The 28mm collars secure discs onto standard-diameter barbells, keeping the load stable during presses, curls and high-volume sets. Sidea offers two complementary solutions: steel springs for quick disc changes and ‘lock pump’-style clip collars for mechanical locking.
Compatible with 28 mm diameter barbells (pump bars, standard barbells)
Two technologies: manual compression spring and clamping lock
Use in the weights room, pump classes and home gym

9019 Pair of Ø 50 mm steel disc spring retainers

Collar & spring

1656 Pair of steel springs Ø 28 mm

6,10€ FEES and TAXES NOT INCLUDED
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1657 Collar Lock Pump Bar Ø 28 mm

Collar & spring

1657 Collar Lock Pump Bar Ø 28 mm

7,63€ FEES and TAXES NOT INCLUDED
Add to cart

Guida completa: Collari 28mm

28mm Collars: A Complete Guide

The 28mm collars are the accessories used to secure discs and bumpers to standard-diameter barbells; the 28-millimetre size is used on pump bar barbells in group classes and on non-Olympic fitness barbells. Sidea offers two products designed for different scenarios: the pair of steel springs (item no. 1656) for the quick disc change typical of group classes, and the pump bar-style collar lock (item no. 1657) when a more secure mechanical lock is required. Both solutions are designed for barbells with 28 mm sleeves and are therefore not compatible with 50 mm Olympic barbells.

What is a 28mm collar: definition and function

The 28mm collar is a retaining device that is fitted to the ends of the barbell to prevent the discs from sliding sideways during exercise. The standard diameter — 28 mm — corresponds to the diameter of the sleeve on standard barbells, as opposed to Olympic barbells, which have 50 mm sleeves. An effective collar does two things: it keeps the discs centred on the sleeve and absorbs the micro-vibrations which, repetition after repetition, would tend to displace them. In the barbells used in pump classes, this is critical: hundreds of consecutive repetitions are performed, and a disc that shifts by 2 cm throws the entire sequence off balance.

The type of clamping mechanism determines how quickly the disc can be changed and the level of safety. The springs open with a light press of the fingers and are instantaneous, whilst screw- or lever-type clamps take a few seconds longer but offer greater hold under dynamic load.

Types of 28mm collars

Compression steel springs

The classic solution for standard barbells: two steel-wire handles that are squeezed manually to open the inner ring and allow the barbell to be fitted onto the sleeve. When the pressure is released, the spring secures the barbell by friction. Quick disc change, minimal space requirements, low cost. It is the long-standing choice of training centres with pump kit and commercial gyms with a range of fitness barbells.

Collar lock pump bar

Mechanical lock with screw or lever fastening on the barbell shaft. Compared to a spring, it provides a more stable grip when the load oscillates repeatedly — useful in exercises such as repeated clean and presses or consecutive thrusters. Part number 1657 is specifically designed for 28 mm pump barbells, where the total load remains modest but the number of repetitions is high.

Collars for curl bars and speciality bars

The same 28mm collars fit EZ curl bars and certain specialist bars with standard sleeves. In this case, the deciding factor is the length of the sleeve available for inserting the collar: short sleeves, such as those on curl bars, require narrow-profile collars so as not to interfere with the discs uploaded.

How to choose: a guide to use cases

Training room with pump classes

For a studio accommodating 20–30 participants per class, with continuous disc changes between sets, steel springs remain the best practical choice. The changeover time is 2–3 seconds per side, and the process is intuitive even for first-time participants. You need a spare partsor on a shelf: the springs become loose after 2–3 years of heavy use.

Personal training studios and home gyms

Those who train with fitness barbells in a controlled environment may wish to opt for the lock pump bar. Individual users will have no issues with the speed of bar changes and will benefit from a more stable grip during long sets. If your equipment also includes Olympic barbells, you should also consider the 50 mm collars.

CrossFit Box

In CrossFit boxes, standard-diameter bars are rare: most of the equipment is Olympic-sized. 28mm collars are only used if there are auxiliary barbells for isolation exercises or rehabilitation. In that case, the steel spring meets the requirement without the need for any additional investment.

Schools, public sports centres and amateur sports clubs

Schools almost always use 28 mm fitness barbells for reasons of safety and overall weight. Springs are included as standard, with a stock of spares proportional to the number of stations.

Technical glossary

Sleeve
The end section of the barbell onto which the weight plates are loaded. The diameter of the sleeve determines the compatibility of the collars and weight plates: 28 mm for standard barbells, 50 mm for Olympic barbells.
Standard barbell
A barbell with a 28 mm diameter sleeve, typical of fitness barbells, curl bars and pump bars. It has a lower stated weight capacity than Olympic barbells and is suitable for medium to low loads and high-repetition sets.
Pump bar
A lightweight barbell designed for Body Pump classes and bodyweight training with moderate resistance. Bar diameter: 28 mm; quick-release discs.
Collar lock
A mechanical locking system that secures the collar to the sleeve using a screw, lever or cam. It provides a tighter seal than springs during repeated cycles and under dynamic loads.
Compression spring
Steel wire collar with two handles which, when squeezed, open the inner ring so that it can be fitted onto the sleeve. Fastened by elastic friction.
Curl bar
W-shaped or EZ-shaped barbell for elbow flexion exercises. The handles are generally 28 mm in diameter and are often shorter than those on a straight barbell.
Shaft diameter vs sleeve diameter
The central bar of the barbell and the sleeve may have different diameters. For the collars, only the diameter of the sleeve matters — that is where the collar is fitted.

