Backup Rings

Backup Rings are rigid sealing components installed alongside O-rings to prevent seal extrusion under high pressure. They act as a mechanical support ring, filling the extrusion gap between the O-ring and the gland, allowing the elastomer seal to maintain its shape and sealing performance even in demanding hydraulic and pneumatic applications. When pressure exceeds the capability of a standard O-ring alone, a properly selected Backup Ring can significantly extend seal life and improve system reliability.

Why Use a Backup Ring?

Many seal failures are not caused by the O-ring material itself, but by excessive clearance gaps that allow the elastomer to deform under pressure.

Prevent O-Ring Extrusion

As system pressure increases, an unsupported O-ring may be forced into the clearance gap between mating components. This “extrusion” eventually causes cutting, tearing, and leakage. A Backup Ring blocks this gap and protects the primary seal.

Extend Seal Service Life

By reducing deformation and mechanical damage, Backup Rings minimize premature seal wear, resulting in longer maintenance intervals and lower operating costs.

Improve High-Pressure Reliability

Backup Rings allow standard O-rings to perform reliably in applications with higher pressures, wider extrusion gaps, or fluctuating pressure cycles without requiring extremely hard elastomer compounds.

Reduce Equipment Downtime

A simple Backup Ring can prevent common seal failures that lead to hydraulic leaks, pressure loss, and unexpected equipment shutdowns.

Backup Ring Materials

Different materials provide different levels of pressure resistance, friction, and chemical compatibility.

Material	Key Benefits	Typical Applications
PTFE	Low friction, excellent chemical resistance, high pressure capability	Hydraulic cylinders, valves, pumps
NBR 90 Shore A	Good wear resistance and economical	General hydraulic equipment
FKM 90 Shore A	High temperature and chemical resistance	Chemical processing, automotive
PEEK	Exceptional strength for extreme pressure	Heavy-duty hydraulic systems

Types of Backup Rings

Selecting the correct style depends on installation method and operating conditions.

Solid Backup Rings – Maximum extrusion resistance for new equipment.
Split (Scarf-Cut) Backup Rings – Easy installation on closed grooves without stretching.
Spiral Backup Rings – Flexible installation while maintaining excellent sealing support.
Contoured Elastomer Backup Rings – Designed to closely match O-ring geometry for improved sealing stability.

Backup Ring Size Chart

The following table covers the complete specifications of the mainstream AS568 standard backup ring, and simultaneously provides dimension data in both imperial and metric units to facilitate selection and comparison.
Note: The axial height dimension “A” is an exclusive parameter for the rubber arc backup ring; the PTFE backup ring adopts a straight end face structure and does not have an arc profile, so there is no definition of this dimension.

