Yair . . . Over the years I guess we have all seen the odd track put on the "wrong way" . . .I think tctractors spotted one on this board recently. So if they were left to run like that what is the effect? An old bloke (even older than me) told me recently that a tanksinker way out in the Territory used to fit new tracks back to front and, when they wore to some rule of thumb dimension he'd turn them and run them to destruction the "Right Way". Due to freight costs it was never worth sending chains out to the coast to turn pins and bushes and he reckoned he got more hours by doing this. Anyone heard of that before, because its a new one on me and I just can't get my head around it. I would add that many of that tractors hours would be walking job to job, not working hard but very abrasive conditions. Cheers.
Sounds like a cunning plan Scrub. Think I'll try it with my next set.
There has been posts on here before about running tracks on backwards some time ago, but when a track is on correctly and going fwd the root of the tooth does not have to rotate against the bush a 1/3 of a turn, going in reverse the bush does a 1/3 of a turn against the sprocket while under load which scollops out the tooth on the reverse side which is very noticeable in fast reverse operations. When the chains are on backwards the rotation against the tooth while under load is happening when going fwd, also the grousers are self cleaning when on the right way due to the way grouser lug pulls out of the ground as it goes around the sprocket, makes a big difference in traction in some soil conditions. One post on here somewhere has a good example of how it all works.
Have heard of a couple around, think one was for a bridge company, that run them backwards. They do it so they can back out of mud better. Tracks on the right way clean best going forward. So putting them on backwards gives a bit less traction going forward and a bit more backing out.
Scrub, yar shoulda told he's dreamin. The tension against the pin and bush is the same what ever way they are put on. Next time you see your mate tell him how you roll start the motor on a towed vibrating roller.
Yair . . . Tones. I think the theory was that that it gave some of the advantages of turning pins and bushes without actually doing it. I can get my head around that part. What I can't figure is what are the dynamics of running the tracks backwards in the first place. Is there accelerated wear? When they were turned the sprocket would be thrusting on the opposite side of the bushes and so obviously the same the same thing with bush clearance on the pins. What I can't figure is what are the dynamics of running the tracks backwards in the first place. Apparently it was best to run them backwards while they were new and "tight" and get (say) fifteen hundred hours out of and then turn them to the correct orientation and theoretically pin clearance in the bush and sprocket tooth to bush clearance would still be close to original values and they would run to destruction having utilised some of the "meat" on the "back side" of the pins and bushes . . . surfaces that never would have been in play had they been run to destruction with out the turn. There has to be some-thing wrong here. Cheers.
Brain twisters... there may be some slight advantage in terms of bushing wear on the outside, but no matter which way you put the chain on, when your pulling in either forward or reverse, the same side of the pin meets the same side of the bushing, the chain is trying to stretch out. Now if you have pipelayers say or some such special critter, maybe you do all your pulling in reverse and it would make sense from a traction point of view. In terms of internal wear on an oval track machine, when going forward the track has only one loaded pin/bushing joint that turns under load at a time, where the chain meets the sprocket. In reverse it's three places, top of sprocket, top of idler, bottom of idler, so with a dry chain you get three times as much internal wear backing up as going forward. Sealed and lubed chains help a lot, and of course with the high drives you have two idlers so you always have three joints operating under load when moving in either direction, thus CAT's endless search for tracks that will hold up.
he's not talking about running machine in reverse. he's saying putting rail's on backwards on track frames. In theory I understand it I have seen the local track shop flunkeys do it before . but when you turned them around you should problely put new sprockets on because they wear in or mate in to the bushings as they wear
Been to a few elevated final drive tractors over the years where the customer was complaining about rough ride. Tracks on back to front will do it most times, especially if your bogie pads are down a bit. It allows the front idler to "drop" slightly as the flat of the pad meets the vertical and then when the lug hits the ground, this causes the idler to bounce up suddenly and sends this impact back through the track frame.
Yair . . . Thanks for replies but nothing here conclusive. I will put it another way . . . if the tracks were allowed to run "back to front" to destruction would they yield less hours that if fitted correctly and if so why? clintm You are probably right with that. The thing is though back then walking gear maintenance was a whole different ballgame. You could cut the old sprocket rims off and fit weld ons but for the most part these blokes built up sprockets, idlers and rollers with weld and these components did many thousands of hours. As I have mentioned on here before some of the first welding I ever did was building up idlers and rollers in place. With rollers we would rig up a syphon from a 44 gallon drum on the truck to dribble on the roller to do a bit of cooling. They were greased twice a day with axle grease so cooking seals was less of an issue. . . in fact I don't even know what those early rollers had in there for seals. Some blokes also built up track links although by the late fifties' this was going out. I mention this so folks can maybe understand the thought process involved with maintenance decisions in remote areas. Labour was cheap and silly buggers like me thought nothing of working all night adding a bit of meat to an idler. It was a lot easier and cheaper to transport a fifty pound box of electrodes over hundreds of miles of corrugated roads than it was a set of rollers or an idler. A feller with a D6 wandering around thousands of square miles of country couldn't justify having a spare set of tracks and I can understand the plan to extend the life any way they could. It's just that I have never heard of this tracks on backwards caper and it's got me beat . . . if it worked and you could get a few more hours why did it not become more common? I should add that these were all scoop (scraper) tractors, they walked many hundreds of miles and seldom saw much reverse. Cheers.
