6x4 Cub
 

For my current project I decided to build my self a 4x6 cub from my collection of parts machines.

The frame and grill comes from 2 123's and the steering pedestal and ported hydraulic pump on the front drive axle came from a 1450. I've made progress since this picture was taken, the motor has been set in place and the driveshafts have been made and installed.

Eventually there will be a dump bed behind the seat but that can wait until after I've got it running and driving.


http://www.onlycubcadets.net/forum/p...pictureid=7387

I've often thought about building the exact same thing but was concerned it wouldn't turn very well or at all with a load in the bed.

That's pretty freekin sweet, what engine you going to be running?
Welcome to OCC.
What part of wisconsin are you from?

I'm about 30 min north of Madison.

For now it will be powered by a 12 horse k-series Kohler but I may upsize it depending on how well it performs having to drive both rear ends.

As for turning it defiantly won't turn as sharp as a stock cub but the front drive axle does have split brakes to help bring it around in a pinch

I sure like it! And any one knows me, knows I seldom leave anything stock.

Looks like fun! :beerchug: Yeah, turning might not be too fun.. :bigthink:

Looks like it could go into a grader too!

Are both axles under power. If they are shoot some pictures of the drive line. Very interesting build. :bigthink:

Welcome to OCC.:beerchug:
Cool looking project, please keep us up to date on the build...:beerchug:

Very cool! Please post some more pictures especially of the manner in which you drive both axles. I like it!

To drive two sets of hydro's all you do us run a shaft off the output of one pump to the input of the other. Why do you guys need to see pics of that? Pretty simple..... it's just a shaft.


So, did you build any oscillation into the driving axles? What are you going to do about frame twist on uneven terrain? How are you going to keep both drive axles on the ground?

awesome........... keep us posted on progress. I love it.

When I asked for pictures of how the second axle was driven, I had more in mind than just pictures of the driveshaft between them. I too am interested in
" did you build any oscillation into the driving axles? What are you going to do about frame twist on uneven terrain? How are you going to keep both drive axles on the ground? " but didn't completely specify exactly what specific interests I had in mind. Sorry I didn't meet the conversation criteria.

I wasn't chastising anyone in particular..... but since you replied, you did ask how they were driven, not how they are mounted. I know you understand the difference, but they are two different things.

I can see from the pics posted it's a solid frame. My question as to their mounting is more of a "did you take into consideration", so I wasn't very specific either. Give me a break, I was trying to be nice.... :biggrin2:

Getting the trunnions hooked together to operate the pumps in unison should prove to be very interesting. Hopefully he'll post some pictures of that.

I would like to see this type of conversion done with some sort of suspension that would allow the axles to move as those in a tandem axle truck. With the CV style driveshaft from a cyclops, it could be made to have enough slip joint to allow the axle movement up and down. Between the two hydros would have to be done in a similar manner. Perhaps if I ever get the time and have a SGT to modify I might try something. My 2072 is my favorite and could never bring myself to weld on it. Guess I'll have to buy some more Cubs!

Drive train as it sits. I was hoping to work on the shift linkage today but other jobs took priority, but hopefully Sunday.

there is no suspension on the drive axles which may be an issue in overly rough terrain but it may function just fine in the environment I plan to use it in, I'll have to get it driving and find out.

Additional bracing will be added to prevent the frame from twisting. I've held off on too many braces until i know were all my linkages are going to run. Also frame work for the bed will need to be built and will be a good place to add additional structure

This is very much a work in progress and somewhat of a design on the fly sort of project. My plan is to concentrate on getting it driving so I can asses how it works and what design changes I need to make.


http://www.onlycubcadets.net/forum/p...pictureid=7388

That's cool. I've been looking at doing something similar but had thought that only one rear axle would drive and the rear most axle would just free wheel (really just for load carrying). Articulating the frame to keep all four wheels on the ground is another challenge, but would be simpler if only the front rear axle had power.

The ability to get power to the rear most axle (or with the rear hydro, controlling both hydros so they turn both axles in sync) seems complicated. Would love to see some close up pics of linkages, etc. once you get it sorted out.

I was thinking about a double seat, so two people could ride side by side.

