gross HP -to- PTO HP ratio

[dirtwhisperer]

looking at the new dk35hst:
gross hp is 38hp, the pto is only 27hp. -thats 11hp less to the pto

the ck35hst puts out 34hp gross and 26.5hp pto thats only 7.5hp less

any reason to explain this ?
seems like the dk35hst doesn't transfer power as efficiently to the pto for some reason ??

 

[BTI]

Bigger HST Pump on the DK35 and also bigger/heavier pto components.
I would like to see them both ran on a PTO Dyno.

BTI

 

[dirtwhisperer]

so the internal gearing is heavier duty on the DK series ?
I guess that would be a good thing other than having less HP at the pto.
Where did you read about the heavier gearing in the DK versus the CK series ?

 

[bluechip]

While I cannot confirm the larger gears on the DK over the CK, I would expect them to be as the DK is a much heavier chassis, about 900lbs more tractor than the CK. It would make sense that as the DK35 and DK40/45SHHST share the same chassis, the gearing would have to me more substanial than the CK 25/30/35HP chassis.

Another clue to the difference in PTO hp as a percentage of engine HP may be the difference between peak HP and HP at "PTO speed". the modern trend in tractor specificaitons seems to be listing the peak HP for the engine. This may not be rated at the same rpm that the engine runs to achiceve the typical 540rpm. With a good flat toruque curve, the more rpm you make, the more HP you have, but for PTO use, you want to run the engine at an effiecient speed that will produce the maximum possible torque at the PTO.
But I'm not an engineer, just a iron peddler...