Hand throttle on RTV-X vehicles

RodRocket

New member
I have been reading up and watching videos that were posted way back since early the Jan 2021 (on this and a number of other Forums), on the benefits of adding a hand throttle to RTV-Xs, and on similar and earlier Kubota models.
It seems the major reason advocating a hand throttle is to raise the base engine speed and torque to drive the snow plows and similar attachments at the correct RPM (and torque). But in real terms, a hand throttle has a broader role to play.

Looking at most modern-day mobile machinery such as tractors, skid-steer loaders, excavators, etc, etc, they now have hydrostatic transmissions to eliminate a clutch and meshing gears and for the ease and simplicity of forward and reverse vehicle motion. But, also with mobile hydrostatic transmissions, they are just about always operate with a high revving governed engine. Why? To keep the engine running in a higher torque band.

Now, it is very likely that the smart engineers at Kubota, have a "standard control system" of electronics and linkages working in unison to keep the engine RPM just high enough to maintain the torque in equilibrium with the force necessary to stroke the transmission swashplate to start and then drive the RTV to the max. power and speed. But to expect a heavy RTV-X to climb up a steep hill from a standstill, with the engine RPM starting at just above idle, is a big ask.

In a practical sense, under higher starting loads, it is much better to utilize a hand throttle to run the engine at higher base RPM and in a higher torque range, and temporally override the standard control system settings. And let the actual HST do its job!

The Kubota RTV-X*** series with a HST is undoubtedly considered a HD mobile machine, and as such are designed to handle the tough jobs around the farm and worksite. Maybe not that fast, but certainly a lot more heavy-duty compared to most "big-boy-toys", à la, UTVs.
In my view, a fully adjustable hand throttle should be standard equipment on RTV-Xs, as HD working vehicles. Not just to warm up cold engines, or just to operate attachments at a higher speeds, but importantly to assist the HST to better manage higher engine RPM and torque outputs, when operating at slow/low ground speed and demanding high load/tractive effort.
 

Bota Fett

Active member
Site Supporter
Me too, me too! I installed the hand throttle on my x1100, IIRC it was about $120 and fairly easy to install. Like other posters I did it for all the hills on my property. It's especially helpful when hauling my trailer around.

In addition to the hand throttle being standard equipment, I'd like to add the rear window screen, and mirrors as well.
 

aurthuritis

Well-known member
Site Supporter
there arent any electronics on the rtv x1100c yet that i know of. all of the relationship from the foot feed through to the hst speed control is controlled by mechanical design. and quite a good design in my opinion. the hand throttle allows full engine power at low hst demand and is a good thing in high torque situations.
 

4570FAN

Member
I agree, the LOCKING hand throttle should be standard on all diesel/hydro RTVs. Not sure why they even bother with the momentary throttle on the x1100c. 🤷‍♂️
Another thing I'd like to see is a Forward/Reverse treddle pedal. Keep a range selector for High/Low, a lever for 4WD, but add a pedal for F/W like a BX tractor. 👍
 

RodRocket

New member
The main advantage of a hydrostatic transmission is the relatively fast change of forward-reverse travel and variable speed on one treadle pedal, very important attributes for FELs, skid-steer diggers and the like. But not really necessary on a mainly-forward transport vehicle. Unless it is being used for semi-regular fast forward-reverse direction under load conditions. If that is the case, then the obvious question would be; are the RVT-Xs engineered to handle such relatively high dynamic forces, shocks on mountings and overall joint fatigue in the long term?
Who can say, but to make it so would likely mean a stronger vehicle at a much bigger price tag.
 
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FTG-05

Active member
I have a hand throttle for a RTV-900 2006 Worksite model. I don't know the part number of it right now. Let me know what part number you need and I'll check it.

A member in good standing who needs it gets it.
 

4570FAN

Member
The main advantage of a hydrostatic transmission is the relatively fast change of forward-reverse travel and variable speed on one treadle pedal, very important attributes for FELs, skid-steer diggers and the like. But not really necessary on a mainly-forward transport vehicle. Unless it is being used for semi-regular fast forward-reverse direction under load conditions. If that is the case, then the obvious question would be; are the RVT-Xs engineered to handle such relatively high dynamic forces, shocks on mountings and overall joint fatigue in the long term?
Who can say, but to make it so would likely mean a stronger vehicle at a much bigger price tag.
"Mainly forward transport vehicle" I understand your point BUT mowers are primarily used forward. As you mentioned, Hydros hold up to loader work, I don't see how an RTV (plowing snow for instance) would be more severe. And Polarass and Bobcat have managed.
 

rbarger

Member
I have a hand throttle for a RTV-900 2006 Worksite model. I don't know the part number of it right now. Let me know what part number you need and I'll check it.

A member in good standing who needs it gets it.
Are you looking to sell the hand throttle?
 

