Six Speeds Why Not Twelve Speeds ?

[BPjunk 184]

Driving Ed Mayhews model 1973 8hp that is equipt with a 16hp Kohler and 6 speed Unidrive (1-1/8 inch axles with 8 pinions) was neat since he installed a larger diameter engine pulley with a smaller diameter transmission drive pulley. This gave a good ... hummmm lets say "road speed" in high range and a good workible gear selection in low range. So I thought ....... how about 12 speeds? This could be done with two sets of pulleys, a set of stock diameters on the engine and transmission then with a larger diameter fasten to the engine and smaller on the transmission (this could be done by several ways) . OK OK I know what your thinking BUT Wild Bill you can not have two drive ratios running at the same time and this is correct. What you would need to do is add a second clutch idler pulley and clutch pedal with a catch mechanisuim to hold one or the other pedal down.

For let's say's we use a mid 60's model (anybody who knows ain't surprized by this), take the 3/4 shaft holding the clutch pedal and lenthen it enough to add the second pedal. Running two clutch rods back ain't that hard but the real trick would be the shaft that the clutch idlers work off of. A sliding gear between the two idlers would have to be worked since the small clutch arm on the left side would have to work both rods. So if worked out ok you could have a set of speeds for faster work (cart hauling, lawn sweeper pulling ect ect) and still retain the factory work ratios.

Yeah Yeah I still drink Diet MT Dew and too much of it ! <_<

Wild Bill

[420lse 18]

I'd love to see that set-up. Kinda like a Bushhog veri speed pully system. But, the v model was more like a 3 speed hydro without the hydro Quote, Yeah Yeah I still drink Diet MT Dew and too much of it

On a serious note, if at all possible, stay far away from aspartame (diet anything). Google says it's bad gugu.

http://www.dorway.com/ one of many many educational areas on aspartame

Diet product users please don't flame me I quit diet everything and my knees feel great!!

[wallfish 17,079]

Interesting concept.

Would it be possible or easier to just "shift" the belt from one set of pulleys to the other. Kinda like a 10 speed bicycle does with a chain.

[rickv1957 72]

That would be an interesting project,go for it!,Rick

[420lse 18]

A movable pully changes the distance between the pullys which changes the speed of the second pully which verrys the speed. Pretty cool set-up.

[TT-(Moderator) 1,145]

Why not just use a variator pulley assembly between the engine and tranz?

It worked for Elmer & Cecil a while back, if I remember correctly.

Edit - that must be the "movable pulley" that 420lse spoke of.

[wallfish 17,079]

I've never got a good look at one of those pulleys but that does seem much easier. Will they hold up under the heavy loads of a larger engine?

[TT-(Moderator) 1,145]

Many of the "throwaway" lawn tractors use a variator drive set-up, as did some JD and Simplicity/AC garden tractors "back in the day".

I worked on a larger MTD not long ago that had an 18hp Briggs twin and a 5speed Peerless transaxle with the variator. It was a decent design, but it was a real pain to replace the belts.

[dodge78 90]

Something like this?

[mavfreak 11]

the mtd variable pully was to cusion the clutch disangangment it really doesn't do much for speed. and the expenxive to replace and hard to find. I know this because i have one. its a '91 18hp I use for mowing. When that pully went bad I just ran a couple of sheet metal screws in it so it no longer works. Can pull a awsome wheelie. I think a snowmoble set up would work and they are prety strong. the newer sleds put out some high hp some even 130hp+.

[Coadster32 793]

I have two snowmobiles, and have driven, and built two mini-bikes with the comet clutch system. They have great torque, and have awesome ground speed. I have thought about putting this system on a WH, but time and $$ need to be right first.

[oldandred 15]

Why not just use a variator pulley assembly between the engine and tranz?

It worked for Elmer & Cecil a while back, if I remember correctly.

Edit - that must be the "movable pulley" that 420lse spoke of.

Thanks Terry now I know what to do with the vary speed sears tractor the that vary speed thingie on the engine

Now how about one on the tranny also ????

[clintonnut 126]

I think the easiest would be to have a backside idler and v idler side by side. When you clutch, the two pulleys wouldn't be contacting either belt. While holding the clutch you could put a lever on the console that would angle the idler pulleys so when you let out the clutch it would only contact one belt.

Charlie

[TT-(Moderator) 1,145]

the mtd variable pully was to cusion the clutch disangangment it really doesn't do much for speed

I goofed....

The one MTD I had was the 18hp twin with a 5 speed but the other was a 13hp single (smaller "tractor") that had the variator drive with only forward and reverse in the transaxle.

The clutch was a totally separate tensioner (on the back belt, I believe) and the variator pulley/two belts did indeed control the speed of the machine.

No matter what, a variator pulley on a movable arm (controlled by a lever) with two belts of the proper size connecting it to the engine and the tranz will allow for variable speed adjustment in all "gears" and ranges.

[piecrazy4 0]

bolens made a variable drive on the 21-hd-01