Pulley Swap Belt Sizes

[Old312-8 11]

I recently came into possession of a Wheel Horse 312-8 with deck for $50. I figured that the 6H gear at 5 miles an hour was not fast enough, so I went ahead and ordered a 2 inch rear pulley. (The transaxle will be modified to handle the speed) I am having bad luck ordering V-Belts online, so I am asking for some help. If anyone knows what size belt to use because they have done a swap or they can just do the calculations, it would be very helpful as I have been waiting a month for a belt. Just want to get the project done.

[ebinmaine 67,506]

Welcome to Redsquare. 

 

No chart I've ever seen. 

 

What size was your original rear pulley?

Thought maybe 6"?

 

Going down to a 2" pulley on a 5/8" belt won't work because it's too much bend for the belt.  

Needs to be at minimum 2.5...  better yet, 3" or larger. 

 

What are you doing to the transmission to make it stronger?

They're pretty stout already. 

 

What type top speed are you aiming for?

 

When doing a pulley swap the best bet is to measure best you can and buy 3 or 4 belts at a time. Choose carefully and return the unused belts. 

 

 

[Achto 27,577]

1 hour ago, ebinmaine said:

When doing a pulley swap the best bet is to measure best you can and buy 3 or 4 belts at a time. Choose carefully and return the unused belts.

 

2 hours ago, Old312-8 said:

I am having bad luck ordering V-Belts online

 

Better off going to an Ace Hardware, Tractor Supply, or other local hardware store. This way you can exchange belts until you find the correct size.

Edited February 5, 2021 by Achto

[Old312-8 11]

I have gotten a 5/8” belt onto a 2” pulley before on a craftsman, it needs to be run a lot to wear the belt down a bit, and I have no problem replacing belts as long as I get the right size. The original was a 6” pulley, went down to a 2” and a 76” belt was too short. I am going for any speed, but I don’t want the transaxle deciding to go out at something over 15 MPH. I am going for any speed, if I am not satisfied I will possibly go full racing mower, but I want to leave some of it original. The only problem was the belt, and considering that I got the tractor for $50, I figured I was going to try to make a budget speed build. Either way, I have ways of modifying pulleys for cheap if it doesn’t work. Just wanted to check to see if anyone has pulley swapped the 8 speed yet.

[Maxwell-8 4,275]

My i won't wanne go down to much in rear size, like Eric said, The pulley will not offer a lot of traction for the belt.

You can use the oem belt if you switch the front pulley too for example a hydro pulley.

 

And maybe the safest way for more speed, bigger tires. Ain't the cheapest tho

Edited February 5, 2021 by Maxwell-8

[ebinmaine 67,506]

The idea is intriguing. I'll certainly give you that. 

 

The thing to remember about a Wheelhorse transmission is that they're designed for a lot of pressure and torque. Not necessarily a lot of high speed. 

@Greentored has one or two cookin right along over 20. Longevity is unknown. 

 

Like @Maxwell-8 states... The 2" pulley is really too small to properly hold a 5/8" belt. A 3" pulley may even go faster because it keeps grip longer. 

You can increase the size of the front pulley but you'll have to modify the belt guard. 

 

FYI 

Do NOT shift a horse transmission in motion. 

ONLY select a gear while completely still. 

 

They are square cut gears and won't take the shifting. 

 

[ebinmaine 67,506]

@Old312-8 here's some inspiration for you. 

I know these aren't Wheel Horses but I had to.....

 

 

 

@Mows4three thanks for sharing.... 

[wallfish 17,000]

It's possible to use that small pulley on the trans but it requires a fixed idler pulley to wrap the belt around it in order to get as much surface contact as possible. Top drawing

Even still, it will most likely slip.

 

How I overcame that problem was the use of a jack shaft and a rubber sided cogged belt used from the jack shaft to the trans. A cogged belt can bend much better to that small of a diameter. Rubber sided belt will grip better but then it's difficult to clutch slip at the engine pulley. second drawing. Done on tractor below

Also had a centrifugal clutch pulley on the engine in one configuration along with a foot pedal throttle. Many changes and configurations were done on this tractor. 

 

At one point it was too fast for comfort so the pulleys and belts were changed to a more controllable speed which was still pretty fast. By the time it was done there was a pile of pulley and belt sizes. BUT, they could be swapped to adjust the speed like slowing it down for taking to a show. I let people ride it if they want. Or speeding it up for a butt clinching white knuckle ride up and down the street.

This tractor was clocked with a GPS going over 35 mph by another member @SALTYWRIGHT after he bought it. He did a post on here somewhere about it

 

Belt sizes are a trial and error thing when doing modifications and buying multiple size belts as suggested is the best way to get a good fit. I use a long belt which was cut to measure belt lengths. Just wrap it around all pulleys and mark a line on it. Measure the end to the line marked and you're in the ballpark.

 

There's not many modifications you can do to the trans if you want to keep all the gearing and reverse. Please share what you have in mind. The only modification I did was drain the gear oil and replace with motor oil. The gear oil is thick so it would be drag on the gears when spinning that fast, motor oil would be much less drag. Sold it many years ago but have seen it pop up from time to time. Trans still going as far as I know.

 

 

 

 

Edited February 5, 2021 by wallfish

[Maxwell-8 4,275]

1 hour ago, ebinmaine said:

You can increase the size of the front pulley but you'll have to modify the belt guard. 