RickW

Member
.... Another thing I'd like to see is a Forward/Reverse treddle pedal. Keep a range selector for High/Low, a lever for 4WD, but add a pedal for F/W like a BX tractor. 👍
I could not agree more. For example this past weekend we were moving some dirt from a stockpile to around our new home. The RTV can carry 2 times the material of my B3030 and move at twice the speed. Lots of switching from H/R to dump the dirt exactly where we wanted it. But the switching from H to R on the selector is a pain especially if it binds up when not on level ground and you have to turn off the machine to relieve enough pressure to shift.

I understand the concerns of is the RTV really constructed for the abuses of uses the quick change from forward to reverse would really benefit. I know that all the dirt we moved this past weekend is not what it is really designed for but that is a rare use for us and not the normally daily duty we use the machine for. Three of the most common attachments for the RTV would really benefit from a F/R treddle pedal. Snow Plow, Snow Blower & the sweeper. All things the RTV is designed to do and these tasks would benefit greatly from a F/R treddle pedal. Even my spray rig that I built for the RTV would benefit as I regularly have to back out of tight spaces when spraying around our property.
 

geohorn

Well-known member
SUPER Site Supporter
I have been reading up and watching videos that were posted way back since early the Jan 2021 (on this and a number of other Forums), on the benefits of adding a hand throttle to RTV-Xs, and on similar and earlier Kubota models.
It seems the major reason advocating a hand throttle is to raise the base engine speed and torque to drive the snow plows and similar attachments at the correct RPM (and torque). But in real terms, a hand throttle has a broader role to play.

Looking at most modern-day mobile machinery such as tractors, skid-steer loaders, excavators, etc, etc, they now have hydrostatic transmissions to eliminate a clutch and meshing gears and for the ease and simplicity of forward and reverse vehicle motion. But, also with mobile hydrostatic transmissions, they are just about always operate with a high revving governed engine. Why? To keep the engine running in a higher torque band.

Now, it is very likely that the smart engineers at Kubota, have a "standard control system" of electronics and linkages working in unison to keep the engine RPM just high enough to maintain the torque in equilibrium with the force necessary to stroke the transmission swashplate to start and then drive the RTV to the max. power and speed. But to expect a heavy RTV-X to climb up a steep hill from a standstill, with the engine RPM starting at just above idle, is a big ask.

In a practical sense, under higher starting loads, it is much better to utilize a hand throttle to run the engine at higher base RPM and in a higher torque range, and temporally override the standard control system settings. And let the actual HST do its job!

The Kubota RTV-X*** series with a HST is undoubtedly considered a HD mobile machine, and as such are designed to handle the tough jobs around the farm and worksite. Maybe not that fast, but certainly a lot more heavy-duty compared to most "big-boy-toys", à la, UTVs.
In my view, a fully adjustable hand throttle should be standard equipment on RTV-Xs, as HD working vehicles. Not just to warm up cold engines, or just to operate attachments at a higher speeds, but importantly to assist the HST to better manage higher engine RPM and torque outputs, when operating at slow/low ground speed and demanding high load/tractive effort.
Another major reason for higher operating RPMs for HSTs are the increased flow of hyd fluid thru the coolers.
Kubota addresses that in the RTV series by adding electric fans and thermostats to the hyd cooling system… because running an RTV/UTV vehicle continuously at higher engine RPMs would be troubling to most operators of vehicles intended primarily for travel….instead of HST-work.
 

aurthuritis

Well-known member
Site Supporter
I could not agree more. For example this past weekend we were moving some dirt from a stockpile to around our new home. The RTV can carry 2 times the material of my B3030 and move at twice the speed. Lots of switching from H/R to dump the dirt exactly where we wanted it. But the switching from H to R on the selector is a pain especially if it binds up when not on level ground and you have to turn off the machine to relieve enough pressure to shift.

I understand the concerns of is the RTV really constructed for the abuses of uses the quick change from forward to reverse would really benefit. I know that all the dirt we moved this past weekend is not what it is really designed for but that is a rare use for us and not the normally daily duty we use the machine for. Three of the most common attachments for the RTV would really benefit from a F/R treddle pedal. Snow Plow, Snow Blower & the sweeper. All things the RTV is designed to do and these tasks would benefit greatly from a F/R treddle pedal. Even my spray rig that I built for the RTV would benefit as I regularly have to back out of tight spaces when spraying around our property.
you need to adjust the dump valve so that you don't need to shut off the engine.
 

TechJunkie

Active member
you need to adjust the dump valve so that you don't need to shut off the engine.
Aurthuritis, is this a straight forward adjustment? I took delivery of my X1140 in mid January and it seems to be 50/50 on shifting without having to bump the throttle or double tap the brakes (a single press doesn’t always seem to do it). Strangely enough even unloaded and on flat ground if the X1140 is in Low gear it sometimes doesn’t want to come out of gear. Brake seems to have no impact and only bumping the throttle works. Other times pressing the brake twice works, other times not. I at least wish Kubota could devise a shifting process that was consistent. Shifting seems to be more of an art than a simple action on these. If adjusting the brake dump valve would be beneficial I would be game to give it a try.

