Estimating center of gravity John Deere 790

[pretendfarmer]

I will be hauling my JD 790 close to 2,000 miles inside my enclosed trailer. I am unable to pull it all the way forward because I have stuff in the front area. My question is where the center of gravity, front to rear, of the tractor with FEL would roughly be. With the FEL and the engine up front, I would assume it would be a bit forward of the actual center measurement rear to front. Is this a wrong assumption?

Right now, as the tractor sits in the trailer, it is essentially centered evenly over the two trailer axles. If I take a tape measure, I have roughly 5'+ in either direction - rear of the tires to the rear, front of the bucket to the front. I do have some heavy tools and things in the front of the trailer - jacks, vise, all sorts of power tools for carpentry, fasteners, etc., but I don't know what all of that weighs. I hauled it about 35 miles and it seems ok, but I am wondering if the tractor is sitting back too far seeing as how 60% of the total weight should be in the front of the trailer. I don't have a way of weighing everything that's in the front of the trailer. I'm just trying to ballpark all of this.

 

[zzvyb6]

You don't say what kind of hitch you have (load equalizing of not), or the capacity of your towing vehicle. As someone with 40 years experience with this situation working for a vehicle manufacturer, my first recommendation is what we call "level frame" on the tow vehicle. This is because the tow vehicle (presumed to be a truck of some sort) is the dominant player in controlling all the actors in the vehicle dynamics actions, so the tires & suspension are specified, designed, and tested in this configuration, even cooling and brake distribution management.
Same for the trailer. Try backing the tractor onto the trailer if these 2 conditions can't be met.

 

[toolslinger]

Can you get a scale under the tongue of the trailer and see where you are? you can even do it with a bathroom scale if you use a lever to reduce the load on it by 1/2, or 1/4 and do a little math.

 

[pretendfarmer]

You don't say what kind of hitch you have (load equalizing of not), or the capacity of your towing vehicle.

Because that was not my question. I have a 4wd Ram 3500 dually diesel pickup.

 

[crashz]

I think I'd want to know my total weight on each axle after the truck & trailer is fully packed. Find a truck scale, pull in loaded with truck and trailer and get an axle weight on each axle. Run it into the parking lot and drop the trailer. Then get axle weights on the truck only.

I'd do this a week or so ahead, in case you want to change equipment or want to ship stuff out separately.

This gives you a lot of information. You will be able to find out the direct load of the tongue weight (not exach a 1:1, but close) and the effect on the tow vehicle. You may find that that frontend is too light and a weight distributing hitch is needed. Or maybe just a few things need to be shuffled around in the trailer.

BTW - do you have loaded rear tires? That will affect the COG and may make backing the tractor on more effective.

 

[pretendfarmer]

The rear tires are not loaded. I was just wondering about the center of gravity for the tractor.

 

[RjCorazza]

Eyeballing the COG of the tractor is information, but not the only (or best) information. I don't know the cog of your machine.
If you absolutely cannot weigh the axles or tongue weight, I would at the very least measure the trucks suspension empty, then again when loaded with your estimated positioning. You will not know how much weight is on the hitch in pounds, but you will at least know there is a positive tongue load.

I use a small hydraulic tongue scale made by Sherline (?) that lets me get the tongue weight correct at 10-15 % of the gross trailer weight. The previous post about using a bathroom scale and lever is totally legit also. Plenty of instructional videos available.
Good luck, and safe travels!

 

[pretendfarmer]

Eyeballing the COG of the tractor is information, but not the only (or best) information. I don't know the cog of your machine.
If you absolutely cannot weigh the axles or tongue weight, I would at the very least measure the trucks suspension empty, then again when loaded with your estimated positioning. You will not know how much weight is on the hitch in pounds, but you will at least know there is a positive tongue load.

I use a small hydraulic tongue scale made by Sherline (?) that lets me get the tongue weight correct at 10-15 % of the gross trailer weight. The previous post about using a bathroom scale and lever is totally legit also. Plenty of instructional videos available.
Good luck, and safe travels!

I don't have a scale, so I think the best thing for me to do is just hitch it up and head to a scale. I already know the tare weight of my truck is 7,840, so if I pull onto the scale without letting the trailer tires on, get a weight, then pull onto the scale to get the gross, then subtract the 7,840 I will know where I sit in terms of tongue weight and gross trailer weight. Thanks everybody.

 

[RjCorazza]

I don't have a scale, so I think the best thing for me to do is just hitch it up and head to a scale. I already know the tare weight of my truck is 7,840, so if I pull onto the scale without letting the trailer tires on, get a weight, then pull onto the scale to get the gross, then subtract the 7,840 I will know where I sit in terms of tongue weight and gross trailer weight. Thanks everybody.

Nothing better than hard numbers!
I know you specifically asked about a JD 790 cog, but the likelihood of someone here having the same machine and configuration is slim. Them knowing the actual cog even slimmer.

 

[pretendfarmer]

Nothing better than hard numbers!
I know you specifically asked about a JD 790 cog, but the likelihood of someone here having the same machine and configuration is slim. Them knowing the actual cog even slimmer.

For me it's just easiest to know the center of gravity of the tractor in order to effectively load the trailer. Seems ok now but for some reason I am wondering if it needs to be forward a little more. It's not that my truck can't handle it, it's just that I don't like to have a load too far to the rear, so I am exercising caution. A poorly loaded trailer is a poorly loaded trailer, regardless of the tow vehicle.