chain tension

[john swenson]

hey friends...i would like your thoughts on this. if the tightness of the chain can be done by pulling the axle like on the rear wheel of a motorcycle ( slotted holes ) is there any need for a tensioner ? this is





hey friends..i would like to hear your thoughts on this. if you can tighten the chain by pulling the axle back ( like on the rear wheel of a motorcycle ..slotted holes ) is there any need for a tensioner ? this is # 60 chain. i know a tensioner may give a little more chain wrap around the sprocket but not sure that's needed . on my redesign of the subframe on my max 2 highboy i had slotted plates made for the front and rear axles. i can easily put tensioners on but if they are not needed i won't. maybe i just need to give it a shot when the project is done. thanks , johnboy va.

[tbone9]

If your chains are outside the tub exposed to the elements I would think tensioners are just another thing to worry about. I say keep it simple. Good luck on your project.

[john swenson]

that's my thought at this point. i plan on making a video of the build to share on here . i'm going with 1 1/2 '' axles also . j.b.

[ARGOJIM]

So not knowing which to reply to I'll keep it simple though it may not matter in your case.
Making the 2 outer wheels slide to adjust your chain tension will also tension your track further. In the adverse, any extreme stress on the track, such as a limb in between track and tire, will probably force one or both of the chains loose along with the track.
Unless I'm overthinking the amount of travel you'll have, without tracks in your current design I'd go with tbone9.

[Noel Woods]

John: Post up a rough draft of what you are talking about. I think that you may have a solid plan and it may work great, before you build it though post it here and let some folks mill it over. With the plan as I understand it, the slotted plate plan works in many pieces of commercial and military equipment, however to adjust on the fly you may need some sort of hydraulic or mechanical actuator to get to the point(s) where you can lock in the tension. Without an actuator you may have to set the tension as well as possible before a ride, but knowing how these things work, it would be wise to be able to adjust in the field. Loss of chain or track tension could make you go in circles or not at all.
I would also think about some bigger chain, maybe #80 and sprockets to take it as well, the 1.5" axles sound great. With greater weight, maybe bigger tires for floatation as well.
Finally, I think there is a reason that every manufacturer gets the chains into the body. I don't know what your experience has been with your version 1 machine so far, but I know when I have helped on swamped machines that the chains get corroded badly and no matter what has been done, other than removal and soaking in oil, they go bad quickly.

[tbone9]

Just another thought. If you’re using cast iron flange bearings weld some key stock the width of the flange along the slots to hold the bearings in place better and keep the slots from getting wallered out. I work on lots of heavy duty conveyer belts that have this setup on the take up pulleys.

[ARGOJIM]

Noel, thats exactly what i thought after my post, lockable turnbuckle adjustment.
Trevor, good idea.

[john swenson]

hey guys.. love the ideas. first of all..after 3 years of the chains exposed i have only replaced them twice and had very little problems. seeing that i'm only in extreme mud at busco 2 times a year, the wear has been minimal on chain and bearings. the new subframe has these improvements over the first one. 1) the sprockets will be between the frame rails and bearings instead of on the outside of the outer frame. ( just like in the original frame in a max 2 ) 2. the plates i had cut are 3/8 '' thick . all the plates have a 1 5/8 '' wide slot so if i need to change bearings , axle or sprocket i just unbolt the 4 1/2'' bolts on each 4'' cast bearing flange and drop axle , bearings and sprocket for easy repair on the workbench. 3) the plates for the front and rear axles have 4 ..1/2'' slotted holes that have 2'' of travel to snug the chain as needed. those 2 plates at each axle will be tied together . in order to snug up the chain, i loosen the 4 bolts on each plate and turn a 1/2'' bolt that will pull the plates back the same amount so the axle stays true to the frame. now considering that 2'' plate travel equals 2 full links in a no. 60 chain..i think thats more than enough distance. even when many of the tensioners are pushed as far as they can go to take up slack.. if you draw them back you can bearly get a half link to take up the slack. as far as the tracks go. i like running just the half tracks . i don't run them tight cause i have lot's of tub clearance. so as i pull the rear axles for chain tension adjustment i may need to let some air out of the rear tires. if i can't get the needed tightness.. the adair shackle track are easy to extend the length. i think once chain stretches to a certain point it stays close untill they need to be replaced. i'm not seeing a need to adjust the axles any more than you would adjust a tensioner. so i'm going to see if there is any need for tensioners. as far as stick getting between the chains and sprockets..i have room to design some guards if needed . the other advantage of the chains under the tub is that on my first design the tracks would drop mud and such right on the chains . now they will stay much cleaner. the 1 2/2'' axles are easy to remove from the hubs if by any chance i bend a 1 1/2'' axle. hope this helps you visualize the design . i hope to take a video of the build at each step. j.b.

[john swenson]

picked up the plates today from the fabricator. those laser cutting machines sure do a nice , clean job. not really any grinding of edges even needed. 3/8 '' is definately heavy duty enough . johnboy va.

[john swenson]

update ... after receiving all the parts i'm in the process of the build and i am videoing as i do the fabricating , etc. final shots will be of the max done and performing. johnboy va.