Hose Types & Pressure Ratings
Choosing the wrong hose causes leaks, fires, and brake failures. Understand every type – PTFE, stainless braided, nylon, and push-on – so you always choose correctly.
Working Pressure vs Burst Pressure
Every hose has two critical pressure ratings that are frequently misunderstood:
Working Pressure (WP)
The maximum continuous operating pressure the hose is designed to handle safely, including pressure spikes and vibration over the hose's service life. This is the number you design to.
Burst Pressure (BP)
The pressure at which the hose catastrophically fails in a new, undamaged state at room temperature. This is a lab test figure – never use it as a design target.
Performance hose manufacturers typically use a 4:1 safety factor – meaning a hose rated at 1,000 psi working pressure will burst at approximately 4,000 psi when new. However, heat, UV exposure, vibration, flexing, and fluid compatibility all degrade this margin over time.
Never select a hose where your system's peak pressure (including transient spikes – water hammer, pump startup surges) approaches the working pressure rating. Always have headroom. For brake systems, use hose rated at a minimum of 3× your maximum line pressure.
Stainless Steel Braided Hose (Rubber Liner)
The most common AN hose used in performance builds. The construction consists of an inner rubber liner (nitrile/NBR for fuel/oil, EPDM for coolant), surrounded by a 304-grade stainless steel wire braid that provides the pressure containment and abrasion protection.
Construction & Grades
- ?Inner liner (NBR / Nitrile): Black nitrile rubber. Excellent resistance to petroleum fuels, oils, and lubricants. Swells slightly with aromatic fuels (high ethanol blends above E50 or methanol) – check compatibility before using with race fuels.
- ?Inner liner (EPDM): Better for coolant, water, and air. Poor resistance to petroleum-based fluids. Often used in coolant bypass and air intake lines.
- ?Braid (304 SS): Single or double braid. Double braid increases working pressure by ~40% and adds abrasion protection. Single braid sufficient for most automotive applications up to -16 AN.
- ?Braid (316L SS): Higher corrosion resistance than 304. Used in marine, salt-air, and harsh chemical environments. Slightly more expensive.
Pressure Ratings by Dash Size
| Dash Size | Hose I.D. | Working Pressure | Burst Pressure | Min Bend Radius |
|---|---|---|---|---|
| -4 | 6.3mm | 1,000 psi | 4,000 psi | 50mm |
| -6 | 9.5mm | 1,000 psi | 4,000 psi | 65mm |
| -8 | 12.7mm | 1,000 psi | 4,000 psi | 90mm |
| -10 | 15.9mm | 750 psi | 3,000 psi | 115mm |
| -12 | 19mm | 750 psi | 3,000 psi | 140mm |
| -16 | 25.4mm | 500 psi | 2,000 psi | 190mm |
PTFE (Teflon) Stainless Braided Hose
PTFE (polytetrafluoroethylene) – sold under the DuPont trade name Teflon – is chemically inert to virtually every fluid used in motorsport. The smooth, non-porous bore also means lower flow resistance and zero permeation (no fuel smell through the hose wall). This makes it the premium choice for any application where fluid compatibility or temperature is a concern.
Smooth Bore PTFE
Standard extruded tube. Excellent flow characteristics. Used for fuel, oil, brake, clutch, N2O, and hydraulic lines. The most common type.
Convoluted/Corrugated PTFE
Accordion-profile inner tube. Significantly more flexible than smooth bore – better for tight routing. Slight reduction in flow rate (~5–8%) due to turbulence. Used in tight engine bay routing where flex is critical.
PTFE Pressure Ratings by Dash Size
| Dash Size | Hose I.D. | Working Pressure | Burst Pressure | Temp Range |
|---|---|---|---|---|
| -3 | 4.8mm | 2,000 psi | 8,000 psi | -70 to +260°C |
| -4 | 6.3mm | 2,500 psi | 10,000 psi | -70 to +260°C |
| -6 | 9.5mm | 2,500 psi | 10,000 psi | -70 to +260°C |
| -8 | 12.7mm | 2,000 psi | 8,000 psi | -70 to +260°C |
| -10 | 15.9mm | 1,500 psi | 6,000 psi | -70 to +260°C |
| -12 | 19mm | 1,200 psi | 4,800 psi | -70 to +260°C |
PTFE hose must not be kinked. Unlike rubber-lined hose which recovers from a mild kink, a kinked PTFE liner develops micro-cracks that are invisible but act as stress risers. Always support bends with gentle radius – minimum 5× hose I.D. for smooth bore, 3× for convoluted.
