chain sprocket axle torque

[john swenson]

anyone know or have a general idea of about how many foot-lbs.of torque are put on a chain..axle.. etc. on these machines when say pulling another machine out of a mudhole or pulling a load up a hill ? how much torque to snap a # 50 chain say. johnboy va.

[ARGOJIM]

John, there may be too many variables to answer this question such as;
Gear ratio
Quality of chain
number of teeth on sprockets
tire size (final gear ratio affected by circumference)
weight of machine
clutch set up
chain size
amount of stuck
amount stuck machine weighs
amount of grade
amount of towable unit on a grade
turning on a grade
etc....

A high quality 50 single could have a tensile strength of about 8500-8900 lbs if that helps.

[john swenson]

thanks jim, that's a good answer and i believe your correct. i'm thinking of some modifications using 4 way gearbox. they are rated in torque lb. ability. will see what the manufacture says in regards to the application i have in mind. johnboy

[garretttpe]

Hi John
My oring chain is rated at 9700 lbs tensile strength

[allwheeldrive]

Tensile strength Doesn't tell much, remember a chain is only as strong as it's weakest link. Standard #50 roller chain has a working rating around 850 pounds. With Heavy duty (extra thick walls) or premium chains with a working load around 1,250 pounds. It doesn't take much gear reduction to produce that level of torque, also with live loads you can momentarily produce levels well over 1,500 pounds with a sudden jerk such as tugging someone out of a pit. Think of it this way, when a car crashes it doesn't hit with only it's resting weight just as a bullet doesn't strike with it's resting weight. Objects can carry 10s of times their own weight in energy even at a couple miles per hour.

I recall an interesting engineering tread about building portal axles for full sized trucks with chains and not gears. The reality was it was impossible as the chain would have to of been over 8" wide to support the momentary loads generated with big tires and high horsepower.

[dirtdobber]

So, assuming the working rating of a #50 chain is in fact 850 pounds, can't we convert that into ft/lbs of torque (just for the fun of it, and to circle back to the original question)? Say the drive sprocket is 6 inches in diameter and the conditions were such that the chain experiences a load of 850 pounds. That's 850 pounds leveraged at 3 inches (.25 feet) from the center of the axle, or 850 x .25 = 212.5 foot pounds of torque. Right? Wrong?

[john swenson]

dirtdobber, i think your pretty much in the ballpark ..... thanks. the reason i was asking was i have been throwing around the idea of changing over my max 2 highboy to shaft drive. all the 2 and 4 way gearboxes are rated in ft. lbs. of torque in there applications. the design is pretty straight forward, but i believe the cost for the components that i priced are up there. $ 200 - $ 300 per gearbox. so i may not do it yet without more research. thanks, johnboy va.

[Rabbit929]

dirtdobber, i think your pretty much in the ballpark ..... thanks. the reason i was asking was i have been throwing around the idea of changing over my max 2 highboy to shaft drive. all the 2 and 4 way gearboxes are rated in ft. lbs. of torque in there applications. the design is pretty straight forward, but i believe the cost for the components that i priced are up there. $ 200 - $ 300 per gearbox. so i may not do it yet without more research. thanks, johnboy va.

I have the blueprints you mailed me! Your design is exactly what I had in mind. What type of gearboxes are you looking at?
I'll upload the blueprints as soon as I get to a printer.

[john swenson]

rabbitt, check out tolomatic co. for one. and w.c. branham co. also. they make a gearbox called slide a shaft that would be ideal. the only thing is when i talked to the engineer there about the application, they are not designed for that kind of torque. also check out '' agri supply co.'' . i think the gearboxes needed for this would be the ones used on post hole diggers,bushhogs, etc. they are rated to take from 40 to 75 h.p. and they are more affordable. the 2 way look to be just right. you will also see a 3 way, but at $ 100 i'm not sure it's heavy duty enough. say's it's for a spreader. . there are some other co.s that make heavy duty ones... but cost ? i'll keep exploring johnboy va.

