SUMC · FLAT TOP CHAIN · SHIMANO
SL Super Light Flat-Top Chain — Shimano 12-Speed
SUMC's SLPRO 12-speed chain in a stealthy Black Diamond finish — the world's only Shimano-compatible flat-top chain, hollow-machined for ultra-light weight and sealed at every pin for long service life.
10,000 KM
Rated Riding Distance, Oil-Sealed Pins
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Flat-Top DesignSUMC is the only manufacturer producing a Shimano-compatible flat-top chain — a design otherwise exclusive to SRAM's own Flattop standard.
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Hollow-Machined Ultra LightPlates and pin shafts hollow-machined to 1-micron precision; pins hardened to 1600+HV with double-nitriding and titanium-nitride coating.
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SL, EL, or No Suffix: What the Name Tells You
SUMC's tier naming isn't just marketing — it describes exactly how the chain is machined. This is an SL (Super Light) chain: it has hollow pins AND cut-out side plates, the lightest construction SUMC builds, bringing this 12-speed flat-top chain down to just 256g. Step down a tier to EL and the pins become solid while the side plates keep their cut-outs, landing at 268.5g. Chains with no suffix at all use solid pins and solid side plates throughout — the sturdiest and heaviest of the three, at 274.3g. As more material is machined away, weight drops and price rises, so you can pick the tier that matches how much you're willing to spend to save grams.
| Tier |
Pins |
Side Plates |
Weight |
| SL |
Hollow |
Cut-out |
256g |
| EL |
Solid |
Cut-out |
268.5g |
| No suffix |
Solid |
Solid |
274.3g |
Why Are These Shimano Chains Flat-Top?
A lot of riders simply like the shape and feel of a flat-top chain — but until now, that design was locked to SRAM drivetrains only. SUMC set out to give Shimano riders more options, engineering a flat-top chain built specifically to run on Shimano systems too. The result is a chain shape that was previously off-limits to Shimano users, now available to them for the first time.
Shimano vs SRAM: What Actually Differs
Both Shimano and SRAM chains use the same nominal chain pitch at a given speed count, but each brand tunes inner link width, pin length, and outer-plate chamfering differently to match its own derailleur cage geometry, cassette tooth-ramp profile, and quick-link/master-link design — Shimano's own quick-link is built differently from SRAM's PowerLock/Flattop link. This entire SLPRO family is explicitly Shimano-tuned, not Sram: this chain is built to shift cleanly on Shimano derailleurs and cassettes. SUMC also produces a separate SRAM-tuned version of this chain at the same tier.
Why SUMC?
SUMC is the only manufacturer in the world producing a Shimano-compatible flat-top chain — a link-plate design otherwise exclusive to SRAM's own Flattop standard. Every pin is sealed with a rubber O-ring that traps lubricant inside the roller and bushing, lubricating from the inside out and rated by SUMC for up to 10,000 km of riding. Inner/outer plates and pin shafts are hollow-machined to a claimed 1-micron precision tolerance for less weight and faster dirt/sediment discharge, with pins hardened to 1600+ HV and finished with double-nitriding plus a titanium-nitride coating. The Black Diamond finish carries a 4-micron anti-corrosion coating, salt-spray tested to 1000+ hours, and is RoHS/REACH/CPSIA compliant.
Specifications
| Speed |
12-Speed |
| Compatibility |
Shimano 12-speed drivetrains |
| Link Design |
Flat-top (crescent) outer plate |
| Chain Pitch |
1/2" x 11/128" |
| Finish |
Black Diamond |
| Links |
126 |
SKU: SMC-SX12SLPRO-BKDM
