Fx24D weigh-in

[Mickey_Fx]

Being a old M.E. with **** tendencies I had to find out what my tractor weighed. There were several BIG surprises after the weigh-in and some caclulations made.

Weigh-in conditions = Me sitting in the seat, quick mount hitch installed but no implement and empty FEL. Ernie told me when I purchased the tractor the tires were filled with calcium solution. Digital scale with 10-20 lb resolution.

Front = 2140#
Rear = 1760#
Total = 3900# (this is the sum of front and rear axles and separate reading of complete tractor)

The calculations:
Center of gravity with no additional weight is 13" in front of the front axle. Not good IMO. The front axle is exactly mid-way between the center of the bucket and the rear axle. Due to FEL dims and weight transfer, for every pound placed in the bucket, the front axle see's 2 additional pounds.

With tires rated for ~900# each, the weigh-in alone show they are overloaded without anything in the bucket. The calculations and the actual weigh-in is saying quite clearly to me, "the tractor is unstable" due to fwd positon of the CoG.

Suggest others with FEL's on their tractor, get them weighed, do some calculations and see what the situation is for your tractor. You may be as surprised and I was.

 

[roxynoodle]

I'm pretty sure my tractor is similar to yours and that's why my front tires are garbage. I've been waiting 5 weeks now for new front tires that were supposed to take 10 days to come in. Your calculations don't surprise me in the least.

 

[scrinch]

Your CG is NOT in front of your front axle. If it was, your tractor would tip up on its front two wheels until the bucket stopped it! And you would have a negative rear axle load. If your axles are about 80" apart, then your CG is about 44" in front of your rear axle...or about 5% in front of midway between the axles. And I don't believe that any weight inside your tires counts toward the their weight-bearing rating. I think their weight rating is for weight transferred from the rim to the tire, not weight inside the tire which only really loads the tread. But that doesn't really matter if your front tires aren't filled with calcium solution.

 

[tallyho8]

Front = 2140#
Rear = 1760#
Total = 3900# (this is the sum of front and rear axles and separate reading of complete tractor)
The calculations:
Center of gravity with no additional weight is 13" in front of the front axle. Not good IMO.

I am sorry but I do not agree with your figures. If your figures were correct, to jack up the tractor. evenly, off the ground, then you would have to place the jack 13" IN FRONT OF THE FRONT AXLE. This could not possibly be the center of gravity. I will check on the wheelbase of the tractor and brush up on my math and figure where the true center of gravity is for you. If I am wrong, I know that the experts on this forum will correct me quickly.

 

[tallyho8]

Scrinch was able to figure it out faster than I was. I agree that the center of gravity is about 5% in front of the midpoint between your rear axle and front axle.

 

[roxynoodle]

Not to hijack this thread, but since I'm getting new tires anyway, should I have those foam filled? I thought the foam might cause them to wear sooner. I don't know that I want calcium chloride. It is in the rear tires of my H and I have been told to move the tractor daily if it is below freezing or it will get tire hop. It is also difficult to park it in a spot it barely fits in and get both valve stems at the tops of the tires.

My loader has curved arms and sticks out farther in front of the tractor than the traditional design loaders do. My front tires weren't very good to begin with but now they are ready to fall off the rims at any moment.

 

[normde2001]

Scrinch was able to figure it out faster than I was. I agree that the center of gravity is about 5% in front of the midpoint between your rear axle and front axle.

But guys, assuming M.E. stands for mechanical engineer, how can this be?

 

[buppy69]

HUH?

Eugene

 

[tallyho8]

But guys, assuming M.E. stands for mechanical engineer, how can this be?

Even an engineer can make a casual mistake now and then. Look at the engineers down in the New Orleans area who designed our levees!!!

 

[Mickey_Fx]

Your CG is NOT in front of your front axle. If it was, your tractor would tip up on its front two wheels until the bucket stopped it! And you would have a negative rear axle load. ...

Boy, was I having a senior moment. Underlaying problem was with the spreadsheet I started last month with focus on front axle loading and identified the CoG as being from the front axle when infact the calc was based on mid-point of wheel base. The 13" figure is correct but referenced from wrong place. Due to the short 60" WB the CoG is 17" aft of the front axle. Must have been brain dead not to instantly see and know the CoG couldn't be in front of front axle. Rest of calculations for front axle loading looks to be good. Oh, on this setup, the center of the bucket to front axle is also 60".

Thanks for thumping me up side the head. I hate it when obvious things like this gets past me. Getting old isn't for the faint of heart.