MB 1120 Coming to America!

VerMonsterRV

Traveler
Harbor Freight. Go 1 size over what you need. I swapped out a Warn and put a Hated Freight one on just for the wireless remote and since they are so cheap I grabbed a spare (carry the spare remote and control box).

I have lifted my R1200RT, K1200LT and the old 1963 R60 BMW with a Ural sidecar. It does make some awful noises but it has not given me any trouble in the last 4 years.

Also stick with the steel cable. The synthetic crushes on the drum too much.
What weight rating winch did you get? I am guessing the total weight with tire and bike (tire ~200lbs, bike 280lbs) will be less than 1000lbs. They have the 2500 on sale now for very cheap ($50, might as well by 2) and since the cable would be run from the chassis to the top of the lift to a turning block the weight the winch would see would be half.
 

VerMonsterRV

Traveler
I haven't tried this method personally.

Thanks, that is, as they say in Asia "same, same but different" (was pretty dangerous when you heard that ;)) to the process we did using Autodesk 360 instead of MeshLab. The problem that Drew (the water jet guy) ran into is that Sketchup had a lot of extra lines (not sure what to call them) that defined rounded corners. He got around it by converting it from stl to igs in SolidWorks and all then was ok. Anyway spent some more time in Sketchup (probably should just learn 360) and got to this point in the design.

Side View, the bottom left hinge point would bolt to the chassis, the bolt holes are not there. Right now I have the design in 1/2" plate but think that might be a bit overkill so am now thinking of reducing it to 3/8". No real science behind that, just seems right.
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Bottom View
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I attached the Sketchup diagram in zip format (zip is allowed to attach to the post), if anyone is interested. Will try to remember to attach the completed model when I am finished.
 

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Grenadiers

Adventurer
Another idea is a Curt Mfg 15,000# adjustable hitch. 1,500# tongue weight, more than enough for a motorcycle and carrier. Above that, a permanent rack for the tire and a swing-out cable hoist; which would lower both. The rack would be big enough for a cooler and other items. Here’s our setup. Ours swings out to access rear garage.
 

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Ozrockrat

Expedition Leader
What weight rating winch did you get? I am guessing the total weight with tire and bike (tire ~200lbs, bike 280lbs) will be less than 1000lbs. They have the 2500 on sale now for very cheap ($50, might as well by 2) and since the cable would be run from the chassis to the top of the lift to a turning block the weight the winch would see would be half.
I use the 2500 but have doubled up the pulleys (4 of them now but one just changes direction). This slows down the assent-descent as well as lower the load on the winch. It handled it for normal bikes without the extra pulley but the sidecar made it grunt a lot.

Also on the 1/2” or 3/8” plate question. You will add about 5lb per square foot for 1/2”. So the engineering answer is to do all the calculations and allow a bit of fudge room for the highly dynamic nature of this load especially offroad. The practical answer is whatever you have laying around and put fish plates on later if needed.
 

luthj

Engineer In Residence
A good factory of safety for dynamic applications like this is 4:1. That would cover most off road type loading. Even if you exceed that, the toughness of the steel means you get a bent, not broken, assembly.
 

Sitec

Adventurer
Nice design! Any thought about how to lock it in place while traveling? I could probably even "borrow" your design and add in a platform for the tire/motorbike to sit on. Any thoughts though on the amount of stress on the lower pivot point? Not being an engineer designing something like this is a bit tricky. The guy that might do the water jet cutting could design the entire thing, even doing finite element analysis, all at a cost of course.

One problem I might see is the ram connection for us. The bottom of my pivots is already as low as I want to go. Actually the platform is also a bit lower but have not worked out a way to address that. Also, the ram would go through our gray water tank.
Hi fella. The 'wheel frame' would lock with just a spring catch on either side. This could be done in such a way where you pull and twist the pins to unlock, and when folded back up, just reverse the process. With the ram, you could have a simple 'hydraulic lockout' tap, or some form of catch that locks upon lifting/closing, but needs to be held open to fold down. That was just a quick sketch based on a pic of the side of your truck (at the moment). If you did a scale 1:10 drawing on a piece of A3 paper of a side view of your truck, you can then make up paper templates and move ram pivot points etc around to suit your build. A centrally mounted ram would work as well as two either side. If space is a premium, the pivot could be at the bottom and the ram at the top (the plus point being that the ram is 'closed' when folded, but the negative point being the ram has less power on the pull stroke). Also, remember that if you add weight further out behind the spare wheels (bikes etc), then the top pivot point on the wheel carrier has to be moved out too to keep the spare wheels in a vertical position when lowering. :)
 

VerMonsterRV

Traveler
So along with the lift I had wanted to put in some recovery tow points and a class 3 trailer hitch. I have been bumbling around on the internet and found 2 reference points where they welded on a 3/4" plate across the end of the chassis. I think the greatest load could possibly be during recovery as I do not intend to pull any huge loads. Now, from my limited understanding Mercedes recommends not to weld anything to the chassis. Is there a problem using the same bolt attachment points that the subframe bolts to? There are only 4 3/4" bolts on each side (all the holes available, that the subframe installed without drilling new holes). I could run the plate farther forward to get to more mounting holes.
 

