Which will cause least compaction?

Andy26

Moderator
Arable Farmer
Location
Northants
I would think the heavier tractor on bigger tyres.

I swapped a 4.5t tractor on 520's for a 4.5t on 480's and there is a marked difference in how they travel on soft ground.
 

Andy26

Moderator
Arable Farmer
Location
Northants
Are you saying that on your 4.5t tractor, the 480's caused less compaction?
Nope the other way round, the larger tyre width being the 520's, travelled so much better than the 480's. I'm probably going to get some 540+ for the new tractor.
 

Refco

Member
Location
County Durham
Ah, okay. Yes, that makes sense. With regards to the OP, as Dave W says, you would need to calculate the footprint of each tyre. And to calculate that, you would need to know each tyre pressure, i would guess.
 

Dave W

Member
Location
chesterfield
Lets assume both sets of tyres are the same make/type, are the same diameter and have the same pressure. i.e they are identical but for the width.

We'd have to guess the footprint length but as they are the same for both it doesn't really matter. We'll go with 500mm.

So A nominal size of footprints would be 650 x 500 = 325000sqmm (3.25metre) and 560 x 500 =280000sqmm (2.8metre)

Compaction is effectively downward pressure or pressure = weight/area.

so.
5470/3.25=1683kg/m
4610/2.8=1646kg/m

so the lighter tractor on 560's compacts less but only just
 

Refco

Member
Location
County Durham
Dave W,

I think maybe you are a decimal place out on the area. 0.65m x 0.5m = 0.325m2 & 0.56m x 0.5m = 0.28m2

Also, you're assuming that the tractor is standing on only one tyre. Arguably, we should also include some front tyres of a size inkeeping with the rears. Is that right?
 
Lets assume both sets of tyres are the same make/type, are the same diameter and have the same pressure. i.e they are identical but for the width.

We'd have to guess the footprint length but as they are the same for both it doesn't really matter. We'll go with 500mm.

So A nominal size of footprints would be 650 x 500 = 325000sqmm (3.25metre) and 560 x 500 =280000sqmm (2.8metre)

Compaction is effectively downward pressure or pressure = weight/area.

so.
5470/3.25=1683kg/m
4610/2.8=1646kg/m

so the lighter tractor on 560's compacts less but only just
A lot would depend on the tyre pressure.
The 650's will have a higher load rating than the 560's. There for, if the 650's were able to run at a lower pressure than the 560's, they would have an even greater footprint.

My money is on the 650's causing less compaction.
 

Two Tone

Member
Mixed Farmer
Assuming that each wheel is run at the same pressure, it’s not just the width of the tyre, but the diameter that will effect what the footprint will be.

Also, assuming that the diameters were the same (and the tyre pressures are the same, there is virtually no difference in the ground pressure the OP’s suggested tyres and tractor weights. However, which is worse, a roughly equal ground pressure over a narrower area, or virtually the same ground pressure over a wider area?
You will do less overall damage to the soil using the narrower wheels on the lighter tractor.
 

aidan

Member
Location
Ireland
A 5470 kg tractor on 650 tyres

or

a 4610 kg tractor on 560 tyres

It was a purely hypothetical calculation. Obviously there are 4 wheels to account for and a million other variables but as long as it's the same for both sets of wheels then it doesn't matter

A lot would depend on the tyre pressure.
The 650's will have a higher load rating than the 560's. There for, if the 650's were able to run at a lower pressure than the 560's, they would have an even greater footprint.

My money is on the 650's causing less compaction.

manufacturers quote a number called the gross flat plate which is the area in contact with the ground when the tyre is loaded I think

rob needs to tell us the rest of the tyre info to make a stab at doing the load/area calculations
 

HarryB97

Member
Mixed Farmer
More than likely they 650s. They are wider and will more than likely be a lot taller leaving a longer footprint. Also depends if they are expensive vf tyres designed to be run at lower pressures.
 

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Man fined £300 for bonfire-related waste offences

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Written by William Kellett from Agriland

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A man has pleaded guilty at Newtownards Magistrates’ Court to waste offences relating to a bonfire next to the electrical sub-station on the Circular Road in Newtownards, Co. Down.

Gareth Gill (51) of Abbot’s Walk, Newtownards pleaded guilty to two charges under the Waste and Contaminated Land (Northern Ireland) Order 1997, for which he was fined £150 each and ordered to pay a £15 offender’s levy

On June 25, 2018, PSNI officers went to Gill’s yard, where they found a large amount of waste consisting of scrap wood, pallets, carpet and underlay.

Discussion with Northern Ireland Environment Agency (NIEA) officers confirmed the site...
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