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Horsepower Ratings — ANSI Roller Chain No. 25

Horsepower rating tables for ANSI #25 roller chain per ASME B29.1. Values are organized by small sprocket speed (rpm) and number of teeth. Yellow cells indicate oil stream lubrication requirements.

Speed, Revolutions/min, Small Sprocket — 50 to 1200 rpm
No. of Teeth	Speed, Revolutions/min, Small Sprocket
No. of Teeth	50	100	300	365	500	700	900	1200
11	0.03	0.06	0.19	0.22	0.30	0.42	0.53	0.70
12	0.04	0.07	0.20	0.24	0.33	0.46	0.58	0.76
13	0.04	0.08	0.22	0.26	0.36	0.49	0.63	0.83
14	0.04	0.08	0.24	0.28	0.38	0.53	0.68	0.89
15	0.05	0.09	0.25	0.30	0.41	0.57	0.72	0.95
16	0.05	0.09	0.27	0.32	0.44	0.61	0.77	1.02
17	0.05	0.10	0.29	0.35	0.47	0.64	0.82	1.08
18	0.05	0.11	0.30	0.37	0.49	0.68	0.87	1.15
19	0.06	0.11	0.32	0.39	0.52	0.72	0.92	1.21
20	0.06	0.12	0.34	0.41	0.55	0.76	0.97	1.27
21	0.06	0.12	0.35	0.43	0.58	0.80	1.01	1.34
22	0.07	0.13	0.37	0.45	0.60	0.83	1.06	1.40
23	0.07	0.13	0.39	0.47	0.63	0.87	1.11	1.46
24	0.07	0.14	0.40	0.49	0.66	0.91	1.16	1.53
25	0.08	0.15	0.42	0.51	0.69	0.95	1.21	1.59
26	0.08	0.15	0.44	0.53	0.71	0.99	1.26	1.65
28	0.08	0.16	0.47	0.57	0.77	1.06	1.35	1.78
30	0.09	0.18	0.50	0.61	0.82	1.14	1.45	1.91
32	0.10	0.19	0.54	0.65	0.88	1.21	1.55	2.04
35	0.11	0.21	0.59	0.71	0.96	1.33	1.69	2.23
40	0.12	0.23	0.67	0.81	1.10	1.52	1.93	2.55
45	0.14	0.26	0.76	0.91	1.24	1.71	2.17	2.86
	Manual or drip lubrication			Bath or disc lubrication

Speed, Revolutions/min, Small Sprocket — 1500 to 4500 rpm
No. of Teeth	Speed, Revolutions/min, Small Sprocket
No. of Teeth	1500	1800	2100	2500	3000	3500	4000	4500
11	0.87	1.03	1.20	1.42	1.69	1.69	1.38	1.16
12	0.95	1.13	1.31	1.55	1.84	1.92	1.57	1.32
13	1.03	1.22	1.42	1.67	1.99	2.17	1.77	1.49
14	1.10	1.32	1.52	1.80	2.15	2.42	1.98	1.66
15	1.18	1.41	1.63	1.93	2.30	2.67	2.20	1.84
16	1.26	1.50	1.74	2.06	2.45	2.85	2.42	2.03
17	1.34	1.60	1.85	2.19	2.61	3.02	2.65	2.22
18	1.42	1.69	1.96	2.32	2.76	3.20	2.89	2.42
19	1.50	1.78	2.07	2.45	2.91	3.38	3.13	2.62
20	1.58	1.88	2.18	2.58	3.07	3.56	3.38	2.83
21	1.66	1.97	2.29	2.70	3.22	3.74	3.64	3.05
22	1.73	2.07	2.40	2.83	3.37	3.91	3.90	3.27
23	1.81	2.16	2.51	2.96	3.53	4.09	4.17	3.50
24	1.89	2.25	2.61	3.09	3.68	4.27	4.45	3.73
25	1.97	2.35	2.72	3.22	3.84	4.45	4.73	3.96
26	2.05	2.44	2.83	3.35	3.99	4.62	5.01	4.20
28	2.21	2.63	3.05	3.61	4.30	4.98	5.60	4.70
30	2.37	2.82	3.27	3.86	4.60	5.34	6.07	5.21
32	2.52	3.01	3.49	4.12	4.91	5.69	6.47	5.74
35	2.76	3.29	3.81	4.51	5.37	6.23	7.08	6.56
40	3.15	3.76	4.36	5.15	6.14	7.11	8.09	8.02
45	3.55	4.23	4.90	5.79	6.90	8.00	9.10	9.57
	Bath or disc lubrication (white cells)					Oil stream lubrication (yellow cells)