DASH	ID (in)	WIDTH (in)	THK (in)	A (in)	ID (mm)	WIDTH (mm)	THK (mm)	A (mm)
004	0.096	0.053	0.049	0.045	2.44	1.35	1.24	1.14
005	0.127	0.053	0.049	0.045	3.23	1.35	1.24	1.14
006	0.14	0.053	0.049	0.045	3.56	1.35	1.24	1.14
007	0.171	0.053	0.049	0.045	4.34	1.35	1.24	1.14
008	0.202	0.053	0.049	0.045	5.13	1.35	1.24	1.14
009	0.234	0.053	0.049	0.045	5.94	1.35	1.24	1.14
010	0.265	0.053	0.049	0.045	6.73	1.35	1.24	1.14
011	0.327	0.053	0.049	0.045	8.31	1.35	1.24	1.14
012	0.39	0.053	0.049	0.045	9.91	1.35	1.24	1.14
013	0.455	0.053	0.049	0.045	11.56	1.35	1.24	1.14
014	0.518	0.053	0.049	0.045	13.16	1.35	1.24	1.14
015	0.58	0.053	0.049	0.045	14.73	1.35	1.24	1.14
016	0.643	0.053	0.049	0.045	16.33	1.35	1.24	1.14
017	0.705	0.053	0.049	0.045	17.91	1.35	1.24	1.14
018	0.768	0.053	0.049	0.045	19.51	1.35	1.24	1.14
019	0.83	0.053	0.049	0.045	21.08	1.35	1.24	1.14
020	0.893	0.053	0.049	0.045	22.68	1.35	1.24	1.14
021	0.955	0.053	0.049	0.045	24.26	1.35	1.24	1.14
022	1.018	0.053	0.049	0.045	25.86	1.35	1.24	1.14
023	1.08	0.053	0.049	0.045	27.43	1.35	1.24	1.14
024	1.143	0.053	0.049	0.045	29.03	1.35	1.24	1.14
025	1.205	0.053	0.049	0.045	30.61	1.35	1.24	1.14
026	1.268	0.053	0.049	0.045	32.21	1.35	1.24	1.14
027	1.33	0.053	0.049	0.045	33.78	1.35	1.24	1.14
028	1.393	0.053	0.049	0.045	35.38	1.35	1.24	1.14
029	1.518	0.053	0.049	0.045	38.56	1.35	1.24	1.14
030	1.643	0.053	0.049	0.045	41.73	1.35	1.24	1.14
031	1.768	0.053	0.049	0.045	44.91	1.35	1.24	1.14
032	1.893	0.053	0.049	0.045	48.08	1.35	1.24	1.14
033	2.018	0.053	0.049	0.045	51.26	1.35	1.24	1.14
034	2.143	0.053	0.049	0.045	54.43	1.35	1.24	1.14
035	2.268	0.053	0.049	0.045	57.61	1.35	1.24	1.14
036	2.393	0.053	0.049	0.045	60.78	1.35	1.24	1.14
037	2.519	0.053	0.049	0.045	63.98	1.35	1.24	1.14
038	2.643	0.053	0.049	0.045	67.13	1.35	1.24	1.14
039	2.768	0.053	0.049	0.045	70.31	1.35	1.24	1.14
040	2.893	0.053	0.049	0.045	73.48	1.35	1.24	1.14
041	3.018	0.053	0.049	0.045	76.66	1.35	1.24	1.14
042	3.268	0.053	0.049	0.045	83.01	1.35	1.24	1.14
043	3.518	0.053	0.049	0.045	89.36	1.35	1.24	1.14
044	3.768	0.053	0.049	0.045	95.71	1.35	1.24	1.14
045	4.018	0.053	0.049	0.045	102.06	1.35	1.24	1.14
046	4.268	0.053	0.049	0.045	108.41	1.35	1.24	1.14
047	4.518	0.053	0.049	0.045	114.76	1.35	1.24	1.14
048	4.768	0.053	0.049	0.045	121.11	1.35	1.24	1.14
049	5.018	0.053	0.049	0.045	127.46	1.35	1.24	1.14
050	5.268	0.053	0.049	0.045	133.81	1.35	1.24	1.14
102	0.077	0.086	0.053	0.045	1.96	2.18	1.35	1.14
103	0.109	0.086	0.053	0.045	2.77	2.18	1.35	1.14
104	0.14	0.086	0.053	0.045	3.56	2.18	1.35	1.14
105	0.171	0.086	0.053	0.045	4.34	2.18	1.35	1.14
106	0.202	0.086	0.053	0.045	5.13	2.18	1.35	1.14
107	0.234	0.086	0.053	0.045	5.94	2.18	1.35	1.14
108	0.265	0.086	0.053	0.045	6.73	2.18	1.35	1.14
109	0.327	0.086	0.053	0.045	8.31	2.18	1.35	1.14
110	0.39	0.086	0.053	0.045	9.91	2.18	1.35	1.14