Giday scrub, R.D.GO13 is dead right what he said about the bushing doing a 1/3 of a turn in the sprocket. With the chains on the right way the pin does the turn , where as back the front the bushing would turn in the sprocket.( does that make sense?) with our sandy coastal soils here would accelerate wear on the bushings I would think? Bill.
Hi Scrub Puller ,I think the main reason against runing tracks on backwards is the design of the grousers.The single bar on a dozer pad is mounted at the leading edge end of the pad. The leading edge is tucked under the trailing edge on the pad that is in front of it when driving forward. This is the direction of load when pushing or pulling forward.This makes a flat contact surface with the ground and not allowing stones and dirt to get forced between the pads. In reverse this is the opposite hence contributing to the increased wear associated with backing up. Hope that makes sense .
Yair . . . D8 Ump and all other folks who commented . . . every thing you have mentioned pretty much makes sense. I am still intrigued though by the fact that this one, probably uneducated old bushman came up with a unconventional method of getting (perhaps) a bit more time out of his tracks. I mean to say, if fitted normally his tracks ran to destruction, the bushes were breaking up and he was running on the pins in (say) five thousand hours . . . if he could put even a thousand hours of wear on the back side of the bushes and pins by running them backwards (under his circumstances) it would be very much worth while. Incidentally while we are talking walking gear . . . I mentioned upthread that track rails used to be rebuilt out in the bush with weld. In the sixty's and seventy's it was normal practice here to have rails rebuilt with submerged arc at the track shop. I think working beach sand with D9G's we used to specify about twenty percent extra height. Cheers.
Hi Scrub Puller,I think we have become a very throw away society and lost a lot of resourceful skills of the older generation.The older tractors could run the tracks to total destruction as l was advised to do when I started out. The modern high performance flying machines perhaps suffer other damage by running to destruction.Labour now is more expensive than just buying new tracks. Cheers Ump
on the subject of tracks , this came up on another forum this week , if you have one track shorter than the other will it still go straight or will it constantly turn one way :Banghead
If you look into the early History of Track Type Tractors, the single bar grouser was towards the rear section of the plate, the CAT 60 tractors can still be seen sporting this type of plate, it was found to carry to much dirt around with it also making dust fly, the grouser was moved to the front section on the plate to aid cleaning also to reduce the amount of dirt travelling around with the track resulting in less dust, it is common to see the CAT 60 with the tracks fitted incorrectly due to this rear set position of the grouser, we have a well tarted up tractor in the U.K. owned by a very well heeled gent that has the tracks fitted backwards, as you would expect I did sort of bring this up sweetly, to be told to "**** Off" you idiot, so this is the low level I have managed to attain, the man knows Jack **** about CAT's but he is very well coined, he does not need to run his tracks backwards as he could probably buy Berco without having a Sub off a Bank, the tractor just looks wrong with chains facing South. tctractors
Yair . . . Good one tctractors. I have been told a few times myself for various home truths rendered. (big grin) I don't suppose the chariot with the southward tracks does enough hours to get any meaningful numbers on hours run and/or wear patterns? You are dead right about the dust . . . clatter a tractor backwards through food deep ash or talcum powder bulldust and it puts more dust into the air than when going forward at the same speed. Cheers.
D4C 24a on the short track with the long track rubbish, if this is on a standard Direct Drive or Power Shift transmission the answer is simple, the F/Drives turn exactly the same amount so the tractor will cover exactly the same distance in a straight direction, the focus being on the fact that the sprockets are linked solid with each other, on a drive that is hydraulic the loading factor will change due to frictional loss most probably resulting in 1 track travelling faster than the other, some forum sites ague about crap to much. Graham Spring is coming, a good looking bit of Sun today, its like a fresh start I Love it tctractors
yes mate it certainly is , hope this is a sign of things to come
If you'd worked for some of the East Anglia/East Midlands outfits I've been with, you'd already know the answer.