Ground Pressure of a lawn roller

[Cat401]

I can't get my head around the answer to this and since this website has some of the smartest people, I know someone will have an answer.......

Lawn Roller #1;
24" dia x 48" wide = 920 lb

Lawn Roller #2;
18" dia x 48" wide = 485 lb

Question.....What is the packing pressure of each roller?

The 18" roller has a smaller footprint vs the 24" .............

 

[Caper11]

The contact point area will be the very close, if not the same on hard ground on both dia drums. Only IF the drum is made of steel, and is not compressible like a truck tire. If the drum compressed at all under its own weight, than the compressed area will need to be calculated.
The constant is the width at 48".
920/48=19.1lbs/in
485/48=10.1lbs/in

 

[TROLLCAT]

just go with the big one

and roll your lawn after dark

 

[Cat401]

The contact point area will be the very close, if not the same on hard ground on both dia drums. Only IF the drum is made of steel, and is not compressible like a truck tire. If the drum compressed at all under its own weight, than the compressed area will need to be calculated.
The constant is the width at 48".
920/48=19.1lbs/in
485/48=10.1lbs/in

they both have a steel face....so the drum will not change shape

I see what you did but my conundrum (if I can put it into words properly) is trying to figure out how much of the drum is on the ground at each moment....yes, they are both 48" wide but when rolling on grass, how much of the 18" face or 24" face is touching the ground. Since the 24" drum has a larger footprint it should have more sq inches on the ground vs the smaller 18". So the 24" drum should have less ground pressure (if they were the same weight), right?

 

[007sevens]

they both have a steel face....so the drum will not change shape

I see what you did but my conundrum (if I can put it into words properly) is trying to figure out how much of the drum is on the ground at each moment....yes, they are both 48" wide but when rolling on grass, how much of the 18" face or 24" face is touching the ground. Since the 24" drum has a larger footprint it should have more sq inches on the ground vs the smaller 18". So the 24" drum should have less ground pressure (if they were the same weight), right?

Your over thinking it, buy the cheap one.

 

[Cat401]

Your over thinking it, buy the cheap one.

lol....you are probably correct...I'm overthinking this....but there must be a formula to figure ground pressure of a cylinder...

actually, I'm leaning towards the heavier one

 

[Summitric]

It would depend how compacted or compressed the ground is, as to how much of the barrel is actually contacting the ground

 

[Summitric]

Like said above, I too believe your overthinking this

 

[Cat401]

It would depend how compacted or compressed the ground is, as to how much of the barrel is actually contacting the ground

Well that is what I am trying to figure out.........is the 18" roller weighing 485 lbs going to have equal or more or less ground pressure than a 24" roller weighing 920 lbs. Will the narrower roller sink into the ground more vs the larger roller?

 

[pete gads]

Stand a dime and a quarter on edge and see which has more on table. They look the same.

 

[pipes]

Well that is what I am trying to figure out.........is the 18" roller weighing 485 lbs going to have equal or more or less ground pressure than a 24" roller weighing 920 lbs. Will the narrower roller sink into the ground more vs the larger roller?

yes in very soft soil the smaller diameter drum will sink deeper. the larger diameter drum will roll easier in soft soil. If it were me I would go with the larger diameter drum. After all bigger is better, just ask any woman.

 

[007sevens]

Well that is what I am trying to figure out.........is the 18" roller weighing 485 lbs going to have equal or more or less ground pressure than a 24" roller weighing 920 lbs. Will the narrower roller sink into the ground more vs the larger roller?

Field Land roller's used to be small diameter drums when they first came out but mainly because of cost. They are harder to pull and don't have the weight of larger diameter drums. IMO They have the same contact large or small. Todays rollers have 42" cylinders instead of the old 30" Cylinders. All roller's are not the same no industry standard. If I was you I would buy the heavy one, you will like the finish better. Once its rolled its rolled, you can't go over it twice with a light roller expecting it to get flatter. You need weight to get a flat finish.

hope this helps.

 

[007sevens]

I could rent you my 55 footer. couple passes and you done

 

[rzrgade]

I built a 6' by30"diameter. Full of water it works out to about 2700lbs if I remember right ...
It rolls and packs great ...
And of course you can let out the water and be at about 1200 for frame and pipe ....
Easy to build and handy as heck ....

 

[Beels]

Field Land roller's used to be small diameter drums when they first came out but mainly because of cost. They are harder to pull and don't have the weight of larger diameter drums. IMO They have the same contact large or small. Todays rollers have 42" cylinders instead of the old 30" Cylinders. All roller's are not the same no industry standard. If I was you I would buy the heavy one, you will like the finish better. Once its rolled its rolled, you can't go over it twice with a light roller expecting it to get flatter. You need weight to get a flat finish.

hope this helps.

Riteway always had a 42" roller. Degelman built a 36" and advertised it as being better, but they've now started building the 42" as well. (I sell both... LOL)

 

[Caper11]

The heavier roller will have better ground pressure.

 

[Cat401]

Interesting!!!

Caper, those pics show what I am getting at...

Look at how much contact the pop can has to the surface...maybe a 2mm where the larger diameter jar has maybe 4mm contact...meaning there is more ground contact with the larger drum relating to possible better floatation/less compaction.

And on a softer surface like a lawn, this will be exaggerated even more so maybe its possible that the lighter 18" roller may have similar ground pressure as the heavier 24" roller because the larger roller has a larger footprint resulting in less compaction....

Come on you math whiz's, let's figure this out...........

 

[pfi572]

Given both gross weights are the same the 24" will be less.
Load the 24" up and compaction is going to be more .
35x12.5 tire verse 30x8 tire , same gross weight ????
What one is going to sink deeper in the snow or mud ??

 

[ABMax24]

With the 24" being almost twice as heavy it will have higher compaction.

If that is not sufficient then I suggest a steam roller.

 

[JMCX]

What are you trying to accomplish? I used a roller to try and get all the dew worm lumps flattened. Even after a good soaking to soften up first didn't work.