New Build Question Sturmey Archer/Jackshaft

[Deleted Member 4613]

I'm thinking about a new build, combining a Sturmey Archer hub/internal brake with a jackshaft and 2 stroke shyhawk gt5 engine. The hub has three gears. Here it is: http://www.amazon.com/Sturmey-Archer-X-RD3-3-Speed-Brake/dp/B0029LKXM8/
The question is would this setup have better low end power from a standing start than the grubee g4 or q-matic automatic? I wish to pull away without pedaling.I can't find any videos with this drive train. Mike

 

[wheelbender6]

Some have said the 3 speed Sturmey isn't durable under engine power. I have no personal experience with it.
IMHO, avoid internal gear hubs (Sturmey, Sachs, Nexus, Sram) and use a derailleur with your motor and jackshaft. It's must cheaper to replace the worn or broken parts on a derailleur setup.
If you do not have a derailleur hangar on your frame, you can go with an axle mounted gear changer.
I do dig the internal geared hubs (I have a Nexus on my pedal powered beach cruiser). I just question their durability and repairability when used under engine power.

 

[Deleted Member 4613]

WB, I appreciate your opinion. Mike

 

[Deleted Member 4613]

I'm slowly turning off on the Grubee Gt5 66cc 2 strokes as I have read too many complaints about finicky carbs, starting, throttlling problems, blown engines, all having to do with the changes grubee made in the latest 2010 line of his 2 strokes. My HS 142 4 stroke is perfectly reliable, easy starting on one pull with no carb problems at all. Why would I take a chance on a 2 stroke?

 

[rustycase]

SA vs CVT

IMO...

There is NO WAY a china 2 stroke will put out the torque that a healthy pedaler can apply to the drive of a bicycle. No way, No how. NOT gonna happen!

Conventional wisdom declares that if you wish to pull away from a stop with enthusiasm, a HF 4 cycle engine with a Comet Torque-A-Verter is the ticket.

We're in the fun zone...
I've got three Sturmey-Archer hubs here and WILL play with them, because I HAVE them. And I'll look forward to seeing the posts on your build !
Next time I see a couple hundred bucks to spare, I shall get the CVT drive system for my 6.5 greyhound, because that IS the way to go.

Don't take MY word on it, review Cobrafreak's thread, and others!

Best
rc

 

[Deleted Member 4613]

Well of course a 6.5 4 stroke with a cvt gets the job done. CVTs are the best solution but they are difficult to mount inside a bicycle frame. I've only seen rear mounting with them. They are also too wide for in/frame mounting, so I don't see cvts as a practical solution for motorized bicycles unless you're happy with a ton of weight sitting on the back fender.

 

[pbeggs]

i run a S/A 8 speed internal gear hub with a jackshaft
works well
drum brake is very good,.. works well

one advantage of the internal gear hub is a static chainline,.. and no need to downshift as you slow (to goes from 8th to 1st in one twist) also you can run heavy chain to the rear wheel

 

[5-7HEAVEN]

IMO...

There is NO WAY a china 2 stroke will put out the torque that a healthy pedaler can apply to the drive of a bicycle. No way, No how. NOT gonna happen!

Conventional wisdom declares that if you wish to pull away from a stop with enthusiasm, a HF 4 cycle engine with a Comet Torque-A-Verter is the ticket.

We're in the fun zone...
I've got three Sturmey-Archer hubs here and WILL play with them, because I HAVE them. And I'll look forward to seeing the posts on your build !
Next time I see a couple hundred bucks to spare, I shall get the CVT drive system for my 6.5 greyhound, because that IS the way to go.

Don't take MY word on it, review Cobrafreak's thread, and others!

Best
rc

There's more than one way to skin a cat, and more than one way to pull away from a stop with enthusiasm.

You don't need a 6.5 hp engine, either. It's all about mechanical advantage/leverage/low gear to harness engine or leg power. That is why a healthy pedaller easily pulls away from a stop.

From how my friend Hawaii Ed operates his china 2 stroke engine with shift kit, it is easy for him to pull away from a standing start.

I have a 2.8 hp Tanaka 47R engine with a shift kit. It makes as much power as a healthy China engine. I seriously doubt that a bicyclist will beat me from a standing start to the top of first gear.

 

[5-7HEAVEN]

Some have said the 3 speed Sturmey isn't durable under engine power. I have no personal experience with it.
IMHO, avoid internal gear hubs (Sturmey, Sachs, Nexus, Sram) and use a derailleur with your motor and jackshaft. It's must cheaper to replace the worn or broken parts on a derailleur setup.
If you do not have a derailleur hangar on your frame, you can go with an axle mounted gear changer.
I do dig the internal geared hubs (I have a Nexus on my pedal powered beach cruiser). I just question their durability and repairability when used under engine power.

I've never ran a 3-speed hub under power. The hub mentioned has gearing which range from 22t to 13t. The eight-speed cassette ranges from 34t to 14t. The 22t in the cassette's cluster is about third gear.

Therefore, using a 3-speed hub is like starting out in 3rd gear with an 8-speed cassette. However, gearing on an SBP shift kit can be as low as 34.49 at the chainring. First gear with a 34t cassette is a stump-pulling 32.57:1

A China engine with this gear would leap off the line at a standing start.

With your 3-speed hub and SBP gearing, first gear with 36t chainring and 1.33:1 = 28.03:1, second gear = 21.07:1, third gear = 15.81:1.
With a 30t chainring, first gear = 33.63:1, second gear = 25.28:1, third gear = 18.96:1.

You will have excellent power from a stop with 33.63:1 and okay power from a stop with 28.03:1.

My new cassette and derailleur cost less than $80. It is not a heavy-duty, bulletproof, top-of-the-line model. I have broken many chains until I solved that issue.

However, the Shimano cassette and derailleur have endured through powershifts and abuse for over a year. I inspect them regularly, and they show no signs of abnormal wear.

I am simply amazed by how OEM drivetrain components live reliably under the abuse of motorized power.

 

[williamsk1936@yahoo.com]

I have a 5-1/2 hp Chinese industrial engine, Jiang Dong, on a Monarch bicycle driving through a S/A jackshaft and it seems up to the challenge. It used to do 42 flat,41 uphill,41 downhill on the governor at 3100 rpm. I replaced the carb with one from a Lambretta scooter and went with a straight exhaust and junked the tank, replacing it with a Hodaka one and did away with the governor. The thing is a lot faster, but speedo quit, so dunno. Gobs of pullaway power in grass in low. No peddles anyhow. I did have to run a 2nd jackshaft due to the wrong drive direction of the tranny. It also freewheels. I use the rope starter. That brings me to why I even got into this forum in the first place. I have a couple of ho hum China Girls and got a wild hair to play a creation game by mounting a couple 1" tubes on an engine and adding until it looks like a motorscooter with 20" bike wheels. I need a rope starter for a China Girl. Seems like there was such a unit available. I was kinda impressed with a 50cc Honda scooter I saw yesterday. Open frame thingy. Kinda cute.