Along these lines, (with dealers over rating their equipment) I ran into the same problem. I asked my dealer for a quote for a chipper for my BX25. He recommended the BXM42 or the BX52S by http://www.wallensteinequipment.com/ca/en/group/wood-chippers-na/3-point%20hitch%20-%20self%20feed-na
I replied back to him pointing out that the BXM42 requires a PTO HP of 30-90HP. Way over what my BX25 puts out. And the BX52S is rated for 18-50 PTO HP. Again over the 17.7 HP at my PTO, but closer. I told him that the BX32S would be the one for my tractor. He then replied that he would typically sell the BX32S for a BX25 tractor, but that typically you want a wider opening for twisted branches, that are small in diameter and well within the HP of the tractor.
My neighbor has borrowed a BX32S and has used it on his BX25. He told me he has to engage and disengage the PTO about 3 times to get the heavy flywheel up to speed without stalling the tractor.
I replied back to him pointing out that the BXM42 requires a PTO HP of 30-90HP. Way over what my BX25 puts out. And the BX52S is rated for 18-50 PTO HP. Again over the 17.7 HP at my PTO, but closer. I told him that the BX32S would be the one for my tractor. He then replied that he would typically sell the BX32S for a BX25 tractor, but that typically you want a wider opening for twisted branches, that are small in diameter and well within the HP of the tractor.
My neighbor has borrowed a BX32S and has used it on his BX25. He told me he has to engage and disengage the PTO about 3 times to get the heavy flywheel up to speed without stalling the tractor.