Laboratory and Test Equipment Casters: How to Choose One

Posted by Kyle Kim on Sep 7th 2026

Most buyers start the same way: they ask what wheel material will hold up to the chemicals in their lab. It is a reasonable question and almost always the wrong one to lead with.

A CarryMaster® caster is not a single material. It is an assembly of up to eight distinct parts, each made of something different, each carrying a different treatment, and each exposed to the environment in a different way. The wheel is one of those parts. The leveler, the foot, the pin, and the shaft are others, and they sit closer to the floor than the wheel does.

Getting the selection right means identifying which parts are actually at risk, calculating the load per mounting point correctly, and knowing exactly where the published product data stops.

Where CarryMaster casters are used in laboratory environments

CarryMaster casters are positioned for manufacturing and industrial environments that include laboratory facilities, as stated in the published product-page copy across the range. That is the extent of the environmental claim the catalog supports.

The more useful information is the Materials and Treatments table published on each product page, which lists the material and surface treatment of every part in the assembly. That is where a laboratory buyer should start.

A caster is not one material, it is up to eight

A laboratory caster should be evaluated part by part, because the published product data covers multiple materials and treatments across the assembly, not a single wheel-level claim. Understanding what each part is made of, and what treatment it carries, is the only honest starting point for a lab-environment selection.

Every CarryMaster product page publishes a Materials and Treatments table. Across the 29 models with published laboratory-environment positioning, the recurring assembly pattern looks like this:

Part	Typical material	Typical treatment
Top plate	SPC steel, or SPC and S45C steel	Zinc galvanized
Ball	STB2	Ni-Cr plated
Frame	ALDC12 aluminum die cast, or SPC steel	Powder coated, or none
Handle	ABS	Colored
Leveler	Swrch 10A	Zinc galvanized
Foot	NBR (nitrile rubber)	Black
Pin / shaft	Swrch 10A	Zinc galvanized
Wheel	PA6 (Nylon 6)	Black

This is the recurring pattern. It is not universal.

Variation is real and matters

There are 26 distinct material-table variants across those 29 product pages. Some models carry no handle. Some have a cup rather than a handle. At least one model uses an S45C steel foot rather than NBR. The table above represents the most common configuration, not a range-wide specification.

This is why the right instruction is to read the Materials and Treatments table on the exact model page you are considering, not to rely on a range-level summary.

Which parts sit closest to the floor

Buyers typically focus on the wheel because it makes contact with the floor surface. That focus is understandable but incomplete. Consider where each part actually sits in the assembly:

The wheel is a molded PA6 nylon polymer in the most common configuration. It contacts the floor surface.
The foot is NBR, a nitrile elastomer, in most models. It sits at the base of the leveler, at or very near floor level.
The leveler is Swrch 10A steel with a zinc galvanized treatment. It is the threaded component that contacts the floor when the caster is locked down.
The pin and shaft are also Swrch 10A steel, zinc galvanized.

When a spill pools on a laboratory floor, the parts at floor level are not only the wheel. The zinc-galvanized steel of the leveler, pin, and shaft, and the NBR elastomer of the foot, are also in the exposure zone. The coating on those steel parts protects the base metal. The NBR foot is an elastomer with its own material properties.

What this means for selection

You can identify what each part is made of and what treatment it carries. What you cannot determine from this catalog is how any part behaves when exposed to a specific substance. That boundary is covered in the next section.

The practical instruction: when evaluating a model for a laboratory application, open the product page, scroll to the Materials and Treatments table, and read it part by part. Note the foot material, the leveler treatment, and the frame construction, not only the wheel material. If a specific part's material or treatment is not listed on the page you are reading, it is not published data and should not be assumed.

What our published data does and does not tell you

Zambus publishes the material and treatment of every part in a CarryMaster caster assembly. It does not publish chemical or solvent compatibility data for those parts. Neither this page nor any product page on zambus.com will tell you whether a given part will tolerate a given substance.

That boundary is not a gap to work around. It is the accurate description of what the catalog contains. Acting as though the published material names imply a compatibility rating would mislead a buyer making a real decision about real equipment.

What to do instead

If your laboratory uses specific substances that could contact the caster assembly, the following steps are more useful than any wheel-material claim:

Identify the specific substances in play and their concentrations. "Lab chemicals" is not a specification. The relevant question is whether a particular substance, at a particular concentration, will contact a particular part.
Bring the part list, not the product name, to whoever holds the compatibility data. The Materials and Treatments table on each product page gives you the part-level materials. That is the input a chemical supplier or materials engineer can work with.
Treat the foot and the plated steel as the primary exposure risk, not the wheel. The NBR foot and the zinc-galvanized leveler, pin, and shaft sit at or near floor level. Those are the parts a pooled spill reaches first.
Protect the floor path when exposure is routine. A caster is not a containment device. If contact with floor-level substances is a regular operating condition rather than an accidental spill, the floor and the caster path need to be addressed as part of the facility setup, not managed through caster selection alone.

The range boundary, stated plainly

CarryMaster does not offer phenolic, polypropylene, PTFE, or stainless steel wheels. If a compatibility requirement points to one of those materials, this range is not the right fit for that application. Saying so is more useful than a qualified answer that leaves a buyer guessing.

