38 and 42 inch rears

[Will 1594]

I swapped my drill tractor this autumn. Gone from 650x42 to 650x38. Tractor is near enough the same weight as the old one and it is noticeable (light chalk soils) that there is less mark from the new tractor.
A few years ago I went on a vaderstad drill training thing. I remember the guy there saying how often people forget to get the right front tyre and that they had data to suggest the front tyre often caused more compaction than the rear. I have gone from 540 to 600 on the front.

Most importantly I like the look of a big tyre on a 38 inch rim

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Bg have you ever worked out yeild difference with wheelings from drill tractor , decent tyres will soon be paid for

 

[Boysground]

Never even tried. There must be some research into it somewhere.
The tractor I just bought was ex demo. The dealer changed the wheels for me, originally it was on 650x42

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[nick...]

Looking at new ones @nick... ??

Allways thinking and hoped to try last autumn but despite being told it would be arranged it never happened
Nick...

 

[Wolds farmers]

I'm know this thread is only discussing the merits of different tyres but if anyone has dual wheel for sale on 650/75 r38 we would be interested. Just bought a tractor on r38 and the old one was on r42s!

 

[Sandy]

I'm know this thread is only discussing the merits of different tyres but if anyone has dual wheel for sale on 650/75 r38 we would be interested. Just bought a tractor on r38 and the old one was on r42s!

I think you get adaptor rings to overcome this

 

[Will 1594]

I'm know this thread is only discussing the merits of different tyres but if anyone has dual wheel for sale on 650/75 r38 we would be interested. Just bought a tractor on r38 and the old one was on r42s!

You might have to put a 520/85/42 along side thta tyre ,to keep inside 4 m if your running 4 m drill ,you just get a step down rim ,

 

[Gerbert]

I swapped my drill tractor this autumn. Gone from 650x42 to 650x38. Tractor is near enough the same weight as the old one and it is noticeable (light chalk soils) that there is less mark from the new tractor.
A few years ago I went on a vaderstad drill training thing. I remember the guy there saying how often people forget to get the right front tyre and that they had data to suggest the front tyre often caused more compaction than the rear. I have gone from 540 to 600 on the front.

Most importantly I like the look of a big tyre on a 38 inch rim

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Without the full tyre size this is very confusing. It's on the side of the tyre and generally there is no x in it.

 

[D14]

what are the benefits of bigger over smaller tyres.are the 42s a lower aspect ratio to remain the same circumference as the 38s.is traction better on either or is the weight carrying capacity and ride better on one over the other.seems several 150hp tractorsare available with either size.just wondering,thanks
Nick...

We are running 650 75 38 Michelin multibib on a 230hp tractor and it performs better than or other 230hp tractor on 710 60 42 eoxobib in terms of grip but it’s not so nice on roadwork.

 

[Farmerdunk]

Got 650/85-38 on my new tractor, old tractor had 650/65/42. Prefer the new tyre.

 

[Nearly]

thefarmingforum.co.uk/index.php?threads/today-at-work.5275/page-4804#post-5878058

Mudguards / cab can be lifted to take taller 42 tyres. Crack on..

 

[Matt L]

Don’t need to lift the cab or mudguards to fit 42 inch rims, you just have to compromise with a lower sidewall height on the tyre.

 

[brentnz]

We are running 650 75 38 Michelin multibib on a 230hp tractor and it performs better than or other 230hp tractor on 710 60 42 eoxobib in terms of grip but it’s not so nice on roadwork.

Interested in your comparison... Were you getting better grip in all conditions with the 650 75 38 or just when the ground is firm. Interested because the flat plate is significantly greater for the 710 60 42 when inflated correctly.

 

[Foxcover]

Interested in your comparison... Were you getting better grip in all conditions with the 650 75 38 or just when the ground is firm. Interested because the flat plate is significantly greater for the 710 60 42 when inflated correctly.

Sometimes a narrower tyre will grip better as it can dig in.

 

[Finn farmer]

Sometimes a narrower tyre will grip better as it can dig in.

That's something you should try to avoid at all costs.

 

[Foxcover]

That's something you should try to avoid at all costs.

Even when ploughing?

 

[Nearly]

Don’t need to lift the cab or mudguards to fit 42 inch rims, you just have to compromise with a lower sidewall height on the tyre.

Yes, but This post was on Today at Work and I thought it was topical. Perhaps the tractor owner didn't want to compromise.

 

[Finn farmer]

Even when ploughing?

Wheelslip increases compaction. Ideally you should have onland ploughs. I try to keep slipping in minimum even when ploughing, we don't have onland ploughs, but ideally our next one will be onland.

My friend made an excellent final thesis on subject. It had over 80-pages of information on compaction and the final statement was that every job should be done with twin wheels if you wanted to keep compaction in minimum. Even ploughing can be done with twins on, but the furrows will look like sh!t. Onland ploughing with twin wheels didn't cause that much compaction. Too wet fields and ploughing was the last thing to do concidering compaction.

 

[D14]

Interested in your comparison... Were you getting better grip in all conditions with the 650 75 38 or just when the ground is firm. Interested because the flat plate is significantly greater for the 710 60 42 when inflated correctly.

Both we set up by Michelin rep as well and we were left some notes for pressures for individual jobs. Generally the one on 710mm does top work while the one on 650 does more draft work. However they do swap jobs so for example on a 7 leg subsoiler the tractor on 650 can pull the subsoiler better. We also see very little difference in footprint between both tyres. Bit for roadwork you pick the 710mm every time as its a much smoother ride.

 

[Foxcover]

Wheelslip increases compaction. Ideally you should have onland ploughs. I try to keep slipping in minimum even when ploughing, we don't have onland ploughs, but ideally our next one will be onland.

My friend made an excellent final thesis on subject. It had over 80-pages of information on compaction and the final statement was that every job should be done with twin wheels if you wanted to keep compaction in minimum. Even ploughing can be done with twins on, but the furrows will look like sh!t. Onland ploughing with twin wheels didn't cause that much compaction. Too wet fields and ploughing was the last thing to do concidering compaction.

If you ploughed on top with dual wheels on clay soil around here in the autumn when it’s damp you will just sit and spin.
580, 620 and 650 tyres will dig in and keep going. I understand your point on compaction though.

 

[njneer]

I think there is basically a trade off point .
Narrower wheel = greater point load over the contact patch better (dig in ) grip and the weight helps with grip but increases compaction.
Wider wheel = lower point load over the contact patch with less compaction but less ( dig in grip) it's a trade off and a balancing act to reduce your compaction but try to maintain maximum traction for the work you are undertaking.
There will be a happy medium somewhere but it will also be relative to the weight of the tractor.