MX Fitness Supply Adjustable Dumbbells Review 2026: Are the MX55, MX70 & MX100 Worth It?

Adjustable dumbbells have been dominated by two names — Bowflex and PowerBlock — for years. MX Fitness Supply, a company out of Rochester, Minnesota, is trying to take them on with a different mechanism: a patented rack-and-pinion design it calls the Positive Lock System. The pitch is simple — instead of a twist dial or a sliding pin, you select a weight and it locks in place with no wobble, no loose plates and no guesswork.

The 2025 lineup is called the EVO Series, and it spans three dumbbells (55, 70 and 100 lb), an adjustable barbell/curl bar, a bench, and a handful of accessories. Everything is built for a home gym, and everything ships with a two-year warranty.

How the Positive Lock System Works

Most adjustable dumbbells change weight with a rotating dial that you turn to slide plates in and out. MX’s approach is different: a rack-and-pinion mechanism where the handle sits in a cradle, you turn a selector to the weight you want, and the plates engage with a positive, mechanical lock. The selling point is confidence — when you lock in 70 lb, it is 70 lb, held rigidly, with nothing rattling loose mid-set.

• Select: dial in the weight on the cradle while the handle is docked.
• Lift: the handle locks the selected plates; the rest stay in the cradle.
• Drop: the positive lock is rated for short drops, backed by the 2-year coverage.

What You Actually Pay

A pair of MX55s at $449 puts MX slightly under Bowflex’s SelectTech 552 at list price, but the gap narrows at the heavier end — the MX100 pair is a serious investment. The headline trade-off: you are paying for the lock mechanism and a knurled steel handle, not a budget build.

The Lineup at a Glance

Ten products, from an $79 plate upgrade to a $899 barbell system. Tap any card to see it on the official site.

MX55 Evolution Series Dumbbells

$449

55 lb per dumbbell — the entry point of the 2025 EVO line.

MX70 Evolution Series Dumbbells

$649

70 lb per dumbbell, upgradeable to 100 lb with a conversion kit.

MX100 Evolution Series Dumbbells

$849

100 lb per dumbbell — the top of the adjustable range.

MX30 Rapid Change Dumbbells (7.5–30 lb)

$199

Clearance — the previous-gen model at a steep discount.

MX125 EVO Adjustable Barbell / Curl Bar

$899

Straight bar + EZ-curl bar, 30–125 lb, with its own stand.

MX Select Adjustable Training Bench

$229

Fully adjustable (-5° to +85°) with six backrest positions.

MX Select EVO Dumbbell Stand

$199

Storage stand for the MX55 / MX70 / MX100 EVO dumbbells.

MX 70-100 EVO Conversion Kit

$279

Upgrade an MX70 to 100 lb with 12 extra weight plates.

MX EVO Micro Weight Plate Upgrade

$79

Smaller increments for finer progressive overload.

MX Select Impact Pads (Pair)

$89

EVA foam pads to protect floors from dropped dumbbells.

What’s Good

The positive lock genuinely feels more secure

The single biggest complaint about twist-dial dumbbells is plates that rattle or feel loose. The rack-and-pinion lock removes that — the weight is held rigid, which matters most on pressing movements where a wobble is unsettling.

A knurled steel handle is a real differentiator

Rubberised or smooth handles are fine for casual use, but serious lifters want knurl — the textured steel grip that stops your hands slipping on heavy sets. MX offers knurled handles as an option, which is unusual at this price point and a genuine plus.

The weight range is genuinely expandable

The MX70 can be upgraded to a 100 lb set with the conversion kit, so you are not forced to buy a whole new set as you get stronger. That is a smarter buy-in than a dumbbell that tops out with no upgrade path.

A real warranty with drop coverage

Two years on manufacturing defects, with a parts-coverage upgrade that even covers drop damage from 32 inches or less. That is more generous than most adjustable-dumbbell warranties.

Pros & Cons

The Honest Downsides

This is the part the marketing skips, and it matters:

You are paying a premium for the mechanism

At $449–$849 a pair, these are not the budget option. A standard set of fixed hex dumbbells costs less for the same total weight — but takes up a wall of space. What you are really paying for is the space saving and the lock, and whether that is worth the premium is the honest question to ask yourself.

The brand is younger

Bowflex and PowerBlock have been around for decades and have huge user bases and repair ecosystems. MX is a smaller, newer company — the products are well reviewed, but the long-term durability record is simply shorter.

Changing weight is not instant

The rack-and-pinion design trades a little speed for security. You dock the handle, dial the selector, and lift — a few seconds per change. That is fine for most training, but if you do high-speed drop-sets, a magnetic or dial system might feel faster.

Read the clearance listings carefully

The B-stock and clearance units are discounted for cosmetic blemishes or because they are the previous generation. They are still covered by warranty, but the older MX30, for example, is not compatible with the new EVO plate upgrades.

Who It’s For (and Who Should Skip It)

This is for the home lifter who wants a full dumbbell rack in one footprint and is willing to pay for a secure, well-built mechanism — especially anyone who values a knurled handle and a real warranty. Skip it if you are on a tight budget, if you rarely lift heavier than 30–40 lb, or if you already own a set of adjustable dumbbells that is serving you fine.

Buying Tips

• Buy the weight you will grow into. The MX70 with a conversion kit is the smart middle path — you are not locked out of heavier work later.
• Get the stand or the pads. The dumbbells are heavy; a stand keeps them off the floor and the impact pads protect your flooring if you train to failure.
• Check clearance first. The MX30 and B-stock units are the cheapest way into the system if you do not need the newest EVO plates.

Frequently Asked Questions

Final Verdict