Ozrockrat

Expedition Leader
How far apart are the holes (along the frame)? That will govern the leverage applied by the vertical load. A single 3/4 grade 8 bolt will give you around 30,000 lbs of clamping force but has a shear strength of around 38000 lbs. which sounds a lot. But when you take the leverage applied from your subframe combined with the dynamic loads it soon gets up there.

On my rack/bumper/tow hitch I run 3 5/8 grade 8 bolts per side but they are spaced fairly evenly with the outside bolts about 24” apart. The outer ones were torqued to around 200 ft lbs. (I really cannot get a torque wrench onto the middle ones). Before I installed the middle bolts I did have one occasion that I was getting movement of the bumper/rack in rough conditions. Now this could of been loose bolts (before I actually torqued them properly up I was just using my right arm strain gauge). But is was enough to get me to remove the bumper and weld in plates to allow for the 3rd bolt on either side.

Now a word of warning. I do not have formal mechanical engineering qualifications. My qualifications are from the Redneck Engineering (as a mate of mine say “Australia is just Arkansas surrounded by beaches”) and a lot of years working with heavy equipment is crappy areas with really smart people who delight in finding new ways to make crap break.
 

Sitec

Adventurer
Another word of warning re recovery of trucks with 'C' section ladder chassis's. Whatever tow points you buy/manufacture etc need to be doubled up, IE, one on each chassis rail. You then need to carry a rated strap or 2 leg chain that hooks to both recovery points and forms a central tow pull. Never extract/recover using one chassis leg. Youtube will tell the story why... :)
 

VerMonsterRV

Traveler
Since this is our first 4WD truck and since we are not used to leaving improved dirt roads we are not used to recovery gear. While planning the tire/motorcycle lift I would like to add a "hitch plate" to the back of the truck. On that hitch plate will be a class 3 receiver for occasional towing and some form of d-rings. Every dump truck I see, there looks to be the weld on type with a WWL of 15,000lbs in the 1" size. When I see pictures of expo trucks though I usually see weld on "shackle mounts", meant to accept a removable shackle. The WWL seems slightly lower going with the removable shackle plus they are a bit more expensive. So, here is the question, what is the benefit going with the removable shackle? Or should I just go with the weld on d-ring?
 

Ozrockrat

Expedition Leader
D rings rattle and you still need a shackle to hook up anything but chains. And I defiantly do not recommend using chains.

My suggestion is to get a recovery rope (kinetic) and a tow rope suitable for your vehicle along with whatever hard/soft shackles required to rig it properly. Also a strap of some type to balance the load across the chassis rails is highly desirable.

https://www.bubbarope.com/industrial/extreme-bubba-30-foot
 

luthj

Engineer In Residence
A removable shackle will let you attach the loop of a kinetic recovery rope, winch eyelet, etc. You also need to carry fewer or them, as they can be moved around as needed.
 

VerMonsterRV

Traveler
Hey all, had a short break with a trip down to Florida to visit my parents and pick up our ~30 gallon 1/2" welded polypropylene gray water tank.
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And we have been busy building the last cabinet (can't believe I can say that :)). This one is right at the entrance with wine storage at the top (planning on installing some mini LED flood lights in the top shelves), coat locker and bookshelf in the middle, fruit/veg shelf and finally a shoe rack at the bottom (I am thinking of lining the shoe area with adhesive backed rubber flooring). Still need to finish the door which should be tomorrow. The top shelves are out of 1/2" acrylic I had left over from the kitchen sink guard. We also replaced the large door handle for the bathroom. It stopped the door from opening all the way to the wall. This new one will allow it to swing right to the wall as we might leave this door open to allow airflow.
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And you can also see the flooring is now installed. I think Heather is pretty happy about that and it is really starting to feel like a home. You can see I still need to measure the 3 drawers in the kitchen. I am pretty sure I will mail order these drawers from a company that will dovetail the corners using 5/8" baltic birch sides with a 3/8" bottom. Will save me a bunch of time as all I will need to do is assemble them and make the drawer fronts. The top narrow drawer is a slide out shelf that has some of the solid surface on.:)
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We have also finally painted the exterior 45 degree corners. Bit of a pain but we have 4 out of the 6 complete.
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We also received the UV sterilizer for our fresh water system. Plan is to use a 2 stage filter for all water (down to .5 micron) and if the water source looks sketchy then run it through the sterilizer after the filters for our drinking water.
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We also got the weld on shackle mounts and shackles. Now just need to get the rear tire/motorbike rack going.

We are going to take a bit of a break and visit Heather's parents. Will be good to get out of the 95 degree heat for a bit. When we get back I am guessing I will need to become a welder as we still have not been able to get any welder's time. First task will be to get the solar panels mounter.
 

biggoolies

Adventurer
Hi. Following your thread. I am thinking of buying a Merc and would like to know what you paid for your new tires. I can’t see that anywhere in the thread. Thanks.
 
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