420 tracks to 350 track links question

[notmeu]

I am in the process of changing my very worn out 420, 5 roller tracks, pads and sprockets over to a 350. My question is the 420 parts book shows that there is 35 pads for my crawler, which is what I have on my crawler. The new chain that they want to sell me is a 36 pad track for a 5 roller 350. Am I missing something here? Is the 350 outside diameter different than the 420's?

[jtrichard]

4 roller 350 uses 32 links 5 roller 350 uses 36 links... when you use the same rails on a 2010 you have to add 3 more links than a 350 has ..in your case you need to remove one link and pad from the 36 link chain

[notmeu]

That's what I was thinking but most of the dealers I talked to thought I had a pad taken out at one time,or the chain was shortened. But I knew my 420 had 35 pads!

[jtrichard]

Lavoy would know better but on a 420 i think some had one more link

[notmeu]

I know the pin spacing is the same between the 420 and the 350. From what I gathered from other posts, the bushing outside diameter is larger on the 350. I just never knew what the length difference is between the two.

[Ray III]

420s came in 4 roller, 5 roller, and 5 roller with oversize idler wheel. I think the latter has 36 links per track.

It is possible that a link was removed to keep your worn track in service, so you should determine what size idler you have.

[Lavoy]

4 roller standard idler is 31, oversize is 32, 5 roller is 35, only came with oversize idler.
The pitch is the same with both tracks, so whatever link count you are supposed to have with the old rails is what you will need with the 350 rails.
Lavoy

[Ray III]

My mistake with the oversize idler, I went out and did count 35 pads on one of my tracks.

[gregjo1948]

If the pin spacing is the same 420--350 pins but, the OD is larger on the 350 bushings, does that mean you would have to change the sprockets to accommodate the difference? Thanks, gregjo1948

[Lavoy]

Correct, you need to change the sprockets to match the diameter of the bushings on the rails you are running. If not, greatly accelerated sprocket and bushing wear will occur.
Lavoy

[notmeu]

Most places that sell aftermarket chain has sprocket rims, their about 125.00. The rim is the outer edge of the sprocket where you just torch off the outer 2-1/2" or so of the 420 teeth then weld on the 350 rim.

[RacinJason]

OK Guys, here's a good one. Maybe someone here will recognize this tractor. Anyway, my newly acquired 420C has a 420 track on one side and a 350 on the other. I forgot to count the links when I was in ME, but think there is 1 more on one side than the other. Won't be going back for another month to check. I'm sure I can come up with a matched pair, but am in no rush. Just hope the Porkys leave my hoses alone. Shot 3 so far. LOL