04/11/2026
The Bobcat T870 is listed with two track sizes, 450 x 86 x 58B (C-lug, D-lug or Z-lug) and 450 x 86 x 56B (C-lug), both 450 mm / 17.7 in wide with an 86 mm pitch, for the solid-mount undercarriage. This guide covers how to tell them apart by link count, the signs of wear and the T870 sprocket, idlers and bottom rollers to check.
Ordering new tracks for a Bobcat T870 starts with the size, and our catalog lists two track sizes for this machine that differ by just two links. This guide gives the Bobcat T870 track size, the three tread patterns, how to tell the 58-link and 56-link tracks apart, the signs that tracks are worn and the T870 sprocket, idlers and bottom rollers worth checking while the tracks are off.
The short answer
Our catalog lists two track sizes for the Bobcat T870 with the solid-mount undercarriage. Width and pitch are the same on both. The link count is the difference, and it decides which track fits your machine.
| Track size | Width | Pitch | Links | Tread |
|---|---|---|---|---|
| 450 x 86 x 58B | 450 mm (17.7 in) | 86 mm | 58 | C-lug |
| 450 x 86 x 58B | 450 mm (17.7 in) | 86 mm | 58 | D-lug |
| 450 x 86 x 58B | 450 mm (17.7 in) | 86 mm | 58 | Z-lug |
| 450 x 86 x 56B | 450 mm (17.7 in) | 86 mm | 56 | C-lug |
Source: Excavator Parts Direct catalog, November 2026. Solid-mount undercarriage. Sold as a single track (price is per track).
Read the size as width x pitch x links. A 450 x 86 x 58B track is 450 mm wide, has 86 mm between link centers and has 58 links. The 450 x 86 x 56B track has the same width and pitch with 56 links. Pick the size first, then the tread.
The two T870 tracks share a width and a pitch, so they look alike on the shelf and on the machine. The difference is two links, which adds up to 172 mm of track length (2 x 86 mm). A track with the wrong link count will not sit right on the undercarriage. Two links too many and the track adjuster may not have enough travel to tension it. Two too few and the track may not go on.
Our catalog does not say which T870 machines take the 58-link track and which take the 56-link track. The reliable check is the track already on your machine. Read the size molded on its side, or count the links. If the old track is missing or the size has worn away, contact us with the machine serial number and we will check.
Our advice
Count the links twice before you order. Mark your starting lug with chalk so you do not count one twice, and check both tracks on the machine, not just one.
If the size is still readable on the side of your old track, use it. If it has worn away, take three measurements:
Width
Measure across the track from edge to edge. A T870 track should measure 450 mm (17.7 in).
Pitch
Measure from the center of one link to the center of the next. Both T870 tracks have an 86 mm pitch. Measure over several links and divide, which gives a truer figure than a single gap.
Links
Count the drive lugs around the inside of the track. A T870 track in our catalog has 58 or 56. This is the measurement that tells the two sizes apart.
If your numbers match 450, 86 and either 58 or 56, you have the size. Our guide to measuring rubber tracks shows each step with diagrams.
Match the size
Compare the size on the old track, or your measurements, with the table above. If the pitch is not 86 mm or the link count is not 58 or 56, stop and check before you order.
Confirm the undercarriage
Our T870 track, sprocket and idler are listed for the solid-mount undercarriage. Our T870 bottom roller listing does not name an undercarriage. If you are not sure which undercarriage your machine has, contact us with the machine details and serial number and we will check.
Choose the tread
The 58-link track is listed with a C-lug, D-lug or Z-lug tread. The 56-link track is listed with a C-lug tread only. The right tread depends on the ground the machine works on most and the jobs it does. Fit two tracks of the same size and tread so both sides grip and wear evenly.
Look underneath first
Before the new tracks go on, inspect the sprockets, idlers and bottom rollers. New tracks on a worn undercarriage wear out sooner.
Our advice
A size that is checked, not guessed, is the quickest way back to work. If anything does not match, talk to the team before you order, so you maximize machine uptime and avoid a return.
These are the checks we recommend on any tracked machine, and they apply to the T870.
If the track keeps going slack after you adjust it, do not assume the track is the cause. A track adjuster with failed piston seals cannot hold tension, and worn sprockets can add to the problem. Here is how to check rubber track tension. The correct tension figure and procedure for the T870 are in your machine’s operator’s manual.
When sprocket teeth wear sharp, they stop holding the track cleanly. The track can slip or jump through the sprocket, and the shock load travels into the final drive. If you see or hear this happen, stop and inspect the sprockets before you carry on.
Deep cuts, missing lugs and steel cords showing through the rubber all mean the track is near the end of its life. A track in that state can fail without much warning, so plan the change before it does.