111	0.452	0.086	0.053	0.045	11.48	2.18	1.35	1.14
112	0.515	0.086	0.053	0.045	13.08	2.18	1.35	1.14
113	0.577	0.086	0.053	0.045	14.66	2.18	1.35	1.14
114	0.64	0.086	0.053	0.045	16.26	2.18	1.35	1.14
115	0.702	0.086	0.053	0.045	17.83	2.18	1.35	1.14
116	0.765	0.086	0.053	0.045	19.43	2.18	1.35	1.14
117	0.831	0.086	0.053	0.045	21.11	2.18	1.35	1.14
118	0.893	0.086	0.053	0.045	22.68	2.18	1.35	1.14
119	0.956	0.086	0.053	0.045	24.28	2.18	1.35	1.14
120	1.018	0.086	0.053	0.045	25.86	2.18	1.35	1.14
121	1.081	0.086	0.053	0.045	27.46	2.18	1.35	1.14
122	1.143	0.086	0.053	0.045	29.03	2.18	1.35	1.14
123	1.206	0.086	0.053	0.045	30.63	2.18	1.35	1.14
124	1.268	0.086	0.053	0.045	32.21	2.18	1.35	1.14
125	1.331	0.086	0.053	0.045	33.81	2.18	1.35	1.14
126	1.393	0.086	0.053	0.045	35.38	2.18	1.35	1.14
127	1.456	0.086	0.053	0.045	36.98	2.18	1.35	1.14
128	1.518	0.086	0.053	0.045	38.56	2.18	1.35	1.14
129	1.581	0.086	0.053	0.045	40.16	2.18	1.35	1.14
130	1.643	0.086	0.053	0.045	41.73	2.18	1.35	1.14
131	1.706	0.086	0.053	0.045	43.33	2.18	1.35	1.14
132	1.768	0.086	0.053	0.045	44.91	2.18	1.35	1.14
133	1.831	0.086	0.053	0.045	46.51	2.18	1.35	1.14
134	1.893	0.086	0.053	0.045	48.08	2.18	1.35	1.14
135	1.956	0.086	0.053	0.045	49.68	2.18	1.35	1.14
136	2.018	0.086	0.053	0.045	51.26	2.18	1.35	1.14
137	2.081	0.086	0.053	0.045	52.86	2.18	1.35	1.14
138	2.143	0.086	0.053	0.045	54.43	2.18	1.35	1.14
139	2.206	0.086	0.053	0.045	56.03	2.18	1.35	1.14
140	2.268	0.086	0.053	0.045	57.61	2.18	1.35	1.14
141	2.331	0.086	0.053	0.045	59.21	2.18	1.35	1.14
142	2.393	0.086	0.053	0.045	60.78	2.18	1.35	1.14
143	2.456	0.086	0.053	0.045	62.38	2.18	1.35	1.14
144	2.528	0.086	0.053	0.045	64.21	2.18	1.35	1.14
145	2.518	0.086	0.053	0.045	63.96	2.18	1.35	1.14
146	2.643	0.086	0.053	0.045	67.13	2.18	1.35	1.14
147	2.706	0.086	0.053	0.045	68.73	2.18	1.35	1.14
148	2.768	0.086	0.053	0.045	70.31	2.18	1.35	1.14
149	2.831	0.086	0.053	0.045	71.91	2.18	1.35	1.14
150	2.893	0.086	0.053	0.045	73.48	2.18	1.35	1.14
151	3.018	0.086	0.053	0.045	76.66	2.18	1.35	1.14
152	3.268	0.086	0.053	0.045	83.01	2.18	1.35	1.14
153	3.518	0.086	0.053	0.045	89.36	2.18	1.35	1.14
154	3.768	0.086	0.053	0.045	95.71	2.18	1.35	1.14
155	4.018	0.086	0.053	0.045	102.06	2.18	1.35	1.14
156	4.268	0.086	0.053	0.045	108.41	2.18	1.35	1.14
157	4.518	0.086	0.053	0.045	114.76	2.18	1.35	1.14
158	4.768	0.086	0.053	0.045	121.11	2.18	1.35	1.14
159	5.018	0.086	0.053	0.045	127.46	2.18	1.35	1.14
160	5.268	0.086	0.053	0.045	133.81	2.18	1.35	1.14
161	5.518	0.086	0.053	0.045	140.16	2.18	1.35	1.14
162	5.768	0.086	0.053	0.045	146.51	2.18	1.35	1.14
163	6.018	0.086	0.053	0.045	152.86	2.18	1.35	1.14
164	6.238	0.086	0.053	0.045	158.45	2.18	1.35	1.14
165	6.518	0.086	0.053	0.045	165.56	2.18	1.35	1.14
166	6.768	0.086	0.053	0.045	171.91	2.18	1.35	1.14
