Hydrostatic quirk or total nonsense?

[sunandsand]

Copy of Family Handyman arrived today, it has an article which touches on a BX2380. Author says he was having trouble filling the bucket on the FEL, and needed a bit more horsepower. He said when he pressed down hard on the "forward" pedal, it "essentially shifted into a higher gear range" which wasn't what he wanted and bogged the engine down. His solution was to shift to 4WD low and try again, which he said solved the problem (I guess more mechanical advantage from a lower range). He wasn't clear if he was having problems filling the bucket by shoving it into the dirt pile, or filling the bucket by push/curl/lift (which I think is the proper procedure since using the FEL as though it was a bulldozer will bend it).

So . . . I have a B2601 with pallet forks. I have sometimes run into problems lifting "stuff" which I know weighs less than the FEL rating. The engine doesn't bog, but the FEL won't lift. I was unloading freight on pallets out of a tractor-trailer, and the FEL wouldn't lift, but it would curl, and that gave me enough clearance to get the pallet out of the trailer, back away, and lower the pallet to the ground.

My question is this - would I have had more lift capacity if I were in low range (I was in medium, 2WD) or did I just happen to find the lift limit of my FEL? Would the gear range affect the output of the hydraulic pump with drives the FEL? I also think the lift capacity of the FEL varies with the height, and the truck bed is 4' off the ground, maybe a little more.

His explanation might also be apples and oranges - if he was playing bulldozer, that shouldn't affect the hydraulics, and he simply asked more of the BX than it could deliver in high range.

Best Regards,

Mike/Florida

 

[newbury]

weighs less than the FEL rating.

But is your system up to spec?
In the past it has been reported that some dealers routinely set their loaders below spec, sometimes as much as 10%. Fewer warranty issues and most people never check their hydraulic pressure.

 

[sunandsand]

But is your system up to spec?
In the past it has been reported that some dealers routinely set their loaders below spec, sometimes as much as 10%. Fewer warranty issues and most people never check their hydraulic pressure.

Don't know . . . how can I check it?

Considering that a LOT of people routinely beat the mortal you-know-what out of things they own, even though they know better (or should), that dealer policy might not be such a bad idea ;-)

 

[4570Man]

It’s operator error. The HST pedal works differently from a car accelerator. You want more throttle and less pedal when the going gets tough. The tractor should have already been in low range which it sounds like it wasn’t.

 

[JWR]

Mike: The Handyman Author gave a misleading article. First, it does not shift into any range. Only the operator shifts to a different range. Certainly he got more forward motion force when HE shifted to low range (which happened to be how he was filling his bucket.) Then you add more mud to the water saying "he might bend the FEL." That is not going to happen. The BX does not begin to have enough traction or power to bend the FEL. The FEL will win that battle all the time.
Then your question: Would you have more lift capacity [with the FEL] if you were in low range ? Answer is NO. In both his tale and yours the range the HST is in does not materially affect the lift capacity of the FEL. That's the simple answer.

Now to clarify a bit: the FEL (or anything else driven via the hydraulic pump) will have more lift capacity at higher rpm. So if either of you lug down the engine rpm by whatever means (such as by lugging it down being in a high range while trying to move forward) then, YES, you would have 'reduced the lift' but that is a misleading rationalization (rationalization is substituting A reason for THE reason.)

Look at it this way, if you stop the tractor, run the engine at rated full rpm, and keep adding weight until the FEL won't lift it anymore that weight will be the same regardless of what range your transmission is in. Including neutral which it is in anyway with your foot off the pedals.

 

[oldnslo]

To answer your question the gear you are in has zero effect on what your loader will lift. With forks the center of the load is potentially farther forward which will reduce the theoretical lift capacity.

And pushing harder on the HST pedals tries to make the tractor go faster Vs giving the tractor more power. This is a misconception that some people have.

 

[Smokeydog]

Chart shows where the position the weight is on forks effects lift.

The curl has breakout force. Caution as this can add to your total lift force.

 

[sunandsand]

OK, this clarifies things immensely.

1) FH writer misunderstands the HST system. He will be happy to know the BX doesn't have enough grunt to bend the FEL. (My neighbor has managed to bend his by abusing it, but it is a much larger tractor.)

2) Hydraulic pump operation is not affected by speed range, and I'm not moving anyway when I'm trying to lift the pallets.

3) Throttle was at full power (on mine, I don't know where his was).

4) I found the lift capacity at height X, and cheated it just a tad with the curl function.

5) The membership of TBN is the *BEST* source of information there is!

Thank you!

Best Regards,

Mike/Florida

 

[IndyIan]

There is a tendency to scoop from the bottom of the pile while driving forward so you are trying to lift way more than a bucketful and if you are in 4wd there's not going to be any wheelspin either, so you can easily run out of pushing power in medium range and start to bypass the HST hydraulics. I'm not sure how many hp it takes to send the load hydraulics into bypass but its several as well which pulls down the rpms a bit too.

 

[jeff9366]

I was unloading freight on pallets out of a tractor-trailer, and the FEL wouldn't lift, but it would curl, and that gave me enough clearance to get the pallet out of the trailer, back away, and lower the pallet to the ground. The truck bed is 4' off the ground, maybe a little more.

It is much safer in max lift unloading situations to raise the load an inch, then have the someone drive the truck out from under the load, then lower the load with the tractor stationary.

That initial 60" of tractor movement at max lift is the most dangerous time, when tractor rollovers occur.