Motorcycle Chain Sizes Explained

The three-digit number on every chain’s outer plate encodes pitch and width. Both must match your sprockets exactly — one wrong digit means the chain won’t work. This guide decodes the numbering system and shows which size fits which machine.

Find Your Chain Size

How to Read a Motorcycle Chain Size Number

Motorcycle chain sizes are encoded in a three-digit code stamped on the outer plate of every chain. The code is not arbitrary — the first one or two digits encode the pitch (the distance between adjacent pins), and the last two digits identify the inner width family. Under JIS B 1801, the standard governing all motorcycle chain dimensions in Japan and Korea, these two values completely define sprocket compatibility requirements.

Decoding “428” and “520” — the two most common pitches

Pitch = 4/8 inch

= 12.700 mm
Applies to: 415, 420, 428

Width code “28”

Inner width = 7.85 mm
Specific to 428 family

Pitch = 5/8 inch

= 15.875 mm
Applies to: 520, 525, 530

Width code “20”

Inner width = 6.35 mm
Specific to 520 family

Note: width code numbers are identifiers — they do not convert directly to millimetres. Always verify against the published JIS B 1801 specification table.

The suffix letters after the base code identify the chain variant: no suffix = standard non-sealed; H = reinforced heavier plates; O = O-ring sealed; X = X-ring sealed; SX = Super X-ring sealed. So “525H-SX” is a 15.875 mm pitch, 7.94 mm inner width, H-grade reinforced Super X-ring sealed chain.

The width code is not a decimal measurement. “20” does not mean 2.0 mm — it identifies the 6.35 mm inner width family of the 520 series. Always use the published specification table rather than deriving measurements from the code number.

The Five Main Motorcycle Chain Sizes in Detail

Two pitch families cover all five sizes: the 12.700 mm (1/2-inch) family for smaller machines, and the 15.875 mm (5/8-inch) family for mid-range and larger machines. Within each pitch family, inner width varies to match the torque capacity and sprocket geometry requirements of different engine classes.

420

420 — Lightest in the 1/2-Inch Family

The 420’s 6.35 mm inner width makes it the narrowest of the 12.70 mm pitch family. At 0.57 kg/m, a 100-link 420 chain weighs approximately 570 g — for a 65–80 kg scooter, this chain weight relative to the machine’s total mass is more significant than it would be on a 200 kg touring bike. Fitting a 428 where a 420 is specified would add 140 g of rotating mass for no measurable strength benefit at 50–125cc power levels.

Pitch: 12 700 mm
Inner width: 6.35 mm
Roller Ø: 7.77 mm
Tensile: 15,6 kN
Weight: 0.57 kg/m
Typical use: 50–125cc scooters, mini bikes

428

428 — The Most Widely Used Worldwide

The 428 is the highest-volume single chain size in the global aftermarket. Sharing pitch with the 420, it adds inner width (7.85 vs 6.35 mm) and roller diameter (8.51 vs 7.77 mm), giving a larger tooth contact area. The standard 428 at 17.8 kN covers most 125–250cc engines; the 428H at 20.6 kN handles the higher-output end without any sprocket change. Its versatility across dirt bikes, street bikes, scooters, dual-sports, and cruisers in the most populated displacement class makes replacement parts universally available.

Pitch: 12 700 mm
Inner width: 7.85 mm
Roller Ø: 8.51 mm
Tensile: 17,8 kN
Weight: 0.71 kg/m
Typical use: 125–250cc street, dirt, enduro

520

520 — Lightest in the 5/8-Inch Family

The 520 moves to the 15.875 mm pitch family — longer pitch means larger roller contact radius at the sprocket tooth, distributing load over a greater arc. Its 6.35 mm inner width — the same as the 420 despite the longer pitch — makes it the narrowest and lightest of the three 5/8-inch variants at 0.91 kg/m. For sport bikes where minimising rotating mass matters, the 520 is the natural specification: a 520H-X at 34.0 kN gives sealed performance at a weight comparable to a standard 530.

