Rear hub - jack shaft

[Large Filipino]

!!!!!!!!!
http://bikerodnkustom3.homestead.com/gallery200.html

 

[toxicmammoth]

It can work.

Here's a pict of the jackshaft I'm using on my project

http://www.motoredbikes.com/attachment.php?attachmentid=54&d=1185814662

 

[srdavo]

I must admit that the more I look at what I drew, the less enamored I am of it. I was just trying to find a way to do this that could be fabricated by an average guy (me)using easily available parts (the ones I have). It was perhaps one of those ideas that sound good, but don't really work. Maybe you know how it is. The idea seemed so good that, in my exuberance, I had to share it. And did so before taking a reasonable amount of time for reflection. I 'll let this idea ferment a bit more. It could turn out to be vinegar rather than wine. But ya never know.

A-van,
dare to dream!! look back at this---> http://www.motoredbikes.com/showpost.php?p=78789&postcount=47

WE used 2 rear hubs as jackshafts...on the same bike!! 3 chains, not counting the pedal side chain. you'll notice one hub was atached bolted to drop-outs...the same way wheels are mounted. the other one, the outer body of the hub is welded solid, and the axle spins freely.
We had zero "out of pocket" expen$e on this build. Just used parts on hand.
(the guy we built this bike for, stopped by tonight on his bike. he loves it....mile wide grin. said he was clocked at 40mph....but 35 is more comfortable.)

dude...share all your ideas.
I really like wine....... but vinegar has it's place in the world, too!!

 

[Alaskavan]

Thanks for the encouragement. I was thinking a bit today about changing my friction drive to chain. Maybe I'll revisit this idea. (Rube Goldberg would be proud of you. )

 

[srdavo]

Rube who??

Deja' vu ?



thanks, A-van....I'm kinda proud of Rube, too. (now that I know who he is)
http://www.rube-goldberg.com/

 

[Screamin Deamon]

Alaska, what kind of bicycle and for what purpose?

do you intend to make full use of how many gears of your cassette?

how many teeth on the rear sprockets(cassette)?

which engine and rpm range are we shooting for?

you could copy ZOMBY'S jackset. weld another crankset hole in the frame and use that as a jackset housing with 5/8" jackshaft.

if you want to make good use of the rear cassette, you need gear reduction at the jackshaft.

that can be calculated when you tell us about the cassette's ratios.

using the gears you suggested would be too much. it'd be like happy time engine and 106-tooth rear sprocket. besides, that 44t sprocket would be the size of a radial sawblade spinning next to your calf.

if your useable cassette gears are 32t/27t/22t/18t, you could use a 12-tooth jackshaft sprocket(left-side) and 10-tooth jackshaft sprocket(right side).

gear ratios with 32t = 19.2:1, similar to happy time engine and 46t sprocket;
27t = 16.2:1..............................................39t sprocket;
22t = 13.2:1..............................................32t sprocket;
18t = 10.8:1..............................................26t sprocket.

if you MUST use the 16t freewheel gear on the right side of the jackshaft, the left-side sprocket needs to be changed to 18t gear. consequently,

gear ratios with 32t = 18.00:1, similar to happy time engine and 44t sprocket;
27t = 15.19:1..............................................37t sprocket;
22t = 12.38:1..............................................30t sprocket;
18t = 10.13:1..............................................24t sprocket.

calculations were verified at http://www.compgoparts.com/TechnicalResources/JackshaftRatioCalculator.asp



i don't think that rear hub will be strong enough for the task. you need stronger support, welded to the frame.

Myron

The motor is a 66cc china doll. Its new and still has to broke in. The bike is a gas tank frame. GTA2. Frame only weighs 8lbs before I started adding everything. Rear wheel is a 26" x 3". front wheel as of now is a 24" x 2"This is a custom chopper I'm building as my daily driver. I'm down by the coast here in texas my elevation is from about sea level to 1300ft
Hello I am working on a similar setup but using a disc brake hub as the jackshaft. I have a 24 tooth that I'm bolting on the left side disc brake holes then on the right-side flange was going to drill and mount a 34 tooth and a 42 tooth.now from the 36 or 42 tooth a chain will go to the rear wheel which has an 18 tooth 3 speed sturmy archer internally geared hub.in 1st gear the wheel only turns 75% of the speed of the 18 tooth sprocket. 2nd gear is direct drive, so the same speed wheel and sprocket then third gear is wheel turns 30% faster than the sprocket. Yes I am thinking of a way to be able to change gears to use both the 42 and 34 that will be bolted to right side flange of jack shaft hub.The cassette since it has the free wheel i was going to remove all the sprockets except for the 13 tooth which a chain will connect to a 44 tooth peddle chain ring. This way when I want to peddle I can but I have the free wheel use when I don't want to peddle and with having the motor sprockets on the flange they will continue powering the rear wheel until you pull in the clutch. I will be honest I don't know much about gear ratios except from motor to hub is 10 to 24 teeth so that's a 2.4 to 1 ratio then you have 34 or 42 teeth to the 18 tooth. Which in 2nd gear being that's it's direct drive you get a ratio of 33 to 18 gives you 1.8 to 1 ratio. Or you can use the 42 to 18 which then is a 2.3 ratio.so I was figuring I'd start peddling with the gears on the 44 to the 18 in 1st gear so that I get the low end torque and ease of take off when I pop the clutch. Then go to 2nd gear then switch the chain to the 34 tooth and drop to 3rd on the wheel hub. Not sure the ratio at peddling means anything other than how easy it will it won't be to peddle from a dead stop which is a 44 tooth to 13 so I have a 3.38 ratio.so if anyone has any advice or if I'm really screwing up, give me a yell at gypsywolf.fabrications@gmail.com or at GypsyWolf.Fabrications@outlook.com or shoot me a text to (210)204-8279

 

[5-7HEAVEN]

Let me help.

Gear ratios are a product of multiplying the quotients of each paired set of sprockets.

You might like 14.94:1 final drive, which is the eqivalent to the CG with a single 36t sprocket.

The CG engine has a built-in ratio of 4.2:1.
With a 10t engine sprocket, that'll be 4.2 x 2.4 x (36t/17t) x 0.7(rear hub)= 14.94:1.

The 36t would be on the rear hub.
The 17t is .on the jack shaft, on the right side.

The 24t is on the jack shaft's left side.

 

[5-7HEAVEN]

I'm having difficulty following your post.

1. You're using a 3-speed rear hub with an 18t sprocket on it.

2. You're using a rear hub as a jack shaft.
A 24t on the left and 36t + a 42t hub on the right.

The 24t connects to the engine; the 36t & 42t chains directly to the rear hub

Somehow, you want to switch gears from 36t to 42t at the jackshaft.

A chain runs from the jackshaft to the 18t rear sprocket.

Am I right so far?

 

[5-7HEAVEN]

You also mention a 13t rear sprocket for pedalling.

Will there be a second chain going directly to the bottom bracket for pedalling?

 

[5-7HEAVEN]

Using the 36t and 42t jackshaft sprockets will drastically RAISE your final drive ratios(lower numerically).

They belong on the rear hub, while the 18t should be on the jack shaft.

Using the 42t at the jack shaft yields 3.02:1 ratio in high gear.
Using the 42t at the rear hub gets 16.46:1 gearing in high gear.

You'd get the results you intended, if you put 36t on the rear hub. At the jack shaft, install a 15t and an 18t sprocket on the right side.

The 24t on the right side is fine.