Can any of you dozer guys tell me why some hi track models have an upper roller and why some do not. And also was cat the only maker of hi track dozers. I seem to remember a very large hi track made by ACCO, possibly biggest dozer ever made.
i know the d11 the company i work for came without one, we ran it for awhile maybe 6 months, before they got one. as for the acco dozer there are some good pics somewhere on here already.
I've never seen one if a idler on top if thats what you mean. IIRC cat a patent out on there high track design just like there cushion hitches on there scraps that they renew. There is a cat hi-track knock off though it has been posted here before.
This is the link to the thread with the ACCO in it the second post has the link to the galleries.
The upper roller helps prevent the "whipping" of the tracks, especially when in reverse, and this helps to increase the pin life. It also helps keep the tracks from sagging onto the roller frame, wearing grooves behind the idler, while shaving life from the rails when they rub there. I have heard estimates of 10 to 15% increase in track life due to the top roller. I have retrofitted all of my larger tractors that did not originally have them.
Upper roller not idler, that would be a strange idea:beatsme
Why Top Carrier roller ? The Hi-tracks originally did not have the top carrier roller. Then it became apparent , the need for one, as JDOFMEMI, has outlined. Cat made it an option, to correct the track slap, as I call it. then later, standard. The track slap was severe in hi speed reverse, and in trying to grade in a turn. So field usage defined problems not foreseen , in the engineering phase. Refinements as time progress's.
Upper carrier rollers in high sprocket dozers. Hi, Northart. The original converted D9G high sprocket test-bed machine had one top carrier roller on each side and the first 2 prototypes, D10X1 and D10X2 had TWO top carrier rollers on each side. The next 2 prototypes -X3 and -X4 did not have any top carrier rollers and neither did the next 10 D10 'pilot' machines or the production run D10's, 84W and 76X series. Why Cat's design engineers on the D10 project figured they didn't them is beyond me 'cos the first thing I thought about when I saw the way those tracks whipped up and down was how much it must increase pin and bush wear. But what would I know? I'm just a mug operator. LOL.
Ya I forgot that the early ones didn't have rollers from the factory, but I don't think I have seen to many that weren't retrofitted.