Hey guys haven't posted in a while but just recently we purchase a 385 peterbilt and installed a 20 ton hooklift system from swap loader. The truck met all of the specs required for the hooklift system. We loaded the truck up with about 17 tons and went to pick it off the ground the front tires came right off the ground. We emptied the truck so it only had about 13 tons and the front tires came off the ground about an inch or so. We have a 4900 international with a 10 ton hook and have maxed it out more than I can remember and never had any problems with the front wheels coming off the ground. If any one has a setup like this and can give me some insight as to what we maybe doing wrong we would greatly appreciate it. We are supposed to hear from the reps by the end of the week. I attach a picture. The box that we are lifting is a 14ft by 8ft with 6ft sides and a 54" hook. I was thinking we should get a 16ft box with a 61" hook height and hoping that would solve the issues.
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Hook lift truck - Need Help
ShadyTree
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AEL, what is your CT on you truck?
Earthmover you are correct we are based out go Monmouth county NJ. I know it's a short truck when you think about a container truck but we want the versatility of a hooklift truck but with the size of a tandem dump truck.
Has anyone ever heard of putting a weight kit on the front of this truck. Our truck dry weighs a little over 28k when we have 20 ton on the truck we have some weight to spare so I wasn't sure if we can add some weight to the front. Adjust the hook height to 61.75 and go to a 16 or 17 ft box
Earthmover you are correct we are based out go Monmouth county NJ. I know it's a short truck when you think about a container truck but we want the versatility of a hooklift truck but with the size of a tandem dump truck.
Has anyone ever heard of putting a weight kit on the front of this truck. Our truck dry weighs a little over 28k when we have 20 ton on the truck we have some weight to spare so I wasn't sure if we can add some weight to the front. Adjust the hook height to 61.75 and go to a 16 or 17 ft box
I forgot to mention that this is when the truck was pick 12 tons. The truck never came off the ground with the initial pick on came off when we pick the box completely off the ground. Like I said the 17 ton box the truck came right up both times
I think if I had a longer box I could probably do that. With the 14ft box the angle of the box is so steep that I wouldn't be surprised if I had something filled to the top of the box the contents would dump out
No, it's a rubber mount Hendrickson suspension. I've looked at the swaploader picture gallery on their web page under the model I bought which is a SL-400 and not one had a stabilizer on the back. I can't figure out what is going wrong. Still haven't heard anything from the reps.
The front axle being set back moves a little weight off the front, but if you look in swaploader gallery they show a low cab forward tandem, so my axle placement idea isn't real strong. You could remove the front bumper and add some some heavy plate until u get it figured out. Then remount ur bumper. You think they would have seen this before and have an idea or fix
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This was my complaint the entire time. With them doing thousands of trucks nation wide why didn't they ever mention to me that with my exact setup I will need a stabilizer setup. This can't be the first time it has happened
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I'm just assuming that the axles are mounted as far back on the frame as possible.
The rotation point on the boom is very far back on that hoist.Additionally the boom seems pretty long for how short that truck is. I don't have any first-hand experience with swap-loaders, but it seems to me that the geometry of the hoist is just weird. Is the boom pin on the hoist at least above or preferably forward of the center point between the axles? assuming that your truck is within their specs, I'm wondering if the hoist on your truck was built for a long Cab-Axle (grunion) and ended up being cut down (from the back) to fit your frame.
I've picked 10 ton with a single axle hook lift (f750) with no problems, definitely felt it unload a bit, but nothing like that. There is definitely something screwy with that.
I'm not going to get out paper tonight and start doing force diagrams, but I'd demand the manufacture gets an engineer involved to figure this out. It's clear that this isn't just a matter of just a funny situation but a clear error at some point. At some point in the design process engineers must of spent a lot of time figuring out how to avoid having this happen.
