NX Series HST Response Control

[wiskioti]

TBN Brain -

I've been a happy owner of an NX4510HST now for about a month. In that time, I've been figuring all the "quirks" of the tractor that the owners manual either doesn't mention (like the Linked pedal/Speed Cruise Control relationship) or barely glosses over (HST Response Control). So, here's my question for the "TBN Brain": For those of you that have an NX tractor and KNOW that your HST response knob works, how can you adjust the knob and FEEL a difference in the way it adjusts the response? In my case, I've turned that knob all the way in both directions and don't notice a change in the way the HST reacts or performs, which makes me wonder if the knob is actually doing something (and perhaps is defective). From someone that knows their knob works, if you could describe exactly what I should be looking for with adjustments in that knob, that would be fantastic! An early "Thanks" to those of you that can answer my question.

Oh, and in case you were wondering about the relationship between the linked pedal and speed cruise control - The speed cruise control does NOT work if the linked pedal feature is enabled. This was not in the owners manual and I thought I may have something not working right when I first tried using the cruise control. It wasn't until try 2 at attempting the cruise control that I remembered there should be dash light for the cruise control function. Looking for the dash indicator for the cruise light made me notice the indicator light for linked pedal, so I turned off the linked pedal and 'BAM!' (John Madden style), I had cruise control.

 

[DieselBound]

My understanding of the response control is that it controls the amount of time between when you hit the travel pedal and when the tractor's HST is actually commanded to move. I only know that mine was set lower and I was frustrated with how long it took before the tractor would start moving. I dialed mine all the way up (fast response) and could tell that, especially when changing travel directions, the tractor would respond quicker. It has value in lessening the responsiveness when you're working in a tight space. Step on your forward travel pedal, move some, pull off and stab the reverse travel pedal; try this for the lowest and highest response settings. If you don't sense any difference then something isn't right: I'm pretty sure that there's a fair amount of difference.

I can't say how long it took before I figured out cruise/speed control: in my mind CC seemed a bit silly (on my property you cannot keep a constant speed because the ground is too rough). I was doing a lot of hauling up and down my local road and I hated having to keep my foot on the travel pedal. I couldn't tell anyone what the sequence is, I can only just do it! (requires flipping several switches it seems)

 

[wiskioti]

Thanks for the info, DB! I'm intrigued that you are defining "response time" as the delay between depressing the pedal and the HST actually moving the tractor. The owner's manual, while not clearly, seems to make is sound like this dial adjusted response time as how fast the HST caught up to the pedal, if that makes sense. I haven't tried this because I don't like the thought of mashing controls, but the way I interpreted the control was if you were to mash the forward pedal to the floor, the "response time" control would dictate how fast the tractor accelerates, whether it's a sudden jerk of acceleration or a smooth acceleration. Being honest, if I'm being picky, my only complaint on the tractor is the delay from the time you press a HST pedal until the time it moves. I'm looking forward to doing some more testing with that dial if you definition of the "response time" is correct.

When I bought my tractor, I had to order the ROPS model, but was able to test drive a cabbed NX at the dealer. The other thing I'm hoping to do with the information I gather from here is go back and test drive that cabbed version again to see if it behaves differently than my NX.

Thanks again!

 

[AWSubie]

I found that I notice the effect of the switch adjustment more during deceleration than in acceleration (also the hydraulic fluid needs to be warmed up from operation, otherwise I don't notice much of a difference). Drive the tractor around for a few minutes before attempting the trial stated below.

Try this: (don't do this on concrete, put the tractor on dirt or gravel) Move the switch all the way to "slow" response and drive the tractor forward at a steady speed and then suddenly lift off of the forward pedal; the tractor should sort of coast to a stop. Then move the switch all the way to "fast" response and do the same thing; the tractor should slow down much more abruptly. If you don't notice any difference at all, something is not right.

 

[DieselBound]

wiskioti, yes, you are right, it's more about a slowing of the hydraulic flow than a "time delay," though the affect is similar. I don't really change it: set at about 80% max all the time.

AWSubie, that's a great way to test! (I know that my B7800, which, clearly, has no such adjustment, is very abrupt- I can almost get whiplash! [direct linkage is clearly faster])