Steering Brakes??

[keeney]

Rich, Thanks for pointing that out. I wasn't aware that there was any possibility of potential damage to the hydro. The videos on Deere's site make a point of showing users locking up one wheel to turn, and tout it as a feature... which it probably is if no damage results. I am more concerned about traction issues, and steering control than sharp turns though that might not make much difference to the potential damage.

I think the main "potential for damage" comes mostly from the possibility to make too sharp of a turn at high speed or on a slope and roll the tractor.

The other "damage" possibility might be if you have 4wd engaged. The tighter turning radius puts more strain on the drivetrain components that are fighting each other due to the rotation rates not being different for the front and rear axles for a pivot turn around one rear wheel. Not an issue with 4wd off, but when you lock the two axles together, the rear wants to spin a lot slower due to only one wheel turning.

As long as you are already on surfaces already appropriate for 4wd (mud, loose dirt, ice/snow), I would not think anything is really being excessively strained by using steering brakes and 4wd toggether, even to the point of locking one rear wheel.

- Rick

 

[bx23barry]

A hydro drive system isn't any weaker than a gear drive system (size for size). The idea that using "steering brakes" on a hydo drive tractor is somehow "worse" than doing so on a "gear" tractor is kinda silly (certainly without technical fact). In fact the hydo drive provides some driveline "shock" protection, so is "easier" on the drivetrain than a "gear" system.
Also when slowing a wheel (as with a steering brake) on a open differential (like all tractors I know of without the diff lock engaged) the other wheel increases speed. Stopping one rear wheel will cause the other wheel to turn twice the speed of both wheels traveling straight (at the same speed setting).
The problem with steering brakes on modern 4x4 tractors is that the front wheels don't turn very sharp. Older 2wd tractors front wheels would turn almost 90 degrees and could nearly be turned (using the brakes) in their own wheelbase at the end of a row thereby saving field waste. Turning a 4x4 tractor the same way will skid the front pretty bad and is indeed hard on front steering/drive parts.
This in no excuse to not have useable steering brakes on 4x4 hydro (or gear) tractors. They are indeed necessary for effective and safe operation for the many reasons already stated.
OK end of rant

 

[daTeacha]

I didn't know if there was some possibility of damage to a hydro or not, which why I phrased the original comment about it the way I did. Thanks for the info.

Now, that makes me wonder why the units with hydros don't have provision for allow use of the brake without disengaging the hydro. They could default to brake use = hydro slowdown, but have a way to deactivate that feature, like the lever used to connect or separate the brakes. Doing something that simple would make the steering brakes more useful.

As far as front wheel steering angle, it seems my DX29 will turn sharper than my 8N did. Maybe my memory is faulty on that score, but I felt I needed the steering brakes on the 8N and I can honestly say I don't miss them much with the DX. It would be nice to have use of them, but the thing is pretty maneuverable as it is.

 

[jimmer2880]

My 4x4 Yanmar F16 will turn sharper than my old JD 318 2wd garden tractor did. I have always been completely amazed at how sharp some of these 4wd tractors turn.

 

[AndyinIowa]

As a vehicle system engineer, I'm fairly certain why Kubota's SCUT's aren't equipped with independant service brakes. Its more to do with marketing and commercial reasons, and less to do with technical barriers.

Each model family has a cost target. Features such as independant braking, independant mid and rear hydraulic lift, rear work lighting, three speed ranges, etc... are all great features, but in Kubota's marketing decisions, they aren't more important than the features that DID end up on a vehicle.

Next, consider the primary customer for SCUT's. A large percentage of buyers and owners are females in their 30's and 40's. (FYI, over 50% of light trucks sold in the US are purchased by female buyers). You can research this more via Yengst, FEMA, and other market industry analyst companies.

Now, WHAT features am I going to put on the tractor? I'm going to put 12vdc outlets for cell phone charging. I'm going to give the operator a work mode and transport mode so the operator doesn't have to choose between 3-5 ranges. I'm going to keep all ground operation controls on the right foot, which is how almost all US drivers drive their cars and trucks. The key will be on the right side of the steering wheel for emergency shutoff.

I'm actually surprised Kubota doesn't have a turn signal stalk with lights and turn signal controls similar to cars.

Bottom line is that independant braking is a function that, although we would like to think is critical, is used less than 1% of the time (based on duty cycle hours for the tractor). I don't argue that its great to have during that 1% of the time, but what about the following:

Front differential lock
Independant brakes
Steering wheel with built in speed steering knob
Quick release hood for servicing
Hydraulic reservoir heater for cold operation
Auto glow plug starting
Rear work light
Tool box
Left or right mounted loader controls
Self cleaning reversible cooling fan
Full skid plates
Rear axle capable of handling dual tires
Full Cat I 3PH with lifting capability
Fully proportional hydraulic control
Rear dual aux hydraulic remotes
Two speed PTO
Speed proportional steering
Foldable ROPS
Tilt steering
Auto resume cruise control

Each of these are features that DIDN'T make it on the BX tractors. Some are available as aftermarket installed options, some aren't. Its easy to blow past cost targets when you listen to every customer and try to make a one-size-fits-all solution. Unless you've designed equipment for global markets, its hard to appreciate how difficult the decision making gets when cutting features or adding features.

IowaAndy