Matching tractor tyre sizes?

[Webster8340]

Hi fellas, looking to replace the tyres on a Massey 6480. At the moment shes wearing a set of 480/65R28 and 600/65R38 tyres, but I was thinking about swapping these for a set of 480/70R28 and 580/70R38. This way I'd have a touch more clearance for baling, and the 580s would be better suited for my plough. The only problem with this is the rolling circumference ratio would be slightly out I think. I've had a look on a Michelin chart, and if my maths is right , the ratio on the old tyres is about 1.317:1, and the new ones would be about 1.290:1.
So long story short, is this an acceptable tolerance between the two, or can the 4wd be calibrated to match, or can anyone suggest another tyre combo to suit?

 

[daveydiesel1]

Them 2 sizes were usually run together on masseys. Wouldnt of thought be much wrong. U could try usin different brands fromt and back as each brands rc will be slightly different

 

[seedman stains]

https://vredesteintyres.com.au/wp-content/uploads/Radial-Tractor-Tyre-Conversion-Table.pdf

 

[Webster8340]

Them 2 sizes were usually run together on masseys. Wouldnt of thought be much wrong. U could try usin different brands fromt and back as each brands rc will be slightly different

I'd got a feeling they were a common pairing, but I wasn't sure. I'll have a shop around some different makes, cheers

 

[Gerbert]

Should be a straight swap. You could go for a 540/65r28 on the front if you like a tad wider.

 

[Webster8340]

Should be a straight swap. You could go for a 540/65r28 on the front if you like a tad wider.

Hadn't thought of 540s, but I think the 480s are wide enough for my needs. Only more expense haha

 

[Tarw Coch]

Should be a straight swap. You could go for a 540/65r28 on the front if you like a tad wider.

And 650/65r38 rear depending on rim size.

650 and 580 should be pretty much interchangeable as should 480/70 and 540

 

[Gerbert]

Yes, but he said that 580 suited the plough better then a 600, so I figured a 540 might be worthwhile, but a 650 wouldn't. Or a 710/60R38, or a 800/65R32, or a 1050/50R32.