PTO categories

[doxford jim]

Hi,

Could someone please explain the differences to a tractor newbie. I have an old MF-65 which I have had for two years and would like to replace. I am looking at 45 - 55 hp range - don't need anything bigger than that.

As I look at the hp sizes I find up to 45hp the pto class/size is 1, going to 50hp and above is 2 and I assume the real large tractors would be 3.

I am sure this has to do with the output shaft size and spline of the pto. Is there anything else that governs this. I would also assume that 2 and 3 categories would mean larger auxiliary machinery.

I have tried the search function and have found nothing that explains the real differences.

Thx for any clarification.

Jim

 

[N80]

You may be confusing PTO sizes with three point hitch classes. I can't say anything about very large tractos but I think the PTO shafts for 540 RPM PTOs are all the same size. But as in all things regarding tractors, I might be wrong!

 

[jimmy1]

I think too that you are talking about the three point hitch categories. The categories increase as to accept larger equipment as the size of tractor and equipment increase. I think cat. 1 and cat.2 may be interchangable but not sure. The rear pto standard is 540 rpm's and getting into larger applications 1000 rpm's is common. Not to confuse this with the 2000 rpm ranges for mid mount equipment.

Jim

 

[scott_vt]

I am sure this has to do with the output shaft size and spline of the pto. Is there anything else that governs this. I would also assume that 2 and 3 categories would mean larger auxiliary machinery.



Jim

Mornin Jim,
The standard size PTO shaft today is 1 3/8". Many years ago some of the tractors had a 1 1/8" PTO. My 1942 Farmall has a 1 1/8" PTO shaft, but my 1949 Farmall Super A has the standard size 1 3/8" PTO. The only categories as far as Cat 1, Cat 2 , Cat 3 are your 3 PT hitch.

 

[doxford jim]

Hi Guys,

Thanks for the insight. It all makes sense now - duh!!. Don't know what I was thinking and of course, when I wanted to know couldn't find the right answer.
Must be getting old real quick )

Thanks again.

Jim

 

[witel]

Here is a link for reference.

 

[N80]

In general, most compact utility tractors have Cat I three point hitches. This has to do with the size of the holes on the ends of the lower lift arms and the top link. These holes correspond to the size of the pins on the implement. Many utility tractors can work with either Cat I or II, meaning that they have 'holes' that accept Class II pins, but you can put Cat II pins on many Cat I implements.

However, on some implements you cannot change the pin size. My box blade is a Cat I and instead of having a bolt-on pin, it has a bracket with two holes that you slide a pin through. This is more durable than a bolt on pin, but does not allow the option of using it with a Cat II tractor (which it was not intended for). My mower (JD LX6) can accept Cat I or Cat II pins.

 

[GaryM]

However, on some implements you cannot change the pin size. My box blade is a Cat I and instead of having a bolt-on pin, it has a bracket with two holes that you slide a pin through. This is more durable than a bolt on pin, but does not allow the option of using it with a Cat II tractor (which it was not intended for). My mower (JD LX6) can accept Cat I or Cat II pins.

What? You don't own a drill?