Was curious to hear from some of yall that have run both what you like and dislike about them on the big and small dozers. I've only ever ran the small one with hystats. Thanks!
Hydrostatics tend to teach people bad habits for running TQ machines. It's called a decelerator and you should use the damn thing when switching directions or turning. As far as the actual operation, I prefer the TQ as it seems more natural to control your speed with your foot. You also don't have the nasty habit of changing your speed/direction if you catch a bump (I remember one incident where a person was towing a tandem using a very short chain. The brakes on the trucks pup failed and jerked the dozer+operator and the jerk caused them to bump the joystick in the wrong direction and stick a ripper through a radiator). Hydrostatics do have one advantage. No need to idle down so you always have full hydraulic power to your implements, even when in a super slow crawl.
i run the tq but 1 time i was on a larger hydro model and since you can have the power up and no decel pedal i was sure glad i had my seatbelt on when i went from forward to reverse the first time.....whew i think once you get used to either one they're both fine just differant.
I've run both hydro and TQ dozers and it's TQ all the way with me. TQ machines seem to be able to put the power down better than hydro machines. I find hydro dozers are all noise and no push. Better yet is a direct drive dozer with hand clutch, they really seperate the men from the boys. Guys that run all the new dozers don't know how lucky they are and how easy they got it. My first dozer was a manual D6 tractor with a straight blade (no tilt on that baby). Think I'm old and past it talking about manual dozers? Only a youngen' only just outta short pants (32ish that is). Hydro should stay strictly on tracked shovels only, thats where it seems to really work. For some reason a track shovels seems to be able to put the power down.
Hydros belong on skid loaders and combines I started out on a D7 3T and the direct drive is the best at getting power to the ground but dozers have come a long way since 1950 and I get to spend my days in a D6R now and I am nowhere near as tired after a long day of work as I used to be. To get down to torque converter vs. hydro we have a Deere 850J that is pretty comparable on paper to a 6r but that is where the comparison stops. We put a chip on the J that gives 20% more power and The 6R and 6T will still walk away from the J. The Hydro transmission is loud they just have a noise of there own. We have tried lots of things to try to improve the efficiency of the J, changed transmission settings, Put some weight on and taken some weight off, nothing has made much difference. The fuel consumption is very noticeable also, building terraces the R and T will burn 7.5 to 8 gph and the J will burn 8.5 to 10 gph. I don’t want this thread to turn out to be a cat vs. Deere argument so I will ad some good points to the deere. Umm o yea it is more maneuverable will out turn a cat and a turn happy operator will wear out a undercarriage in a lot less time than a ds machine. But it is nice in the brush and fence rows. Like I said they belong in a skid loaders and combines. I cant say much about smaller machines or brands other than deere because I haven’t been around them. Just one more thing we noticed about the chip it didn’t hurt the fuel consumption in fact I think it helped a bit.
There is nothing wrong with Hydro's. I find them much easier to run and much easier to train noobies on. Howebe the biggest downfall to hydrostat machines is the loss of power, I heard one time that you loose 60% of engine power to the ground through a total hydro machine as apposed to 10% through a gear/clutch so I would guess that a TC machine would be 30% ????? I am going off of memory on the numbers so they may not be totally accurate but they are close. Deere and CNH and Deutz have came out with a variable speed trans, it operates with a planetary gear set and it adjust how fast or slow the planet gears turn in order to adjust ground speed. it is truly the single neatest option I have ever been around it's just too bad that it's a $10-$20 thousand dollar option With all of that being said, I believe on large machines(D7 size +) you may see the variable speed trans before you see hydros, you have to think that it would have been a lot cheaper for CaT to develop a larger hydro system rather than to develop a whole new electric dozer for the D7E. Pj
Variable trans? Just wonder what you mean by "variable transmission"? Cat and Komatsu now have multible speed options on their machines, e.g. the D6N has a traditional 3 speed power shift trans with 2 extra "soft" gears, the extra speeds being made by reducing engine speed rather than with mechanical gears. And then of course there are the hydrostatics with infinite speeds. Many hyd´s nowadays have 3 preset speeds, it seems to mimic the trad. 3 speed tq´s. I must say I like the tq´s you can really feather with the delelarator.
I saw one of those variable transmissions tore apart the other day. It was something else. It was out of a fendt tractor, a little over 100 hp. Fendt was the first to market this sort of tranny that i know of. It was likely thought of years ago, but they went to market with it first. Anyway, the best way to describe the concept is to understand how a planetary gear set works. Its hard to describe if you don't already know, but the gist of it is the gearset has 3 inputs/outputs. Differently, it has 1 input shaft and 2 outputs, or vice versa. The idea someone came up with is hook the input shaft to the engine, an output shaft to the final drive, and the third shaft to a hydraulic motor. The output shaft speed is a function of the speed of the other 2 shafts, and you use the variable speed hydraulic motor to give you a variable speed output from a fixed engine speed. That is the basics. Then you can throw in some speed and torque sensors, a fuel map, and a computer, and you can get a seriously cool tranny that manages fuel use while meeting the power and torque needs at the final drive. It really is pretty cool. CNH, Deere, Agco all have thier own variation on this theme. New combines have it as well, as it is replacing hydrostatic drives. In more detail, looking at that transmission torn apart, Fendt has used a hydrostatic transmission to control that third variable speed shaft. Makes a lot of sense once you see it. The whole thing is self contained in a neat little package the size of a medium cardboard box I'm sure somewhere on the net there is a neat little graphic to make this a lot clearer.
This variable transmission sounds like an ingenious idea. Only, it must cost some extra energy to turn that hydraulic motor. And would possibly add some extra noise. Probably better suited to larger tractors than hydrostatics though.
see that's the neet thing about the Variable trans, it is 100% gear drive, the input shaft of the trans spins the ring gear and there is a hydraulic motor (very small) that controlls how fast the planet gears spin, and then the tractor is driven off the sun gear.......viola variable speed . even reverse if needed. hope that decription was accurate and clears it up. also there is no more % of HP loss than a normal clutch/gear trans Deere calls it the IVT (infinately variable transmission) Pj