One idea I had for driving both axles was to get a rear end with internal brakes, then install disk brake axles in it. Bolt a chain drive gear to the front disk rotor and have a chain run to the rear axle with similar gear bolted to that rear end's disk brake rotor. So the front axle drives the rear axles at the exact same speed via the chain drive. Do that on one or both sides. This would work on either a hydro or gear drive rear end.

I saw something similar to what you are talking on a large truck (early semi) at an antique show. It ran a belt between the axles on each side. May have been a Mack?

I think if you have brakes on both axles and put turning brake pedals on your tractor, it would make turning much easier.

Maybe mount the rear transaxle just a titch lower than the front to put weight on the front axle with a load on it.



Randy

I'm guessing that a lot of you guys making suggestions haven't ever driven a tandem axle truck, or a tractor....

Turning brakes aren't going to really make any difference. On a tandem, the center of the turn is dead between the two axles. Mounting one axle higher or lower than the other would cause a no-drive situation and may even cause the differential to lose equal drive and it just spin out. Without a walking beam type suspension, you may lose drive traction on opposite wheels and just spin out. Just like on a tandem axle truck on snow/ice/mud will. That's why anyone who drives a twin screw off road wants a power divider and differential lock. Now, the tandem hydro axles, because of how they are driven, wI'll function as a truck with the power divider kicked in, but a loss of traction on uneven terrain, or even as simple as driving into a building with a "hump" could cause spin out. *IF* you are on flat level ground, no ditches, nothing but flat yard..... as long as there isn't say, a 2"or 3" dip or hole, it may work just fine..... but I see the yard in the background of the pic, and looks like up next to the house has quite a rise to it, and the corn in the background is running downhill to the left, so how flat is it really? Using the ATV tires that you did should actually make it better, as they are low pressure and may have more flexibility for uneven terrain. Not having enough weight distribution on the steer axle would make it hard to turn also. You are quite essentially building a truck, not a tractor.

Syncing the two hydro's together isn't hard at all. Been done more than once by others building articulated 4 wheel drive machines. You can use a cable, or linkage. Whichever is easier.


I think it's a cool project. I'm not opposed to it at all. I just don't want to see a whole lot of time spent to find out that it has drive/traction issues. Just trying to pass on what I know to be true, and get the OP to either consider it, or apply it. Hopefully in doing so save a lot of build time.

Jonathan, I'm not arguing here, I agree with all your statements about traction but in a semi truck tandem axle with the power divider unlocked, doesn't the wheel with the least traction see the power output due the the differential in the power divider? If the power divider is locked in and the rear centers are no spins, then all four drive correct? So in the case of this project, because the back rear axle is positively driven by the shaft passing directly thru the front rear, wouldn't the back one still be driving even if the front one was totally off the ground and spinning? There is no lost motion or disconnect of the driveshaft as it passes thru the front hydro. Even so, with no suspension at least one or two of the four rear tires will most likely be off the ground most of the time on rough terrain. I think it's a cool project too and like you would like to see the OP succeed.

In a semi with the power divider locked you get power
being transfered to both axles but still have open differentials, just like a 4 wheel drive pick up locked in 4 wheel. With it locked in, you have it right it goes to the wheel with the resistance.
You'll need three drive wheels on the ground for this thing to move. Unless you put a spool in one carrier.

Stan, (That is the right name isn't it? Hope so.) I didn't think you were arguing. I was pretty sure you understood, as you made the comment about it needing walking suspension like a truck. You made a couple statements that prove you understand (below). You and Green stripe (sorry bud, I can't recall your name) seem to get it. I broke down some responses below. :beerchug:


[QUOTE=Green stripe wide frame;434518]In a semi with the power divider locked you get power
being transfered to both axles but still have open differentials, just like a 4 wheel drive pick up locked in 4 wheel. With it locked in, you have it right it goes to the wheel with the resistance. [QUOTE]

Yes, this is correct. Green stripe answered it very well!

Now, for discussion and explanation purposes, an all wheel drive vehicle (AWD) has a transfer case just like a pickup would and it has a differential between the front and rear axles just like a power divider in a truck axle. The power divider is just that, a differential, between the two axles. (Further explanation for other readers.) Yes, on a tandem drive (twin screw as it's called) if one wheel loses traction, all power goes to that wheel and it spins. If you lock in the power divider, then it locks the differential between the two axles and equal power will go to both axles. So, if one wheel spins, the differential in that axle will supply power to the slipping wheel, but power will still be supplied to the axle with no slip and you can drive out. If you have a case of two wheels spinning (one on each axle) then the power divider lock will have no effect. You will also have to lock the differentials to get power going to all 4 drive wheels equally. I know you guys covered it, and understand, but I just wanted to go into it a little farther. :beerchug:


Yes, but even with the divider unlocked, all four drive equally unless you are 1.) turning. Or 2.) you have wheel spin.

