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John Burleson Hyde County, North Carolina | Some bulldozers have tracks that run the length on the dozer, others have triangled shaped tracks. Why is this? Pros and cons? Thanks. |
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Centralia, MO | Caterpillar introduced the high drive sprocket because it allows the use of a planetary final drive with the output shaft in line with the differential rather than having to use gearing to drop the elevation of the output down to the lower drive sprocket. The planetary final drive is much stronger. |
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NW Washington | I think the high drive makes for a more efficient drive line design and gets the drive sprocket out of the dirt. This also permit the track be on the ground further in the rear for better traction an balance.
BTW Clectrac had a little high drive crawler in about 1920 and there have been others along the way.
http://cletrac.org/pages/model/pic-F.html |
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Wallis, TX | Agree with JDflyer & I'll add the length is longer which means less revolutions per mile, in theory longer track life. Others will say the pin is moving around the rear roller under a load which will shorten track life. Take your pick on which you believe. |
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Centralia, MO | I didn't mean to imply that Cat invented the idea. Only that when they changed their line to this design that was their rationale. |
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Agent Orange: Friendly fire that keeps on burning. | Back in the days of the flat track crawlers, you needed an ag model crawler if you were going to use it for farming. A different model was required for dozer work. Unless you paid attention, it was hard to see the difference until you removed the dozer and tried to farm with a dozer tractor. The construction machine was way back heavy because it didn't have the blade to counter balance it and the down force from the drawbar load made it even worse. Likewise, if you happened to find an ag CAT and think you could fit it with a blade, you'd be disappointed also because then you'd have a machine that was nose heavy. This balance was determined by how far ahead or back the track was. As you might expect, the machine had to be special built to change the balance for different applications. The high drive machines were easier to adapt to differing balance requirements. While still no trivial task, all you really need is a different track frame and mounting point and you don't need to change the chassis like was required on the flat track machines.
As has been mentioned, the planetary finals on the high drives are much more robust than the old bull gear and pinions that were found on the flat track machines. While I guess you could mount a planetary down at ground level, it would take more gears to accomplish it than you need when just mounting the drive up high.
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Extreme SW Minnesota Iowa border | My favorite part of the high tracks is they lower rear idler is just an idler. Have seen a few cat finals killed by backing into hard things all day long. The shock is not directly transmitted to the drive gear. |
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WC Iowa | A nice benefit to the high track design is easier clean out in the winter time. Alot more space clean the mud away from the idlers so it only takes a few min instead of the 10-15 or so it takes on our deere machines. i cant say there are many cons other than longer rails and more pads to pay for when you replace them. Oddly enough when cat came out with their new D7E they went back to flat track design, wish they would make a D6 model like it. |
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Agent Orange: Friendly fire that keeps on burning. | You can put the drive where it needs to be and just run wires to it.
If you look closely at the photos of the drivetrain on that machine, you'll notice something else missing -- no transmission needed and you have stepless speed ratios in either forward or reverse. |
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Brazilton KS | Kinda like a Deere 750 or 850, or a 1550 Case, or a Liebher. |
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Sac & Story county IA | The D8 13A that I put the 8V-71T in is so much lighter than it was with the 6 cylinder. The machine will spin way more now. Way different machine balance. Not so front heavy. I like it better now.
I got the feeling those were made more for scraper pulling than dozer work.
The low torque power of the 2 cycle is easier on the driveline than the Cat engine. I hope that gives me more years of running with wore out components. |
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| i love my liebherr |
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Difference between bulldozer tracks?
