I ripped a link out of one of my tracks on my Hanix S&B300. The current tracks match the oem spec from my parts manual: 300 wide x 109 pitch x 39 link, which is not available from anyone in my area. My tracks are long-link, where only every second sprocket tooth engages a pin, so I could also go to a matching short-link. Half of 109mm would be a 54.5mm short pitch track, which is also not available. I've had a couple of track suppliers tell me that a 300x52.5x80 track (common) will fit my machine. I can't see how this would work, as the pitch is 2mm off. Over the 11 sprocket teeth that are engaged across half the circumference of the sprocket it would be 22mm (7/8") out of pitch from first to last tooth. Am I missing something? I just got off the phone with a track salesman that told me he "guarantees 100%" this track will fit my machine, but couldn't explain to me how the pitch difference wouldn't be a problem. I'm thinking I should go pull a sprocket off my machine and measure the pilot and bolt pattern to see if I can find an 82.5 pitch sprocket that will fit my final drive to get myself into a more common track pitch, but the track salesman I spoke to told me that's unnecessary.
Are the sprocket teeth worn? Post a pick of the sprockets
I'll get some good pictures of the sprockets this weekend. The machine is out of town. I'm planning to go out there and pull the bad track off on Saturday to bring to town. I have the link that ripped out and I'm planning to just drill and bolt it through the track to get me going again temporarily until I can get new tracks. Hopefully it'll hold for a little while if I only walk straight, as I still have about 500' of trench to dig out there.
When cleats are ripped out, it is usually caused by the sprocket teeth worn into a hook shape.
This is the best I could find in my phone pictures. I'll get a picture with the track off on the weekend.
The sprocket doesn't look bad. I think the cleat just ripped out because the track is old and full of cracks. I did notice the top guides are getting pretty worn out. The bottom rollers and idler turn easily, and I don't feel excessive play in anything, except maybe the side-to-side play in the idler slides. Back to the pitch issue, does anyone have any advice around using the 82.5 pitch track that's being recommended to me? Am I on the right path looking for replacement sprockets to match the 82.5mm pitch, or is the salesman right when he says the 2mm pitch difference won't matter and I can run these sprockets?
That's how all tracks work. You will note that the sprocket has an odd number of teeth (again always the case) so that every rotation of the sprocket the track bushings/driver dogs engage in a different tooth (odd vs even) of the sprocket. This video may be useful. I know it is for steel track but rubber ones work exactly the same way.
That was previously my understanding as well, having only paid attention to my own rubber tracked mini and larger steel undercarriage used on forestry machinery. Researching replacement tracks I've found that almost all modern rubber tracked mini-excavators are using short pitch tracks where every sprocket tooth engages a pin. I just went over to my local John Deere dealer to confirm, and every new and used rubber tracked piece of equipment they have there is short pitch (JD, CAT, Kubota). JD35: Cat 306:
Kubota: So.. My sprocket measures: Pilot diameter: 210mm Number of teeth: 21T Bolt pattern: 12x 12mm bolts eq. spaced on 232mm BCD I tediously went through all of the sprocket offerings on Rubber Track Canada and found one that looks like it might work. SP101/128/00 21 tooth, 210mm pilot, 12 Bolt It's used on Terex TC29/TC35, Hanix H26B/C, H36 B/C, Bobcat 325,328,329,331,334,x325,x328,x331,x334. All of these machines take 82.5mm pitch track. I'll call Rubber Track Canada tomorrow to see if they can measure the bolt pattern for me.
Keeping an eye on this thread... I'm in a similar but slightly different boat. Current tracks (Camso SD) are 300x52.5x88link but got destroyed very quickly in sharp rock. Camso's HXD only come in 300x55x88 at the closest and I'm wondering if the pitch difference of 2.5 can be overcome with new sprockets but see some salesman tells you it's no big deal. An inherent lack of trust in salesmen means I'll keep heading down the sprocket road too... FWIW Camso has a 'product selector' online that spits out the SD model no problem for my machine but DOES NOT list the HXD with slightly different pitch, pointing further towards your salesman just trying to make a sale. Interestingly I just looked up the Bobcat 334 that you listed on Camso's product selector. It shows OEM specs as 320x52.5x80. What they have that they claim to fit is HXD in 12" x 2.17" x 77links or SD in 12" x 2.07" x 80links. Running the conversions I'm seeing 2.17" = 55.118mm and 2.07" = 52.578mm --- the plot thickens?
My new sprockets arrived and they appear to be the identical casting to the original sprockets, without the wear. I compared the root diameter of the old sprockets vs. the new ones and the old ones have worn down to 11.970" from the new sprocket measurement of 12.310". My track pins are 1.25" diameter, so I used some 1 1/4" OD fender washers to compare the pitch of my old sprockets and the new sprockets. The reduced root diameter has actually narrowed the pitch of the old sprockets, as the pins are moved closer to the center of the sprocket on a shorter arc. The new sprockets are almost perfectly 52.5mm pitch, and the old sprockets that I had expected to be closer to 55mm pitch are around 49mm. The pitch of the sprocket decreases as the root of the sprocket teeth wears down. Mudfarmer: My 109 pitch tracks were working great on the old sprockets, and the half pitch of 109mm across the arc of a 21T sprocket works out to 55.116mm, so you might be alright with that track, but you may want fresh sprockets to maximize your pitch to better share the load between sprocket teeth. You can use the same method I used above on your current sprockets to check how they will align.
Very nice analysis, sir! This thread is going to be handy for many confused folks in the future. Let us know how it all works out for you. I can't afford to gamble and don't have a lot of time for screwing around at the moment so maybe should just stay like for like but also can't afford to trash tracks in a few hundred hours with perfectly good tread just deep cuts causing them to come apart. Maybe I need to revisit if the Camso HXD are really *that* much better than the SD. The 55 pitch @ 88 link would be almost 9in longer overall circumference than the 52.5 @ 88link. They do have the 55 pitch in 84 link (exact same length as 52.5 @ 88) but may have discontinued as it's flagged "check remaining stock" Also 85 link which would only be ~2.5in longer which seems like maybe not a big deal? Plot thickens again. Sorry for the hijack!