Just to reiterate, with the divider locked, it supplies power (solid shaft) to both axles equally. Only reason not to have it locked all the time is so that it steers easier.


Yes. That is absolutely correct. One axle can come completely off the ground, and as long as both tires on the opposite axle are still in solid contact, then it will still drive.


Yes, both of these are correct. 3 wheels will need to be in contact, OR one whole axle. So, if the correct 2 come off the ground, it will still drive. More on this below.



Now, it wouldn't seem that this would really be an issue. But believe me, go off road with a twin screw truck, and even with suspension, and a loaded trailer, it doesn't take much to get one wheel on each axle to lose traction. Kick the power divider in and it gets much better, but even then, it still isn't very hard to lose traction. Example: I was backing a semi into my driveway at home last fall. Just backing off a gravel road, into a gravel drive that goes just slightly uphill, and lost traction altogether. Once a wheel spun, it dug a hole, and wham! Stuck. Power divider in, (truck doesn't have diff lock) and it still couldn't do it. I finally got the truck to move forward just enough, that I could pull forward and go back again (a little faster this time) and got into the drive. But it really is amazing how with a big truck, with suspension, and plenty of weight, it will spin out and your done. That's why I'm so certain that this thing will need at least some sort of flex between the two axles. One tire on it goes up on a hill/bump whatever, it can pull traction from two wheels pretty quick. Now, if the truck had ag tires on it.... maybe it would have been fine. Again.... with those ATV tires, there may just be enough wheel flex to make it work. I haven't been around JD Gators much, but they are an ATV with tandem drives. I do not know what type of drive system they have, but they seem to work pretty well. Also, Terra Gator makes a 5 wheel sprayer/spreader that has a tandem drive rear. It doesn't have any suspension on the rear, but it has floater tires which have a lot of give. I would also assume since it's an off road vehicle, that it has both a divider lock, and diff lock.

Jon - yeah I understand the concept. I've been a heavy truck mechanic for 41 years now. I wanted to present the issue in the form of questions to help everyone understand. I knew from past posts that you have heavy truck experience. Few people realize that more tires on the ground can actually hurt traction, and I'll use the example of trucks with a tag axle (non-driving axle(s) solely for weight carrying capacity). When trucks with tag axles are on rough terrain, the first thing the driver does is lift the tag up to the transfer the weight and help keep the drive axles on the ground. I had thought about the JD Gator too. They have a walking beam of sorts and are chain driven between the two rear wheels on the same side and use flotation tires as well. From the looks of things on the Gator the front axle does all the work and probably has an open spool. I doubt you'd turn it if it were a no spin.
Stan

I had a quick thought about using "turning brakes" on the tandem drive. On new class 8 trucks with automatic traction control, the computer automatically applies the individual wheel brake on the wheel that is spinning thereby forcing the power to the opposing wheel with traction. If this Cub Tandem (?) has turning brakes and has the open center differentials as they are from the factory, couldn't the builder step on the brake of the side that is spinning and force power to the other side? I can see this would be a constant issue, stepping on the proper brake every time a wheel lifts and spins. Just a thought.

The JD 6x4 Gator frame actually allows the front drive wheels to be slightly off the the ground. Thus when empty and the posi is not engaged is drives and turns very easily. However, that dynamic changes once significant weight is in the cargo box or two fatties are in the seats. All six tires are low pressure ATV tires that are designed with traction and flotation in mind.

That's interesting. Having the suspension lift the front rear axle when empty would make it much more nimble for turning. I've never actually been close to one, only pictures.

Stan, I knew you were a heavy truck mechanic. I wasn't over explaining for your benefit. :beerchug:
For the record, I too have the same experience you do, I just have more like 20 years in it.... but I also have been a mechanic for Case IH, grew up farming (and still do), had my CDL since I was 19, and worked on industrial machines (dozers, backhoe, trackhoe, ect), oilfield equipment and on automotive. My training was in diesel heavy duty, but when I had my shop I also worked on automotive. (Not bragging, just stating experience.)


