Undercarriage, New Technology

John C. · Sep 15, 2019

I've completed the next video on track type undercarriage. I'm sure there is plenty of info I've missed so feel free to let me know about it. I think I've kind of exhausted my knowledge on this subject for now so let me know if there is anything you would like to see done in the future. If it works for you, a like here and on YouTube would certainly be appreciated. A subscription to my channel would be nice as well.

Undercarriage, New Technology

StanRUS · Sep 16, 2019

John C,
Enjoyed your informative videos.
One biggie contributing to shortened undergear life, running tracks too tight!

Cat, Inc. SystemOne warranty 4yrs or 6,000hrs.

John C. · Sep 16, 2019

That seems to be the company line up here. I've seen and heard on several occasions where a product support guy or a mechanic gets to the site of a failed link and spouts out that the undercarriage was run too tight.

Someone should let the local dealer know about that warranty. They haven't honored it up here in three for four years that I know of.

Sanya_Promstal · Sep 18, 2019

Many times I heard from the "old generation" of owners of equipment that the quality of the undercarriage has become worse. And we are talking about new technologies))

alaskaforby4 · Sep 18, 2019

I saw this awhile ago and was wondering the reasoning behind a sprocket looking idler??

John C. · Sep 18, 2019

Thank you for posting that. I've heard about those but not seen one yet. I was told yesterday that there is a machine with them in the Tukwila yard. It's called a cupped idler and the word I got from a sales guy was that they were supposed to be quieter. I don't believe that for a second. About a year ago I saw one with bumps that fit in between the bushings and was wondering about those. I didn't get photos of it.
I'm going to guess that it has something to do with the packing issue.

Bls repair · Sep 18, 2019

Help keep track from slipping off of idler And track sliding on idler if clogged with dirt or frozen?

walkerv · Sep 18, 2019

John C. said:
That seems to be the company line up here. I've seen and heard on several occasions where a product support guy or a mechanic gets to the site of a failed link and spouts out that the undercarriage was run too tight.

Someone should let the local dealer know about that warranty. They haven't honored it up here in three for four years that I know of.

I have had a set of system one tracks on a d6n replaced under warranty a few years ago , it is prorated warranty though. They had about 4000 hrs on them 8900hrs on machine , more then 13 failed joints on each side i think i got 30% percent of on the new chains. I replaced all of the original bottom rollers at that time front wheels already replaced shortly before tracks due to one breaking.

Nige · Sep 18, 2019

The D6N in this thread has got at least one fitted. They appear to be unique to SystemOne undercarriage. See post #21 on Page 2.
https://www.heavyequipmentforums.com/threads/cat-d6n-lgp-2006.78587/

Cmark · Sep 18, 2019

They're called Sprocketed center tread idlers. To the best of my knowledge only factory fitted to the D6K. Why they are on a 6N I don't know.

Nige · Sep 18, 2019

I get the impression that the D6N that’s the subject of the thread in question may be somewhat of a Bitza....

John C. · Sep 19, 2019

Thinking some more about those sprocketed idlers and the comment about the track sliding on the idler made me wonder if the wheel at times doesn't turn when the tracks are still turning. In that case the bushings would be turning as the chains move over the wheel. I'm thinking the bushings are only supposed to turn slightly as they engage and disengage the sprocket teeth. They are not designed to turn over the two thirds of the circumference of the idler wheels. Put the cups in the wheel and force it to turn might be the idea.

I wonder why Cat went to that style of idler instead of using a conventional one like Komatsu does?

ih100 · Sep 19, 2019

John, there was a concern early on that the bushes could roll round the sprocket as you describe, which was the idea behind the scolloped idler. It did turn out to be a non-issue which is why you don’t see them fitted across the board now. Don’t know if you can have scolloped as a special order or not. I saw one 963 with scolloped idlers, and one with a shouldered conventional idler on S1. Neither were standard machines though.

Are the scolloped idlers standard on the 6K? I’ve seen a couple of K’s with plain idlers.

StanRUS · Sep 19, 2019

John C. said:
I wonder why Cat went to that style of idler instead of using a conventional one like Komatsu does?

EDIT:
Cat was playing caught up to Komatsu?
Rotating Bushings, new ideal 1967
https://patents.google.com/patent/US3492054A/en

John C. · Sep 19, 2019

That's not what I said. My question is why is it necessary for the bushings to ride directly on the idlers when the Komatsu chains ride on conventional idlers.

Cmark · Sep 19, 2019

One of the ideas behind the center tread idler is to prevent scalloping of the links and so give longer chain life and a smoother ride.

John C. · Sep 19, 2019

I agree on that point. A couple of points I've seen on that are first of all the rails on the links have the wider section on both the outside and inside links which can ride on a flanged idler. Also if you look at the Komatsu idlers in the video you will see the wide sections ride perfectly on the flanges of the idler. There is more surface area to mitigate the scalloping. I would think that on Cat's oval track machines that the center tread idler would be no advantage at all.

StanRUS · Sep 20, 2019

John C. said:
That's not what I said. My question is why is it necessary for the bushings to ride directly on the idlers when the Komatsu chains ride on conventional idlers.

John C. said:
There is more surface area to mitigate the scalloping. I would think that on Cat's oval track machines that the center tread idler would be no advantage at all.

Improved Primary Guiding and to prevent scalloping! Ref: photos @ right side, upper photo Sys1 with conventional idler. Lower photo Sys1, same machine, equal hours and center guided idler
https://caterpillar.scene7.com/is/content/Caterpillar/C10507958

John C. · Sep 20, 2019

The problem I have with what Cat is saying is that the failure point is now on the bushings. All the System 1 undercarriage I have measured have a ton of rail left but the chains are replaced because of too many leaking joints. On standard chains, the most expensive component is the chain links. So with System 1 you are throwing away unused value in the links for a dubious savings in vibration and noise?

Cmark · Sep 20, 2019

Cat recognised leaking seals on the rotating bushings as a problem some time ago and as a consequence brought out the relieved tread idler. Have you noticed any difference with these?

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