Pitch: 15,875 mm
Inner width: 6.35 mm
Roller Ø: 10.14 mm
Tensile: 26,5 kN
Weight: 0,91 kg/m²
Typical use: 250–600cc sport, naked, inline-4

525

525 — The Balance Point Between 520 and 530

The 525’s 7.94 mm inner width is 1.59 mm wider than the 520 and 1.59 mm narrower than the 530. That wider roller provides more tooth-face contact area than the 520 — distributing load across a broader band of the sprocket tooth at a given chain tension. The trade-off versus the 520 is modest: 0.98 vs 0.91 kg/m, a difference of 70 g per metre. The 525 is typical OEM specification for adventure bikes, parallel-twin naked bikes, and sport tourers in the 650–750cc class.

Pitch: 15,875 mm
Inner width: 7.94 mm
Roller Ø: 10.14 mm
Tensile: 26,5 kN
Weight: 0.98 kg/m
Typical use: 400–750cc adventure, naked twin

530

530 — Widest Standard, Highest Peak Strength

The 530’s 9.53 mm inner width makes the broadest tooth-face contact of the three 15.875 mm variants. At 1.09 kg/m for the standard, it is the heaviest — but on a 250 kg touring machine this is not a meaningful consideration. The strength advantage of the 530 family appears clearly in the SX-grade: the 530-SX at 43,0 kN is the highest tensile strength in the Korea Ever-Power range. For a fully-loaded touring motorcycle where combined mass exceeds 450 kg, the 530-SX’s structural margin over the working load is both technically sound and practically reassuring.

Pitch: 15,875 mm
Inner width: 9.53 mm
Roller Ø: 10.14 mm
Tensile: 26.5 kN (530-SX: 43.0 kN)
Weight: 1.09 kg/m
Typical use: 600cc+ cruiser, tourer, large naked

All Five Sizes — Complete Specification Table

Storlek	Lutning (mm)	Inre bredd (mm)	Roller Ø (mm)	Standard Tensile	Top SX Tensile	Vikt (kg/m²)	Engine Class
420	12.700	6.35	7.77	15,6 kN	—	0.57	50–125cc scooter, mini bike
428	12.700	7.85	8.51	17,8 kN	28.0 kN (SX)	0.71	125–250cc street, dirt, enduro
520	15.875	6.35	10.14	26,5 kN	36.0 kN (SX3)	0.91	250–600cc sport, naked, MX
525	15.875	7.94	10.14	26,5 kN	40.0 kN (525-SX)	0.98	400–750cc adventure, naked twin
530	15.875	9.53	10.14	26,5 kN	43.0 kN (530-SX)	1.09	600cc+ touring, cruiser, large naked

What You Can and Cannot Mix

Pitch determines sprocket tooth spacing — the 12.70 mm pitch chains (420, 428) will not engage correctly on 15.875 mm pitch sprockets, and vice versa. Within the same pitch family, inner width also must match the sprocket tooth gap. A 520 roller (6.35 mm wide) will not seat correctly in sprocket grooves designed for a 530 roller (9.53 mm wide) — the narrower roller sits between the tooth faces rather than against them, causing immediate abnormal wear.

✓ Change without new sprockets

420 → 420H (same pitch + width)
428 → 428H (same pitch + width)
428 → 428H-O or 428H-X (same)
520 → 520H, 520H-O, 520H-X (same)
525 → 525H, 525H-SX (same)
530 → 530H, 530H-O, 530-SX (same)

✗ Requires new sprockets

420 → 428 (different inner width)
428 → 520 (different pitch entirely)
520 → 525 (different inner width)
520 → 530 (different inner width)
525 → 530 (different inner width)

What you can always change freely within the same base size number: the chain variant suffix. Standard → H-grade → O-ring → X-ring → Super X-ring — all in the same base size (e.g. all “520” variants) — fit the same sprockets. The variant suffix changes the sealing system and plate gauge, not the pitch or inner width that determines sprocket compatibility. Upgrade at any chain replacement without touching the sprockets.