I did not know that the Gators frame was set up so that the front axle was slightly higher. I have worked on them before, but not at any extent. I didn't remember that they were chain drive. That set up would make for a good steering, and good off road capabilities.

A walking beam like a grader uses would be best..... but might be too costly and time consuming a build. Not really any easy way to make walking beam suspension either. Using one drive axle, with a chain drive to the other axle would really be the simplest. Or even one drive axle that chain drives all 4 tires like the Gator.

Either way, it will be an interesting build to watch and see how it turns out! :popcorn:

what about building some tracks to go around each pair of wheels, then you only have to deal with left or right loosing traction, and then use the brakes to help steer. that would be interesting.

Wouldn't have to build them.... you can buy them. They make them for skid steer loaders. Just order the size you need! :biggrin2:




But they are PRICEY! :bigeyes:

In that case it would be better to use a dummy axle for the second set rather than two live axles.

Turning brakes work on the tractors, skid steers and dozers in have ran, why wouldn't it help turn this once it has a load on?





Randy

Why? It would work fine with two driving axles. Actually, probably better with two drives. Either way, it would be a b***h to steer with tracks!



Tractors have single drive axles, so brakes work.

Skid steers have two hydrostatic drive motors. One for each side, then chain drive to the wheels. No brakes. When you move the handles, you simply stop the flow of oil to one drive and it "skids" to turn. Or you can reverse the direction of one set of drives, while the other is going forward.... and it "skids" to turn. But that's the key, the wheels skid. That's why it's called a "skid steer". You aren't steering it with a steering axle. Completely different than this set up. Ever drive a skid steer with a load in the bucket on grass? It isn't very friendly to a yard! :bigeyes:

Dozers have tracks, and a drive for each side. They steer EXACTLY the same way as a skid steer loader, only they use brakes and can't reverse drive one track. Now the track tractors like the Cat Challengers use a different system..... but again, no front steering axle. COMPLETELY DIFFERENT.

Like I said, what the OP is building is basically a twin screw truck. Would steering brakes make a difference..... maybe, but there are a lot of "IF'S". It's a long way to the steering axle.... *IF* they were really good brakes, and on both axles, and the load was only on the rear, and he could get them to work together, then yes, they would probably "help". But the disk brakes on a CC axle are marginal at best. I really don't think they are going to do much. I know on a SGT with steering brakes, you can step on the brake and you can't slide the front end around like you can with a tractor. (Unless you're carrying a 48" tiller on the rear.) When I've tried to use them, I didn't think they did squat really. I've never had one that could lock up a wheel. Just not big enough brakes. Convert them to hydraulic calipers from a 4 wheeler and you might get it to work. If you could get the brakes to hold enough to be able to lock up both wheels on one side, I think it would just drag the tires, start to steer and just tear up a lot of grass in the process. I think the best thing is to get more weight on the steer axle because it will steer it if it can get traction.

Yes, I know how they all work.

Now, if you had no load on the rear axles they would not do much. But with a load, if you turn the wheels and grab a brake, they would help, pretty simple really.

Yes, brakes on both axles.

And yes, I have run a skid steer on grass, dirt, asphalt, gravel and slick concrete. The slick concrete is really kinda fun, drift into the corners! But asphalt sucks, it grips and is a real bear to turn without throwing your load outa the bucket!






Randy

That's no joke.....

My understanding of a walking beam twin axle arrangement is that is allows the two separate rigid axles to pivot relative to each other as well as to move up or down relative to the other axle. Essentially keeping all four tires on the ground with approximately equal loads. Is this correct?

Yes.

Walking beam is different that independent suspension like in an air ride equipped set up. But the walking beam is better with keeping equal load on all four tires.

Hey Jon - that might be a fun build, use four small air bags for suspension and panhard bars/torque arms to locate the axles. Of course now you'd need a source of air for the bags ----- :bigthink:

Considering the use of two cub rear ends as is being discussed.

If you mounted one of the pair of axles rigid to the frame and allowed the second axle to float up/down and pivot, that would accomplish much the same thing, right? Only one of the pair would need to actually need to float.

If you did this, would that allow you to power only one axle? The second axle would just be a tag axle, load bearing but not driving. And by floating it, it would not cause loss of traction to the rigid axle. Am I thinking correctly?