Kubota RTV Heavy Modifications...Yes, you CAN safely lift!

   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift! #1  

carbonitehunter

New member
Joined
Apr 24, 2017
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indianapolis indiana
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Deere, Kubota
I'd like to offer a bit of potentially useful information for those who have the aptitude/resource/desire; First-off, I customize off-road vehicles, and specialize in Kubotas and XUV Gators, and no...not advertising here but, I'm seeing some not so accurate information. That said, you can easily lift your 900, 1100 RTVs without strain that equates to shortened equipment life but, you have to do it correctly, which isn't all that hard. I would suggest this as a starting point though; the front differential on the last generation RTV's is an "Open" type, meaning it's nearly useless when you hit slop/ice/or any situation where one front wheel loses traction, as THATS the wheel more your power will go to...kinda counter-intuitive, from a design and engineering standpoint. Add that fact to a machine weighing over a couple thousand pounds and it becomes obvious Kubota had only their self-interest in mind when they put that differential in the RTV line...frankly, they were thinking warranty and axle-claims. Not to worry...you can fix that PAST blunder, as Kubota themselves got tired of being picked-on by the rest of the industry for that shortcoming in off-road capability, as the x series now has limited-slip. Still not locking, but certainly much better than an open. Truth is, heavy as these machines are, compared to the size axles you can realistically fit through frame/control arms, you're better off with limited slip, as you'd otherwise be buying axles on a regular when you forgot to UNLOCK that front-end in high-traction surfaces. All that said, ALL Kubota RTV's use the same 8/35 pinion/ring gearing. That means from your little gas-burning 400, all the way up to the RTV X1100C pimp-mobile, the gearing is the same. So, you can buy yourself a X-Series limited-slip front diff, and it pairs perfectly to even your 500 gas-burner's transmission, for the biggest and sweetest upgrade you can do these these "Open" differential models, both past and new. The best tires in the world are of little use if they dont receive power when you need it. All the lift in the world is useless if all you do is sit above the muck looking down at it, because you cant move forward. On the RTV 900/1100, the diff hung from the frame, whereas the X series it stands in the frame (think, stalactite/stalagmite) and so mild modification to the bash/skid plate, and you can bolt the X-series diff right in...notch the skid in the rear, and drill bolt-holes and you're there. Some shimming to get the CV clearance exactly centered. Inboard CV shaft is splined differently from the the last generation RTVs, whereas the outboard joint is splined the same...a bitter-sweet obstacle to overcome. On one hand, you will either have to order a set of custom shafts with stock-RTV 900/1100 length, splined for the x on the inner joint, or, you can simply build your own axles using a set of both...used is fine. Thats the bitter. The sweet is that you end-up with a better/heavier axle, as the old inner joints have nearly zero plunge in that tripod, and are smaller/weaker, whereas the newer axle does-not bolt to the diff, which created more room for plunge in the cup..becomes important if you go the next step and do a longer-travel suspension, or even a decent lift. Anyway, sounds complicated but, it's not, really. You can buy a new X series, or you can modify the one you have for a fraction of the cost, and in the end is actually BETTER than the X...I can say this, as I own both. My X is highly modified as well, but it's a turd in comparison, as far as durability. If I had to give one up, that X would be out of here. It has 14 inches of minimum clearance now, and is a general beast but, the older 1100 walks on it in every way. I pulled my prowler fifth-wheel around with the 1100...no problem. Did it with my X and bent the frame - if every picture tells a story, well, look at that one. Even my XUV Gator pulled that fifth-wheel, no problem. Anyway, for those interested in plans/ideas, I can guide you. By the way, getting those custom axles made is a bunch cheaper than most folks think...not much more than a premium set of stockers. I build my own for myself and customers. As far as those shackle-lift kits for the rear...bad idea unless you also drop the front of that leaf down as well...all you do is angle your receiver down, so while the engine cradle DOES come up, the receiver points down. Use greaseable U-joints, and lift BOTH ends of those leaf-springs, and you've done yourself some justice, and no...it IS NOT too much stress for the U-joint/slipper style axles...just keep em greased with A MOLY FORTIFIED grease, and the slipper sealed and lubed, and you can expect normal life from them. Over about 2.5 inches though and you're gonna get annoying vibrations and likely premature wear. Same with the front of the 900 and 1100s front-ends...don't just do the 2" strut-spacer...yeah, you can, but it will throw-off the geometry of the frontend and cause handing/wear issues. If you also lower the frame-ears for the control arm by the same two inches and now you're talking. At stock ride-height the front axles are nearly level, so a 2" lift of ANY manner is not a danger to those CVs. I've safely taken stock axles to 35 degree angles and never an issue...especially with those tripod inners on the X-series axles.
 