How to Find the Correct Size for Your Motorcycle

1Read the outer plate stamp — the size code is stamped on every chain’s outer plate. Read it directly: e.g., “428H” = 428-pitch H-grade. This is the definitive identification method.
2Check the service manual — every motorcycle’s owner’s manual or workshop manual lists the OEM chain specification under “drive chain” or “final drive.” This will include both size and standard link count.
3Send us the motorcycle details — make, model, and year. We identify the correct specification from our reference database and confirm before you order. No charge, no obligation.

Manufacturing Every Size to JIS B 1801

All five sizes — 420 through 530 — are produced on dedicated lines with pitch, inner width, roller diameter, and plate height verified against JIS B 1801 reference gauges before dispatch.

Korea Ever-Power Motorcycle Chain Co., Ltd. — five production facilities, ISO 9001 certified

Chain Sizes and Sprockets — All Pitches In Stock

Order single units or wholesale quantities. Stocked sizes dispatch within 3–7 business days. Mixed-size orders consolidated in one shipment.

Standard — 420 till 530

Non-sealed · 15.6–26.5 kN

H-Grade — 415H to 530H

Reinforced · Up to 30.5 kN

O-Ring — 415H-O to 530H-O

Sealed · 600–1,000 km lube

Super X-Ring — SX Series

530-SX at 43.0 kN peak

Replacing chain and sprockets together? Fram- och bakdrev för motorcykel för alla platser.
Kedjehjul →

Vanliga frågor

How do I find which chain size my motorcycle needs?＋

Read the number stamped on the outer plate of the existing chain. If the stamping is worn, check the service manual or owner’s manual under “drive chain specifications” — it will list both the size code and the standard link count. If neither is accessible, send us the motorcycle’s make, model, and year and we confirm the specification from our reference database.

Why do 520, 525, and 530 all show the same 26.5 kN standard tensile?＋

At the standard level, the three 15.875 mm pitch variants use similar plate gauges — the width difference is in the inner dimension, not in the structural plate. The tensile advantage of wider variants appears in the H-grade and sealed versions: 530-SX at 43.0 kN, 525-SX at 40.0 kN, 520H-X at 34.0 kN. At the standard level, the width advantage is in per-tooth contact stress distribution rather than total break load.

Can I put a 525 chain on a 530-spec motorcycle for weight saving?＋

Technically possible but requires replacing both sprockets. On a touring machine where the manufacturer specified 530, the wider roller was the engineering decision for that machine’s load profile. The 110 g per metre saved is negligible on a 250 kg tourer. The conversion makes more sense for performance machines where rotating mass is a genuine engineering target — confirm that the 525-grade sealed variant provides adequate tensile strength for the engine output and load conditions.

What link count does my replacement chain need?＋

Count the links on the removed chain before discarding it — count each pin as one link through a full circuit. Common link counts: 420/428 machines typically use 96–114 links; 520/525/530 machines typically use 108–120 links. If uncertain, ordering one or two extra links with a spare master link is cheaper than ordering a second chain when the count runs short.

What is the 415 chain and where does it fit?＋

The 415 shares the 12.70 mm pitch of the 420 and 428 but has a narrower 4.77 mm inner width. It is used on 50cc racing machines and some mini-bikes where minimum chain mass is the priority. The 420 covers most small-displacement applications where the 415’s extreme narrowness is unnecessary, and the 420’s wider roller provides better load distribution on standard sprocket profiles at those power levels.

Confirm Your Chain Size Before You Order

Korea Ever-Power stocks all five pitches — 420 through 530 — in standard, H-grade, O-ring, X-ring, and Super X-ring. Send us your chain number or motorcycle model and we confirm the correct specification at no charge.

Full dimensional data for every size and variant on individual product pages.

View All Chain Sizes

Redaktör: Cxm

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