40C wrong track installed?

[petehdgs]

I have a question about the track on my 40C. This track has 30 links per side instead of 31 and has track shoes are riveted onto the track links with 4 rivets on a six hole pattern.

I have been investigating putting rubber track shoes on this tractor so it can be run on the pavement and be used in parades. The people at MWEsales in ohio have a system and might possibly be able to supply bolt-on rubber track pads or a complete track if I were interested. They specifically asked me to measure the track and roller frame components to see if they could help.

I found an interesting dilemma: The track pitch itself has a pin-to-pin distance of 6 inches, but the sprocket pitch measures 5.77 and at best is 5.87. I am wondering if this is the way it is supposed to be or if I have the wrong track installed?

Sprocket pitch measures 5.77 to 5.87 depending on how you look at it.
Valley to valley, adding 1/8 for the odd tooth offset, multplying by Pi, dividing by 23 teeth and multiplying by two: 19.5 +.0.125 + 1.5 = pin center dia of 21.125 x 3.1416 = 66.366 / 23 x 2 = 5.7709
Point to point: 21.25 + 0.25 = 21.5 x 3.1416 = 67.544 / 23 x 2 = 5.8734
Neither of these is 6 inches. I wonder if I have the wrong track installed on the tractor?


All the photos I have seen show track shoes bolted on with two bolts through the center of the track links, but this track has a six hole pattern on track link winged flanges, and the shoes are riveted to the flanges with 4 half-inch rivets leaving the ceter hole open. I wonder if this is a track from a different machine, or an optional track, or the wrong track for this tractor.

This track is supposed to have had pins and bushings rotated and is supposed to be at 1/2 life on them. So I carefully measured the bushing OD at 1.5 inches and used a log binder to pull in the slack on the chain and remeasured. There is less than 1/4 inch takeup in six track linnks the way I measured, and I could be wrong as I measured on the top side.

Got any ideas?

[JimAnderson]

Pete,
The 6 inch pitch is correct for that vintage JD track.The 1.5 inch
measurement is correct for 40c bushings.Really worn sprockets will
throw off what you have left to determine their pitch. The bushing would
contact the gullet at a greater radius with a new sprocket.
The only machines that I have seen with rivetted pads are Olivers
but never on a Deere.With a fifty year old machine who knows what a
a creative tinkerer has done to get one more job or season out of the
machine.Could you post a picture of the tracks on your crawler?
Luck JimAnderson

[Lavoy]

6" pitch and riveted is Oliver tracks, I have seen several Deere crawlers with Oliver tracks on them. Hard as hell on sprockets, Deere pitch is 5.75 or 23" across 4 links, so the Oliver tracks don't sit in the Deere sprockets, and really tend to open them up if run long term.
Lavoy

[doc40c]

hi Pete, my 40c also had riveted pads on it when I first got it. We assumed they were Oliver but when I talked to a dealer for old Oliver crawlers he informed me that mine were Case. Lavoy is right, the longer pitch is hard on the sprockets if used for a long time. Good luck on your project! Randy from Michigan.

[petehdgs]

So I had the idea that the track link bushing diameter affects the sprocket pitch, and making a dummy bushing will test this theory. I worked out that 2.25 in OD track bushing will make the sprocket pitch 5.976 in or 151.787 mm. That is pretty close to an exact match. I took a compass, a paper plate and scissors and cut a perfect circle 2.25 in diameter and placed it in the sprocket valley. A PERFECT FIT. Now the real question is do you want a perfect fit, or do you want an imperfect fit to create a wiping action across the sprocket teeth?

Also, is the correct pitch 6 in, or 5.75? Should the track link bushings be 1.5 OD or 2.25? Wiping action or no wiping action?

So many questions about a seemingly simple subject.

To answer your question about pics: I am new here and don't know how to use all the featuresa of this site. How do I post them?

[JimAnderson]

Pete,
Lavoy is correct,as usual, about Jd track pitch for the series in
question.It is 5.750 not 6 inch as I posted earlier.I made the first measurement with a scale and goofed.The eyes ain't what they used
to be.I went back out to the shop and shoved a 1 inch pin into a NOS
link segment bushing and made a measurement with dial calipers.
Sorry about the confusion,as the kids say "my bad"
Luck,JimAnderson

[petehdgs]

Thank you all for your replies! I am figuring 5.75" Pitch with 1.5" bushings. It looks like I have an Oliver or Case track on my machine.

Got any ideas on where I should look for another track and selling this one? I know I am working with MWEsales but it never hurts to look everywhere.

One Miracle at a time!

[Lavoy]

Pitch is pitch, bushing diameter has nothing to do with pitch unless you are trying to game the system by in effect increasing the effective diameter of the sprocket by sitting higher up in each cup.
Lavoy