cylinder, bronze rod, and external fan cone. It was on a little go-kart made from 1/4" sch. 80 pipe and an English Ford headlamp for a gastank. Looked like a BUG kart but very small as he only weighed 19 lbs at 2-1/2 yrs old. He could carry a broadslide through milk cartons like a pro. He never dinged the coffee table with his peddle tractor so that was why I did it. I could pick it and him up and carry them onto the local micro/go kart track and give him a push start. Very soon cooked the rod and went to the largest cylinder that would fit the case, needle brg. rod and crank and cooling shroud from a light plant. Then it went to a minibike with hand truck wheels and a chrome dinette chair for exhaust in a home cookin' manifold, and the head was cut off and replaced with an 11:1 C.R. head and transfer passage stuffed, Allstate Puch piston carb, pyramid reed cage, raised port windows, etc. It would cackle real good. THEN the big deal. A 20" bike front fork in 1"I.D. 4130cr-mo tubing connected to a steering head with another 20" front fork. a plate hanging down to mount the motor in, 2 cut -down James 125 front fork legs for rear suspension, a rectangle of 1/2" EMT conduit hinged at the steering head to carry the seat and tank which I made from GRP on styrofoam bucks with water-soluable wall-sizing to protect it and an oil filler cap from a M/C and door-closer dead-end nuts to mount with cast in. The seat had a teardrop faring on it
The wheels were 20" balloon with motorized bicycle. spokes and the S-A- tranny with a peddle sprocket. A jackshaft welded behind the engine on the frame tube. A 1/2" cold roll footbar with kickstarter rubbers at the top of the rear fork. A compression release for throttle, no brakes. Knee-notch tank. Racey lookin lil toy. Anyhow it had a centrifugal clutch and twist-grip shift. If he missed a gear, the thing rapped up and then when it engaged I had more parts for the fruit jar. So far I haven't destroyed the tranny on the 4-stroke as I am more careful and it isn't so quick to rev. OK for pix see "3-speed 6-1/2 HP Monarch". I can send more with your address. P.S. The cap was opened and hole cut in tank glass, and a cup of thinner and then hot water made an empty tank. DONT EVER blow fg sanding partical dust of the skin. It went IN and also into the family laundry. My baby daughter sat in the tub in baking soda quite a bit as it got into diapers. Yes, we used cloth diapers in those days. A vacuum cleaner is the only way to go.

 

[silverbear]

http://motorbicycling.com/showthread.php?t=43193

Above is the link to trackfodder's build.

Below is a link to a build thread done by camlifter a couple years back...
http://motorbicycling.com/showthread.php?t=11499

SB

 

[silverbear]

And here are three photos sent to me today from Curtis Fox. Please feel free to comment on what you see in the photos as it may help others of us understand better what we're looking at.
Thanks Curt!
SB

 

[silverbear]

trackfodder,
I don't mean to be high jacking your thread off into a direction you don't want. I'm hoping that your build thread and any other commentary you might offer on the idea of 3 speed jack shaft transmissions suggested here will help spur further thought along these lines. I think what you've done is awesome. Thanks for sharing with the rest of us who would like to have gears from salvaged parts.
SB

 

[bowljoman]

Bottom line is that they work ****ing killer, and if geared right are practically unbreakable under normal motorized use.

As a jackshaft, they see a far higher RPM and lower over-all tork load.

this

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

I think they are better than these just for not having a chain.

http://www.niagaracycle.com/categories/torker-tristar-sturmey-archer-3-speed-coaster-brake-hub

Classified as a Motorized FOot scooter, legal in most states on all roads 25mph or less. I just keep the shifter and top speed a secret when they ask

Mine

 

[bowljoman]

Who needs peddles?

 

[The_Aleman]

Wonder how the hubs would hold up under higher hp

Beauty of using a MaxTorque clutch or the like is they are usually "soft" on the drivetrain, it comes down to clutch engagement tuning and ratios.
That clutch never really loads anything hard abruptly, but yet you have to figure an IGH can only handle so much torque input.
From my experience, more than 75 lb/ft is risky. A well-adjusted Sturmey can take that, but an equivalent Shimano is less.
The Rohloff 14-speed is rated for nearly 100, but it's far from cheap. Still, no matter what, shifting methods and adjustment are key.

Example, long read.: My HS49 at SBP'd 69:1 (20/100,11/18,9/76) to bottom bracket is about roughly 135lb/ft of torque to the pedal crank;
That's a ~230lb man standing on typical 175mm cranks. My setup potentially sees over 250lb/ft when pedaling, although I stay seated.
Reduced further, being 69:1 to 44/15 and a 5-speed Sturmey, that ranges from 125+lb/ft in 1st gear to 55+ in 5th.
My HS49+4G+SBP 3 and 5-speed setups can be really hard on the gears due to the abrupt lockup at 2500-3000 RPM.
I actually have a 50% throttle limit now, but it's a twitchy-quick clutch, so it works well for my setup. Full throttle pedaling can strip gears.
Drawback is total engine disconnect during off-throttle. My 4G still uses the original 11T freewheel.
Still, I have my shifter set up where pedal redline is the same as engine redline in every gear.

Hub RPM is definitely important! But also know this: a shift-able jackshaft technically makes your setup illegal.

SickBikeParts gets around that by their product being a single-speed crank assist. Your bicycle has the gears.

Who needs peddles?

You means pedals? I surely do. I don't ride scooters. I'm a Motor-assisted Bicyclist who loves the benefits of pedaling.

They are many.

 

[msrfan]

SB, I just found this one so far. I guess any heavy duty 3 speed coaster brake hub would work with a sprocket welded to the spoke flange. Let me know if you want it.