Medical Cart Wheels: How to Replace the Casters on an Existing Cart
Posted by Kyle Kim on Oct 11th 2026
Replacing the casters on a medical cart you already own
Replacing the casters on a procedure cart, instrument cart, supply cart, utility cart, or diagnostic cart is a different job from specifying casters for new equipment. The cart already exists. The mount holes are already drilled or threaded, the wheel size is already fixed by the caster on the cart, and the load is already known. The task is to find a replacement that fits what is there, not to design from scratch.
The Carrymaster® medical plastic caster range covers 30 products across three series, all swivel. That boundary matters from the start: if the cart currently runs on rigid casters, the medical plastic line is not the right route, and the path is different (covered in Step 4). For every other cart, the process runs in the same order: identify what is on the cart now, match the rating to the cart and what it carries, then select from the medical plastic range.
Standards, braking types and cleanability are covered in the medical caster standards and braking guide.
Start here: Before ordering anything, pull the old caster and record four things from it. Step 1 walks through exactly what to look for.
Step 1: Identify what is on the cart now
Before selecting a replacement, record four things from the caster that is coming off the cart. Getting these four details right prevents an order that looks correct on paper but does not fit the cart.
1. Mount type: flange or stem
Turn the old caster over and look at the top of the housing. A flange mount (also called a top-plate mount) has a flat plate with bolt holes at the corners. It sits flush against the underside of the cart frame and is secured with bolts through those holes. A stem mount has a vertical post that inserts into a socket or hole in the cart frame. Within the Carrymaster medical plastic line, some size codes also offer a round stem variant.
Identifying which type is on the cart determines which rows of the medical plastic table are available to you. If the cart uses a flange mount, you need a flange-mount replacement. If it uses a stem, you need a stem-mount replacement. The two are not interchangeable. For a full comparison of how flange and stem mounts differ in practice, see the stem vs flange casters guide.
Do not attempt to measure the bolt pattern or stem thread by eye from the old caster. The dimension drawings on the Carrymaster product pages are the reference. If the old caster's dimensions are unclear, contact Zambus with the measurements to confirm the match.
2. Swivel or rigid
Check whether the caster housing rotates freely around its vertical axis. If it does, the caster is swivel. If the wheel is fixed in one direction and the housing does not rotate, the caster is rigid. This single check determines whether the medical plastic line applies at all. All 30 Carrymaster medical plastic casters are swivel. If the cart has rigid casters, go directly to Step 4.
3. Brake present or not
Note whether the old caster has a brake pedal or lever. The medical plastic line offers braked and unbraked versions within each row. Replacing a braked caster with an unbraked one, or the reverse, changes the cart's behavior when parked.
4. Wheel-size band
Measure the diameter of the old wheel in inches, or read it from the label if one is present. The Carrymaster medical plastic line groups into three wheel-size bands: 2 to 3 inches, 4 to 5 inches, and over 5 inches. The wheel size reference page lists every available size within each band. Record which band the old caster falls into before moving to Step 2.
Record before you order: mount type, swivel or rigid, brake present or not, and wheel-size band. These four data points drive every selection in the steps that follow.
Step 2: Match the rating to the cart and what it carries
Every caster in the Carrymaster medical plastic line carries a per-caster load rating expressed in pounds. The replacement must meet or exceed the per-caster load the cart places on each corner. If the replacement rating is too low for the cart and its contents, the caster is underspecified regardless of how well the mount and wheel size match.
The arithmetic for calculating the per-caster load from the total cart weight belongs in the load-capacity guides, not here. Use the caster wheel load capacity overview for the method, and the load capacity ranges guide for how to apply ranges to a selection.
Two points that apply directly to this selection:
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Braked vs unbraked rating: Within every row of the medical caster table, the braked and unbraked versions carry the identical per-caster rating. Choosing the braked version does not reduce the rated capacity of that caster.
-
Mixed sets: A replacement set should be matched across all four corners by family and size code.
Once the per-caster load figure is in hand, bring it to the medical plastic table in Step 3 and filter by rating alongside mount type and wheel-size band.
Step 3: Choose the replacement from the Carrymaster medical plastic range
The Carrymaster medical plastic line contains 30 products across three series: ACMC, ACMCT, and ACMCH. All 30 are swivel. The table below is the complete selection grid. Use the four data points from Step 1 and the per-caster rating from Step 2 to find the row that fits.
Medical plastic caster selection table
|
Series |
Size code |
Capacity lbs/ea |
Wheel-size facet |
Mounts available (each with and without brake) |
|---|---|---|---|---|
|
ACMC |
76 |
198.42 |
2 to 3 in |
Flange, stem |
|
ACMC |
102 |
264.55 |
4 to 5 in |
Flange, stem, round stem |
|
ACMC |
127 |
297.62 |
Over 5 in |
Flange, stem, round stem |
|
ACMCT |
76 |
132.28 |
2 to 3 in |
Flange, stem |
|
ACMCT |
102 |
176.37 |
4 to 5 in |
Flange, stem |
|
ACMCT |
127 |
220.46 |
Over 5 in |
Flange, stem |
|
ACMCH |
127 |
198.42 |
Over 5 in |
Mount type not stated |
For how the three series differ on materials and mounts, and how to narrow the 30 models to one, see the Carrymaster medical plastic caster series guide.