If a set of tracks wears out well before the last set did, look at the parts underneath before you fit new ones. Material packing between sprocket teeth, rollers and the track also speeds up wear, so keep the undercarriage clean. Our guide to spotting a worn sprocket shows what to look for, and these five tips to extend rubber track life cover other common causes.
Spinning the tracks, unnecessary reversing, high travel speed when it is not needed and always turning in the same direction all add wear. They wear the tracks and the sprockets that drive them.
With the tracks off, the whole undercarriage is in plain view. That makes a track change the best time to inspect it. Here is what our catalog lists for the T870:
| Part | Per machine | Undercarriage | Weight each |
|---|---|---|---|
| Drive sprocket | Ask the team | Solid-mount | Not listed |
| Idler | Front and rear positions listed | Solid-mount | Not listed |
| Bottom roller | 8 | Not named in the listing | 26.9 kg (59.3 lb) |
| Track adjuster | Not listed online: ask the team | Ask the team | Not listed |
Source: Excavator Parts Direct catalog, November 2026. Kilogram weight converted from the catalog’s pound figure.
The sprocket bolts to the final drive and its teeth engage the track to drive the machine. Our catalog lists a T870 sprocket for the solid-mount undercarriage. Sprocket wear is hard to judge by eye, so compare yours with an unused sprocket of the same type. Wear builds faster in reverse and at higher travel speeds. Ask the team to confirm how many your machine needs when you order.
Idlers guide the track around each end of the track frame and work with the track adjuster to hold tension. Our catalog lists the T870 idler in front and rear positions, for the solid-mount undercarriage, so order the position you are replacing. Check for worn running surfaces, damaged flanges and oil leaks. With an idler off, it is also the easiest time to check or replace the track adjuster.
Bottom rollers run along the underside of the track frame and carry the machine’s weight on the track. Our catalog lists 8 per T870. Look for flat spots, worn flanges, oil leaks and rollers that no longer turn, and check every one, including the rollers that are hard to see. We advise changing bottom rollers as a set, because a single new roller sits proud of the worn ones and wears faster. Our guide to track rollers explains each type.
The track adjuster sits between the track frame and the idler and keeps the track tensioned. If tension will not hold, check it for leaks and failed seals. We do not currently list a T870 track adjuster online. If yours needs replacing, contact us with the serial number and we will check what we can supply. Our guide to track adjusters explains how they work.
Our advice
If the sprockets, idlers or rollers show wear, replace them with the tracks. It is one job and one round of downtime, and the new tracks start on a sound undercarriage.
These are the T870 parts in our catalog. The track, sprocket and idler are on the Bobcat T870 parts page for the solid-mount undercarriage. The bottom roller has its own listing.
More Bobcat parts
Our catalog lists two track sizes for the Bobcat T870 with the solid-mount undercarriage: 450 x 86 x 58B and 450 x 86 x 56B. Both are 450 mm (17.7 in) wide with an 86 mm pitch. The first has 58 links and the second has 56.
Both T870 track sizes in our catalog are 450 mm (17.7 in) wide.
Only the link count. Both tracks are 450 mm wide with an 86 mm pitch. One has 58 links and the other has 56, so the 58-link track is two links longer.
Read the size molded on the side of your old track, or count the links around the inside of the track. If you cannot do either, contact us with the machine serial number and we will check.
The 450 x 86 x 58B track is listed with a C-lug, D-lug or Z-lug tread. The 450 x 86 x 56B track is listed with a C-lug tread only.
Yes. We sell T870 tracks individually, and the price shown is for one track.
Follow the procedure and tension figure in your machine’s operator’s manual. If the track will not hold tension after adjustment, check the track adjuster and the sprockets. We do not currently list a T870 track adjuster online, so contact us with the serial number if you need one.
Our catalog lists the T870 idler in front and rear positions, and lists 8 bottom rollers per machine.
Common signs are a track that will not hold tension, a track that slips or jumps on the sprocket, deep cuts or missing lugs, steel cords showing through the rubber, and tracks that wear out much faster than the last set. Check the sprockets, idlers, bottom rollers and track adjuster at the same time, because worn parts underneath shorten the life of new tracks.
Related guides
Need tracks or undercarriage parts for your T870?
Tell us your machine, its serial number and what you need. We will confirm the right parts and send a quote. Shipped across the USA.
Get a quoteTalk to the teamBobcat and T870 are trademarks of their owner. The make and model names are used only to identify fitment. Excavator Parts Direct parts are aftermarket replacement parts, not genuine OEM parts, and Excavator Parts Direct is not affiliated with any manufacturer named.
Contact our helpful sales team today.