The wheel materials CarryMaster offers across the full catalog are: PA6 nylon, MC nylon, polyurethane, TPR, and rubber. Those are the options. The product pages publish the exact wheel material for each model.

Working out load per mounting point

The right caster capacity for a laboratory bench or instrument cart starts with the total loaded equipment weight divided by the number of casters, then increased by a safety factor of at least 1.5. Skipping the safety factor, or assuming all casters share the load equally, produces an undersized selection.

The calculation method

The steps are straightforward:

Establish the total loaded weight of the equipment: the frame, the work surface, all installed instruments, and the maximum anticipated load during use.
Divide by the number of casters under the equipment.
Multiply the result by a safety factor of at least 1.5.

The safety factor accounts for two real conditions: floors in laboratory environments are rarely perfectly level, so load distribution across four casters is rarely equal; and equipment loads change when drawers are opened, instruments are repositioned, or personnel lean on a bench.

A worked example

A mobile laboratory instrument cart weighs 180 lbs unloaded. It carries instruments totaling 240 lbs. Total loaded weight: 420 lbs. The cart runs on four casters.

420 lbs divided by 4 casters = 105 lbs per caster
105 lbs multiplied by 1.5 safety factor = 158 lbs required capacity per caster

The AC-50F or AC-50S at 110 lbs per unit would be undersized for this application. The ACT-400F or ACT-400S at 441 lbs per unit would be correctly rated with significant margin.

Dividing by four and selecting at the raw per-caster figure, without applying the safety factor, produces a caster rated at roughly two-thirds of what the application requires. The safety factor is not optional.

For a full treatment of the load capacity calculation, including how to handle asymmetric load distribution and equipment with fewer than four casters, see the caster wheel load capacity guide.

Wheel material and laboratory flooring

Wheel material selection for a laboratory floor is primarily a floor-interface decision: how the wheel rolls, how it distributes load, and how it interacts with the floor coating. It is not a shortcut to a compatibility claim.

Laboratory floors are commonly epoxy-coated, sheet vinyl, or sealed concrete. The wheel material affects how a caster performs on each of these surfaces:

PA6 nylon is a hard wheel. It rolls easily under load and requires less push force on smooth surfaces, but it concentrates load at the contact point and transmits more to the floor surface.
Polyurethane is softer. It spreads load across a larger contact area, which reduces point loading on the floor and generally produces a quieter roll on hard surfaces.
TPR and rubber wheels are softer still, with the highest floor protection and the most rolling resistance under heavy loads.
MC nylon is available in the range for higher-load applications. See the materials guide for a full comparison.

For a full comparison of wheel materials, tread characteristics, and floor interaction across CarryMaster's range, see the caster wheel materials and types guide.

Leveling a bench that has to sit still

Leveling casters are the right fit when a laboratory bench or workstation needs to move freely during repositioning and then hold a stable, non-rocking stance once placed. A standard swivel or rigid caster rolls but does not level; a leveling caster raises the wheel off the floor when the leveler is deployed, locking the equipment on its foot rather than its wheel.

For benches that carry sensitive instruments, an uneven floor under a non-leveling caster produces a rocking stance that no amount of shimming fully corrects. A leveling caster solves this at the point of installation.

For guidance on choosing between leveling caster types, deployment methods, and capacity ranges, see how to choose a leveling caster. Browse the full leveling casters range to find models verified for laboratory environments.

Stem or flange on a lab frame

The correct mount type depends on the attachment geometry of the equipment frame, not on the application category. A lab bench frame with a threaded socket takes a stem mount. One with a flat plate surface takes a flange mount. Matching the mount to the frame is the decision; the caster category follows from it. For a full comparison of stem and flange configurations, see the stem and flange caster mounting guide.

A short specification checklist

A laboratory caster specification is complete only when you have confirmed the load per mounting point, the mount geometry, the floor type, and the exact part-level materials for the specific model. Use this checklist before ordering:

Application type: bench, instrument cart, test rack, environmental chamber, or mobile workstation
Total loaded weight: frame, work surface, instruments, and maximum in-use load
Caster count: the number of mounting points on the equipment
Required capacity per caster: total loaded weight divided by caster count, multiplied by a safety factor of at least 1.5
Leveling or non-leveling: does the equipment need a stable locked stance once positioned?
Mount type: stem or flange, matched to the frame geometry
Floor type: epoxy, sheet vinyl, or sealed concrete
Model-level materials check: open the specific product page and read the Materials and Treatments table part by part
Compatibility requirement: if the application requires a published compatibility rating for a specific substance, that data is not available in this catalog

To explore models with published laboratory-environment positioning, browse the leveling casters and non-leveling casters ranges and open the Materials and Treatments table on each product page. If you have a known load and floor type and need help matching a model, contact us to specify.

Frequently asked questions

What are laboratory equipment casters made of?

Laboratory equipment casters are assemblies of multiple parts, each made of a different material, rather than a single uniform component.