   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift! #4  
This thread has given me a good laugh at least.. I actually took time to read the draft the OP posted. Appreciated your willingness to share your knowledge, but it is so disorganized and jumbled that unless someone already has your knowledge, they would not be able to follow it. Carry on.
 
   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift!
  • Thread Starter
#5  
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I guess the point in the above is that, I have not needed a date in a bunch of years...married a Colts cheerleader. So, strictly a "how-to" post. And basically a depiction of what we do with, and how we use, Kubota RTVs. I take them to The Hatfield & McCoy Trails Spring and Fall, every year. I know more about these machines and what they CAN and CAN'T do, than most Kubota trained mechanics. Everyone has a fragile RZR...really sucks when the mountains have those pop-up storms and blizzards and you happen to be in one. And the fun that comes from the expressions on the faces of those on turbo RZR 1000's as you roost past them on a Gator XUV...priceless
 
   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift! #6  
Personally, I appreciate the effort carbonitehunter went through to explain the mods that he has successfully made to Kubota RTVs. I did read his descriptions, and no - I did not understand fully what he was describing. I don't have a Kubota RTV nor do I wish to modify one owned by anyone else.

Although it may be irritating for one to take the time to read the descriptions carbonitehunter presented, that is a self-imposed pain if you have no interest. It's easy enough to simply go past the thread if you have no interest in the topic. Perhaps surprising to some, a topic that is of no interest to me, may contain very valuable information to others.

Ease up guys - this is a free forum which means it is free to discuss whatever topic, within boundaries, of the topics one wishes to discuss. And personal attacks are NOT within those boundaries.
 
   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift! #7  
Re-formatted into paragraphs
I'd like to offer a bit of potentially useful information for those who have the aptitude/resource/desire;

First-off, I customize off-road vehicles, and specialize in Kubotas and XUV Gators, and no...not advertising here but, I'm seeing some not so accurate information. That said, you can easily lift your 900, 1100 RTVs without strain that equates to shortened equipment life but, you have to do it correctly, which isn't all that hard.

I would suggest this as a starting point though; the front differential on the last generation RTV's is an "Open" type, meaning it's nearly useless when you hit slop/ice/or any situation where one front wheel loses traction, as THATS the wheel more your power will go to...kinda counter-intuitive, from a design and engineering standpoint.

Add that fact to a machine weighing over a couple thousand pounds and it becomes obvious Kubota had only their self-interest in mind when they put that differential in the RTV line...frankly, they were thinking warranty and axle-claims.

Not to worry...you can fix that PAST blunder, as Kubota themselves got tired of being picked-on by the rest of the industry for that shortcoming in off-road capability, as the x series now has limited-slip. Still not locking, but certainly much better than an open. Truth is, heavy as these machines are, compared to the size axles you can realistically fit through frame/control arms, you're better off with limited slip, as you'd otherwise be buying axles on a regular when you forgot to UNLOCK that front-end in high-traction surfaces.

All that said, ALL Kubota RTV's use the same 8/35 pinion/ring gearing. That means from your little gas-burning 400, all the way up to the RTV X1100C pimp-mobile, the gearing is the same.

