3 Pt hitch/PTO different categories? (2025)

The Category of the 3 pt hitch is .............? Well, now you have got me thinking . OK, I am sure someone that knows will post.

I think the Category of the hitch is related to size. For example, my friend's tractor has a Cat I and Cat II. The "balls" in the 3 pt. arms have 2 different size holes in each of them to accept different size pins. You simply rotate the ball to the size, either cat 1 or 2.

The difference in PTO's is the most common 540 RPM and the 1000 RPM. It is not related to the 3 pt hitch. What I mean is you can have 540 RPM in Cat. 1,2,3, or 1000 RPM in all 3.

Basically the catergories is based on how much HP you have and the more HP you have, the larger the pins gonna be. To make this more confusing, if you have a cat 1 machine, you can also use cat 0 attachaments with sleeve adapters or cat 3 and use cat 2, cat 1 cat 0 but the cat 0 stuff probably will bend like tinfoil with all the HP the machine has.

Category 0 3 Point Hitch
This category is intended for tractors up to 20 Horsepower
Toplink Pins are 5/8" diameter
Lift Arm Pins are 5/8" diameter

Category 1 3 Point Hitch<- - - Most common
This category is intended for tractors 20 to 45 Horsepower
Toplink Pins are 3/4" diameter
Lift Arm Pins are 7/8" diameter

Category 2 3 Point Hitch
This category is intended for tractors 55-95 Horsepower
Toplink Pins are 1" diameter
Lift Arm Pins are 1 1/8" diameter

Category 3 3 Point Hitch
This category is for tractors above 95 Horsepower
Toplink Pins are 1 1/4" diameter
Lift Arm Pins are 1 7/16" diameter

Thanks for the info, this table from tractordata.com is really helpful, great drawing too for us "less informed" tractor people...

Three-point hitch specifications
Category Hitch pin size Lower hitch spacing Tractor drawbar power
upper link lower links
0 17 mm (5⁄8") 17 mm (5⁄8") 500 mm (20") <15 kW (<20 hp)
1 19 mm (3⁄4") 22.4 mm (7⁄8") 718 mm (26") 15-35 kW (20-45 hp)
2 25.5 mm (1") 28.7 mm (1 1⁄8") 870 mm (32") 30-75 kW (40-100 hp)
3 31.75 mm (1 1⁄4") 37.4 mm (1 7⁄16") 1010 mm (38") 60-168 kW (80-225 hp)
4 45mm (1 3⁄4") 51 mm (2") 1220 mm (46") 135-300 kW (180-400 hp)

Does this mean that although you can get inserts for the hitch pins in order to use a lower category implement, you really can't use that implement because of the lower link arm spacing?
For example if i have a category 2 3 pt hitch, but want to use a log splitter (or anything) that was made for a cat 1 hitch, it won't work because the link spacing on the cat 2 tractor would be 32" whereas the splitter is set up for link arms with 26" spacing?

Opti-Mist said:

Re: PTO speed and splines. Yes, there are SAE standards for PTO shaft size and splines as well. 540 rpm takes a 1-3/8" 13 spline shaft. 1000 rpm is larger and more splines - right now I don't recall.

Click to expand...

Finally found some more about this here.... TractorData.com - Power Take-Off Types

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Another one:

SpeeCo Inc. Farming accessories and tools, log splitters, post hole diggers and custom manufacturing.

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