540 or 1000 flexwing mower?

[Richard]

My tractor has both PTO's so I can go either way.

Local dealer has Bushhog 2515 in stock with 540 input.

He does NOT have a 1000 version in stock.

If you are buying for yourself:

1. Do you really care which one you use?
2. If you do, WHICH do you prefer?
3. If 1000 shaft and he's got to order it, how much more are you willing to pay for that verses a 540 shaft unit "on the lot"?

I've never used a 1000 shaft unit so I'm presuming there are gearbox differences between the two (or is it JUST the shaft?)

 

[jthibodeau89]

Gearbox ratio is different. Less torque for same hp.

 

[Industrial Toys]

I had a 540, but would like a 1000 as the torque on drive line components must be less.

BUT, always thinking ahead, thinking a 540 would be more valuable as more people can use it.

 

[Zebrafive]

If I understand correctly, a 1000 rpm drive line will handle more torque than a 540 rpm drive line?

I would guess resale would be lower, since there are fewer 1000 rpm PTO tractors out there?

Another consideration, is if you were to replace tractors, you would need to be sure it 1000 rpm PTO.


I would buy which ever I could buy for the best/lowest cost.

 

[Richard]

Gearbox ratio is different. Less torque for same hp.

Since engine RPM's are the same (at PTO speed) and the blades are turning (essentially) the same yet, there are shaft speed differences.... would it be reasonable to say that:

540 shaft: the stress is higher on the tractor side because the mower might have higher gearing and
1000 shaft: the stress is higher on the mower side because the gearing is lower

??


I've always had a bit of a road block digesting the "why" of the differences.

I can accept the blind statements but I'm OCD and curious enough that I like to know why.... (yeah, drove my mother nuts growing up!!)

 

[dieselscout80]

I would guess resale would be lower, since there are fewer 1000 rpm PTO tractors out there?

Only if you are dealing with smaller tractors almost all +75 horse power tractors have 1000 RPM PTOs and many don't even have a 540 PTO. Also as HP increased there are two sizes of 1000 RPM PTO the smaller 1 3/8" (20-spline) and a larger size 1 3/4" (21 Spline).

I know IH had dual speed (540 & 1000) in the 1960s on the 1066 and other tractors and JD 4020s had that option too.

 

[jthibodeau89]

Torque on blade shaft is about same. Torque on input shaft and pto is down 46%. Input torque capacity is a primary factor in size of drive line; gears, shafts, and u-joints are sized based on torque, not rpm. Only shaft stiffness (diameter) is based on rpm.

Per above comment, HP is a function of rpm and torque. To keep shaft torque in a reasonable range, high HP requires higher rpm.

 

[jthibodeau89]

I can tell you the gear boxes on my 3210 BH were not very happy when i didn't notice my 70hp tractor's pto was accidentally set to 1000rpm.

Also, engine rpm may be different for 1000 vs 540 pto speed. On my AgcoAllis 5670 the 1000 pto is a few hundred rpm higher engine speed.

 

[Zebrafive]

Only if you are dealing with smaller tractors almost all +75 horse power tractors have 1000 RPM PTOs and many don't even have a 540 PTO. Also as HP increased there are two sizes of 1000 RPM PTO the smaller 1 3/8" (20-spline) and a larger size 1 3/4" (21 Spline).

I know IH had dual speed (540 & 1000) in the 1960s on the 1066 and other tractors and JD 4020s had that option too.

My experience is with smaller tractors, thanks for posting. I was not sure what HP the 1000rpm became common to have

 

[dieselscout80]

My experience is with smaller tractors, thanks for posting. I was not sure what HP the 1000rpm became common to have

I can understand I would not have known had I not worked with larger equipment when I was younger.