Trailer Loading and CQ - Hypothetical Discussion

MossRoad · Jan 20, 2015

Here's a link to the formulas...
Levers

dodge man · Jan 20, 2015

Sounds like problems I worked in college. Just the trailer sitting still is a static problem. I think your getting into "moments" with this problem, meaning the weight farther away fron the axle has more effect than the weight close to the axle. I can't answer your question though. Then you get into the dynamics of the load when it moves, a entire new set of problems.

dodge man · Jan 20, 2015

I'm not sure the lever formula is100% valid since you don't have a point load but a load of the trailer over its entire length.

timswi · Jan 20, 2015

If it were me, I'd just hire a small crane. I did that with a 50' beam when I built my house and the crane barely even grunted so I'm certain it could handle a trailer frame of similar length..The owner said what he was doing for me was nothing for the truck.. Much safer.

MossRoad · Jan 20, 2015

dodge man said:
I'm not sure the lever formula is100% valid since you don't have a point load but a load of the trailer over its entire length.

I agree. I figured 4000# hanging 16' off of each side would cancel each other out. So would the 16' on each side carrying that 4000#. So, I came up with 2000# in a length 8' long starting 16' from the axle and ending 24' from the axle, then took the middle of that, which is 20', since I don't know any better! :laughing:

MossRoad · Jan 20, 2015

Trying to find a calculator to calculate tongue weight.... pretty much everyone tells you to use a tongue scale.... no kiddin? There's got to be a mathematical formula for it somewhere.

Beltzington · Jan 20, 2015

Thanks for all the input, I worked my numbers out from center toward the ends, 4' = 1000lbs. If the axle is carrying 9k at 24' then all that is left for the "tongue" weight is 1000lbs. At this point I figured there has to be a formula. I do need to know the axle weight and the tongue weight to insure they are within my tractors lifting ability and the axle rating. What really concerns me is the effect on the balance during the move, I guess I could use some light rope to secure to the FEL for some control but if things really go south the rope would break and the 10K bridge can go where it wants without me and the tractor attached. Then I will call the crane company

timswi · Jan 20, 2015

Beltzington said:
Thanks for all the input, I worked my numbers out from center toward the ends, 4' = 1000lbs. If the axle is carrying 9k at 24' then all that is left for the "tongue" weight is 1000lbs. At this point I figured there has to be a formula. I do need to know the axle weight and the tongue weight to insure they are within my tractors lifting ability and the axle rating. What really concerns me is the effect on the balance during the move, I guess I could use some light rope to secure to the FEL for some control but if things really go south the rope would break and the 10K bridge can go where it wants without me and the tractor attached. Then I will call the crane company

very interesting math/physics question though.

Beltzington · Jan 20, 2015

Here is the proprosed bridge location 16' will just make level on the other side.
View attachment 407770

CobyRupert · Jan 21, 2015

Ok, now I understand your question.
Tell me where I go wrong:
32' feet, representing 8000 lbs are in balance. (10000lbs x 32/40)

That leaves 2000 lbs and 8' of trailer, the center of this weight being 4' from the hitch, and 20' from the axle.
Said differently this is 2000 lbs at a spot that is 1/5 & 4/5 of the span. So 4/5th (1600lbs) on the tongue and 1/5th ( 400lbs) + the 8000lbs (in balance)= 8400lbs on the axle. :confused3: