rear tires

Finnbair2020 · Oct 16, 2012

OK-- probably a dumb question-- I was offered some rear tractor tires in a barn today- probably at a reasonable price. One is a 11-36 on what I think is a massey harris rim. The other is a 12.4-38-- not on a rim. I usually run 13.6-38's on my farmalls an on an Oliver 770. Would the MH rim by some odd stroke of luck be interchangeable with a farmall rim?-- it looks roughly the same. Would it be useable to have a 12.4-38 on one rear rim and my usual 13.6-38 on the other? New tires are so expensive now, I'm trying to make these tires useful at some point...

Dave_Id · Oct 16, 2012

I bought a Cockshut 30 (Farmcrest)that had two different size tires. the right one was bigger. Someone told me this was for plowing so the bigger tire was in the furrow, and made the tractor more level, hence more comfortable for the driver... You can tell this story to anyone that asks.

Bill Lisbon · Oct 16, 2012

Running 2 different tires is not a good idea. It is hard on your diff gears.

Anonymous-0 · Oct 16, 2012

both tires are 38's the only diff is one will be a shade wider, it WONT hurt the differential as long as both are the same diamater, the width dont matter, 12.4 to a 13.6

sflem849 · Oct 16, 2012

(quoted from post at 17:38:08 10/16/12) both tires are 38's the only diff is one will be a shade wider, it WONT hurt the differential as long as both are the same diamater, the width dont matter, 12.4 to a 13.6

That is not entirely true. 12.4 vs 13.6 vs 14.9 vs 15.5 all have a different height. As for hard on differential gears...then so is turning. I suppose it could accelerate wear. It isn't like they are "locked in" when you are going in a straight line. Even a pound difference in air pressure would make the differential spin at different speeds. Heck, if that is true you couldn't moldboard plow because the furrow tire slips more than the land tire.

David G · Oct 16, 2012

Any difference in height will cause wear in the differentials.

The lubrication must be adequate to minimize this wear. I would not recommend using different sizes as a plan, it will get by for a time, but what will that time be.

rustred · Oct 16, 2012

not really.they turn so slow that it would never wear anything out. what hurts a diff. is when you get stuck with your pickup and have one wheel spinning 50 mph and the other one stationary. those little spider gears are just spinning on the pin and wearing it out. seen this happen and repaired many diff's due to this. cant see it doing any harm on a tractor, as it would be all in slow motion when your travelling in a straight line. thats the whole purpose of the diff. is to allow one wheel to turn faster than the other on corners.

LA in WI · Oct 16, 2012

sflem849,

I don"t have a dog in this hunt, but...

Think about your last sentence in your reply.
When a tractor is pulling hard while plowing, which wheel slips the most?

LA in WI

sflem849 · Oct 17, 2012

(quoted from post at 21:49:50 10/16/12) sflem849,

I don"t have a dog in this hunt, but...

Think about your last sentence in your reply.
When a tractor is pulling hard while plowing, which wheel slips the most?

LA in WI

I plowed a little wet last year, but mine was the tire in the furrow not the tire on hard ground. That may not be true all the time though. That was wet conditions and worn out tires.

sflem849 · Oct 17, 2012

For the record, I would NEVER run two different size tires on my tractor as a permanent plan. It wouldn't hurt if you just did it to get the tractor to roll.

NoNewParts · Oct 17, 2012

(quoted from post at 19:30:53 10/16/12) OK-- probably a dumb question-- I was offered some rear tractor tires in a barn today- probably at a reasonable price. One is a 11-36 on what I think is a massey harris rim. The other is a 12.4-38-- not on a rim. I usually run 13.6-38's on my farmalls an on an Oliver 770. Would the MH rim by some odd stroke of luck be interchangeable with a farmall rim?-- it looks roughly the same. Would it be useable to have a 12.4-38 on one rear rim and my usual 13.6-38 on the other? New tires are so expensive now, I'm trying to make these tires useful at some point...

pull it onto a hard surface, and use air pressure differences
(within reason)
to make the height close, and run em
on 3 of my tractors with matching tire sizes and wheel widths,
but different brand tires per side, the tire heights aren't even close.
one with 12.4-38's is so obvious, seen from a distance, you think
it's getting a flat tire.
I don't drive on pavement, so I don't worry about it.

sflem849....run into the same problem here.
hard clay, have to have a little moisture in it, or
you can't pull anything thru it.
When a little damp, the clay is so slick, the furrow tire
is always spinning

LarryM · Oct 17, 2012

The same rim that will fit a Farmall M or H will fit some years of the Massey Harris, minneapolis moline, john deere, case, and maybe others. I don"t think it was ever used on an oliver.

mkirsch · Oct 17, 2012

The 36" (thirty-SIX) inch tire won't fit on any of your 38" tractors. Even if you swap rims.

It might be nice to have on hand to help someone else out, or maybe you'll pick up a Farmall C or something else with 36" tires. If the seller is just going to throw the tire away and/or it's cheap enough, buy it.

The 12.4x38 will make a fine spare. Odds are you won't like how it looks, or how the tractor sits a little cockeyed, but it's better than nothing at all.

Differential on a slow-moving tractor is not a problem. It is on a truck/car because the tires are spinning over 600RPM at 60MPH.

dhermesc · Oct 17, 2012

I agree with the comment about the differential, if its that weak that an inch two in tire height makes a difference it's beyond hope anyway.

We have tractors with 1000s of hours with only one dual while pulling a plow - that puts wear on a differential, breaking ground on terraced land puts wear on a differntial, having an inch or two difference in the overall tire diameter is nothing.

There is a degree of constant slip going on when ever the tractor is under load, and if its not under load - who cares?

LA in WI · Oct 17, 2012

sflem849,
We have a spring plow day, and one guy always shows up with an AC and he always puts too big of a plow on it. Guess he is trying for attention....and he gets a short ways down the field and the left wheel is spinning merrily and he is stopped. Then he plows shallow the rest of the day.

I remember "back when we plowed" that some guys put a dual on the left side to help with traction.

Ya ain"t supposed to plow when it"s wet...naughty, naughty!!
LA in WI

rear tires

Finnbair2020

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Dave_Id

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Bill Lisbon

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Anonymous-0

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sflem849

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David G

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rustred

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LA in WI

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sflem849

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sflem849

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NoNewParts

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LarryM

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mkirsch

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dhermesc

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LA in WI

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