20/10/2026
The Bobcat T66 is listed with a 50-link, 86 mm pitch rubber track in two widths, 320 mm (12.6 in) and 400 mm (15.7 in), with C-lug and Z-lug treads. This guide covers how to confirm the fit, the signs of wear and the T66 idlers and undercarriage parts to check.
Ordering new tracks for a Bobcat T66 starts with the track size. This guide gives the Bobcat T66 track size in each width and tread we list, shows how to confirm the fit, explains the signs of worn tracks and covers the T66 idlers and other undercarriage parts to check while the tracks are off.
The short answer
The track listed for the Bobcat T66 has an 86 mm pitch and 50 links. It comes in two widths. The 320 mm width is listed with two treads and the 400 mm width with one. Here are the sizes from our catalog:
| Track size | Width | Pitch | Links | Tread |
|---|---|---|---|---|
| 320 x 86 x 50B | 320 mm (12.6 in) | 86 mm | 50 | C-lug or Z-lug |
| 400 x 86 x 50B | 400 mm (15.7 in) | 86 mm | 50 | C-lug |
Source: Excavator Parts Direct catalog, October 2026. All sizes are sold as a single track (price is per track).
The width you need is the width on your machine now. If you are thinking about changing width, talk to us before you order.
If the size is still readable on your old track, use it. If it has worn off, three measurements give you the size:
Width
Measure straight across the track from one edge to the other. On a T66 track this should read 320 mm (12.6 in) or 400 mm (15.7 in).
Pitch
Pitch is the distance from the center of one link to the center of the next. On the T66 track this should read 86 mm.
Links
The link count is the number of drive lugs around the inside of the track. The T66 track has 50.
Put the three numbers together, width x pitch x links, and you have the size. Our guide to measuring rubber tracks shows each step with diagrams.
Match the size
Compare the size on your old track, or your own measurements, with the table above. Pitch should be 86 mm and the link count 50. If either is different, stop and check before you order.
Confirm the width
Choose the same width as the track on the machine now: 320 mm or 400 mm.
Confirm the machine
Check the model plate and note the serial number. If you are not sure the machine is a T66, contact us with the machine details and serial number and we will check.
Choose the tread
The 320 mm track is listed with a C-lug or Z-lug tread. The 400 mm track is listed with a C-lug tread. The right choice depends on the ground the machine works on most and how it is used. Tell us about the job and we will help you choose.
Our advice
Getting the size right first time 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.
If the slack keeps coming back after you re-tension, the cause is not always the track. Check the sprockets and the track adjuster too. A track adjuster with failed piston seals cannot hold tension. Here is how to check rubber track tension. Your machine’s operator’s manual gives the correct tension figure for the T66.
Sharp, worn sprocket teeth no longer hold the track cleanly. The track can slip or jump through the sprocket, and that shock load also reaches the final drive. If you see or hear the track jumping, stop and inspect the sprockets before you carry on.
If a set of T66 tracks has worn out well ahead of the last set, look at the sprockets, idlers and rollers before you fit new tracks. Material packing between the sprocket teeth, rollers and 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 the other common causes.
How the machine is driven matters as much as the parts. Avoid spinning the tracks, unnecessary reversing, high travel speed when it is not needed, and always turning in the same direction. Each one adds wear to the tracks and to the sprockets that drive them.
With the track off, every part of the undercarriage is easy to see. Here is what our catalog lists for the T66 undercarriage today:
| Part | Per machine | Weight each |
|---|---|---|
| Idler | 2 | 25.5 kg (56.2 lb) |
| Drive sprocket | Not currently listed | Not listed |
| Bottom roller | Not currently listed | Not listed |
Source: Excavator Parts Direct catalog, October 2026. Weight converted from the catalog’s pound figure.
Idlers guide the track around the ends of the track frame and work with the track adjuster to keep the track at the right tension. Our catalog lists 2 idlers per T66. Check for worn running surfaces, damaged flanges and oil leaks. If an idler is coming off, it is also the easiest time to check or replace the track adjuster.
The sprocket bolts to the final drive, and its teeth engage the track to move the machine. Sprocket wear is hard to judge by eye, so compare your sprocket with an unused one of the same type. Wear builds faster in reverse and at higher travel speeds. Fitting new tracks to worn sprockets risks the slipping and early wear described above. We do not currently list a T66 sprocket.
Bottom rollers run along the underside of the track frame and carry the weight of the machine on the track. Look for flat spots, worn flanges, oil leaks and rollers that no longer turn. We advise changing bottom rollers as a set: a single new roller sits proud of the worn ones and wears faster. We do not currently list a T66 bottom roller.
Our advice
If the idlers, sprockets or rollers show wear, replace them with the tracks. That way it is one job and one round of downtime, and the new tracks start on a sound undercarriage. If you need a part we do not list for the T66, speak to the team.
These are the T66 parts in our catalog. You can also browse them on the Bobcat T66 parts page.
More Bobcat parts
Our catalog lists the Bobcat T66 track in two widths, both with an 86 mm pitch and 50 links: 320 x 86 x 50B and 400 x 86 x 50B. Order the width your machine runs now.
The T66 tracks in our catalog are 320 mm (12.6 in) or 400 mm (15.7 in) wide. Measure your old track, or read the size on it, to confirm which width you need.
It is the track size, written width x pitch x number of links. A 320 x 86 x 50B track is 320 mm wide, has an 86 mm pitch and has 50 links.
Yes, in the 320 mm width. Our catalog lists the 320 x 86 x 50B track with a C-lug or Z-lug tread, and the 400 x 86 x 50B track with a C-lug tread.
Yes. We sell T66 tracks individually, and the price shown is for one track.
Our catalog lists 2 idlers per machine for the Bobcat T66. Check both idlers whenever the tracks are off.
Common signs are a track that will not hold tension, a track that slips or jumps on the sprocket, and tracks that wear out faster than the last set. Check the sprockets, idlers, rollers and track adjuster at the same time.
Related guides
Need tracks or undercarriage parts for your T66?
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