A hydro pulley was on my 314-8, seems like the belt guard wasn't modified, but could be wrong.

 

1 hour ago, ebinmaine said:

They are square cut gears and won't take the shifting. 

True, but tecumsh alloy trannys are also straitcut gears and they do take shifting on the go nicely.

@Old312-8 Wheel Horses are small tractors, not went for speed . If you need speed, buy a mower with a tecumsh, or even better chain driven tecumsh. Solid axle, whit a sprocket, 50 mph no problemo.

Edited February 5, 2021 by Maxwell-8

[ebinmaine 67,506]

31 minutes ago, Maxwell-8 said:

alloy trannys

The aluminum transmissions made by peerless that I've seen are MADE to be shifted on the fly.

they are designed to do so and they are also meant to be disposable with a short-term life which is not the same as a Wheelhorse transmission

 

Manual Wheel Horse transmissions are NOT meant to be shifted while moving. Ever.

That's the biggest reason why we see third gears that are worn out.

 

 

[Greentored 3,214]

I've played the pulley game many times- you are NOT going to get a little 2" pulley to really grip bud. If you want speed, you'll need to run a larger engine pulley, and at LEAST a 3.5" trans pulley. A common size the offroad guys run on the Wheel Horses is a 7" engine/5" trans. I run a 8/5 on my 14hp B100 bomber, its good for 13mph at a low 3000rpms with stock height tires.  26" tires are worth an easy 1.5mph alone.

My 654 trail bomb had a souped up 11hp OHV, I had a 8/3 ratio and 26" tires, it ran 28mph on gps. Never had a bit of trans issue and that was the early, 'weaker' 1" axle/4 pinion 3 speed, running straight 10w30 in it.

There are rumours of guys who have pulley'd these things to run 50+mph- and the trannys dont last long at all.

Here is something to think about- input shaft speed. Without going into all the goofy calculations, input speed on a stock machine would be ABOUT 2500rpms to run ABOUT 5mph. This means, you have to spin that little shaft and its gears at 7500 just to have a 15mph top speed, and to run 20mph- yeah- 10,000 rpm! Believe it or not, rpms in this range dont seem to hurt them, although im sure theyre not going to last 30+ years like they originally did.

I HAVE had luck shifting on the fly with both my offroad bombs, but once in awhile they will grind if I dont catch it absolutely perfect. As with anything- if you can do it without grinding, youre not hurting a thing, but if you ARE grinding, dont expect much life at all, especially at the rpms you are buzzing that poor trans at! 

Personally, if you want to have some fun and have it last more than a summer (or less), pulley swap it to run 15-18mph, run some good quality oil in it, do like @ebinmaine said and DONT shift on the fly, and that ol trans will probably run like that for years!

Oh, one more thing- never, ever, EVER touch the hi-low shifter on the fly or force it whatsoever- those shift forks are not strong and will bend if you look at them wrong

[Greentored 3,214]

3 hours ago, wallfish said:

It's possible to use that small pulley on the trans but it requires a fixed idler pulley to wrap the belt around it in order to get as much surface contact as possible. Top drawing

Even still, it will most likely slip.

 

How I overcame that problem was the use of a jack shaft and a rubber sided cogged belt used from the jack shaft to the trans. A cogged belt can bend much better to that small of a diameter. Rubber sided belt will grip better but then it's difficult to clutch slip at the engine pulley. second drawing. Done on tractor below

Also had a centrifugal clutch pulley on the engine in one configuration along with a foot pedal throttle. Many changes and configurations were done on this tractor. 

 

At one point it was too fast for comfort so the pulleys and belts were changed to a more controllable speed which was still pretty fast. By the time it was done there was a pile of pulley and belt sizes. BUT, they could be swapped to adjust the speed like slowing it down for taking to a show. I let people ride it if they want. Or speeding it up for a butt clinching white knuckle ride up and down the street.

This tractor was clocked with a GPS going over 35 mph by another member @SALTYWRIGHT after he bought it. He did a post on here somewhere about it

 

Belt sizes are a trial and error thing when doing modifications and buying multiple size belts as suggested is the best way to get a good fit. I use a long belt which was cut to measure belt lengths. Just wrap it around all pulleys and mark a line on it. Measure the end to the line marked and you're in the ballpark.

 

There's not many modifications you can do to the trans if you want to keep all the gearing and reverse. Please share what you have in mind. The only modification I did was drain the gear oil and replace with motor oil. The gear oil is thick so it would be drag on the gears when spinning that fast, motor oil would be much less drag. Sold it many years ago but have seen it pop up from time to time. Trans still going as far as I know.

 

 

 

 

 

@wallfish on your top pic- have you tried this and been successful? Man, I did this on Hoss to get some more belt grip while plowing. "It worked" is an understatement ha! I had to remove it, as when it engaged, it was VIOLENT, no matter how easy I was with the clutch.  Im talking, like triple disc race car clutch stuff- in or out, ZERO in between.

[Old312-8 11]

Alright, now that I have heard what you guys are saying and I am thinking about another tractor for speed. I am going to keep this one somewhat original and just have a 4” rear pulley.

[ebinmaine 67,506]

Just now, Old312-8 said:

4” rear pulley

Even with a 4" rear pulley it'll be pretty strong. 

Those 12 horse Kohler engines are torquey  ...

 

Do a search here on the site for "baseline" or "base line" and you'll see what alot of us do to a new to us tractor. 

 

Any questions.... Just fire away.