Weight calculation at a distance

How do you calculate weight applied to an axle when hung a distance away from center. For example, 100lbs on a bracket 4ft from the axle. I used to do bridge formulas in high school physics but that was 47yrs ago. Keep it simple please.

I dunno Dave. Kinda sounds right but I think there's something missing. I tried all ways of phrasing what I wanted from Google and not sure I ever got there. It's not real important but thinking about building a 3pt weight bracket so weight can be easily removed when not needed. If I want #1000 added to the rear axle via weight on the 3pt,how much is needed?

in reality it may be better to use the CENTER OF GRAVITY for the tractor, which may be a couple feet in front of the rear axle... but this gives you a good idea of how it works, using the rear axle as the PIVOT POINT.

lets say the tractor weighs 5000 pounds.. If you add  400 pounds to the 3 point, the tractor now weights 5400 pounds, not 6000 pounds....

Edited by steve(ill) - 01 Jan 2022 at 10:07am

I get the jest of it. There are a lot of variables going on here. I can get the wheel base and distances  from axles I'm working with. My 8070 weighs 19000 lb. The front axle weighs 4420. Ballast websites recommend 100-130 lb /hp. What number do I pick? My engine is turned up from 172? hp. Last dyno said 220. (shortened life I know) I don't want to "use" it all so I pull tools that fit the 170 number but do it with ease. Websites say 25-30% frt and corresponding 70-75% rear for 2wd. Which numbers do I use? Dr Allis says he used 2 of 400# wts per side on 7060's with loaded inners. I have 1 set per w/loaded tires. That's where I'm guessing 1000# added to rear axle. I would prefer to have a 3pt attachment to "easily" add/remove weight. Don't need it when singled out doing 28% side dress. I have 1400# of suitcase wts not on the tractor which hang at least a foot in front of axle. This gets a little complicated and confusing. I've used it as is for 12 yrs so maybe I should just punt! This wet fall got me to wondering if a little more weight would be beneficial.

Steve, I’ve been following both of your post and it sounds to me that your issue is not weight but traction. Can you fix traction with more weight? Sure, to a point. But with wet conditions you have to factor in drag. Back when our 7045 was the big horse here, we pull a 24 ft. FC. It weighs a little over18000 lbs. We never had more than 800 on the front rack. First pas on unworked ground low 5th power shift and it was always stuck to the ground. Second pass low 6 and still good. But if wet, I couldn’t hold it down. In the fall with 7 shank soil saver on corn stalks, low 4 it didn’t slip but was slow. Low 5 slipped more but was faster. Guess my point is weight wasn’t my problem, speed and drag were. Maybe I’m off the mark here but this is a lot better than talking about Covid.

Both duals have near full tread depth as inners(Firestones) have somewhere around 500hrs. The outers are Goodyear which have less bars but still deep tread. All are radials. I don't see me buying another set of Firestones to put on outside. 20.8's would be nice but I didn't want to buy 4 tires back when I put the new inners on. Will just live with it I guess. Technically the rim size should change. More $$$$$ Best advice would probably be stay in shed when wet.

Any weight you leverage off the back wouldn't help steering either and unless you mount it on top of a quick hitch I would think it would be a pita when hooking implements. The only benefits would be when pulling wagons or something with very little tongue weight

Correct Dan. With spread axle duals you turn with the brakes as is. If I added some rear wt I'd add some frontend weights too. Was thinking I could build a structure to hang on 3pt which suitcase wts could be fitted to. I would want it spread in the center to clear hoses and give visibility to drawbar. 6-100# front wts back there might be close to 800# at the axle. I could put the other 8 on the front or something like that. My brother-in-law just retired from farming. They have a 3000# weight  built for 3pt he offered me. I looked and measured. Would interfere with hose bracket on field cult and block view of drawbar. It's 22in dia x56in long 3/8 metal tube with end caps. It's filled with knock outs from a punch press. Has a removeable lid so it could be emptied some but would take serious modification for me to use it. About as easy to start from scratch.

@MACK; Force=Mass x Acceleration. Acceleration in the English (not Metric) system is about 32 ft./sec/sec.  And remember, # IS a measurement of force. IIRC, "slugs" is the measurement for mass in the English system. Beyond that, the math starts to confuse me. I'm hoping that some people smarter than me will chime in soon. HTH. 

Thanks JTOOL. This was years ago, and what I was working on worked.           MACK