A dumbbell set that converts into a 40kg barbell without any additional equipment.

The Bitumen Adjustable Dumbbells 2x 20kg operates as two independent dumbbells for isolation training and, with the included connector rod, joins into a single 40kg barbell for compound lifts. All plates are rubber-coated cast iron on standard 28mm bars, and four spin-lock collars hold the loading configuration fixed during use. The complete set totals 40kg and arrives ready to use out of the box.

Each dumbbell is loaded with 3kg, 2.5kg, and 1.25kg rubber-coated plates, giving you multiple weight combinations below the 20kg maximum on each side. Add or remove plates to set the right load for each exercise, then tighten the spin-lock collar before your first rep. The connector rod threads directly onto the existing bar ends, so switching from dumbbell to barbell mode takes less than a minute without any tools.

Floor protection built into the design.

The rubber coating on every plate serves a practical function beyond aesthetics. Hard flooring common in home and apartment settings takes cosmetic damage quickly from bare cast iron, and the rubber layer on these plates prevents that contact entirely. This applies both during training, when plates shift slightly during loading, and during storage, when plates are rested on the floor between sessions.

Noise reduction is the second effect. Rubber-coated plates seat more quietly against the bar collar during loading changes, and the sound of setting the dumbbell down between sets is noticeably lower than bare iron on hard floors. For households in shared buildings or with noise-sensitive neighbours, this is a practical advantage that bare-iron sets do not offer.

Here is why the Bitumen Adjustable Dumbbells 2x 20kg is the best choice for our customers.

This set was designed for people who want a single purchase that covers both dumbbell and barbell training without requiring a rack, a separate barbell, or multiple sets of fixed weights. The 40kg combined capacity handles a broad range of exercises across upper body, lower body, and core training.

The rubber-plate construction addresses a real limitation of standard cast iron sets in home environments, where floor protection and noise management matter as much as load capacity.

Here are 6 reasons we believe the Bitumen Adjustable Dumbbells 2x 20kg is the right fit for your household.

Two Training Modes from One Purchase

Two 20kg dumbbells and a connector rod give you the full function of a dumbbell pair and a 40kg barbell without buying two separate pieces of equipment.

Rubber Plates Protect Your Floors

The rubber coating on every plate prevents scratches and scuffing on tile, marble, hardwood, and laminate surfaces, making this set usable directly on home flooring without a mat.

Spin-Lock Collars Hold Under Load

The threaded collar system keeps plates locked against the bar during pressing, pulling, and hinging movements. There is no spring-based mechanism to weaken or fail over time.

20kg Per Dumbbell Covers a Wide Training Range

At up to 20kg each, the dumbbells support a full programme of upper body and lower body work, from lighter accessory movements through to loaded single-leg and bilateral compound exercises.

Standard 28mm Hole Diameter

All plates are drilled to the 28mm standard, so they are compatible with other conventional bars you may already own or purchase separately.

Compact Storage Profile

Two loaded dumbbells and a connector rod store in a small floor space or a sports bag. There is no rack, no frame, and no permanent footprint required.

Frequently Asked Questions

How does the barbell conversion work, and do I need tools?

Thread the connector rod into the end cap of one dumbbell bar by hand, then screw the second dumbbell bar onto the rod’s other end. No tools are required. The joined assembly produces a single barbell loaded with all the plates from both dumbbells, up to 40kg total.

What plate combinations are available per dumbbell?

Each dumbbell includes 4x 3kg plates, 2x 2.5kg plates, and 2x 1.25kg plates. Loading all plates brings each dumbbell to 20kg. Removing plates in any combination allows you to set a lower working weight to suit the exercise.

Are the rubber-coated plates safe to use on ceramic tile and marble floors?

Yes. The rubber outer layer prevents direct metal-to-floor contact and absorbs the force of the dumbbell being placed down. This makes the set suitable for use on the hard flooring typical of home interiors without placing a gym mat underneath.

Are the handles comfortable for high-rep sets?

The plastic-coated 28mm handles provide a smooth, non-abrasive grip surface. They are suited to higher rep work where bare knurled steel would cause discomfort, though users who prefer aggressive knurling for heavy low-rep work may find the finish less secure under maximum loads.

Can I use the plates with other bars I already own?

Yes. The 28mm bore is a standard size that fits the vast majority of conventional dumbbell and barbell bars on the market. The rubber coating does not affect plate compatibility.

What is included in the set, and is anything sold separately?

The complete set includes two dumbbell bars, all rubber-coated plates (4x 3kg, 2x 2.5kg, 2x 1.25kg per bar), four spin-lock collars, and one connector rod. Nothing additional is required to begin training with both configurations.

Complete Set Weight	40kg
Configuration	2 x 20kg adjustable dumbbells, convertible to 1 x 40kg barbell
Plates Per Dumbbell	4 x 3kg, 2 x 2.5kg, 2 x 1.25kg
Plate Material	Rubber-coated cast iron
Bar Material	Plastic-coated steel
Bar Diameter	28mm (standard)
Plate Hole Diameter	28mm (standard)
Collars	4 x threaded spin-lock
Connector	1 x barbell attachment rod
Colour	Black
Warranty	2 years

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Bitumen Adjustable Dumbbells 2x 20kg

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A dumbbell set that converts into a 40kg barbell without any additional equipment.

Rubber-Coated Cast Iron Plates

Threaded Spin-Lock Collars

Connector Rod Barbell System

Plastic-Coated Steel Handles

Floor protection built into the design.