fast and slow

Looking to make an off road and on road tractor using one belt double pulley.like high and low ..anyone have ideas for moving belt onto double pulleys of Spicer transmission? One will be six inch pulley and the other will a three and half welded on top of each other on the trans?

Interesting idea, but likely very difficult to implement. While it might be possible to put a belt guide on a handle to "shift" the belt between pulleys, your bigger problem is the belt itself. If the pulleys are different sizes, the belt will need to be, too. And since a belt can only be one size... well, it[s an issue.

Maybe if you[re lucky, you can set up a clutch with enough takeup in it, to compensate. Now, there's THIS problem: Pulley alignment. If the pulleys aren't all lined up properly, you toss belts.

Maybe if you used 3 belts it would work. Like one off from the engine to a jackshaft with your two-tier pulley on it. Put a two-tier pulley on the rear and run two belts with a clutch on each of those. Might work, although the clutch would need to travel a lot to neutralize the idle belt so it doesnt accidentally grab.

Only other way i could think of is to get two belts and two pulleys, one small and one big, and just swap out pulleys and belts whenever you want to go fast or slow.

Just set up two clutches, one for each belt, and lock the one you are not using open.

I thought about this with a right angle gearbox becuse of how heavy duty they are. Complicated but cool! Maybe this would work good for a speed mower, turn a 5 speed into a 10 speed

Moose and I kicked this Idea around the other night in chat


for a horizontal shaft engine and trans

Make a horiz jackshaft with the motor driving the shaft.
Put diff size pulleys on each end
use 2 blade engagement clutch levers to operate.... one side up, on side back drives one gear ratio, switch for the other.

same a stretches Idea, just using blade engagement clutches since they already have the lockout buttons

Thanks everyone for the ideas....they all sound great even some of which I have thought of. just have one tractor at the moment that I like to race around on the street then want go play in the woods ...trying to build a multi pupose tractor..I have another tractor coming but I'm going to make that a four wheel drive

Right now I have a john deere Lt 150 5 speed that does around 35 mph ...engine cranks about 4000 rpm it will lift the front end even at like half throttle and first gear

I think you can achieve this idea with one belt but it wont be an on the fly type of idea. You will need 4 pulleys.

Take your 6 inch pulley and have that attached first onto your engine, then under it weld on a three and a half inch pulley.

On your tranny have a three and a half inch pulley on it first and then weld a 6 inch on top of it.

Then when ever you want to switch it ( romping or road drives ) You a just switch the belt pulleys and you can achieve multiple ratios with one belt. This is actually implementing the same type of system a milling machine uses to adjust the speed the drill bit spins.

You will need to have your belt tensioner In the middle of the length of the belt because that's considered the axis on which the belt will pivot a little bit. It might need some de bugging but It works in my head lol   

the54 wrote:

I think you can achieve this idea with one belt but it wont be an on the fly type of idea. You will need 4 pulleys.

Take your 6 inch pulley and have that attached first onto your engine, then under it weld on a three and a half inch pulley.

On your tranny have a three and a half inch pulley on it first and then weld a 6 inch on top of it.

Then when ever you want to switch it ( romping or road drives ) You a just switch the belt pulleys and you can achieve multiple ratios with one belt. This is actually implementing the same type of system a milling machine uses to adjust the speed the drill bit spins.

You will need to have your belt tensioner In the middle of the length of the belt because that's considered the axis on which the belt will pivot a little bit. It might need some de bugging but It works in my head lol   

You might be in the ballpark here. My drill press agrees with you, anyhow. As far as the clutch goes- normally one uses one or two pulleys, the right size for the belt. This may not work here. Perhaps wide pulleys or stacked ones are in order. Just thinking about alignment here.

I was actually thinking of taking the orginal pulley stack for eng \ deck..weld them together and figuring wider pulleys for the clutch..I was wondering about making something like. a deraillure idea( on a mountain bike) .that way I could change speed setting from the seat and never get off..it will require some work ..even if I leave the small pulley on trans.and give it a 1:1 ratio from small pulley on eng. The other thing I was thinking is that my deere has two pedals one brake clutch the other was deck height one of my ideas was to make everything double on the bottom just opposite ...run two belts one pedal controls fast setting the other slow and steady. Both pedals operating the brake linkage..installing lock tabs on either pedal to lock them at disengage and use the speed needed...

The derailer Idea will work, but you will need 2... one for each end, synced together (maybe one long hinged piece)

The biggest problem faced in this idea (horizontal pulleys, vertical shaft) is belt retention. You will need room for the belt to jump pulleys, which presupposes room for it to fall OFF.

If I were to actually attempt this on a vertical shaft, I'd make a 3 belt system similar to MTD's varidrive, only using step pulley's instead of variable pulleys. A smack center section that looks amazingly like the setup on a lathe or drill press. your derailer idea will work better on a system like that. have the clutch actually move one of the pulley shafts in and out to allow for rolling gear changes... wouldn't need much movement, a 1/4 inch or so to allow slippage and repositioning.

well Im bored so I am gonna tackle this the only way I know how... paint shop

well my trial expired on sketchup and paint is proving to be... irritating so I give up... more or less I was thinking just capture the belt in the pulleys so it can either be in high or low just not allowed to come off the idler would have to have a long travel spring so I was thinking you could use one of these air assisted hood catches like they have on car hoods and trunk lids to capture the belt I was thinking just weld a plate to the top and bottom of your pulley stacks to keep it from wandering. the shifter would just be a simple bar on a pivot front and back would have to pivot in 2 directions or you could just do it by hand so long as you turn the engine off lol dont need anyone losing hands

Older bolens used a system just like your talking about, here is a video of it running, and showing how it works
https://www.youtube.com/watch?v=Q3OYzjvT28Y

lol wow I shoulda been a engineer back in the day

That's a pretty good video ..I'm gonna try some of these ideas and find out what will work the best..

Moose wrote:

well Im bored so I am gonna tackle this the only way I know how... paint shop

well my trial expired on sketchup and paint is proving to be... irritating so I give up... more or less I was thinking just capture the belt in the pulleys so it can either be in high or low just not allowed to come off the idler would have to have a long travel spring so I was thinking you could use one of these air assisted hood catches like they have on car hoods and trunk lids to capture the belt I was thinking just weld a plate to the top and bottom of your pulley stacks to keep it from wandering. the shifter would just be a simple bar on a pivot front and back would have to pivot in 2 directions or you could just do it by hand so long as you turn the engine off lol dont need anyone losing hands

Slightly off-topic but sketchup doesnt expire. http://help.sketchup.com/en/article/39436

A vari-drive will change the size of the pulleys for you, I believe. Solves all your problems. You could try an automatic like the comet clutch setup for go-karts too.   

Shifting the belt from one pulley to another while running would be toung on the belt and pulleys as well. I don't think the belt would like it, even if you incorpored a tensioner. Just my $.02