Within every row, the braked and unbraked versions carry the identical rating. All are titled Light-Duty.
How to read the table
Work left to right across the row that matches your cart:
-
Series: Start with the series. ACMC and ACMCH share the same wheel material (TPR); ACMCT uses a PA + PU wheel. If the materials post has already guided the wheel-material decision, use that to filter the series first.
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Size code: This corresponds to the wheel-size band from Step 1. Size code 76 covers the 2 to 3 inch band, 102 covers 4 to 5 inches, and 127 covers over 5 inches.
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Capacity lbs/ea: The per-caster rating must meet or exceed the figure from Step 2. The highest rating in the medical plastic line is 297.62 lbs per caster (ACMC 127).
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Mounts available: Confirm the mount column includes the type identified in Step 1. Not every row offers all three mount styles. The ACMCH 127, for example, does not state a mount type on its product page; contact Zambus before ordering if that series is under consideration.
-
Brake: Every row in the table offers a braked and an unbraked version. The brake mechanism on the medical series is not described on the product pages.
A worked example
A procedure cart has four stem-mount swivel casters, two of them braked, in the 4 to 5 inch band, and its load works out at no more than 176.37 lbs per caster. Two rows fit: ACMCT 102 at 176.37 lbs per caster and ACMC 102 at 264.55 lbs per caster, both offered in stem mount with and without a brake. Choosing ACMC 102 means two ACMC-102SSB braked casters and two ACMC-102SS unbraked casters, all rated 264.55 lbs per caster with TPR wheels. If the load were above 264.55 lbs per caster, no 4 to 5 inch medical plastic row would qualify, and the over 5 inch band is the next place to look.
Materials by series
The product pages describe the materials for each series as follows:
-
ACMC: Frame PA6, brake PA6, wheel core PP, wheel TPR (Thermo Plastic Rubber). Top plate and bolt SPC and S20C, zinc treated.
-
ACMCT: Frame ABS (76 and 102 series), Nylon (127 series); brake Nylon; wheel core ABS (76 and 102), Nylon (127); wheel PA + PU.
-
ACMCH: Frame PA6, brake PA6, wheel core PP, wheel TPR.
The product descriptions across all three series note "Easy Pivoting & Quiet Rolling", "Light Weight & Corrosion-Resistant Structure", with listed applications including "Medical Devices" and "Light Load of Trolley & Carts". Use those descriptions as stated; the product pages do not support stronger characterizations.
Step 4: If the cart has rigid casters
There is no rigid caster in the Carrymaster medical plastic line. All 30 medical plastic products are swivel. If the cart currently uses rigid casters and a like-for-like rigid replacement is needed, the route is through the ACSU series and ACLU series, both of which offer rigid flange mounts.
Rigid flange options: ACSU and ACLU
|
Series |
Size code |
Capacity (lbs/ea) |
Mount |
Wheel |
|---|---|---|---|---|
|
ACSU |
40 |
33.07 |
Rigid flange |
Polyurethane |
|
ACSU |
50 |
44.09 |
Rigid flange |
Polyurethane |
|
ACSU |
64 |
66.14 |
Rigid flange |
Polyurethane |
|
ACSU |
76 |
77.16 |
Rigid flange |
Polyurethane |
|
ACSU |
102 |
88.18 |
Rigid flange |
Polyurethane |
|
ACLU |
100 |
220.46 |
Rigid flange |
Polyurethane |
|
ACLU |
127 |
242.51 |
Rigid flange |
Polyurethane |
|
ACLU |
150 |
264.55 |
Rigid flange |
Polyurethane |
ACSU product pages list "Light Load of Trolley & Carts, Medical Devices" as applications. ACLU pages list "Trolley & Carts". Both series use polyurethane wheels. That is a factual difference from the medical plastic line, which uses TPR wheels (ACMC and ACMCH) and PA + PU wheels (ACMCT). The caster wheel materials guide covers the material comparison in full.
If the cart currently has rigid casters but a change to all-swivel or a mixed swivel-and-rigid configuration is under consideration, the configuration principles are covered in the swivel vs rigid casters guide. That decision belongs before selecting a specific product.
Symptoms and the specification to check
When a cart is not performing as expected, the specification is the first place to check before ordering a replacement. Each symptom maps to one or more of the specification checks in Steps 1 to 3. The checks are qualitative; none requires a force measurement.
Cart is hard to push
-
Check that all four corners use the same wheel-size band.
-
Check that the per-caster rating across the set meets the cart and load.
-
Check that the caster family is consistent across all four corners. ACMC and ACMCT casters use different wheel materials (TPR and PA + PU).
Cart wobbles
-
Check that the mount type on each replacement matches what is on the cart. Check that each flange-mount caster seats flush against the frame.
-
Check that the size code is matched across all four corners.