167	7.018	0.086	0.053	0.045	178.26	2.18	1.35	1.14
168	7.268	0.086	0.053	0.045	184.61	2.18	1.35	1.14
169	7.518	0.086	0.053	0.045	190.96	2.18	1.35	1.14
170	7.768	0.086	0.053	0.045	197.31	2.18	1.35	1.14
171	8.018	0.086	0.053	0.045	203.66	2.18	1.35	1.14
172	8.268	0.086	0.053	0.045	210.01	2.18	1.35	1.14
173	8.518	0.086	0.053	0.045	216.36	2.18	1.35	1.14
174	8.768	0.086	0.053	0.045	222.71	2.18	1.35	1.14
175	9.018	0.086	0.053	0.045	229.06	2.18	1.35	1.14
176	9.268	0.086	0.053	0.045	235.41	2.18	1.35	1.14
177	9.518	0.086	0.053	0.045	241.76	2.18	1.35	1.14
178	9.768	0.086	0.053	0.045	248.11	2.18	1.35	1.14
201	0.202	0.118	0.05	0.04	5.13	3	1.27	1.02
202	0.265	0.118	0.05	0.04	6.73	3	1.27	1.02
203	0.327	0.118	0.05	0.04	8.31	3	1.27	1.02
204	0.39	0.118	0.05	0.04	9.91	3	1.27	1.02
205	0.455	0.118	0.05	0.04	11.56	3	1.27	1.02
206	0.518	0.118	0.05	0.04	13.16	3	1.27	1.02
207	0.58	0.118	0.05	0.04	14.73	3	1.27	1.02
208	0.643	0.118	0.05	0.04	16.33	3	1.27	1.02
209	0.705	0.118	0.05	0.04	17.91	3	1.27	1.02
210	0.765	0.118	0.05	0.04	19.43	3	1.27	1.02
211	0.828	0.118	0.05	0.04	21.03	3	1.27	1.02
212	0.891	0.118	0.05	0.04	22.63	3	1.27	1.02
213	0.953	0.118	0.05	0.04	24.21	3	1.27	1.02
214	1.016	0.118	0.05	0.04	25.81	3	1.27	1.02
215	1.078	0.118	0.05	0.04	27.38	3	1.27	1.02
216	1.141	0.118	0.05	0.04	28.98	3	1.27	1.02
217	1.203	0.118	0.05	0.04	30.56	3	1.27	1.02
218	1.266	0.118	0.05	0.04	32.16	3	1.27	1.02
219	1.334	0.118	0.05	0.04	33.88	3	1.27	1.02
220	1.397	0.118	0.05	0.04	35.48	3	1.27	1.02
221	1.459	0.118	0.05	0.04	37.06	3	1.27	1.02
222	1.522	0.118	0.05	0.04	38.66	3	1.27	1.02
223	1.647	0.118	0.05	0.04	41.83	3	1.27	1.02
224	1.772	0.118	0.05	0.04	45.01	3	1.27	1.02
225	1.897	0.118	0.05	0.04	48.18	3	1.27	1.02
226	2.022	0.118	0.05	0.04	51.36	3	1.27	1.02
227	2.147	0.118	0.05	0.04	54.53	3	1.27	1.02
228	2.272	0.118	0.05	0.04	57.71	3	1.27	1.02
229	2.397	0.118	0.05	0.04	60.88	3	1.27	1.02
230	2.522	0.118	0.05	0.04	64.06	3	1.27	1.02
231	2.631	0.118	0.05	0.04	66.83	3	1.27	1.02
232	2.756	0.118	0.05	0.04	70	3	1.27	1.02
233	2.881	0.118	0.05	0.04	73.18	3	1.27	1.02
234	3.006	0.118	0.05	0.04	76.35	3	1.27	1.02
235	3.131	0.118	0.05	0.04	79.53	3	1.27	1.02
236	3.256	0.118	0.05	0.04	82.7	3	1.27	1.02
237	3.381	0.118	0.05	0.04	85.88	3	1.27	1.02
238	3.506	0.118	0.05	0.04	89.05	3	1.27	1.02
239	3.631	0.118	0.05	0.04	92.23	3	1.27	1.02
240	3.756	0.118	0.05	0.04	95.4	3	1.27	1.02
241	3.881	0.118	0.05	0.04	98.58	3	1.27	1.02
242	4.006	0.118	0.05	0.04	101.75	3	1.27	1.02
243	4.131	0.118	0.05	0.04	104.93	3	1.27	1.02
244	4.256	0.118	0.05	0.04	108.1	3	1.27	1.02
245	4.381	0.118	0.05	0.04	111.28	3	1.27	1.02
246	4.506	0.118	0.05	0.04	114.45	3	1.27	1.02
247	4.631	0.118	0.05	0.04	117.63	3	1.27	1.02
248	4.768	0.118	0.05	0.04	121.11	3	1.27	1.02
249	4.893	0.118	0.05	0.04	124.28	3	1.27	1.02
250	5.018	0.118	0.05	0.04	127.46	3	1.27	1.02
