Interesting Tractor Tyre Observation!

GAM

Member
Mixed Farmer
I went to see the tyre fitting company to see the three makes of tyres he had offered me for my 390 on 16.9 x 34,
MRL, CEAT, & Vredestein, just for piece of mind, not that I would be able to judge quality and wear by there visual appearance.
Well, they were very much the same, the real only difference was the diameter! this varied quite a bit! I am not sure of the Max & Min tolerances, yet I do know that 25mm difference in diameter will give you approximately 75mm rolling diameter difference! is this a concern when fitting a set of rear or front tyres?
 

dowcow

Member
Location
Lancashire
I went to see the tyre fitting company to see the three makes of tyres he had offered me for my 390 on 16.9 x 34,
MRL, CEAT, & Vredestein, just for piece of mind, not that I would be able to judge quality and wear by there visual appearance.
Well, they were very much the same, the real only difference was the diameter! this varied quite a bit! I am not sure of the Max & Min tolerances, yet I do know that 25mm difference in diameter will give you approximately 75mm rolling diameter difference! is this a concern when fitting a set of rear or front tyres?

Yes. This is why it is often recommended you use the same brand of tyres front and rear, and why it is better to change all 4 tyres at the same time. Many people don't however, and there is a certain % of wiggle room outside the ideal scenario of perfectly matched tyres.
 

Bury the Trash

Member
Mixed Farmer
Its nothing, nothing to do with width.:rolleyes:

Its to do with sidewall height .

op, if you are not replacing the fronts and they are a worn, obviously ? and the tractor is not used a lot go with the lowest ones,for a best match atm.
aamoi i wonder what type of tyre was originally fitted. ?
its all to do with Rolling radius and rolling circumfirence, which is affected as said above by wear and also tyre pressure , as its the distance between the centre and bottom of the tire, with weight on it iyswim,thats why if you blow your rear tires up the bike/tractor /car will go faster in the same gear /revs
some technical bits here.

bascially , choosing either of them wont be a problem, else the manufacturers would be sued a few times i guess, by now.

but i would'nt worry about it at all.
 

dowcow

Member
Location
Lancashire
You should worry a little about it. Tyres that are far from being in the correct ratio front to back will cause a drive line shock every time 4wd engages on a hard surface.... which means every time you tap the brakes on the road or in the yard. Over a short period of time, it will be handled okay, but over the lifetime of the tractor it will have some effect to bearings and propshafts. It will also increase tyre wear in the field.

As said, it varies from manufacturer to manufacturer, and even from specific model of tyres from the same manufacturer.
 

glasshouse

Member
Location
lothians
You should worry a little about it. Tyres that are far from being in the correct ratio front to back will cause a drive line shock every time 4wd engages on a hard surface.... which means every time you tap the brakes on the road or in the yard. Over a short period of time, it will be handled okay, but over the lifetime of the tractor it will have some effect to bearings and propshafts. It will also increase tyre wear in the field.

As said, it varies from manufacturer to manufacturer, and even from specific model of tyres from the same manufacturer.
Does a 390 engage 4wd when braking?
 

dowcow

Member
Location
Lancashire
Does a 390 engage 4wd when braking?

It's a legal requirement for going 40km/h I think. Maybe 30km/h? The early Masseys that had it used to make a point about it with an Auto4wd badge on the bonnet when it was a new feature. I can't remember whether it was our 699 or the 3075 that had the logo.
 

Richard Smyth

Member
Arable Farmer
It's a legal requirement for going 40km/h I think. Maybe 30km/h? The early Masseys that had it used to make a point about it with an Auto4wd badge on the bonnet when it was a new feature. I can't remember whether it was our 699 or the 3075 that had the logo.

1993 mf 3095 40 kmh didn’t have a logo saying that.
The 40 kmh 390t 2wd didn’t have it either and it would leave the 3095 behind
 

Bury the Trash

Member
Mixed Farmer
some people take the fuse out anyway because it can be a pita in some situations on the road or in the yard , shouldnt need it with trailler brakes.
our tractors dont have it either as theve got front brakes as well as back, much more civilised .
 

Bury the Trash

Member
Mixed Farmer
It wears out the splines
hell of a shock to the system ,doesnt help cornering on the road either

mind you to start with it was thought a good idea , reasonable i suppose, simple 4 wheel braking
''true story , chap i know couple of mile away down the road ,retired now but was a small dairy farmer , inteligent and good practiacally with it as well, he bought a Ford 7610 4wd drive , early electric solenoid ones didnt have it but he thought about it and did the switch and connection bit from the brake pedal s , to his tractor ,told Ford about it ...and they adopted it from then on. dont know how much he got paid tho.
 

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JCB has launched new Fastrac 4000 and 8000 Series tractors with an all-new electronics infrastructure which is claimed to deliver higher levels of performance. According to JCB, the new Fastrac iCon operator environment has three key features: iConfigure – creating a bespoke control experience for every operator iConnect – integrating advanced precision agriculture technology iControl – redefining operation through new driveline software The 175hp to 348hp (133kW to 260kW) Fastracs feature the new iCon armrest console and touch-screen display to provide flexibility in operator allocation and operator information, as well as a new transmission control strategy to enhance operator comfort and powertrain efficiency, says the manufacturer...
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