Where Can I Buy CAT Excavator Sprocket Replacement Parts in Ontario?

A CAT sprocket is defined by three numbers: the tooth count, the pitch the teeth are cut to, and the bore and mounting geometry that put it on the final drive. Get all three right and the sprocket drops on and runs the track the way the original did. Get one wrong and the machine will still move - which is exactly why a wrong sprocket is more expensive than a part that does not fit, because it takes a track out with it before anyone notices.

Last updated: October 5, 2026

This guide covers the numbers to verify before ordering in Ontario, how to tell a sprocket is finished rather than merely worn, and the documentation worth having behind the part.

The numbers to verify before you order

Three checks close the fitment question, and all three are readable on the machine or in the parts book.

The part number, cross-referenced to your machine. Start from the CAT number for your model and build series, then ask the supplier to cross-reference it against their own listing. A sprocket that is correct for one 300-series machine is often the wrong part for another. Tooth count, pitch and profile. The tooth count is obvious; the pitch and the profile of the teeth are what engage the track links. A sprocket cut to the wrong pitch will still accept the track and then destroy it, so this is the number to have in writing rather than to eyeball. Bore and mounting geometry. The bore fits the final drive, and the mounting holes have to line up with the hub pattern - check the number and the hole spacing rather than the diameter alone.

The sprocket range lists these parts by machine and part number, which is the right way to read a listing: from the number you have, not from the photo.

If you do not have the parts book to hand, all three numbers are findable on the machine. The part number is usually cast or stamped into the sprocket body, and it is worth wiping clean and photographing before it goes back into service. The tooth count is a matter of counting, and the pitch can be read from the track specification for your machine, which is the number that has to agree with the sprocket - how a track is measured covers where that number comes from. The bore is measurable with the sprocket off the final drive, and the mounting geometry is easier to confirm by tracing the hub face than by measuring hole centres by hand. Recording all three while the machine is apart saves a second dismantling if the first part ordered turns out to be wrong.

When a sprocket is finished

Sprockets wear in a predictable way, and the point to replace one is before the teeth stop carrying the load properly.

What you see	What it means
Teeth rounded or hooked toward the drive side	The teeth are climbing the link instead of sitting in it - the track is being stretched and the bushings worn
Uneven tooth wear around the sprocket	Misalignment or a track running off line; a new sprocket will wear the same way unless that is corrected
Broken or chipped teeth	Impact damage; check the final drive and mounting surfaces before fitting anything new
A track that skips under load	Pitch no longer matching, which can be the sprocket, the belt, or both

The practical rule is that a sprocket gets replaced with the track rather than after it. Fitting a new belt onto hooked teeth is the fastest way to shorten the life of the belt; fitting a new sprocket onto a stretched belt leaves the same mismatch in the other direction. Where both are near the end of their life, doing them together is cheaper than doing them twice.

What to ask for behind the part

A sprocket is a machined, heat-treated part, and the paperwork is what separates two visually identical units. Four items are worth having.

The cross-reference - your machine, model, serial number and part number, in writing. The material and heat-treatment information, because hardness at the tooth surface is what decides how the sprocket wears against the link; a supplier who can state the treatment is a supplier who knows what they are selling. Traceability for the batch the part came from. And warranty terms as a period plus an operating-hours cap, whichever comes first, with freight responsibility named for a claim - because on a part this size, who pays return freight is the difference between a warranty and a gesture.

On the OEM-or-aftermarket question in Ontario, both routes are legitimate. A dealer supplies the factory part with the factory's backing; an aftermarket specialist supplies an equivalent fitment, usually with shorter lead times and better availability of the parts around it. What matters either way is the three fitment numbers and the documentation, not the label.

The field check before you order

If the machine is in the yard and you want to close the question quickly, four checks will do it. Verify the part number against the parts book for your machine and build series - not against the model name - and confirm the mounting holes line up with the hub pattern on the final drive. Inspect the existing teeth for wear, chipping and rounding, and compare the wear around the sprocket: even wear all the way round points to normal life, while a pattern concentrated in one area points at misalignment or a track running off line. Measure or read the bore, and count the teeth. Then confirm the pitch against the track you intend to run on it, because a sprocket and a track that disagree on pitch will still assemble and then destroy each other.

Two of those checks are worth doing before ordering even when you are confident: the bore and the pitch. They are the two where a listing can look correct and still be wrong, and both are cheaper to check with a caliper and a parts book than to discover on the machine with the final drive apart.

Making one last

Sprocket life is decided mostly by what happens around it. Correct track tension, measured where the manual says to measure it, keeps the teeth engaging the link properly rather than riding up it. Alignment, checked when a track is fitted, keeps wear even around the sprocket instead of concentrating it. Cleaning the undercarriage after abrasive work keeps grit out of the engagement. And replacing the surrounding wear parts - rollers, idlers, the belt itself - before their wear reaches the sprocket is what stops the assembly from taking turns at failing.

If you are assessing the whole undercarriage, reading the wear indicator on the sprocket is the quickest way to make the replace-or-keep decision, and it is worth doing at the same time as the track inspection rather than separately.

There is one habit above all of them. A sprocket and a track are a matched pair, and the pitch is what binds them: keep the track tensioned to the figure in the manual, keep both sides aligned, and replace the pair together when either reaches the end of its life. A machine that has been through two tracks on one sprocket is a machine whose next sprocket will be bought in a hurry, on a day chosen by someone else.

This article is part of the drive sprockets guide, which covers how a sprocket is identified, how it wears and when to replace it with the chain.

FAQs

When should an excavator sprocket be replaced?

When the teeth are hooked or rounded toward the drive side, when wear around the sprocket is uneven, when teeth are broken or chipped, or when the track skips under load because the pitch no longer matches. In practice the sprocket belongs in the same job as the track, and replacing it early is cheaper than replacing a belt it has worn out.

Do aftermarket CAT sprockets meet OEM tolerances?

They can, but tolerances are a claim you verify rather than accept: ask for the tooth count, pitch, bore and mounting geometry in writing against your machine, and for the material and heat-treatment information. Those four things are what "meets OEM tolerances" actually means on a sprocket.

Where can I buy excavator parts in Ontario?

From the dealer network, from undercarriage specialists and from general parts marketplaces. The trade-off is documentation against convenience: a local supplier who can cross-reference the part number and state the warranty terms in writing is worth more than a cheaper listing that cannot do either.

Can I mix an OEM sprocket with an aftermarket track?

Yes, provided both meet the same specification - the pitch and tooth profile of the sprocket have to match the links of the belt, whichever badges they carry. What you should not do is pair a new sprocket with a stretched belt, or a new belt with hooked teeth, because the mismatch wears both.

How long does a CAT excavator sprocket last?

It depends on ground, tension, alignment and how the machine is operated, so the useful reference is your own records rather than a general figure. Record the hours when you fit one, keep the track tension to the manual's figure, and the second sprocket will tell you what your duty cycle really costs.