251	5.143	0.118	0.05	0.04	130.63	3	1.27	1.02
252	5.268	0.118	0.05	0.04	133.81	3	1.27	1.02
253	5.393	0.118	0.05	0.04	136.98	3	1.27	1.02
254	5.518	0.118	0.05	0.04	140.16	3	1.27	1.02
255	5.643	0.118	0.05	0.04	143.33	3	1.27	1.02
256	5.768	0.118	0.05	0.04	146.51	3	1.27	1.02
257	5.893	0.118	0.05	0.04	149.68	3	1.27	1.02
258	6.018	0.118	0.05	0.04	152.86	3	1.27	1.02
259	6.268	0.118	0.05	0.04	159.21	3	1.27	1.02
260	6.518	0.118	0.05	0.04	165.56	3	1.27	1.02
261	6.768	0.118	0.05	0.04	171.91	3	1.27	1.02
262	7.018	0.118	0.05	0.04	178.26	3	1.27	1.02
263	7.268	0.118	0.05	0.04	184.61	3	1.27	1.02
264	7.518	0.118	0.05	0.04	190.96	3	1.27	1.02
265	7.768	0.118	0.05	0.04	197.31	3	1.27	1.02
266	8.018	0.118	0.05	0.04	203.66	3	1.27	1.02
267	8.268	0.118	0.05	0.04	210.01	3	1.27	1.02
268	8.518	0.118	0.05	0.04	216.36	3	1.27	1.02
269	8.768	0.118	0.05	0.04	222.71	3	1.27	1.02
270	9.018	0.118	0.05	0.04	229.06	3	1.27	1.02
271	9.268	0.118	0.05	0.04	235.41	3	1.27	1.02
272	9.518	0.118	0.05	0.04	241.76	3	1.27	1.02
273	9.768	0.118	0.05	0.04	248.11	3	1.27	1.02
274	10.018	0.118	0.05	0.04	254.46	3	1.27	1.02
275	10.518	0.118	0.05	0.04	267.16	3	1.27	1.02
276	11.018	0.118	0.05	0.04	279.86	3	1.27	1.02
277	11.518	0.118	0.05	0.04	292.56	3	1.27	1.02
278	12.018	0.118	0.05	0.04	305.26	3	1.27	1.02
279	13.018	0.118	0.05	0.04	330.66	3	1.27	1.02
280	14.018	0.118	0.05	0.04	356.06	3	1.27	1.02
281	15.018	0.118	0.05	0.04	381.46	3	1.27	1.02
282	15.989	0.118	0.05	0.04	406.12	3	1.27	1.02
283	16.989	0.118	0.05	0.04	431.52	3	1.27	1.02
284	17.989	0.118	0.05	0.04	456.92	3	1.27	1.02
309	0.45	0.183	0.076	0.06	11.43	4.65	1.93	1.52
310	0.513	0.183	0.076	0.06	13.03	4.65	1.93	1.52
311	0.575	0.183	0.076	0.06	14.61	4.65	1.93	1.52
312	0.638	0.183	0.076	0.06	16.21	4.65	1.93	1.52
313	0.7	0.183	0.076	0.06	17.78	4.65	1.93	1.52
314	0.763	0.183	0.076	0.06	19.38	4.65	1.93	1.52
315	0.825	0.183	0.076	0.06	20.96	4.65	1.93	1.52
316	0.888	0.183	0.076	0.06	22.56	4.65	1.93	1.52
317	0.95	0.183	0.076	0.06	24.13	4.65	1.93	1.52
318	1.013	0.183	0.076	0.06	25.73	4.65	1.93	1.52
319	1.075	0.183	0.076	0.06	27.31	4.65	1.93	1.52
320	1.138	0.183	0.076	0.06	28.91	4.65	1.93	1.52
321	1.2	0.183	0.076	0.06	30.48	4.65	1.93	1.52
322	1.263	0.183	0.076	0.06	32.08	4.65	1.93	1.52
323	1.316	0.183	0.076	0.06	33.43	4.65	1.93	1.52
324	1.388	0.183	0.076	0.06	35.26	4.65	1.93	1.52
325	1.513	0.183	0.076	0.06	38.43	4.65	1.93	1.52
326	1.638	0.183	0.076	0.06	41.61	4.65	1.93	1.52
327	1.763	0.183	0.076	0.06	44.78	4.65	1.93	1.52
328	1.888	0.183	0.076	0.06	47.96	4.65	1.93	1.52
329	2.013	0.183	0.076	0.06	51.13	4.65	1.93	1.52
330	2.138	0.183	0.076	0.06	54.31	4.65	1.93	1.52
331	2.268	0.183	0.076	0.06	57.61	4.65	1.93	1.52
332	2.393	0.183	0.076	0.06	60.78	4.65	1.93	1.52
333	2.518	0.183	0.076	0.06	63.96	4.65	1.93	1.52
334	2.643	0.183	0.076	0.06	67.13	4.65	1.93	1.52
