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| D9G |
Viewed here we see a photo of a Caterpillar D9G taken about 1975. This was not our machine, but it was clearly the biggest Cat of the day. Cat, of course, is a trademark of Caterpillar, who is one of the worlds largest manufacturers of heavy equipment. Intended for jobs where serious Cat work was needed, every logger has dreamed of owning one, but few have. The Cat D9 has for many years been the staple of bulldozers against which other machines are judged. Dozers of this size are king in a rock quarry (where bigger is better) but like the even larger Fiat Allis 31 featured at the top of this page, the machines are clumsy and should not be your first choice for landscaping your front yard.
This D9G is no match for the FIAT ALLIS 31 featured at the top of this page, but it is close, actually about half a size class smaller. The FA31 hadn't been invented yet when this machine was in its prime. Careful observers will note that for quite a few years now most Cat brand dozers have been of the High Drive variety in which the drive sprocket is located somewhat forward and above the track line creating a triangular shaped track. This simplifies the logistics of drive train design and improves ground clearance because final drive gears don't need to stick down to within a few inches of the ground, but compounds issues of track wear as the tracks have to bend 3 times for every revolution of the track instead of 2. To compensate for this problem Cat included the sealed and lubricated tracks which is quite a change from the traditional tracks that were just steel on steel linkages. Nevertheless, tracks cost serious money are represent a major operating expense item on any track machine.
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| D9N |
Cat has a way of evolving their models. They have been making D9 dozers since the 1950's but not all D9's are equal. As they have changed them the letter following the D9 has been incremented. The current model is up to about a D9R, but this 1988 model will give you a feeling for what the the current dozers look like. Horsepower creep means that every new model is a little bigger and a little more powerful than the previous model. Cat has been using this high drive design for about 20 years now, but no one else has emulated it.