Jackshaft DIY Jackshaft / Freewheel / Shift Kit

[jimraysr]

Pull Start Kit.

I got mine from Zoom Bicycles. http://www.zoombicycles.com/

They are $20 or I think $15 if ordered with a complete engine kit.

BTW, they seem to have the most complete parts inventory of any site I have visited. They are in BC.

I just scanned through the 8 - 10 posts you guys have put up in the last 24 hours and my brain is cramped, and I didn't even try to understand it all.

Questions, do you ever sleep? )

Being left handed I prefer to talk in numbers rather than letters.

Jim

 

[210061741]

I said it wouldn't be easy.

The math can be difficult.
Luckyily it is done now and you only need the results.
The idea here is to go through the whole process.
Explain the hows and whys as much as i can.
I would reccomend doing your own calculations.
What you learn will be worth the time.

Once i generate some drawings maybe it'l be easier to visualize.

I hardly sleep when i get going on a prject like this.
I'm on vacation for the week so only a 4 more days to go as far as i can.
Then i won't get as much done each day.

I Figure if everyone contributes there specialties to this project it will turn out totally awswem.

 

[210061741]

Gear Train Diagram

DON'Y WORRY GUYS I'M MAKING PROGRESS.

Wait till you see this drawing.

It will be the foundation of our skyscraper and the pilar of our strength.
Most of our design work will come from here.

Yes Yes Yes

WE WILL HAVE DIMENSIONS FOR SPROCKET LOCATIONS. (down the road)
WE WILL HAVE CHAINLENGTHS # OF LINKS ECT. ECT. ECT. (AS NEEDED)
WE WILL HAVE CHAIN TENSION AND LOADS

WE CAN HAVE ANY DATA WE WANT.

SO C'MON

Lets use this time to add any useful info you can think of here.
If you can think of something we should put here SPEAK UP

Where is everone else at.

There missing all the fun.

Drawing #1 to be posted tonight ???? SOMETIME Tonight!!!!
Guess i won't be sleepin again.

 

[210061741]

Gear Train 1 Cad Dwg

Here is the drawing.
Things should be pretty clear.
We will add to it as we go.

you have to see this.

 

[Fabian]

210061741

Please take into account that the dyno graph is depicting "rear wheel horsepower" NOT crankshaft horsepower.

Frictional losses need to be taken into account through the drive train.

I like the presentation of your schematic - If you are local (Melbourne, Australia), please feel free to spend some time and teach me the basics of CAD.

Fabian

 

[jimraysr]

Effective diameter of driven wheel.

I noticed on the Sick Bike Parts drawing that the rear wheel is listed at 81"+ in circumference. True of course until you set on the bike, then you have an effective diameter somewhat less than 26". The engine RPM would indicate a given speed for each sprocket, but in fact each would be a little less.

Just nitpicking. )

Jim

 

[Fabian]

yes, i think you have to work with a figure of 98% of circumference to take into account the flat part of the tyre when it has a reasonable pressure load applied to it.

210061741 would be able to confirm or repudiate that figure and factor it into his equations.

Fabian

 

[210061741]

Calculation accuracy.

That is correct....

However these are just guidelines.
Statics and Strenths Evaluation.

To be 100% accurate is very tough.
There are allways variables and some unknowns.
We are after the average max load under normal situation.

Many things will change this.
Head modifications, Expansion Chambers, Carb.
Anything that increases the output of the motor will change these figures.

Thus far we are analizing the gear train to properly size the components.
Very time consuming and tedious work.
I've spent 3 days solid working on this allready.

Is it worth it.
Definatly.... there is no guessing or assumption going on here.
Remember we are building the system with a safty factor.
That means our system can actually handle much more than we ever expect to output.
Our goal would be to withstand a failure of any part in the system.
Say the rear bearings were to seize.
And the motor is at full torque.
We wouldn't want the front freewheel or jackshaft to break loose and mame us.

No we would want a key between the shaft and a gear to shear off.
Easy to fix and nobody got mamed.

Consistency is the key.
One must be consistent.

 

[Fabian]

I like the saftey aspect you are building into the system: "quote" No we would want a key between the shaft and a gear to shear off.
Easy to fix and nobody got mamed.

 

[210061741]

Chain Stress / Tension Calculations

BTW U Guys can call me Rich.

Sorry for the 210061741 that i used to sign up to forum so i could remember it.

My Single Sign On ID at work.

Can I change that????

-------------------------------------------------------------------------

Ok time to have some fun again.

Now that we have Torque and Rpm we can figure our Tensile Stress in the chains.

This will be good for more than this project.

I have seen much speculation on chain stretch / breaking ect. ect. ect.
what to use?????
Bicycle chain? / #41 / #415

I would guess the chain issues most people have are do to a few things.

Misalignment.
Master Links
Incorrect distance between motor sprocket and rear wheel sprocket #1
Motor shifting to the side.
Rear wheel warping / bearing wear.

I'm guessing that the standard chain is more than strong enough.
Lets go find out.

First i need to get some dimensions.

The distance from the center of the Crank to the Center of the rear Sprocket.

The distance from the center of the motor sprocket to the first jackshaft sprocket.

The distance from the center of the 2nd jackshaft sprocket to the center of the crank.

Angles would be nice but we wont have them until we get further in the design.

Anyone have these dimensions???
Please post yours.
If they are accurate.
IE: Not Just measured with a Tape or Yardstick.

ONCE WE FIGURE THESE STRESSES OUT WE CAN HAVE SOME REAL FUN.

BTW: I WILL BE CHEATING HERE.

The cad software will figure this all for me.

This way i can do the fun part.
Create more drawings.

Less tedious than doing math.

Be back later with more drawings and results.