420 track

[bulldozerman]

How tight should my tracks be for my 420c ?

[Lavoy]

About an inch and a half of sag give or take.
Lavoy

[TI420]

I guess I'll throw my 2 cents in even though Lavoy is the expert and has the most experience - my personal experience is "it depends"...

I did some repair work this Summer and adjusted the tracks to about one inch of sag and went off for a test drive... Didn't get very far and threw one track off the bottom rollers on uneven ground.

It seems that if your pins and bushings are very worn (I'm leading the pack in this regard..), then you get what is called "the snake" - which means that if you lay the track out on the ground, you can curve it side to side because there is so much slop in the bushings. When this is the case, it seems that tighter is better - and I have heard guys on here say, "as tight as you can get them" - but that makes me afraid of breaking something - like the curved upper idler bracket...

What I ended up with is getting them pretty tight without much sag at all, but making sure that at rest, my tensioner springs are not at all compressed, and it makes me feel a little better also if I can lift thr track off the upper idler with my hands - althought not too easily...

In the end, roller and pin and bushing wear seems to be the real key versus tension if you are starting to throw tracks. I can see where if i DID NOT have "the snake", it would be a heck of alot harder for my track to wander off the bottom rollers, because when you are moving around, it doesn't seem to take too much effort for the tensioner springs to get pushed in - even though at rest it seems like it would take alot...

That's kind of a ramble, but maybe helps to lend some insight - I thought tightening would be my solution, but with the existence of "the snake", I seem to have a "1st gear crawler" until new pins and bushings come along...

Hope this helps! - Chuck

[Tigerhaze]

I've had to keep my 2010 tracks a little tighter than the book specs for the reasons that TI420 described; I have a really worn undercarriage and got tired of reattaching thrown tracks.

[Ray III]

About an inch and a half of sag give or take.
Lavoy

That is what my operator's manual says for 4 roller tracks, but for 5 roller tracks it's only 1/2" to 3/4" of sag on each side of the upper roller because the upper roller reduces the span and consequently the amount of droop with a given tension.

[Lavoy]

I shoud have qualified my post sorry about that. One other consideration is that there are two different upper idler supports, the older style that is curved, and the later straight style. With the straight style, the sag will not be uniform.
Lavoy