So, you can buy yourself a X-Series limited-slip front diff, and it pairs perfectly to even your 500 gas-burner's transmission, for the biggest and sweetest upgrade you can do these these "Open" differential models, both past and new. The best tires in the world are of little use if they dont receive power when you need it.

All the lift in the world is useless if all you do is sit above the muck looking down at it, because you cant move forward. On the RTV 900/1100, the diff hung from the frame, whereas the X series it stands in the frame (think, stalactite/stalagmite) and so mild modification to the bash/skid plate, and you can bolt the X-series diff right in...notch the skid in the rear, and drill bolt-holes and you're there. Some shimming to get the CV clearance exactly centered. Inboard CV shaft is splined differently from the the last generation RTVs, whereas the outboard joint is splined the same...a bitter-sweet obstacle to overcome.

On one hand, you will either have to order a set of custom shafts with stock-RTV 900/1100 length, splined for the x on the inner joint, or, you can simply build your own axles using a set of both...used is fine. Thats the bitter. The sweet is that you end-up with a better/heavier axle, as the old inner joints have nearly zero plunge in that tripod, and are smaller/weaker, whereas the newer axle does-not bolt to the diff, which created more room for plunge in the cup..becomes important if you go the next step and do a longer-travel suspension, or even a decent lift. Anyway, sounds complicated but, it's not, really.

You can buy a new X series, or you can modify the one you have for a fraction of the cost, and in the end is actually BETTER than the X...I can say this, as I own both. My X is highly modified as well, but it's a turd in comparison, as far as durability. If I had to give one up, that X would be out of here. It has 14 inches of minimum clearance now, and is a general beast but, the older 1100 walks on it in every way.

I pulled my prowler fifth-wheel around with the 1100...no problem. Did it with my X and bent the frame - if every picture tells a story, well, look at that one. Even my XUV Gator pulled that fifth-wheel, no problem.

Anyway, for those interested in plans/ideas, I can guide you. By the way, getting those custom axles made is a bunch cheaper than most folks think...not much more than a premium set of stockers. I build my own for myself and customers.

As far as those shackle-lift kits for the rear...bad idea unless you also drop the front of that leaf down as well...all you do is angle your receiver down, so while the engine cradle DOES come up, the receiver points down. Use greaseable U-joints, and lift BOTH ends of those leaf-springs, and you've done yourself some justice, and no...it IS NOT too much stress for the U-joint/slipper style axles...just keep em greased with A MOLY FORTIFIED grease, and the slipper sealed and lubed, and you can expect normal life from them.

Over about 2.5 inches though and you're gonna get annoying vibrations and likely premature wear.
Same with the front of the 900 and 1100s front-ends...don't just do the 2" strut-spacer...yeah, you can, but it will throw-off the geometry of the frontend and cause handing/wear issues.

If you also lower the frame-ears for the control arm by the same two inches and now you're talking. At stock ride-height the front axles are nearly level, so a 2" lift of ANY manner is not a danger to those CVs. I've safely taken stock axles to 35 degree angles and never an issue...especially with those tripod inners on the X-series axles.
Thanks for the useful information, I might have to look into that for our RTV500. We don't plan on lifting it, but a little more traction might be useful.
Out of curiosity, are the CV joints the same to where you could order inner CVs for an X and mate them to outers for an older RTV?

Aaron Z
 
   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift! #9  
Thanks for taking the time to show the improvements that can be made to the Rtv's. I love mine and use it almost every day, but the truth is, I would love a little more traction at times.

Can't believe you pounded that whole thing out on a blackberry, that would have put me in a frustration coma. Just a friendly tip for next time, breaking a long post into a few paragraphs makes it easier to read.

Learned a couple of things, that's the reason I come here every day.
 
   / Kubota RTV Heavy Modifications...Yes, you CAN safely lift! #10  
Thanks to the OP for taking the time to share the experience and knowledge.
 
 
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