would this transmission design work

[Bobby]

hey guys

for those of you that read my other thread about the homemade transmission, that might not happen.

so because i need so much torque and i wanted speed i thought of using a Baja 250cc 5 speed transmission. since it is a drive shaft, i was wondering if this design would work if not please let me know why:

The engine shaft faces the back of the seat, on the shaft is the 5 speed tansmission which changes the direction of the output shaft to the back left tire, on the drive shaft is a sprocket that has a 1:1 ratio with the axle(that way the only gearing is in the trans)

if that does not make any sense please feel free to ask questions about it

Here is a rough drawing of it

Thanks Bobby

 

[souperman000]

I am a bit confused on how it switches the driveshaft orientation.

 

[Bobby]

the input shaft( from the engine) goes in forward and the transmission changes it to the left so to answer your question it changes because of how the transmission was designed

 

[Bobby]

souperman000 there is a drawing of it in my first post on this thread

 

[souperman000]

alright I got it. thanks

 

[OzFab]

I'm not familiar with the trans itself so I have a few questions for you to ponder:
1. Is this like a standard motorcycle/ATV transmission where it's part of the engine or is it separate (like a harley)?
2. How will you link the trans to the engine? It would need some kind of clutch
3. Are you sure a 1:1 final drive will be enough to get a decent amount of speed from it?

 

[Bobby]

Its seperate like a harley
the engine shaft goes into the trans and the transmission has a built in clutch
1:1 is good because all my gearing is going to be from the trans it self

 

[Bobby]

Sorry fabroman it is like a standard atv setup the trans is mounted to the engine

 

[Bobby]

ok im just going to use bicycle cassetes that way i can get torque and speed

 

[fowler]

A 250 will rip bike gears apart

Think if u can break a bike chain by peddling too hard
What will a 250 do

 

[Doc Sprocket]

What happened to your original tranny concept and why won't it work?

 

[Bobby]

Fowler
1. Im using a 338 and 2. Ive never broken a bike chain

 

[Bobby]

Toystory i cant use my homemade tranny becuz it wouldnt give me the speed i want so im going to use bike cassetes that way i can get the torque i need to get it moving and the speed i want

 

[Doc Sprocket]

I'm not sure I follow you. If the tranny was to be homemade, then you are in total control of the gear ratios used, no? Please- tell us about what you had planned. I am very curious, and maybe we can help make it happen!

 

[Bobby]

Toystory the homemade transmission was two gears that slide back and forth on rails.
And yes if it was homemade i would be in control of the gears but i can only put 2 gears on/in it so i would only be able to have speed or torque and reverse. So im putting bike cassetes on it that way i get torque and speed

 

[Doc Sprocket]

Umm... Okay. And- don't use the bike gears. You'll rip the spit out of them much faster than it took you to install them.

If the transmission idea was a two-speed, it should be completely doable, and you may not be thinking of the big picture. You have gears in the tranny, at whatever teo different ratios you like. You ALSO have to connect the engine to the tranny, and connect the tranny to the axle. BOTH connection points afford you the opportunity to compound the reduction, and fine-tune the final drive ratio. Example- your homebrew tranny has a 4:1 low and a 2:1 high. So- put a 10T sprocket on the output, and a 20T on the axle. NOW you're left with 8:1 first gear, and 4:1 second gear. Torque AND speed. Make sense, now?

 

[Bobby]

toystory your not understanding what im saying. im saying that "technically" its a 2 speed 1 forward and 1 reverse and nuetral is in the middle so thats why im saying i would either have torque or speed

 

[Doc Sprocket]

Then it's not a two-speed- its an F-N-R gearbox. Calling it a two-speed implies two forward gears.

 

[Bobby]

oh yea i forgot it is a F-N-R

 

[OzFab]

I have a F-N-R trans from a riding mower, built into the rear axle assembly; may be something to think about...
I've also been thinking about compound gearing like a bicycle setup, but using stronger components; haven't got far though...

As stated above, using bicycle components would be a waste of time & money. With the amount of torque from a 338cc, you wouldn't move coz they would explode with the first touch of the gas pedal.

I like your ingenuity, you just need to think on a larger scale