1 1/8'' vs 1 3/8" PTO shafts

JustBill

New User
I think I need an education on the relative merits of the 1 3/8" PTO shaft. As I understand it, it is more robust, but unless you replace the hydraulic pump you are still stuck with 1 1/8" shaft as it goes into the hydraulic pump. What am I missing.
 
All that changes is the bearing retainer and the output size. The spline end that goes thru pump and shifter stays the same.
 
(quoted from post at 19:17:08 06/24/20) So If I don't have, or plan to have a 1 3/8" implement it won't make any difference, right?

Right. And there are a number of cheap adapters that you can install that allow you to attach 1 3 /8 " if need be.
Some of them, however require you to shorten your PTO driveline due to their length.
Replacing the PTO shaft on your N is VERY easy and inexpensive.
Then you're set to run modern implements.
I get it. I am one that likes to keep things stock.
This is one exception.
Just my $0.02....
 
In 1950 the ASAE (American Society of Agricultural Engineers)introduced the larger 1-3/8" diameter spline PTO shaft and has been the industry standard ever since. They don't make or sell the old 1-1/8" PTO shaft anymore. There are low cost solutions to use if you have the OEM PTO shaft. The cheapest is a simple sleeve that slips over the shaft and pins with a roll pin -see pic. For a few bucks more but a lot cheaper than replacing the entire PTO shaft is an ORC (Over Running Coupler) that attaches to old PTO 1-1/8" shaft and has the 1-3/8 shaft for use.

PTO ADAPTOR SLEEVE:
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Tim Daley(MI)
 
(quoted from post at 21:11:45 06/24/20)..... unless you replace the hydraulic pump you are still stuck with 1 1/8" shaft as it goes into the hydraulic pump
Never heard of or seen such an animal. As Shaun said, just the output size of the shaft is different between the two.

(quoted from post at 22:17:08 06/24/20) So If I don't have, or plan to have a 1 3/8" implement it won't make any difference, right?
Right.

In fact, if you use something like an 1-1/8 belt pulley, you need the 1-1/8 PTO
 
Yep, I forgot to add that important piece of info in my earlier post. The 1-3/8" splined PTO shaft is only the output end as Jim said. You don't buy a whole new pump, they don't make the beast, and thus not needed. The NAA introduced the 1-3/8" PTO shaft as OEM standard issue and the size still used today. The shaft is a tad longer than the original 1-1/8" shaft and thus the PTO cap will hit. That is where the square cap comes into play. Like I said, the 1-1/8 shaft is no longer made. DEARBORN made an adaptor too -see PIC. Also stated, get a sleeve or ORC adaptor if you need to run a mower, combine, or spreader. How may actually use their belt pulley? A Cordwood saw maybe? If it ain't broke??? I'd move on to better things to send time and money on like PM. Don't sweat he petty stuff and don't pet the sweaty stuff... ; > )

DEARBORN PTO ADAPTOR:
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fKma91Wh.jpg
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Tim Daley(MI)
 

I replaced my 1 1/8" shaft with a 1 3/8" shaft purchased right here on YT. Yes the splined shaft is a little longer as you said but the shaft I got here came with a new PTO cover already on it so there was no problem.
 

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