automatic chain tensioner

[mudbug3]

This is the Monstercraftman torsion spring ,chain tensioner that I ordered for my Max IV and Hustler Bigfoot. It takes the chain stack up automatically. If you have the room to make them fit, this a great chain tensioner to install on your amphib. You have the choice of a tensioner that pulls the chain down or one that pulls the chain up.


Monstercraftsman

[amphibious drew]

Boy those look nice, but too steep for my budget right now.

[liflod]

I've tried something similar in the past and I do not think it works very well. All of the tensioners from the factory do not allow any give once the adjustment is made either manually or automatically. With the spring loaded tensioner, it is possible for the chain to walk-off the sprokcets under the right situation. There's alot of frame flex and twist on thiese machines and with temporary misalignment between sprockets, it could happen.

[hydromike]

I see the same potential flaw in that setup. I think these tensioners are designed to apply tension in one direction, and don't "lock" to stop movement going in the opposite direction (i.e., "reverse" in an AATV). Remember that the tension side of the chain is swapped when you change direction of the machine. There is a LOT of force on the tensioners when you have the tension side of the chain on the tensioner side. It's a great start to an idea, but I think they'd have to be extremely rugged to hold up to a heavy machine with gobs of torque going in "reverse".

~m

[mudbug3]

hydromike

Point well taken. This is the reason why I,m using the Monstercraftman style tensioner on my Max IV, is based on what has aleady been proven. The Argo Centuar uses a torsion spring in the middle ,with a shoe style slider on the top to pull the chain down, and another shoe style slider on the bottom to push the chain upward. I talked to an Argo dealer named Ken Bost, and he told me that he had sold an Argo Centaur with this style of chain tensioner ten years ago, and the tensioner shoes have only needed replacing twice. He also told me that this style of chain tensioner has,nt failed in the ten years that its been in service. The forum member BW6 ( Ray ) designed a torsion spring tensioner very similar to what the Argo Centaur uses on its 8x8 for his all aluminun , BW11 6x6 amphib, and its worked out great.

The forum member bonchrs made a spring tensioner that only pushed downward on the chain, and it worked out great. We went riding together at River run atv park, and he worked the sticks very hard on his Hustler 950. At the end of the day his chain still did,nt need adjustment, but I had to adjust the chains on my Max IV. We both made three separate trips to River run atv park, and I had to adjust the chains on my Max IV each time we went, but bonchrs only had to adjust his spring tensioner once. I can see your point , but I can only speak from my experiece of seeing them work

By the way, these torsion spring tensioners are made out of 1/4 inch steel , with a VERY STRONG spring , and are extremely rugged! If any thing fails,, it would be the bracket that it attaches to. This torsion string is so strong that I can hardly move the adjustment arm a 1/2 " inch with my hand! The manual tensioner on my Max IV uses a sprocket that has a slide adjustment to push down on the top of the chain. My thoughts are to remove the sprocket slide tensioner , build onto the stock bracket ,and then replace with the Monstercraftman tensioner.
If the factory bracket has,nt failed yet, why would it fail if I weild a 1/4" inch plate on top of it to install the Monstercraftman tensioner? I know this is all based on my own theory , but I,m willing to try it on my Max IV to test my theory out

[jeffery9076]

here is some heavy duty roller sprocket i thought of a while back Econobelt Handbook of Timing Belts and Tensioners - Q450 Databse they have alot of tensioners check them out

[hydromike]

I wanted to bump this thread to see if Mudbug has had a chance to try these tensioners out yet. If it turns out they work as well as you'd hoped, there are quite a few different locations we could use these on various AATVs.... The primary chain on the six chain Attex ST models comes to mind....

I particularly like this model, with the pin-stop. They have a poly-roller model that may be applicable, too....


~m

[brushcutter]

I see the same potential flaw in that setup. I think these tensioners are designed to apply tension in one direction, and don't "lock" to stop movement going in the opposite direction (i.e., "reverse" in an AATV). Remember that the tension side of the chain is swapped when you change direction of the machine. There is a LOT of force on the tensioners when you have the tension side of the chain on the tensioner side. It's a great start to an idea, but I think they'd have to be extremely rugged to hold up to a heavy machine with gobs of torque going in "reverse".

