Matching PTO HP to an Attachment

[SanDucerro]

What are the consequences of having too much PTO HP for a given attachment?

I'm looking for a medium duty rotary tiller and the min/max ratings are in-between my available tractors PTO HP ratings. Our L3130 is rated at 24 PTO HP and the M7040 is at 64 PTO HP. Most of the medium duty tillers I'm finding are in the 50 PTO HP range - which is too much for the L3130 and too small for the M7040. So, what might happen if I run a tiller with a recommended 50 HP rating on the 64 HP M7040?

The sales guy at the local dealer says no worries - the M7040 will pull the tiller just fine. But I'm not sure he's understanding my concerns. The M7040 will obviously pull the tiller, I'm worried the tractor won't even know it's back there and eventually trash the unit. Is this a valid concern? Or do the attachment manufactures overstate/understate the equipment's PTO recommendations?

Thanks!

 

[oosik]

Keith,
I ran a snow blower with 40 pto hp max on my Kubota which has 56 pto hp. Nothing ever happened. I would guess - if the implement is not shear bolt protected - something else would break. Such as U-joint. However, like your dealer indicated - I would not give it a second thought, especially if your new tiller will be shear bolt protected. You might find that every so often you shear a bolt. DO NOT go to a larger shear bolt if it is protected in that manner. Just purchase a rotary tiller that is shear bolt protected and go smack some dirt.

 

[SanDucerro]

In this case the tiller I'm looking at has a slip clutch - which I should have mentioned at the start. This might be my biggest worry as I ran a 5' SQ600 Bush Hog shredder on the M7040 and toasted the slip clutch. I knew the SQ600 was way too small for the M7040, but I figured I'd just take it easy. However, with the cab on the M7040 I never heard the poor SQ600 squealing in protest before the slip clutch went up in flames. Now - having said this - the SQ600 was over 10 years old and the slip clutch hadn't been adjusted AND had been stored outside all its life. As such, the M7040 toasting the slip clutch may have had more to do with the condition of the slip clutch plates and not as much with the power of the M7040. But that's where my worries are on the tiller...