Opti Cast Iron Dumbbell Set Review

This is about as cheap as real cast iron gets: black iron plates on spinlock bars, from Argos, for around £45, with 20kg total so roughly 10kg per hand. For a tight budget, or a first set to learn the movements, it does the job, and the iron itself lasts forever.

The compromises are the ones every budget cast iron set makes, and a couple specific to this one. The screw collars are slow, there is no carry case, and the bare iron needs the odd wipe to keep rust off. For a few pounds more the Men's Health box set adds quick spring clips and a case; for more weight and finer steps the PROIRON goes further. But as the cheapest honest iron, the Opti earns its place.

The Opti uses spinlock screw collars, the traditional kind you wind down the thread by hand. They hold securely, but they are slow: every weight change means unwinding two collars, swapping plates, and winding them back on firmly. Mid-workout, that is a real interruption, and if you do not tighten them fully they can rattle loose.

This is the main thing that separates it from the slightly dearer Men's Health set, which uses quick spring clips instead. If you will change weight often, that difference is worth the few extra pounds. If you tend to use one weight for most of a session, the screw collars matter less and the Opti's lower price wins.

Cast iron is the cheapest way to own real weight, and structurally it lasts forever. The catch is the surface: bare or painted iron can chip and surface-rust if it is stored somewhere damp or handled with sweaty hands and left unwiped. It is cosmetic rather than dangerous, and a wipe-down with a little oil keeps it in check, but it is upkeep that coated weights do not need.

There is no carry case here either, so the plates and collars live loose, which is worth planning storage for. None of this is a dealbreaker at the price, but it is the reality of budget cast iron: you trade a little convenience and upkeep for the lowest cost.

Great for

• The tightest budget for real cast iron
• Beginners learning the movements before committing more
• Anyone who tends to use one weight for most of a session
• Homes wanting same-day Argos collection

Not for

• Frequent weight changes (the screw collars slow you down)
• Anyone who will progress past 10kg per hand
• People who want zero upkeep or a tidy case (Men's Health, or coated weights)
• Dropping or heavy abuse

The Opti cast iron set is the budget-of-the-budget pick: real cast iron for around £45 from a high-street name, enough to start with at 20kg total. It is held back by slow screw collars, no case, and the upkeep bare iron needs. If those do not bother you and price leads, it is a sensible first set. For a few pounds more the Men's Health box set is nicer to use; for more weight the PROIRON goes further; and for no rust and drop-ability, rubber hex is the upgrade.