Back to the main topic, I have wondered about the benefits of the hand throttle if not using a broom, snow blower, or pulling heavy items up hill. When I was just looking at my X1140 the other day to acquaint myself with how it is put together and where the hand throttle would mount, I noticed my throttle cable has more slack to it than I would have expected. It goes 25 on level road with the throttle to the floor, but the amount of slack made me curious if I was loosing a lot of pedal due to the amount of slack and if removing some of the slack would be beneficial. I don’t want to screw up my machine tinkering without knowledge.
 
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geohorn

Well-known member
SUPER Site Supporter
The brake pedal should unload the transmission as already mentioned…. I have installed a placard on my dash so family members and friends who use it can see “Apply Brake to Change Gears”. But I also often find that the shift lever will not fully enter the detent of a newly selected gear…..and when that occurs… I lightly “tap” the accelerator pedal to move the gear-teeth so they will engage….and that solves the issue.

As for the hand throttle: I ordered the parts (about $130) and have been lazy about making the actual installation…but it looks (and is) a simple affair….. And should allow me to increase engine RPM before facing the steep hill so that it doesn’t “bog-down”. (Yes, I also am aware that simply letting up on the pedal will enable it to climb the hill just fine….but I’d sometimes like to do so at a faster speed.)
 

aurthuritis

Well-known member
Site Supporter
Aurthuritis, is this a straight forward adjustment? I took delivery of my X1140 in mid January and it seems to be 50/50 on shifting without having to bump the throttle or double tap the brakes (a single press doesn’t always seem to do it). Strangely enough even unloaded and on flat ground if the X1140 is in Low gear it sometimes doesn’t want to come out of gear. Brake seems to have no impact and only bumping the throttle works. Other times pressing the brake twice works, other times not. I at least wish Kubota could devise a shifting process that was consistent. Shifting seems to be more of an art than a simple action on these. If adjusting the brake dump valve would be beneficial I would be game to give it a try.

Back to the main topic, I have wondered about the benefits of the hand throttle if not using a broom, snow blower, or pulling heavy items up hill. When I was just looking at my X1140 the other day to acquaint myself with how it is put together and where the hand throttle would mount, I noticed my throttle cable has more slack to it than I would have expected. It goes 25 on level road with the throttle to the floor, but the amount of slack made me curious if I was loosing a lot of pedal due to the amount of slack and if removing some of the slack would be beneficial. I don’t want to screw up my machine tinkering without knowledge.
since your rtv is so new i would let it break in before i adjusted anything. the shifting gets easier as the hours build up but never really go completely away
 

RodRocket

New member
Just a reminder about hydrostatic transmissions. They have a variable displacement piston pump, that changes output by the angle of the swashplate, and in turn, the stroke of the pistons in the rotating group. Most can stroke from max. in forward, stroked to neutral, and then max. in reverse, which changes the flow and direction of the oil in almost one smooth action.
I don't know, but most likely the RTV-X only strokes in only one direction from neutral, based on having to select forward and reversed external of the pump.
Remember also, mechanical power is a combo of speed and torque, one is up when the other is down for the same power either input or output.
In hydraulics, power is the combo of flow and pressure. Just as electrical power is the combo of current and voltage.
So when you back off climbing a hill, the available power is transferred from flow to pressure, which related to transferring from speed to torque. It is of course torque that climbs the hill, at the sacrifice of speed.
To a good degree, a hand throttle increases to power at the start, which at low speed is an increase in torque.
The common function of the hand throttle is to increase engine RPM, so as to increase hydraulic oil flow to the attachments at low ground speed.
 

ItBmine

Well-known member
I agree, the LOCKING hand throttle should be standard on all diesel/hydro RTVs. Not sure why they even bother with the momentary throttle on the x1100c. 🤷‍♂️
Another thing I'd like to see is a Forward/Reverse treddle pedal. Keep a range selector for High/Low, a lever for 4WD, but add a pedal for F/W like a BX tractor. 👍
Me too!! I snow plow with my RTV so forward/reverse pedals would be awesome for me. I have learned the technique with my shifter but sometimes it still does get stuck. Pedals would be sooo much faster when plowing.
 

Jim

New member
Alright I bought a hand throttle for my X-1120. The included installation directions are terrible. Does anyone have better instructions or better yet a video link?
 

geohorn

Well-known member
SUPER Site Supporter
Alright I bought a hand throttle for my X-1120. The included installation directions are terrible. Does anyone have better instructions or better yet a video link?
I thought the instructs were pretty clear….except for how to attach that control-knob to the stamped-steel-mount for it… but my Son-in-law took it upon himself to do the install for me…. so I found the installation to be exceptionally EASY. (Get your daughter married-off to a handy type and buy some beer to share with him while you watch.) :ROFLMAO:

One thing that I’ve noticed: The hand-throttle does not significantly improve hill-climbing…as it only races the engine….the “go pedal” can still stall the engine if you overload it. The manual states that the hand throttle is for running hydraulics, etc….not for driving. I don’t have addt’l hyds…. so I might not have much use for it…. unlike the SIL who I put to work re-plumbing the utility-room this last weekend.…. Very helpful that guy.) :17875:
 
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