Comparison of 28mm Sidea collar models

CodeModelType of lockCompatibilityTypical use
1656Pair of steel springs Ø 28 mmManually compressed springStandard 28 mm barbells, curl bars, pump barsPump classes, training room, frequent disc changes
1657Collar Lock Pump Bar Ø 28 mmMechanical clamping28 mm fitness pump bars and barbellsLong sets, individual training, prolonged endurance

Frequently Asked Questions about 28mm collars

Answers to the most frequently asked questions about compatibility, differences compared to Olympic collars, durability and maintenance can be found in the FAQ section of the page.

Why choose Sidea

Sidea has been manufacturing and distributing professional fitness equipment since 1999, with its operational headquarters in Gambettola, Romagna, and a warehouse covering over 4,000 m². For our 28mm weight collars, we take the same approach as we do with all our barbell accessories: no over-the-top marketing, just the essentials to cover the two real operational needs — quick-release or mechanical locking — and stock availability for replacement in training centres. We are the official distributor for StrongFirst and Luxiaojun, we are sponsors of the Summit of Strength and exhibiting at FIBO. For those planning a new gym, we offer our Gym Design service with bespoke 3D renderings.

Domande frequenti - Collari 28mm

  • No. The 28 mm collars are only compatible with barbells featuring a 28 mm sleeve, i.e. standard barbells, curl bars and pump bars. Olympic barbells have 50 mm sleeves and require collars specifically designed for that size. Always check the sleeve diameter before purchasing: measure it at the end where you load the discs, not on the central shaft.
  • It depends on the context. Steel springs (item no. 1656) are quicker to fit and remove, making them ideal when you change discs frequently during a session — which is typical of pump classes. The collar lock (item no. 1657) provides a more stable mechanical hold during long sets or exercises involving repeated swinging movements. In group exercise studios, springs are predominantly used; in home gyms or personal training studios, the collar lock is often preferred.
  • Yes, with intensive use, the spring gradually loses its elasticity. In a studio running 15–20 pump classes a week, the typical service life is 2–3 years, after which the spring’s tension decreases and it is advisable to replace the pair. In home settings or personal training studios, the lifespan is considerably longer. A quick test: if the spring does not spring back into position immediately after being compressed, it is time to replace it.
  • The main limitation is not the collar but the length of the barbell sleeve. On standard fitness barbells and pump bars, the sleeve typically accommodates 3–5 weight plates per side, after which there is no space left for the collar. Also bear in mind that 28 mm barbells have a lower load capacity than Olympic barbells: always check the stated load capacity of your barbell.
  • Only if the bumpers are designed for a 28 mm hole — they do exist but are less common than standard Olympic bumpers. Most bumpers on the market have a 50 mm hole and are designed for Olympic barbells. If you’re using 28 mm barbells, use rubber-coated cast iron discs or dedicated ‘pump’ discs, which have a hole that matches the barbell’s sleeve.
  • No, both competitive and amateur powerlifting use Olympic barbells and 50 mm collars, typically the competition version with a quick-release lever mechanism. 28 mm collars are used for a different range of applications: fitness barbells, pump classes and curl bars for isolation exercises. For heavy squats, bench presses and deadlifts aimed at maximum strength, you need full Olympic equipment.
  • The collar is slipped onto the sleeve after the discs have been loaded; it is positioned so that it is in contact with the last disc, and the screw or clamping lever is tightened until the collar is securely locked onto the rod. There is no need to use excessive force: a firm tightening is sufficient. To remove it, loosen the mechanism and slide it off. With practice, this becomes second nature and takes just a few seconds.
  • The pair of steel springs (item no. 1656) is sold as a pair – two pieces per barbell. For the collar lock pump bar (item no. 1657), please check the sales configuration on the product sheet, which specifies whether the item number refers to a single piece or a pair. You always need two collars on a barbell, one on each side.
  • No, the Sidea lock pump bar clamps are tightened manually using the screw or the built-in lever, without the need for keys or tools. The design is intended for everyday use in the gym, where quick and repeatable operations are required. Only in the event of exceptional maintenance — such as replacing the screw or cleaning the internal mechanism — might a standard screwdriver be required.
  • Mechanically speaking, yes, but springs made of untreated steel tend to rust quickly in damp environments or when exposed to the elements. If the equipment is permanently located in an outdoor gym or an unheated space, consider replacing the collars more frequently or protect them by storing them indoors after use. Lock collars with a body made of engineering plastic are less susceptible to moisture.
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  • Yes, Sidea is an authorised supplier on the MEPA (Public Administration Electronic Marketplace). Public bodies, schools, universities, local authorities and public sports facilities can purchase Sidea equipment via the Acquisti in Rete PA platform. For information on product codes and direct MEPA orders, please contact Sidea customer service.
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  • Sidea has been designing and distributing professional fitness equipment since 1999: over 25 years’ experience serving gyms, sports coaches, CrossFit boxes, personal training studios and enthusiasts of advanced home fitness. Official distributor for StrongFirst and Luxiaojun, exhibiting at the FIBO international trade fair and technical sponsor of the Summit of Strength. Every product is developed with a focus on durability, functionality and suitability for real-world use. The Gym Design service offers bespoke design with 3D renderings. A warehouse covering over 4,000 m² in Gambettola (FC) ensures rapid order fulfilment, direct technical advice and a special price list for professionals and amateur sports clubs (ASD).