~m

I would have to agree Mike, there is an inherent flaw in this type design, it will only tension in one direction, therefore I don't see them working very well. Another thing is they are very pricey for the amount of material that you are buying, even for the lower priced unpainted style. I can't believe that the springs on these would be enough to overcome the torque applied when the chain direction is reversed. They will still allow slack to be thrown to the other side of the sprocket. I also tried Boncrshr's tensioners and could not get them to hold the slack out of the chains when I reversed, even with the machine off the ground and no load other than just the tires. Now maybe my springs were just not as strong as Scott's but they were strong enough that I had to use a pry bar to get the tensioners on. I did however use his design without the springs and have been well pleased with that set-up. I have, therefore, yet to see the advantage of spring tensioners, Some argue that it keeps the chains from slapping when you reverse direction, but if you think about it, if your chains are tensioned properly, there shouldn't be a lot of slack to be slapping around to begin with. My opinion is that you are far better off with ANY tensioner that HOLDS a constant tension and doesn't allow any slack to be pulled, thrown, or tossed around anywhere.

BTW after having gone through the initial stretch on my chains, I have tightened the rear chains 3 times each, the front left 4 times(3 of those due to broken axle) and the front right twice-IN 2 YEARS that's good enough for me, and I have less $$$ in all 6 of mine than you can buy 1 of these for!

Now lets think about this: I have always kept a close eye on my running gear, and I see checking chain tension as part of routine maintenance, and although it is nice to have tensioners that hold, why would I want any tensioner that makes me think I don't need to go to the trouble of pulling the floorboards and checking the chains, which could cause me to miss some other possibly worse problem?

[Noel Woods]

As indicated, the uni-directional chain tensioner may not be the best solution, but I think it would work under most situations. I would install these adjusters in support of the main direction of travel (forward) and keep in mind that reverse usage would need to be done with the thought that you would need to go somewhat easy.
Secondly, Monstercraftsman is actually working a bi-directional set-up, once done, this should alleviate any problems associated with the one way (motorcycle) adjuster.

[chris davison]

Bi directional auto chain tentioner

I was reading your posts and the problems with chain tentioners so I made a quick hand drawing of an Idea I have to solve all these problems. This works in both directions of vehicle and supplys constant chain tention and does not have to lock and needs no adjustment. Dang that all sounds to good to be true dosent it?
in this drawing you have two delrin shoes being pulled together constantly by a 30 lb spring pivoting at pivot point #2 this is the constant chain tention that needs no adjustment. When the vehicle moves forward the top chain will go straight across and the tentioner will pivot at pivot point #1 that could be a shoulder bolt in the side of your chain case. You put it in reverse and the bottom chain goes straight and again the tentioner pivots at pivot point #1 What do you think? I hope I can put this pic in correctly.

[chris davison]

[mudbug3]

chris davison

Thanks for posting a picture of this chain tensioner idea.

[Bw6]

I was reading your posts and the problems with chain tentioners so I made a quick hand drawing of an Idea I have to solve all these problems. This works in both directions of vehicle and supplys constant chain tention and does not have to lock and needs no adjustment. Dang that all sounds to good to be true dosent it?
in this drawing you have two delrin shoes being pulled together constantly by a 30 lb spring pivoting at pivot point #2 this is the constant chain tention that needs no adjustment. When the vehicle moves forward the top chain will go straight across and the tentioner will pivot at pivot point #1 that could be a shoulder bolt in the side of your chain case. You put it in reverse and the bottom chain goes straight and again the tentioner pivots at pivot point #1 What do you think? I hope I can put this pic in correctly.

Chris, don't know where your pic is, but what you are describing has already been done. If you have access to an Argo dealer he can show you a pic and/or order them for you. They are used on the Centaur 8x8, I just purchased the torsion springs and UHMW sliders, and fabricated the rest. I use this design for all my tensioners on BWII, they are automatic, troublefree, and with some imagination you can mount them is several different positions. The only limitations is the amount of spce you have between the bottom chain strand and the tub. You need clearance for the tensioner to pivot for reverse.

[chris davison]

For some reason the pic is in the 7:58 post of mine that little red square. I was just thinking about the problems and came up with this tentioner having never owned a store bought rig before or seen any of thier tentioners but Ive delt with chain problems for 40 years and fabricated many of my own tentioners I am running # 80 chain and so will have to fab it all. Pic is also in the Gallery under other aatvs.