335	2.768	0.183	0.076	0.06	70.31	4.65	1.93	1.52
336	2.893	0.183	0.076	0.06	73.48	4.65	1.93	1.52
337	3.018	0.183	0.076	0.06	76.66	4.65	1.93	1.52
338	3.143	0.183	0.076	0.06	79.83	4.65	1.93	1.52
339	3.273	0.183	0.076	0.06	83.13	4.65	1.93	1.52
340	3.398	0.183	0.076	0.06	86.31	4.65	1.93	1.52
341	3.523	0.183	0.076	0.06	89.48	4.65	1.93	1.52
342	3.648	0.183	0.076	0.06	92.66	4.65	1.93	1.52
343	3.773	0.183	0.076	0.06	95.83	4.65	1.93	1.52
344	3.898	0.183	0.076	0.06	99.01	4.65	1.93	1.52
345	4.028	0.183	0.076	0.06	102.31	4.65	1.93	1.52
346	4.153	0.183	0.076	0.06	105.49	4.65	1.93	1.52
347	4.278	0.183	0.076	0.06	108.66	4.65	1.93	1.52
348	4.403	0.183	0.076	0.06	111.84	4.65	1.93	1.52
349	4.528	0.183	0.076	0.06	115.01	4.65	1.93	1.52
350	4.653	0.183	0.076	0.06	118.19	4.65	1.93	1.52
351	4.778	0.183	0.076	0.06	121.36	4.65	1.93	1.52
352	4.903	0.183	0.076	0.06	124.54	4.65	1.93	1.52
353	5.028	0.183	0.076	0.06	127.71	4.65	1.93	1.52
354	5.153	0.183	0.076	0.06	130.89	4.65	1.93	1.52
355	5.278	0.183	0.076	0.06	134.06	4.65	1.93	1.52
356	5.403	0.183	0.076	0.06	137.24	4.65	1.93	1.52
357	5.528	0.183	0.076	0.06	140.41	4.65	1.93	1.52
358	5.653	0.183	0.076	0.06	143.59	4.65	1.93	1.52
359	5.778	0.183	0.076	0.06	146.76	4.65	1.93	1.52
360	5.903	0.183	0.076	0.06	149.94	4.65	1.93	1.52
361	6.028	0.183	0.076	0.06	153.11	4.65	1.93	1.52
362	6.278	0.183	0.076	0.06	159.46	4.65	1.93	1.52
363	6.528	0.183	0.076	0.06	165.81	4.65	1.93	1.52
364	6.778	0.183	0.076	0.06	172.16	4.65	1.93	1.52
365	7.028	0.183	0.076	0.06	178.51	4.65	1.93	1.52
366	7.278	0.183	0.076	0.06	184.86	4.65	1.93	1.52
367	7.528	0.183	0.076	0.06	191.21	4.65	1.93	1.52
368	7.778	0.183	0.076	0.06	197.56	4.65	1.93	1.52
369	8.028	0.183	0.076	0.06	203.91	4.65	1.93	1.52
370	8.278	0.183	0.076	0.06	210.26	4.65	1.93	1.52
371	8.528	0.183	0.076	0.06	216.61	4.65	1.93	1.52
372	8.778	0.183	0.076	0.06	222.96	4.65	1.93	1.52
373	9.028	0.183	0.076	0.06	229.31	4.65	1.93	1.52
374	9.278	0.183	0.076	0.06	235.66	4.65	1.93	1.52
375	9.528	0.183	0.076	0.06	242.01	4.65	1.93	1.52
376	9.778	0.183	0.076	0.06	248.36	4.65	1.93	1.52
377	10.028	0.183	0.076	0.06	254.71	4.65	1.93	1.52
378	10.528	0.183	0.076	0.06	267.41	4.65	1.93	1.52
379	11.028	0.183	0.076	0.06	280.11	4.65	1.93	1.52
380	11.528	0.183	0.076	0.06	292.81	4.65	1.93	1.52
381	12.028	0.183	0.076	0.06	305.51	4.65	1.93	1.52
382	13.028	0.183	0.076	0.06	330.91	4.65	1.93	1.52
383	14.028	0.183	0.076	0.06	356.31	4.65	1.93	1.52
384	15.028	0.183	0.076	0.06	381.71	4.65	1.93	1.52
385	16.008	0.183	0.076	0.06	406.6	4.65	1.93	1.52
386	17.008	0.183	0.076	0.06	432	4.65	1.93	1.52
387	18.008	0.183	0.076	0.06	457.4	4.65	1.93	1.52
388	19.006	0.183	0.076	0.06	482.75	4.65	1.93	1.52
389	20.006	0.183	0.076	0.06	508.15	4.65	1.93	1.52
390	21.006	0.183	0.076	0.06	533.55	4.65	1.93	1.52