The rotation point on the boom is very far back on that hoist.Additionally the boom seems pretty long for how short that truck is. I don't have any first-hand experience with swap-loaders, but it seems to me that the geometry of the hoist is just weird. Is the boom pin on the hoist at least above or preferably forward of the center point between the axles? assuming that your truck is within their specs, I'm wondering if the hoist on your truck was built for a long Cab-Axle (grunion) and ended up being cut down (from the back) to fit your frame.
I've picked 10 ton with a single axle hook lift (f750) with no problems, definitely felt it unload a bit, but nothing like that. There is definitely something screwy with that.
I'm not going to get out paper tonight and start doing force diagrams, but I'd demand the manufacture gets an engineer involved to figure this out. It's clear that this isn't just a matter of just a funny situation but a clear error at some point. At some point in the design process engineers must of spent a lot of time figuring out how to avoid having this happen.
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When the hook begins to lift the bin off the ground, what is the distance between the bin hook and the rear of the truck. To maximize weight lifting capacity this distance should be as minimal as possible and the arc of the bottom front of the bin should just clear the rail/roller as the lift travels through its path.A guess of what the issue is (without seeing more photos) would be that the lift is installed to far to the rear. Can you show some side view photos?
It's a pretty simple statics problem but I would need all relevant dimensions to help you work it out. I'd also need the empty front axle weight.
It's a pretty simple statics problem but I would need all relevant dimensions to help you work it out. I'd also need the empty front axle weight.
I totally agree with you about something is wrong with the truck. We have a smaller hooklift and have maxed out the lift capacity on some boxes and the truck still didn't come up in the front. I have been going back and forth with the people that installed it and swap loader. The best answer I got from swap loader was that is normal what is happening to my truck. They suggested a stabilizer after the fact and he won't come and see my truck because he doesn't think anything is wrong with it. I have the people that installed it coming next week so hopefully when they see it in person they can let the rep for swap loader know. I will try and get more images up with some dimensions so you guys can give me your best input.
I'll take some pictures tomorrow and also get you some dimensions. How would I get you front axle weight? Would I just put the front wheels on a scale? The front axle is a 20,000lbs with 46,000lbs rears.
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If your truck can't even lift that box off the ground without the front wheels coming up , that is a serious issue and it makes the truck pretty much useless. Sorry I can't help more as I am not too familiar with hook lifts but I am with roll offs. Who ever manufactured and installed the hook lift should have known better and explained to you the possible issues with a shorter frame etc. best of luck and keep us posted.
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I don't have any personal experience with hooklifts either but I can see why people with single axles have an easier time lifting loads. The center of rotation is between the rear axles on a tandem vs the rear axle on a single axle and in this case that adds 2ft to the equation. What is the wheel base of the truck and what is the empty FA weight. I can scale the dimensions of the rest from the drawing.
Overlaying some lines and arcs onto the side view image (in order to simulate motion) it is apparent that you have two things working against you at the point the bin comes off the ground: the first is the bin weight and the second is the horizontal force as the hook tries to drag the the bin forward. I'm assuming that you are reversing at the same time as you are trying to lift? This will apply an opposite moment (down force at the front). Also, if possible, loading the bin to the rear as much as possible will help too.
Overlaying some lines and arcs onto the side view image (in order to simulate motion) it is apparent that you have two things working against you at the point the bin comes off the ground: the first is the bin weight and the second is the horizontal force as the hook tries to drag the the bin forward. I'm assuming that you are reversing at the same time as you are trying to lift? This will apply an opposite moment (down force at the front). Also, if possible, loading the bin to the rear as much as possible will help too.
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I was comparing your photo to the photo on the swaploader site and the pivot point of your frame does seem to be further back than theirs. The boom rotation pin on theirs is right on the tandem group center whereas on yours it appears back near the front of the rear-most axle? Hard to tell exactly from the perspective of the photo.
might be worth sending this guy an email http://www.truckpaper.com/listingsdetail/detail.aspx?OHID=4830329 to see if he had the same problem. Seems to be almost the same truck as yours.
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