Question 1

How much more load does a 25-3 carry vs a 25-1?

Accepted Answer

25-3 (triple-strand) has an allowable working load of 350 lb versus 140 lb for 25-1 (single-strand) — a 2.5× increase. Multi-strand roller chain carries roughly N× the load of single-strand at the same pitch and outer envelope. Pitch (0.25"), roller diameter (0.13"), and plate dimensions are identical across strand counts — the sprocket must match (multi-strand sprockets carry N parallel tooth tracks).

Question 2

What ISO chain is equivalent to 25?

Accepted Answer

25 is dimensionally identical to ISO 04C. Both designate the same chain: 0.25" pitch (6.35 mm), 0.13" roller diameter, 0.125" width between inner plates. ANSI B29.1 and the matching standard pin those dimensions to identical values across manufacturers — the designation IS the cross-reference.

Question 3

Are 25 chains from different brands interchangeable?

Accepted Answer

Yes, dimensionally. 25 from Tsubaki, Renold, Diamond, Senqcia, and Donghua all share identical pitch (0.25"), roller diameter, width between plates, pin diameter, and plate thickness — ANSI B29.1 pins these to manufacturer-independent values. Brands differ in heat treatment grade and brand-rated allowable working load — premium (heat-treated / proprietary-metallurgy) grades from major manufacturers share dimensions with the standard parent but carry higher allowable loads. Always verify the brand-rated working load against your service factor before substitution.

Designation	ANSI 25 / ISO 04C
Pitch	0.25" (6.35 mm)
Roller diameter	0.13"
Width between plates	0.125"
Pin diameter	0.091"
Plate thickness	0.03"
Plate height	0.23"

Canonical PN	Strands	Min tensile (lb)	Avg tensile (lb)	Allowable load (lb)	Mass (lb/ft)	Detail
25-1	single-strand	780	1,050	140	0.094	25-1 →
25-2	double-strand	1,560	2,100	240	0.181	25-2 →
25-3	triple-strand	2,340	3,150	350	0.282	25-3 →

25 Roller Chain — Strand-Count Comparison

Shared Dimensions (all strands)

Get a PDF cross-reference table

Per-Strand Load & Mass