391	22.006	0.183	0.076	0.06	558.95	4.65	1.93	1.52
392	22.993	0.183	0.076	0.06	584.02	4.65	1.93	1.52
393	23.993	0.183	0.076	0.06	609.42	4.65	1.93	1.52
394	24.993	0.183	0.076	0.06	634.82	4.65	1.93	1.52
395	25.993	0.183	0.076	0.06	660.22	4.65	1.93	1.52
425	4.551	0.236	0.117	0.095	115.6	5.99	2.97	2.41
426	4.676	0.236	0.117	0.095	118.77	5.99	2.97	2.41
427	4.801	0.236	0.117	0.095	121.95	5.99	2.97	2.41
428	4.926	0.236	0.117	0.095	125.12	5.99	2.97	2.41
429	5.051	0.236	0.117	0.095	128.3	5.99	2.97	2.41
430	5.176	0.236	0.117	0.095	131.47	5.99	2.97	2.41
431	5.301	0.236	0.117	0.095	134.65	5.99	2.97	2.41
432	5.426	0.236	0.117	0.095	137.82	5.99	2.97	2.41
433	5.551	0.236	0.117	0.095	141	5.99	2.97	2.41
434	5.676	0.236	0.117	0.095	144.17	5.99	2.97	2.41
435	5.801	0.236	0.117	0.095	147.35	5.99	2.97	2.41
436	5.926	0.236	0.117	0.095	150.52	5.99	2.97	2.41
437	6.051	0.236	0.117	0.095	153.7	5.99	2.97	2.41
438	6.274	0.236	0.117	0.095	159.36	5.99	2.97	2.41
439	6.525	0.236	0.117	0.095	165.74	5.99	2.97	2.41
440	6.774	0.236	0.117	0.095	172.06	5.99	2.97	2.41
441	7.024	0.236	0.117	0.095	178.41	5.99	2.97	2.41
442	7.274	0.236	0.117	0.095	184.76	5.99	2.97	2.41
443	7.524	0.236	0.117	0.095	191.11	5.99	2.97	2.41
444	7.774	0.236	0.117	0.095	197.46	5.99	2.97	2.41
445	8.024	0.236	0.117	0.095	203.81	5.99	2.97	2.41
446	8.524	0.236	0.117	0.095	216.51	5.99	2.97	2.41
447	9.024	0.236	0.117	0.095	229.21	5.99	2.97	2.41
448	9.524	0.236	0.117	0.095	241.91	5.99	2.97	2.41
449	10.024	0.236	0.117	0.095	254.61	5.99	2.97	2.41
450	10.524	0.236	0.117	0.095	267.31	5.99	2.97	2.41
451	11.024	0.236	0.117	0.095	280.01	5.99	2.97	2.41
452	11.524	0.236	0.117	0.095	292.71	5.99	2.97	2.41
453	12.024	0.236	0.117	0.095	305.41	5.99	2.97	2.41
454	12.524	0.236	0.117	0.095	318.11	5.99	2.97	2.41
455	13.024	0.236	0.117	0.095	330.81	5.99	2.97	2.41
456	13.524	0.236	0.117	0.095	343.51	5.99	2.97	2.41
457	14.024	0.236	0.117	0.095	356.21	5.99	2.97	2.41
458	14.554	0.236	0.117	0.095	369.67	5.99	2.97	2.41
459	15.024	0.236	0.117	0.095	381.61	5.99	2.97	2.41
460	15.524	0.236	0.117	0.095	394.31	5.99	2.97	2.41
461	16.004	0.236	0.117	0.095	406.5	5.99	2.97	2.41
462	16.504	0.236	0.117	0.095	419.2	5.99	2.97	2.41
463	17.004	0.236	0.117	0.095	431.9	5.99	2.97	2.41
464	17.504	0.236	0.117	0.095	444.6	5.99	2.97	2.41
465	18.004	0.236	0.117	0.095	457.3	5.99	2.97	2.41
466	18.504	0.236	0.117	0.095	470	5.99	2.97	2.41
467	19.004	0.236	0.117	0.095	482.7	5.99	2.97	2.41
468	19.504	0.236	0.117	0.095	495.4	5.99	2.97	2.41
469	20.004	0.236	0.117	0.095	508.1	5.99	2.97	2.41
470	21.004	0.236	0.117	0.095	533.5	5.99	2.97	2.41
471	22.004	0.236	0.117	0.095	558.9	5.99	2.97	2.41
472	23.004	0.236	0.117	0.095	584.3	5.99	2.97	2.41
473	24.004	0.236	0.117	0.095	609.7	5.99	2.97	2.41
474	25.004	0.236	0.117	0.095	635.1	5.99	2.97	2.41
475	26.004	0.236	0.117	0.095	660.5	5.99	2.97	2.41