Speed, Revolutions/min, Small Sprocket — 5000 to 12000 rpm
No. of Teeth	Speed, Revolutions/min, Small Sprocket
No. of Teeth	5000	5500	6000	7000	8000	9000	10000	11000	12000
11	0.99	0.86	0.75	0.60	0.49	0.41	0.35	0.30	0.27
12	1.12	0.97	0.86	0.68	0.56	0.47	0.40	0.34	0.30
13	1.27	1.10	0.96	0.77	0.63	0.53	0.45	0.39	0.34
14	1.42	1.23	1.08	0.86	0.70	0.59	0.50	0.43	0.38
15	1.57	1.36	1.20	0.95	0.78	0.65	0.56	0.48	0.42
16	1.73	1.50	1.32	1.05	0.86	0.72	0.61	0.53	0.47
17	1.90	1.64	1.44	1.14	0.94	0.79	0.67	0.58	0.51
18	2.07	1.79	1.57	1.25	1.02	0.86	0.73	0.63	0.56
19	2.24	1.94	1.70	1.35	1.11	0.93	0.79	0.69	0.00
20	2.42	2.10	1.84	1.46	1.20	1.00	0.86	0.74	0.00
21	2.60	2.26	1.98	1.57	1.29	1.08	0.92	0.00
22	2.79	2.42	2.12	1.69	1.38	1.16	0.99	0.00
23	2.98	2.59	2.27	1.80	1.47	1.24	1.04	0.00
24	3.18	2.76	2.42	1.92	1.57	1.32	0.22	0.00
25	3.38	2.93	2.57	2.04	1.67	1.40	0.00
26	3.59	3.11	2.73	2.17	1.77	1.49	0.00
28	4.01	3.47	3.05	2.42	1.98	0.00
30	4.45	3.85	3.38	2.68	1.98	0.00
32	4.90	4.25	3.73	2.96	0.35	0.00
35	5.60	4.86	4.26	2.76	0.00
40	6.85	5.93	4.91	0.00
45	8.17	5.23	1.38	0.00
	Bath or disc lubrication (white cells)				Oil stream lubrication (yellow cells)

Required horsepower (table rating) = (horsepower to be transmitted × service factor) / multiple-strand factor

Related tools

How to Use These Tables

Identify the small sprocket tooth count and operating rpm.
Read the table horsepower for the intersection of teeth and rpm.
Compute required table rating using the note above (include your service factor and strand factor).
Verify lubrication method per the legend; yellow cells require an oil stream.

Lubrication Legend

Manual / drip: Suitable for lower speeds (see first table footnote).
Bath / disc: Required as speed increases; most mid-range cells.
Oil stream (yellow): Continuous directed oil stream needed at higher speeds/powers.

Engineering Notes

Ratings are for ANSI No. 25 chain under standard conditions from ASME B29.1.
Ensure correct sprocket alignment, chain tension, and wrap; inadequate wrap reduces capacity.
For shock, start/stop, or dusty environments, increase service factor and improve lubrication/guards.
For multi-strand drives, apply the proper multiple-strand factor before selection.

Frequently Asked Questions

What if my rpm is between table values? Use the next higher speed rating or interpolate conservatively, then check lubrication requirements.

When do I need oil stream lubrication? When a cell is highlighted yellow or when heat and wear cannot be controlled by bath/disc methods.

Can I use these ratings for other chain sizes? No—these values are specific to No. 25. Use the proper table for each chain size.

Reference

ASME B29.1 — Precision Power Transmission Roller Chains, Attachments, and Sprockets