Cart tips when moved
-
Check the per-caster rating on every corner against the cart and its load.
-
Check that the caster family and size code are matched across the full set.
Cart drifts when parked
-
Check whether the current caster set includes braked casters and, if so, whether the braked positions are sufficient for the cart's use.
-
Check the medical plastic caster table to confirm that the row under consideration offers a braked version. Every row in the medical plastic line offers both braked and unbraked variants. If the cart needs brakes and the current set has none, a replacement set that includes braked casters is the specification change to make.
Ordering replacement casters
Before placing an order, confirm the following against the cart:
-
Mount type: flange, stem, or round stem
-
Configuration: swivel (medical plastic line) or rigid (ACSU or ACLU)
-
Brake: braked or unbraked version needed
-
Wheel-size band: 2 to 3 in, 4 to 5 in, or over 5 in
-
Per-caster rating: meets or exceeds the load figure from Step 2
If the old caster's dimensions are unclear, or if the ACMCH 127 mount type is a question, do not estimate. Bring the old caster's measurements to Zambus and Zambus can confirm the match against the product-page drawings.
Zambus, Inc. is located in Palisades Park, NJ. Reach Zambus by phone at (973) 777-4922 or by email at sales@zambus.com.
Contact Zambus to match a replacement caster
Frequently asked questions
Can I put braked casters on only two corners of a medical cart?
Yes. Every Carrymaster medical plastic row is sold with and without a brake at the same rating, so one set can combine, for example, two ACMCT-127SFB braked casters and two ACMCT-127SF unbraked casters. Which corners carry the brakes is a decision for the cart's design and use; the Carrymaster product pages do not specify brake positions.
What if my cart needs more than 297.62 lbs per caster?
The Carrymaster medical plastic line tops out at 297.62 lbs per caster (ACMC 127). Above that, the Carrymaster ACMU and ACMM swivel flange casters, whose product pages list Medical Devices among their applications, are rated 881.85 to 1,763.70 lbs per caster. Brake versions exist only on ACMM 100, 125 and 150. Confirm mount and wheel-size band before switching series.
What should I send Zambus if the old caster has no model number?
Send Zambus the four details plus two photos: the mount type, whether the caster swivels, whether it has a brake and the wheel diameter, with one photo of the top plate or stem and one of the whole caster. Email sales@zambus.com or call (973) 777-4922, and Zambus can compare them against the Carrymaster product-page drawings before you order.
Can I mix ACMC and ACMCT casters on the same cart?
Both series offer flange and stem mounts in the 76, 102 and 127 size codes, but at different ratings and with different wheels. The Carrymaster ACMC-102 is rated 264.55 lbs per caster with a TPR wheel; the ACMCT-102 is rated 176.37 lbs per caster with a PA + PU wheel. Matching one series across all four corners keeps one rating and one wheel material on the cart.
Can I use a non-medical Carrymaster caster on a medical cart?
Yes, where the product page lists it. Carrymaster ACSU casters, rated 33.07 to 88.18 lbs per caster, list "Light Load of Trolley & Carts, Medical Devices" as applications and come in swivel stem and swivel flange versions, with brake versions in sizes 64, 76 and 102. Their wheels are polyurethane, unlike the TPR and PA + PU wheels of the medical plastic line.
Do the ACSU and ACLU rigid casters come with a brake?
No. Carrymaster lists no rigid caster with a brake. ACSU 64, 76 and 102 and ACLU 100, 127 and 150 each offer a swivel version with a brake at the same rating as the rigid version, so a cart with rigid ACSU or ACLU corners can take its braking from swivel corners of the same series and size.
Will a Carrymaster caster fit a cart made by another manufacturer?
It can, if the mount type, wheel-size band and rating match. A Carrymaster replacement is matched to a cart by those three specifications, not by another brand's part number. Compare the dimension drawing on the Carrymaster product page with the old caster, or send the old caster's details to Zambus at sales@zambus.com before ordering.
Do TPR wheels and PA + PU wheels behave differently on the same floor?
The Carrymaster product pages do not compare how TPR and PA + PU wheels behave on floors. They state the materials only: ACMC and ACMCH wheels are TPR (Thermo Plastic Rubber), and ACMCT wheels are PA + PU. The Zambus caster wheel materials guide compares wheel materials in general terms.
Should I replace all four casters or only the damaged one?
Carrymaster publishes no rule on this. If the damaged caster's exact model is still in the range, a like-for-like replacement keeps the same rating, mount and wheel-size band at that corner. If it is not, replacing all four from one Carrymaster series and size code avoids mixing ratings and wheel materials on the same cart.
How do I read a Carrymaster medical caster model number?
A Carrymaster model number reads as series, size code and configuration. ACMC-102SFB, for example, is the ACMC series, size code 102, swivel flange, with brake. The medical suffixes are SF (swivel flange), SS (swivel stem) and SRS (swivel round stem), with a trailing B for the brake version. Size codes 76, 102 and 127 correspond to the 2 to 3 inch, 4 to 5 inch and over 5 inch bands.