Anti-collapse helix steel wire construction that protects your pump from cavitation. The last line of defense between your reservoir and your hydraulic system.
Standard
SAE J517 100R4
Working Pressure
2 – 21 Bar
Bore Range
DN19 – DN102
Temperature
-40°C to +100°C
Reinforcement
Helix Wire + Textile
Inner Tube
Oil-resistant NBR
Fluid Compatibility
Petroleum, Glycol, Water
Custom Lengths
Available
Standard size range for the SAE 100R4 hydraulic suction hose. Custom lengths and non-standard bore sizes available on request.
| Dash Size | ID (mm) | OD (mm) | Working Pressure (Bar) | Burst Pressure (Bar) | Min. Bend Radius (mm) | Weight (kg/m) |
|---|---|---|---|---|---|---|
| -12 | 19.1 | 33.3 | 21 | 84 | 190 | 0.64 |
| -16 | 25.4 | 39.7 | 17 | 68 | 230 | 0.82 |
| -20 | 31.8 | 46.0 | 14 | 56 | 280 | 1.10 |
| -24 | 38.1 | 54.0 | 10 | 40 | 330 | 1.40 |
| -32 | 50.8 | 66.7 | 7 | 28 | 400 | 1.80 |
| -40 | 63.5 | 82.6 | 5 | 20 | 500 | 2.38 |
| -48 | 76.2 | 97.6 | 2 | 8 | 600 | 3.10 |
Sizing tip: For suction lines, target fluid velocity ≤ 1.5 m/s. Formula: Required bore area (cm²) = Flow rate (L/min) ÷ (600 × velocity). Always round up to the next standard size.
A hydraulic suction hose connects the fluid reservoir to the hydraulic pump inlet — the most critical and most overlooked segment of any hydraulic circuit. Unlike pressure hoses, suction hoses operate under negative pressure (vacuum). Instead of being pressurized outward, they must resist being crushed inward by atmospheric pressure.
Standard flexible hoses collapse under vacuum. A collapsed suction hose causes immediate pump starvation, leading to cavitation — the violent implosion of vapor bubbles inside the pump that erodes metal surfaces in seconds. This is why suction hoses require a rigid internal helix wire to maintain bore geometry at all times, regardless of operating conditions.
⚠ Critical: Never Substitute a Standard Hose on the Suction Line
Wire-braided pressure hoses (SAE 100R1/R2) will collapse under suction vacuum, causing immediate pump cavitation. Only SAE 100R4 or equivalent anti-collapse construction is acceptable for pump inlet applications. A collapsed suction hose can destroy a hydraulic pump within minutes of operation.
Every hydraulic system with a pump has a suction line. The application determines bore size, length, and routing — the hose specification remains the same: SAE 100R4 anti-collapse construction.
Designed for transferring hydraulic oil, lubricants, and petroleum-based fluids in low-pressure industrial and mobile hydraulic systems.
Used to deliver lubricating oils smoothly between reservoirs, pumps, and machinery components to reduce wear and overheating.
Installed between the hydraulic reservoir and pump inlet to ensure stable fluid supply under suction conditions.
Every suction hose we manufacture is engineered with one priority: keeping your hydraulic pump alive.
Every SAE 100R4 hose undergoes vacuum collapse testing during production. Hoses that fail to maintain bore geometry under full vacuum are rejected. Your suction hose will not collapse in the field.
Bore diameter variation between hoses in the same batch causes uneven pump inlet conditions across multi-pump systems. Kingdaflex manufacturing maintains tight bore tolerances per SAE J517 — confirmed by laser dimensional checking on every production batch.
Return and suction hose connections are where leaks and failures start. We supply factory-crimped assemblies with matched ferrules and fittings in BSP, JIC, NPT, ORFS, and DIN thread forms — eliminating the compatibility risk of mixed-source components.
Standard 25m / 50m / 100m reels available from stock. Factory-cut custom lengths with crimped ends for OEM and service replacement applications. No minimum for standard items; MOQ applies to custom specifications only.
The fundamental difference is pressure direction. Standard hydraulic hoses (SAE 100R1/R2, EN853 1SN/2SN) are designed to resist internal pressure pushing outward — they are reinforced against burst. Suction hoses (SAE 100R4) must resist atmospheric pressure crushing them inward under vacuum. A standard wire-braided hose will collapse under suction vacuum because its reinforcement is optimized for burst resistance, not collapse resistance. The helix steel wire inside SAE 100R4 acts as an internal spring that holds the bore open against external atmospheric pressure. Never use a standard pressure hose on a suction line.
Size the suction hose bore to limit fluid velocity to 0.5–1.5 m/s at maximum pump flow rate. The calculation is: Required bore area (cm²) = Maximum flow rate (L/min) ÷ (600 × target velocity m/s). For example: a pump requiring 80 L/min at 1.0 m/s target velocity needs a bore area of 80 ÷ 600 = 0.133 cm², which gives a minimum ID of approximately 41mm — select DN51 as the next standard size. Always round up, never down. An oversized suction hose has negligible downside; an undersized one causes pump cavitation.
Yes — SAE 100R4 is equally suitable for both suction and return line applications, and its anti-collapse construction makes it over-specified (but perfectly safe) for return-only circuits. Using R4 on return lines is common practice in mobile equipment where a single hose specification simplifies stocking and replacement. On return circuits with pressures above 21 bar (such as those with back-pressure from coolers or filters), step up to EN854 3TE (50 bar rating) rather than using R4 near its pressure limit.
Industry guidance suggests inspecting suction hoses every 12 months and replacing proactively every 4–6 years, or per the equipment manufacturer’s maintenance schedule — whichever is sooner. Any of the following is grounds for immediate replacement: visible outer cover cracking or hardening; inner tube deformation or soft spots detectable by squeezing along the hose length; corrosion or weeping at the fitting ends; kinks or permanent deformation in the bore; or any evidence of past partial collapse (flat spots or internal oval deformation visible through the open ends). Do not wait for visible leaks — suction hose failure causes pump damage, not visible fluid loss.
Standard SAE 100R4 with NBR inner tube is compatible with petroleum-based hydraulic fluids, glycol-water fluids (HFC type), and most diesel and lubricating oil applications. For biodegradable fluids — specifically HETG (vegetable oil-based) and HEES (synthetic ester) fluids increasingly specified on agricultural and forestry equipment — contact Kingdaflex for our EPDM-inner-tube specification. Standard NBR is not compatible with ester-based biodegradable fluids and will swell over time, restricting bore flow and contaminating the fluid. Always confirm fluid compatibility before specifying hose inner tube material.
Standard SAE 100R4 products are available in 25m, 50m, and 100m reels with no minimum order quantity for standard items. Typical dispatch is 7–15 business days for catalog sizes. Factory-cut custom lengths with crimped end fittings have a 15–25 business day production lead time. Non-standard bore sizes, special cover compounds (EPDM, Nitrile-EPDM blend, abrasion-resistant), or custom color / private-label printing require 20–30 business days. Contact our team with your volume forecast for priority scheduling and OEM/distributor pricing.