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
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.
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.
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))
I saw this awhile ago and was wondering the reasoning behind a sprocket looking idler??
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.
Help keep track from slipping off of idler And track sliding on idler if clogged with dirt or frozen?
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.
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. HeavyEquipmentForums
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.
I get the impression that the D6N that’s the subject of the thread in question may be somewhat of a Bitza....
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?
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.
EDIT: Cat was playing caught up to Komatsu? Rotating Bushings, new ideal 1967 https://patents.google.com/patent/US3492054A/en
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.
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.
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.
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
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?
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?
CMark, Thanks for the post If you look at the D6T in the video you will notice it has the relieved tread on all the idlers. Problem I had with the relieved tread is that there isn't a generally accepted way to measure the wear on it. I haven't been with the Cat dealer in a couple of years now so haven't had direct access to past histories of how it has been working. The operator on the machine in the video said that machine hadn't had any undercarriage problems in the approximately 3,700 hours on the machine. They did have problems on a prior "R" model. I thought this machine was showing more wear than I would have expected for that amount of hours but I didn't measure it to make sure. This is a dump site and that machine pushes spoil from excavations in the greater Seattle area. Do you know if all the dozers got the relieved idlers?
Measuring the relieved tread idlers is the same as standard center tread. There should be a machined area on one side of the idler which is used as a reference for the tread height. I don't know for sure if the relieved tread idlers are now standard system one fitment, but I suspect they may be.
They seem to be standard on the D6T. I don't know about the rest. I haven't seen any literature from Cat showing where a reference mark might be. The front idlers would be rough to find that mark unless it was cut all the way around the wheel. What is your experience with System 1?
My experience with S1 is limited. I got involved to a degree when it first came out and, as we know, had some problems leading to us converting some machines back to conventional U/C. However the majority of our customers at the moment are D8 and bigger. We have a couple of newish track loaders on our patch with S1 and I haven't heard any real complaints and they seem to be holding up OK as far as wear goes.
I guess it might be better to find out from anyone else who might be running the new stuff how it is doing. So if anyone has any experience with it or any more information, please feel free to post.
Here's the official word on measuring centre tread idlers. The diagram referenced is the one I posted earlier.
talking with guys running the new stuff, they are very finicky on track adjustment and clean out, when they do fail prematurely, its been ran to tight , to loose, or not cleaned properly. they are fine for a guy running under warranty but when it runs out better have cat man on speed dial, you will have a hard time tearing into it without the special cat tooling. it looks to me like they put all the wear on the pins and less on the rail,i run all rail assemblies to destruction no pin turns, a waste of money in my eyes.just wish they made the high track with a bigger front and back idler, rails wear out quick touching a small spot on small idlers.
Idlers, rollers and sprocket from a D6N i’ve Just been working on. S1. Tell me what you think.
I think it's ***ked …….. Track & carrier rollers have taken a pounding. Idlers not so much unless they were replaced in between the last U/C overhaul and now. Front & rear idlers pretty much the same wear %..? Working conditions..?
I think that’s a fair assessment, Nige. 5500 hrs, original idlers front and rear, virtually original profile and virtually no wear on bearings, original sprocket segments not far from original profile, and the rollers speak for themselves. Wish I’d thought to take pictures of the box links and rails. They had some scolloping but Barely measurable with feelers and straight edge, but the wear on the rail edges was horrendous. 90% of its life has been on topsoil, 10% on sand. Quite a bit of batter work. 12 box links were shot, the others good enough to keep working. This is the trouble with S1, you can’t rework a box link, only replace. Can you imagine running new rails on those idlers, or worn rails to new rollers? Anything besides new chains with new rollers is a bodge.
I don't think I would have any trouble running another set of chains on that stuff. Did you get those roller measured. It would have been nice to see how far down the roller flanges were on the track pins. Measuring those front idlers is what I was talking about in an earlier post. You would be hard pressed to get some kind of calipers on there now, let alone with the chains and pads in the way. The real problem though is that you aren't getting even wear rates across all the components. A percentage of wear on those rollers might give us a feel of how much money is getting thrown away when you install all new. Thanks for the photos and the post!
I’d put new chains on the idlers and sprockets, but certainly not on the rollers. As you say, John, the wear is uneven, and at UKP £12000 per chain I wouldn’t take the risk. The biggest enemy of S1 IMHO is anything forcing the chains to twist, be it wide grousers or unevenly worn rollers. I think on a D3 or 4 and the right application, such as spreading and minimal side-sloping a set of S1 would last 7 or 8000 hours. Trouble is those applications aren’t too common. I’d also be interested to know how they survive on a 953 over the long haul. Any takers?
I'm beginning to think that to get the most out of S1 over the long haul, you are going to have to store used until other used get to where it matches to get a decent runout. Do you think you can get away with just rollers and chains then? To compare your Pounds to Dollars, a pair of chains is over $28,000 with out the pad swap. I might be a little sore about only getting 4,000 hours on working easy material.
We could get away with rollers and chains on this one, and yes, if you had a few machines the same pitch and the puller to do the job, you could mix and match old chains. Finning reckon on 4 man-hours a link. Your prices come out a bit cheaper, but over there you have competition between dealers, we only have Finning Cat.