The recurring construction across CarryMaster models includes a PA6 nylon wheel, an NBR nitrile rubber foot, zinc-galvanized Swrch 10A steel for the leveler, pin, and shaft, an ALDC12 aluminum die-cast or SPC steel frame, and an STB2 ball with Ni-Cr plating. The top plate is typically SPC steel, zinc galvanized.

There are 26 distinct material-table variants across the 29 CarryMaster models with published laboratory-environment positioning. Some models omit the handle entirely; some substitute a cup. The only reliable source for a specific model's construction is the Materials and Treatments table on its product page.

Which part of a caster is most exposed to a chemical spill?

The parts most exposed to a floor-level spill are the foot, the leveler, and the pin and shaft, because those components sit at or nearest to floor level where pooled liquid accumulates.

The frame carries a published description of corrosion-resistant structure on 30 CarryMaster product pages. That description applies to the frame construction, not to the wheel, and it describes a structural characteristic of the frame material and treatment, not a response to chemical attack.

The wheel contacts the floor surface but is elevated above a pool in normal use. The foot, in most CarryMaster models, is NBR nitrile rubber sitting directly at the base of the leveler.

Does Zambus publish chemical or solvent compatibility data for its casters?

No. Zambus publishes the material and treatment of every part in a CarryMaster caster assembly. It does not publish chemical or solvent compatibility data for those parts.

There is no compatibility chart, no exposure rating, and no list of approved substances anywhere in the catalog. This is not a data gap that will be filled on request; it is the accurate description of what the catalog contains.

If a published compatibility rating for a specific substance is required before specifying a caster, that data must come from a source other than zambus.com.

What wheel materials does CarryMaster offer?

CarryMaster offers five wheel materials across its full catalog: PA6 nylon, MC nylon, polyurethane, TPR, and rubber.

Across all 142 live product pages, polyurethane appears on 87 models, MC nylon on 45, rubber on 30, PA6 nylon on 24, and TPR on 18. A single model may be available with more than one wheel material option.

CarryMaster does not offer phenolic, polypropylene, PTFE, or stainless steel wheels. Those materials appear on zero of 142 product pages.

How do I calculate the load capacity I need for a laboratory bench or instrument cart?

The required capacity per caster equals the total loaded weight of the equipment divided by the number of casters, then multiplied by a safety factor of at least 1.5.

Total loaded weight includes the equipment frame, the work surface, all installed instruments or contents, and the maximum anticipated in-use load. It does not mean the empty equipment weight.

The safety-factor-adjusted figure is the number to match against a product's rated capacity. A caster rated exactly at the pre-safety-factor number is undersized for the application.

What safety factor should I use when specifying casters for lab equipment?

Use a safety factor of at least 1.5 when specifying casters for laboratory equipment.

The 1.5 factor accounts for floors that are not perfectly level, which means load distribution across four casters is rarely equal, and for in-use load changes caused by opening drawers, repositioning instruments, or personnel leaning on a bench or cart.

A caster operating at its rated limit under ideal conditions has no margin for the conditions laboratory environments routinely produce.

Do I need leveling casters for a laboratory workstation?

Leveling casters are the right choice when the workstation needs to move freely and then hold a stable, non-rocking stance once positioned.

Not every laboratory workstation requires leveling casters. A cart that moves frequently and does not need a locked stance can use non-leveling swivel casters. The relevant question is whether the equipment, once placed, needs to sit without rocking on a floor that may not be perfectly level.

Browse non-leveling casters for applications where positional stability is not a requirement.

Should I choose a stem or a flange mount for a lab bench frame?

Choose the mount type that matches the attachment geometry of the lab bench frame, not the application category.

A stem mount is correct when the frame has a threaded socket or a hole sized for a stem insert. A flange mount is correct when the frame has a flat plate surface with bolt holes.

If the original caster used a stem, the replacement should use the same stem diameter and thread pitch. If it used a flange, the bolt pattern and plate dimensions need to match. Substituting one mount type for the other requires a frame modification that is outside the scope of caster selection.

What wheel material suits an epoxy or sheet vinyl laboratory floor?

Polyurethane is generally the better choice for epoxy and sheet vinyl floors because it spreads load across a larger contact area and is less likely to mark or indent the floor surface under sustained load.

PA6 nylon is harder and rolls more easily, but it concentrates load at a smaller contact point. On a softer floor coating such as sheet vinyl, a hard wheel under a heavy bench can leave indentations if the equipment sits in one position for extended periods.

Rubber provides the softest contact and the highest floor protection but adds rolling resistance, which matters on manually moved equipment.

How do I find the exact materials used in a specific CarryMaster model?

Open the product page for the specific model on zambus.com and scroll to the Materials and Treatments table, which lists the material and surface treatment of every part in that assembly.

The table is published on individual product pages, not at the series or category level. Do not assume that all models in a series share the same materials; 26 distinct material-table variants exist across the 29 models with published laboratory-environment positioning.

An additional 19 CarryMaster product pages include the words "laboratory equipment" in their meta description but do not carry the laboratory-environment sentence in the visible body copy. When verifying a model's laboratory-environment positioning, confirm the statement appears in the visible page body, not only in a meta description.