When you're comparing trolleys, mobile workbenches or warehouse steps, it's easy to fixate on deck size and load capacity and skim straight past the castor line in the spec sheet. That's a mistake. The castors and wheels under a piece of mobile equipment decide how hard it is to push, whether it steers or wanders, how it behaves on rough ground and whether it stays put when parked. This guide explains what each part of a castor specification means, so you can judge heavy duty castors, wheel materials and brake options when choosing equipment. One honest note up front: we supply castors fitted to the trolleys, benches and steps we sell — not as loose components — so this is buyer education for choosing the right mobile equipment, not a castor catalogue.
Swivel vs fixed castors: how equipment steers
A swivel castor rotates 360° around its mounting, so the wheel trails behind the direction of push. A fixed castor rolls in one line only. The combination fitted determines handling:
- Two swivel + two fixed — the classic platform-truck layout. The fixed pair keeps the truck tracking straight down an aisle; the swivel pair (usually at the handle end) does the steering. Our GPC Apollo distribution trucks use exactly this pattern: two 200mm swivel rubber castors paired with two fixed pneumatic wheels.
- Four swivel — maximum manoeuvrability for tight workshops, lifts and congested floors. The trade-off is that the trolley can drift on long straight runs and on slopes. Bott's Perfo panel trolleys and Verso mobile cabinets run four-swivel layouts for exactly this reason — they live around workstations, not in transport aisles.
Braked castors: stability when parked
Any equipment someone works at — rather than simply moves — should lock still. The common industrial pattern is two braked swivel castors out of four, which is what you'll find across the Bott range: Verso mobile cabinets, maintenance trolleys and Cubio mobile benches all carry 125mm castors with brakes on two wheels. Mobile access equipment goes further: GPC Climb-It mobile steps use braked swivel castors or a locking system that raises all four wheels off the floor entirely, so the steps sit on solid feet while someone is on them. If people climb it or machine parts on it, insist on brakes.
Wheel diameter: why bigger rolls easier
Diameter is the single biggest influence on rolling effort. A larger wheel bridges cracks, thresholds and expansion joints instead of dropping into them, and needs less force to keep moving. Across our range you'll see the pattern: compact Bott Verso workstands ride on 100mm industrial castors, panel trolleys and mobile benches step up to 125mm heavy-duty castors, and the Apollo powered trucks — built to carry serious loads across yards — run 200mm wheels. As a rule of thumb, choose the largest diameter the equipment offers if your floors are anything less than smooth concrete.
Wheel materials: matching the tyre to the floor
- Rubber — quiet, floor-friendly and grippy; the standard choice for general warehouse and workshop trolleys. Slightly higher rolling resistance than hard wheels.
- Pneumatic — air-filled tyres that absorb bumps, kerbs and rough yard surfaces; fitted to the load-bearing end of our Apollo distribution trucks for outdoor work.
- Nylon and polyurethane — hard-running wheels common across the industry: nylon rolls easiest but is noisy and unforgiving on uneven floors; polyurethane splits the difference between rubber's grip and nylon's easy rolling. Where a product we list uses these, the wheel spec is stated on the product page.
Load ratings: read the whole spec, not just the castor
Castor load ratings are quoted per castor, but the figure that matters when buying equipment is the unit's stated total capacity — the manufacturer has already matched the castors to the frame. Two practical points still apply. First, uneven floors can momentarily throw most of the load onto two or three wheels, which is why quality makers over-specify castors rather than sizing them at exactly a quarter of the total load. Second, capacity claims assume an evenly distributed load: a concentrated point load in one corner of a platform truck works its castors far harder than the same weight spread across the deck.
What this looks like across our range
On mobile workshop storage, expect 100–125mm castors with two braked swivel wheels — enough to reposition a loaded cabinet, stable enough to work at. On platform trucks and distribution trolleys, expect larger diameters, swivel/fixed steering layouts and rubber or pneumatic tyres matched to indoor or yard use. On mobile safety steps, expect braked castors or retracting-wheel systems certified to EN 131. For more on choosing the equipment itself, see our guides to platform trolleys and trucks and mobile workbenches.
Castors & wheels FAQ
Should swivel castors go at the front or the back? On a two-swivel/two-fixed truck, swivels belong at the handle end — you steer from where you push, the fixed pair anchors the far end.
When do I need braked castors? Whenever the equipment is worked at while stationary — mobile benches, tool cabinets, panel trolleys — and always on mobile steps or platforms that people climb.
Pneumatic or solid wheels outdoors? Pneumatic tyres are kinder over kerbs, gravel and broken tarmac and reduce load-shake. Solid rubber avoids punctures and needs no pressure checks. For a yard with decent surfaces, solid rubber is the lower-maintenance pick.
Do you sell replacement castors? We supply castors fitted to equipment rather than as loose spares. If a castor on equipment bought from us needs replacing, contact us and we'll point you to the right manufacturer part.
All prices in GBP. Questions about whether a trolley or bench will cope with your floors? Get in touch — we're engineers, and we'll give you a straight answer.