Adjustable Dumbbells: Dial, Pin, and Thread Types Compared

Adjustable dumbbells come in three main designs: dials or twist handles, pins or switches, and threaded screws or collars. Dials are quick, pins and switches let you see what’s locked, and threaded handles are cheapest per pound and slowest to change. As of Nov 2026, a pair near 50 lb lists from about $470 to about $620. Check recalls before anything else, because one notice covered about 3,844,200 BowFlex units. Our strength accessories guide compares them with fixed sets.

Dial, pin, and thread types

Dials and twist handles

You turn a dial or handle while the dumbbell sits in its tray, and the mechanism picks up the plates.

• BowFlex’s 552 runs from 5 to 52.5 lb with 15 settings. The 1090 runs from 10 to 90 lb with 17 settings.
• NUOBELL uses a twist handle, with 5 to 50 lb and 5 to 80 lb pairs in 5 lb steps.

You rely on parts you can’t see, and this is the design family with the biggest recall.

Pins and switches

A pin or switch locks the handle to a chosen number of plates.

• PowerBlock is the classic pin design.
• REP Fitness’s FAST Series, developed with a Canadian inventor, uses magnetic pop-pins on side rails and goes from 10 to 125 lb.
• REP Fitness’s QuickDraw uses flip switches, cycle-tested 100,000 times by the maker’s account, from 5 to 60 lb.

A pin isn’t automatically safe. The recalled ProForm Rapid Strike set used a manual selection pin.

Thread and screw-on

You add plates by hand and lock them with a threaded piece.

• Titan’s 200 lb chrome set has 19.5-inch threaded handles, four lock collars, and 24 plates. It goes from 5 to 100 lb per dumbbell. Titan rates the handle for 150 lb.
• Ironmaster’s Quick-Lock uses locking screws and chrome-plated steel handles, from 5 to 45 lb in 2.5 lb steps.

Collars still matter here. The CPSC recalled about 77,200 Impex dumbbell handles in 2021 because locking collars could slip. Those were Olympic plate handles, but the warning carries over.

Expandable adjustable dumbbells and expansion kits

Expandable adjustable dumbbells let you buy a lower top weight now and add plates later.

Do the math before you commit. For QuickDraw, buying a 30 lb pair at about $335 plus six add-ons at about $240 comes to about $575, which is the 60 lb pair’s price. Buying in stages costs nothing extra there before shipping, but price the whole path on any system.

Length matters too. QuickDraw grows from 12.2 inches at 30 lb to 18.5 inches at 60 lb, because more plates sit on each end. If you’ll never lift the top stage, don’t pay for it.

Weight steps and length

Steps. Jumps of 2.5 lb help most on small lifts, where 5 lb is a big percentage. Ironmaster moves in 2.5 lb steps, and BowFlex’s 552 does up to 25 lb. NUOBELL, QuickDraw, and the FAST Series move in 5 lb steps, and the last two offer 2.5 lb if you accept a small imbalance.

Length. Long dumbbells can hit your thighs on curls or get in the way at the bottom of a press, in our judgment. Ironmaster is 9 inches at 20 lb and 11.5 inches at 45 lb, the shortest we found at that load.

Drop policy

For a commercial floor, read the commercial terms. PowerBlock sells a commercial model with a 1-year commercial warranty, while Ironmaster’s lifetime terms cover home use by the original owner.

Adjustable dumbbell recalls

These are the CPSC’s figures, and they matter most if you’re buying used.

On the BowFlex notice, Johnson Health Tech Trading had 12 reports and no injuries on units it sold, and Nautilus had 337 reports, including 111 with injuries such as concussions and broken toes. Sales ran from as early as 2004 through May 2025, and only listed serial ranges are covered. Its 3.7 million headline covers Nautilus’s sales alone.

Plates dislodging is the shared hazard in nearly all of these. Remedies differ, from new trays to refunds in voucher form, so follow the notice for your model.

• Find the label. BowFlex’s model and serial number are on a sticker under the tray. FitRx prints them on the side of the tray.
• Search by name. Look on the CPSC site before you buy any used pair, and stop using a recalled set right away.
• Read the absence carefully. We didn’t see PowerBlock, Ironmaster, NUOBELL, or QuickDraw in a CPSC title search for “dumbbell.” That isn’t proof of safety.

BowFlex still sells models named 552 and 1090, with current listings describing metal parts. The notice doesn’t address those, so check any serial number.

What the research says

There isn’t any we can use. Our database search found no comparison of adjustable and fixed dumbbells, and nothing on mechanism types or failure rates. The recall data is the closest thing to durability evidence, and it counts reports, so it can’t give a failure rate by design.

Published specs by model

Price tiers

Compare by top weight, and remember that all of these are pairs. A fixed 5 to 50 lb hex set lists around $1,100 for scale.

Safety

• Check the lock every set. Look and listen for a pin, switch, dial, or screw that hasn’t fully seated, and for rattling that’s new.
• Follow the tray rules. Several designs only adjust nested in the tray. Keep it flat, and replace a cracked one.
• Lift clear of your feet. Plates dislodging is the recurring hazard, so keep your feet and head out of the line of a falling plate during overhead and seated work.
• Stop for sharp pain. If you have a joint or back condition, talk to a physician or physical therapist before training heavy.