How to Select the Right Backup Ring

Consider Operating Pressure

Higher pressures generally require stronger backup materials such as PTFE or PEEK. As pressure increases, the need for extrusion resistance becomes more critical.

Check Pressure Direction

One-direction pressure: Install one Backup Ring on the low-pressure side of the O-ring.
Bi-directional pressure: Install two Backup Rings, one on each side of the O-ring, to provide protection regardless of pressure direction.

Evaluate Clearance Gap

Larger gland clearances increase the likelihood of extrusion. Backup Rings are especially recommended when machining tolerances cannot be minimized.

Match Material Compatibility

Always verify compatibility with:

Hydraulic oil
Water glycol fluids
Fuel
Steam
Aggressive chemicals
High-temperature media

Common Problems Backup Rings Solve

Properly selected Backup Rings help eliminate:

O-ring extrusion
Seal nibbling and tearing
High-pressure leakage
Premature seal failure
Damage caused by excessive gland clearance
Reduced service life in hydraulic systems

Instead of switching to excessively hard O-rings that may compromise low-pressure sealing, Backup Rings provide a more balanced and reliable engineering solution.

Improve High-Pressure Sealing Performance

Backup Rings are one of the most effective ways to enhance O-ring performance in demanding applications. By preventing extrusion, reducing seal damage, and improving pressure capability, they help engineers increase equipment reliability while lowering maintenance costs. Selecting the correct material, ring style, and installation configuration ensures long-term sealing performance in even the most challenging operating environments.

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Backup Rings

Backup Rings

Why Use a Backup Ring?

Prevent O-Ring Extrusion

Extend Seal Service Life

Improve High-Pressure Reliability

Reduce Equipment Downtime

Backup Ring Materials

Types of Backup Rings

Backup Ring Size Chart

How to Select the Right Backup Ring

Consider Operating Pressure

Check Pressure Direction

Evaluate Clearance Gap

Match Material Compatibility

Common Problems Backup Rings Solve

Improve High-Pressure Sealing Performance