HST Question

[dillo99]

This is probably a silly question but I'll ask it anyway!

If you are driving the tractor (no loads) does the pedal down half way in high gear cause more transmission wear than the pedal all the way down in low gear? I am assuming that the HST is NOT like a clutch and therefore there is no additional transmission wear from 1/2 pedal. Right?

I have some bumpy spots on my trails and so I tend to travel in high gear but vary the pedal frequently to slow down over bumps. After doing this for quite a while I started to wonder if this was somehow causing more wear than if I just traveled in low gear and kept the pedal at full.

Thanks in advance for any insight!

Mike

 

[ovrszd]

This is probably a silly question but I'll ask it anyway!

If you are driving the tractor (no loads) does the pedal down half way in high gear cause more transmission wear than the pedal all the way down in low gear? I am assuming that the HST is NOT like a clutch and therefore there is no additional transmission wear from 1/2 pedal. Right?

I have some bumpy spots on my trails and so I tend to travel in high gear but vary the pedal frequently to slow down over bumps. After doing this for quite a while I started to wonder if this was somehow causing more wear than if I just traveled in low gear and kept the pedal at full.

Thanks in advance for any insight!

Mike

Makes no difference at all and under the circumstances you described you are doing no harm to the HST. It is not like a clutch. When you have the pedal only halfway down, it isn't slipping like riding a clutch pedal would create. That's why they describe it as infinite. The gear selection is after the HST and is used as a multiplier to increase torque to the rear axle.

 

[mcconoughey]

"does the pedal down half way in high gear cause more transmission wear than the pedal all the way down in low gear?" That is a superb question for which I can clearly state "I don't know." In a high gear, half speed position, the individual hydrostatic pump parts operate under a higher hydraulic pressure, but only half as often. Does the higher pressure, lower number of cycles reduce overall wear? I will guess that it does reduce wear, but my thinking is indirect. On tests reported in the Society of Automotive Engineers technical papers, the Detroit Diesel company had a technical paper that showed lower engine cylinder wear at a given power output at lower RPM operation. However, when RPM was lowered below a certain level, cylinder wear increased. Without full load, I suspect that pump pressures are moderate even in high gear. Hydrostatic pumps and diesel engines have in common the fact that both contain cylinders and pistons that operate under pressure and incur wear over time. The many other differences makes it risky to draw the inferences that I present above.