Pepin Adjustable Dumbbells: The Quebec Maker and the REP x Pepin FAST Series
Pepin adjustable dumbbells explained: the Quebec-made lines and the REP x Pepin FAST Series, compared by weight range, size, pop-pin mechanism and long-term wear.
Last updated September 2026
Contents13
- Four product lines, sold two ways
- FAST Series weight range and increments
- Size by ceiling weight
- How the pop-pin works
- Long-term wear, from two reviews
- Fine-tuning below the 5 lb step
- How the FAST Series compares to other heavy sets
- Storage at this weight
- Why the rail design stays short
- Check stock before you plan
- Care tips for a pin-and-rail set
- Who Pepin adjustable dumbbells suit
- Our verdict on Pepin adjustable dumbbells
Pepin adjustable dumbbells come from a small maker in Quebec, Canada. Pepin built its name on hand-made spin-lock and spring-pin dumbbells, sold at dumbbellpepin.com. REP Fitness later partnered with Pepin to mass-produce the design as the REP x PEPIN FAST Series (REP Fitness). This guide explains both versions, how the pop-pin works and who it suits.
Pepin adjustable dumbbells use a spring pin on a rail to pick the weight. The REP x Pepin FAST Series comes in pairs that top out at 60, 80, 100 or 120 lb per hand. It stays short for its weight. Its one repeat complaint is a cradle that can stick if you rack it carelessly.
Four product lines, sold two ways
Pepin's own site lists four lines: the FAST Series, the Olympic Series, the Pro Series and the HD Series. All ship direct from St-Ephrem de Beauce, Quebec (dumbbellpepin.com). Most shoppers will find the REP x Pepin FAST Series in stock. It is a mass-produced version of the same design, sold through REP's own store.
Pepin's direct Pro Series includes fixed cast-iron sets. It also offers adjustable handles rated 5 to 60 lb or 5 to 120 lb, sold without plates (dumbbellpepin.com). Complete Pro Series pairs come with plates in five set weights: 110, 150, 190, 230 and 270 lb. Stock on Pepin's site moves around. When we checked, every Pro Series listing showed as out of stock.
Pepin also sells its own FAST Series direct. That includes an adjustable kettlebell that the site says does not fit REP's hardware. Pepin lists its FAST pairs by total set weight: 160 lb (2 x 80), 200 lb (2 x 100) and 240 lb (2 x 120). Those match the per-hand ceilings REP sells, so both stores carry the same design at the same tiers. Add-on plates of 2.5 lb and 1.25 lb, plus a stand, are sold as separate items from both.
FAST Series weight range and increments
REP sells the FAST Series as four pairs by ceiling weight: 60, 80, 100 and 120 lb per hand. All start around 20 lb per hand and move in 5 lb steps (REP Fitness, Garage Gym Reviews). Optional add-on plates of 1.25 lb and 2.5 lb let you fine-tune below the 5 lb step. You can also offset each side to reach extra settings (Garage Gym Reviews).
A 120 lb ceiling puts the FAST Series in the heavy class of adjustable dumbbells. Our 100 pound roundup compares the sealed sets that reach that range and can be bought today.
Size by ceiling weight
Length grows with the ceiling you buy (Garage Gym Reviews):
| FAST Series pair | Length per dumbbell |
|---|---|
| 60 lb per hand | about 11.5 in |
| 80 lb per hand | about 13.5 in |
| 100 lb per hand | about 15.5 in |
| 120 lb per hand | about 17.5 in |
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That is short for the weight. A 120 lb adjustable dumbbell under 18 inches long beats most plate-loaded systems at that ceiling.
How the pop-pin works
The FAST Series does not use a twist handle or a dial. A spring-loaded pin rides on a rail beside the handle. Pull the pin out, slide it to the weight mark, and it pops back in and holds with a magnet (Garage Gym Reviews).
The handle is 38 mm thick, which is thicker than a standard Olympic barbell. It has an electroless nickel finish and volcano knurling. The plates are CNC-cut steel with a black powder coat. The rail uses UHMW plastic inserts where the pin rides (Garage Gym Reviews). REP's own listing confirms the steel plates and a fully knurled handle, with laser-marked weights on the rail.
Long-term wear, from two reviews
Two reviewers used the FAST Series for an extended time. Both point to the same strengths and one weak spot. Massenomics reported only minor cosmetic wear after about seven months. It praised the knurled handles, clean finish and dovetailed plates. Jungle Gym Reviews describes an all-steel build with UHMW liners to cut wear, solid enough to back a lifetime mechanism warranty.
The repeat complaint is the cradle. Massenomics notes that sliding a dumbbell back in at an angle can wedge a plate, most often when you are tired late in a set. REP has also announced lower-profile pins for the small 2.5 lb add-on plates, since the first design could catch on your hand.
Neither review reports wobble or rattle at rest. Jungle Gym Reviews does note slightly more plate play than the original Canadian-made Pepin. That comes with looser tolerances in mass production.