[allwheeldrive]

Dirtdobber Seems sound to me, this is an interesting point john swenson and good sourcing of components from other applications besides automotive. It should be considered when one realizes how small and punny diffs look in Polaris products even though they run sometimes over 100 HP, you can get away with less when you've got so much less weight being hauled around. Though I have to wounder. If the intent of building a shaft driven machine was to produce a 6x6 that you could really abuse, pull and overload beyond chain driven specs wouldn’t you want your shaft driven components to be well beyond the rating of their contemporary chain units? Finding the components that mimic the durability and work load of a chain equivalent is good engineering for efficiency of cost and weight however would you not be self defeating the original goal of a 6x6 with many times the durability of a chain driven unit? It would probably just be easier to swap out the sprockets and chains to something much more beefy like #70 all around than building from scratch, and you would be hard pressed to break a chain ever again.

[flippy]

if the gear box for the brush hog hooks up to a category 2 and up 3 point hitch it will be plenty strong enough.I used to own a ford 1948 8n tractor with a backhoe and front end loader rated at only 28 hp that thing was a beast,using a brush hog was a real experience,that brush hog attachment sucked out alot of power from that tractor,that 3 point brushhog gearbox was indestructable.I dont think you would have a problem ,but thats just my opinion.Mine was an old piece of american iron.

[dirtdobber]

A gearbox off of a bush hog would be way overkill, as flippy notes they are heavy. Then, to get to a 3 or 4 way gearbox, to comes off a pretty good size bush hog, which is even heavier. They are designed to handle the shock of hitting a stump and surviving given all the inertia of the driveline powering it. They are protected by a clutch though.

Grainger offers all kinds of gear boxes with a wide variety of sizes and configuration, and they look pretty expensive too.

Here's an interesting thought - if you used a gear box with a worm drive configuration would you need brakes? I'm being a little silly with this question but really, you can't free wheel a worm drive.

[Rabbit929]

The main reason o took interest in this subject is that I was researching drive systems for motorcycles.
Why Harley chooses belts, reliability and touring choose shaft, and high torque racers choose chain.
A drive system saps power, less power loss=higher maintainance more power loss=lower.

(Generally speaking
Chain: 5% power loss Highest maintainance
Belt: 11% power loss Mid maintainance
Shaft: 20% power loss. Lowest maintainance


Look how small the right angle gearbox is for a motorcycle. Look how many wheels you have on a 6x6.
I think something slightly tougher than a motorcycle box would be more than sufficient, but the biggest factor it needs to be cheap and abundant. We could have the ability to make a truly bullet proof machine, and if manufactures took an interest in this idea, these machines would become far more popular I presume. I've seen people walk away from bikes because of chains, just because you need to check on them often. Ideally, sprockets only are rated to last for 2-3 new chains, at $80-$120 per sprocket, shaft driven becomes quite appetizing.

[john swenson]

hey guy's...i'm enjoying the discussion. the main goal for me exploring shaft drive is less maintenance on chains and sprockets and tensioners. i was really not thinking of a tougher machine. as i said before, i have know doubt it could be set up where there were only the 2 chains off the t20. other thing is just the fun of being creative for me. and the way my max 2 has the subframe design, there is plenty of room and options for doing this. i don't think there is room inside the tub on the regular maxes without alot of changes. if those slide a shaft boxes were strong enough, i believe i could change mine over pretty easily. the worm drive gears would be good as long as they are enclosed. i will keep exploring the possibilities.... must be some components out there that could be applicable maybe.... keep the ideas coming johnboy va

[Rabbit929]

Yes I would think a person would have to redesign the subframe so the gearbox could bolt right to it where it attaches to the axle. Could prolly delete the inner bearing/bushing, maybe have the gearbox casing bolt to the frame, or have it floating and keep the inner bearings?

If a person wanted more speed or more torque, it would all be adjustable by switching the input sprocket on the whole setup.