Grip is decided by three things: the handle material, the knurling pattern cut into it, and the handle diameter. The BrainGain SmartBells Pro range uses a knurled steel handle, which holds a sweaty grip far better than the smooth moulded plastic or rubber handles fitted to most dial sets. If you train heavy, do high-rep pulling, or your hands sweat, a knurled steel handle is the single upgrade you will notice on every set.
Nobody shops for a dumbbell by its handle. Then you get 40 kg overhead with damp hands and the thing starts rotating in your palm. Grip is the part of an adjustable dumbbell you touch on every rep, and it varies more between brands than the plates do. Here is what actually matters.
What Knurling Actually Is
Knurling is the crosshatch pattern machined into a steel handle. The raised diamonds give your skin something to key into, so the bar does not rotate when your hand is damp. It is standard on barbells for exactly this reason, and it is the reason a gym dumbbell feels secure while a smooth plastic handle feels slippery.
Knurling comes in depths. Passive knurling is shallow and comfortable but offers less bite. Aggressive knurling grips hard and can tear skin on high-rep work. Most quality equipment sits in the middle, which is where the SmartBells Pro handle sits: enough bite to hold a heavy press, not so sharp that a set of twenty curls shreds your palms.
Handle Types Compared
| Handle type | Knurled steel (SmartBells Pro) | Moulded plastic | Rubber or foam sleeve | Smooth chrome |
|---|---|---|---|---|
| Grip when dry | Excellent | Fair | Good | Fair |
| Grip when sweaty | Excellent | Poor | Fair | Poor |
| Works with chalk | Yes | Barely | No | Slightly |
| Wears over time | Very slowly | Can polish smooth | Tears and compresses | Polishes smooth |
| Feels like a gym dumbbell | Yes | No | No | Partly |
| General handle-type behaviour based on BrainGain handling tests, August 2026. Rival handles shown as generic types, not specific brands. | ||||
The pattern is clear. Knurled steel is the only option that holds up once your hands are wet, and the only one chalk genuinely helps. Rubber sleeves feel pleasant in the shop and compress or tear within a year of hard use.
Handle Diameter Matters More Than People Think
A handle that is too fat forces your fingers open and turns every set into grip training whether you wanted it or not. Too thin and the weight digs into your palm. Standard gym dumbbells sit in a comfortable middle band, and good adjustable dumbbells copy that.
This is a common failure of block-style sets. Because the selector cage wraps around your hand, the effective grip space is constrained and the handle sits inside a frame rather than free in your palm. It is not a knurling problem, it is a geometry problem, and no amount of grip texture fixes it. The round-head BrainGain design leaves the handle open on both sides, so your hand sits where it would on a fixed dumbbell.
Where Each BrainGain Set Lands
1. SmartBells Pro range: knurled steel, best grip
The Pro line is the one to buy if grip is your priority. The machined knurl holds through sweaty pressing and heavy rows, it takes chalk properly, and it will not polish smooth the way plastic does. The 41.5 kg Pro is the pick for heavy lifters, and the 23.5 kg Pro is the entry point into the same handle.
2. SmartBells 40 kg and 24 kg: secure grip, better value
The standard SmartBells 40 kg and 24 kg use a textured handle rather than machined steel knurling. For most home training that is entirely sufficient, and they keep the open round-head geometry that lets your hand sit naturally. If you are not chasing maximal grip and want the best price per kilogram, these are the smarter buy. See the cost-per-kilo breakdown for that maths.
When Grip Is the Deciding Factor
Three cases. If you pull heavy, rows and Romanian deadlifts load the grip hard, and a slipping handle ends the set before the muscle does. If your hands sweat, plastic handles become genuinely unsafe overhead. And if you use chalk, only a knurled steel handle gives the chalk something to work with.
If none of those apply, and you train in the 10 to 15 rep range with moderate weight, handle texture matters much less. Buy on range and price instead, and read the full buyer's checklist.
Looking After a Knurled Handle
Wipe the handle down after sweaty sessions, because salt is what corrodes steel. Do not oil it, since oil fills the knurl and kills the grip. If the knurl ever clogs with chalk, a dry nylon brush clears it in seconds. Done that way a steel handle outlasts every other part of the dumbbell.
Frequently Asked Questions
Which adjustable dumbbells have knurled handles?
Is a knurled handle better for adjustable dumbbells?
Does knurling hurt your hands?
What handle diameter is best?
How do I stop a handle rusting?
- BrainGain SmartBells Pro 41.5 kg, €689, chrome, knurled steel handle, eu.braingain.fit, checked 24 August 2026. eu.braingain.fit
- BrainGain SmartBells Pro 23.5 kg, €469, eu.braingain.fit, checked 24 August 2026. eu.braingain.fit
- BrainGain SmartBells 40 kg, €449, eu.braingain.fit, checked 24 August 2026. eu.braingain.fit
- Handle material and knurling behaviour, BrainGain handling test notes, August 2026.
Best grip: BrainGain SmartBells Pro
Knurled steel handle. Open round-head geometry. EU delivery from Hamburg.