Fine-tuning below the 5 lb step
REP sells 2.5 lb add-on plates that slide onto the rail next to the main pin. They let you land between the standard 5 lb marks (Massenomics). That helps with warm-up ramps and drop sets, where a full 5 lb jump is too big. Offsetting each side with the same plates adds more options. It does take an extra step compared with a dial where every setting is built in.
How the FAST Series compares to other heavy sets
Pepin's 120 lb pair is not the only adjustable dumbbell built past the usual 50 to 80 lb range.
| REP x Pepin FAST (120 lb pair) | NUOBELL S 5100 | Ironmaster Quick-Lock (with kits) | |
|---|---|---|---|
| Ceiling per hand | 120 lb (125 lb in some listings) | 100 lb | 120 or 165 lb |
| Standard step | 5 lb, finer with add-ons | 5 lb | 2.5 lb |
| How you change weight | Spring pin on a rail, magnetic hold | Twist handle | Manual locking screws |
| Length | about 17.5 in at max | about 21.6 in | about 14.5 in at the 75 lb base |
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The pin-and-rail motion is faster than Ironmaster's hand-tightened screws. It is slower than a single twist or dial turn, since you slide a pin to a mark. For the highest ceiling in the shortest body, the FAST Series stands out. For the fastest change between sets, a twist or dial set wins, with a lower ceiling. Our NUOBELL adjustable dumbbells and Ironmaster adjustable dumbbells pages cover those two sets in full.
Storage at this weight
A 120 lb pair puts real load on whatever it sits on between sets. REP sells a matching stand built to hold the FAST Series at full weight (REP Fitness). If you buy one of the heavier pairs, budget for that stand. A tray made for a 50 lb twist set is not always rated for twice that load.
Why the rail design stays short
Most adjustable dumbbells grow longer as the ceiling climbs, because plates stack along the handle. Pepin's rail-and-pin design packs plates more tightly around the rail. That keeps the 120 lb pair under 18 inches. The trade-off, per both long-term reviews, is the cradle alignment issue. A shorter body saves real shelf space, but rack it with care.
Check stock before you plan
Stock varies between Pepin's direct lines and the REP version. When we checked, the Pro Series was out of stock on dumbbellpepin.com. The REP x Pepin FAST Series was the version on sale through REP's store. The two companies manage stock on their own, so check the exact listing you plan to buy.
Care tips for a pin-and-rail set
Slide each dumbbell straight down into the cradle, never at an angle. That one habit avoids the wedged plate both reviewers flag. Check that the pin has clicked fully home before you lift. Keep the rail free of chalk and grit, since dirt can slow the slide. Wipe the steel down if your gym gets damp.
Who Pepin adjustable dumbbells suit
The FAST Series fits a lifter who wants a short, high-ceiling dumbbell and doesn't mind a pin-and-rail motion. The 120 lb pair is unusually short for its class. Long-term reviews suggest the build holds up well if you handle the cradle with care. Pepin's Pro Series handles and sets are another option, but check stock and specs on dumbbellpepin.com first.
If you would rather buy a set with a steel switch from the same retailer, read our REP Fitness QuickDraw review. To compare twist, dial and block sets you can order today, see our best adjustable dumbbells roundup.
Our verdict on Pepin adjustable dumbbells
Pepin adjustable dumbbells are a real, well-built design from a small Quebec maker. The REP x Pepin FAST Series is the easy way to buy one, with pairs up to 120 lb per hand in a short body. It suits heavy lifters who want a compact set and will rack it with care. If you want the fastest change or a set you can order in more places, start with our roundups instead.
Questions people also ask
Is Pepin a real dumbbell brand?
Yes. Pepin is a small dumbbell maker in Quebec, Canada, known for hand-built spin-lock and spring-pin adjustable dumbbells sold at dumbbellpepin.com. REP Fitness later partnered with Pepin to mass-produce the design as the REP x PEPIN FAST Series, sold through REP's own store (REP Fitness, dumbbellpepin.com).
How does the Pepin FAST Series mechanism work?
It uses a spring-loaded pop-pin on a rail beside the handle. You pull the pin out, slide it to your weight mark, and it clicks back in and holds with a magnet (Garage Gym Reviews). It feels closer to a spring-pin barbell collar than a twist handle or dial.
How heavy does the Pepin system go?
REP sells the FAST Series in four pairs by ceiling: 60, 80, 100 and 120 lb per hand, all starting around 20 lb. Some listings put the same design at up to 125 lb per hand (REP Fitness, Garage Gym Reviews). Pepin's own Pro Series also offers adjustable handles rated 5 to 60 lb or 5 to 120 lb.
How does the FAST Series hold up over months of use?
Massenomics wrote a long-term review after about seven months of regular use. It reports only minor cosmetic wear and praises the knurled handles, clean finish and dovetailed plates. It also notes that a careless return to the cradle can wedge a plate, most often late in a workout when you are tired.
Does the Pepin FAST Series come with a warranty or a stand?
Jungle Gym Reviews describes an all-steel build with UHMW plastic liners on the plates and cradle bottoms. It says that build supports a lifetime warranty on the mechanism. A matching stand and storage cart are sold separately through REP Fitness.