Nylon Braided (Lightweight) Hose
Nylon-over-rubber construction offers a significant weight saving – up to 40% lighter than equivalent stainless braided hose for the same dash size. The trade-off is reduced working pressure (350–500 psi vs 1,000 psi for stainless) and less abrasion resistance from the softer nylon outer braid.
Available in multiple colours (blue, red, black, clear) making it popular for visible engine bay builds. The pressure rating is more than sufficient for naturally aspirated fuel systems, oil coolers, and coolant lines where pressures rarely exceed 80–120 psi in operation.
Nylon braided hose is not suitable for turbocharged fuel systems where fuel pump dead-heading pressure can reach 80–100 psi rail pressure, plus dynamic surge. Use stainless braided or PTFE for any turbocharged application.
Push-On Hose
Push-on hose connects directly to a barbed fitting – no hose end tools, no crimping. The hose grips the barb through interference fit and is retained by a hose clamp or the barb geometry alone depending on design. Quick to assemble and very low cost.
The fundamental limitation is the 250 psi working pressure restriction across all dash sizes. This makes push-on hose suitable only for return lines, overflow/breather vents, coolant overflow, and catch-can connections – never for pressurised fuel supply, oil pressure, or brake lines.
Available in blue (-4 to -12) or black (-6 to -12) CPE elastomer outer cover. The CPE (chlorinated polyethylene) outer is more UV-resistant and fuel-tolerant than plain PVC. Always use the correct AN barb push-on fitting rather than substituting plumbing barbs, which have different OD tolerances.
Silicone Hose
Silicone hose is not part of the AN fitting system but is commonly used in performance applications for coolant, intercooler charge pipes, and air intake ducting, paired with T-bolt or worm-gear clamps rather than AN fittings.
Use silicone for:
- ? Coolant hoses (radiator, heater, bypass)
- ? Intercooler charge pipes (-30 to +180°C)
- ? Air intake ducting
- ? Vapour and breather hoses
Never use silicone for:
- ? Fuel lines (silicone degrades rapidly)
- ? Oil lines (swells and softens)
- ? Brake lines
- ? Power steering
Full Hose Comparison Table
Stainless Steel Braided (Rubber/EPDM liner)
CP0721
Inner Liner
Nitrile (NBR) or EPDM rubber
Outer Cover
304 stainless steel braid
Temp Range
-40°C to +150°C
Fitting Type
Reusable AN swivel ends
Working Pressure
700–1,000 psi (dash dependent)
Burst Pressure
2,800–4,000 psi
Compatible Fluids
Fuel, oil, coolant, air, water
Not Suitable For
Brake fluid (DOT), methanol, acetone
PTFE / Teflon Stainless Braided
CP0724 / CP0725
Inner Liner
Extruded PTFE (Teflon) smooth bore
Outer Cover
304 stainless steel braid
Temp Range
-70°C to +260°C
Fitting Type
Reusable or crimp AN ends
Working Pressure
1,500–2,500 psi (dash -6)
Burst Pressure
6,000–10,000 psi
Compatible Fluids
All fluids – fuel, oil, brake fluid, coolant, N2O, hydraulic, power steering, AC
Not Suitable For
Nothing – PTFE is universally compatible
Nylon Braided (Lightweight)
CP0723
Inner Liner
Nitrile (NBR) or CPE
Outer Cover
Nylon fibre braid
Temp Range
-40°C to +150°C
Fitting Type
Reusable AN ends or crimp
Working Pressure
350–500 psi
Burst Pressure
1,400–2,000 psi
Compatible Fluids
Fuel, oil, coolant, air
Not Suitable For
Brake fluid, high-pressure hydraulics
Push-On (No-Crimp)
CP0722
Inner Liner
Nitrile / CPE elastomer
Outer Cover
PVC or nylon outer
Temp Range
-40°C to +100°C
Fitting Type
Push-on barb (no hose end tools needed)
Working Pressure
250 psi (all sizes)
Burst Pressure
1,000 psi
Compatible Fluids
Fuel, oil, coolant, air – low pressure only
Not Suitable For
Brake lines, high-pressure fuel rails, turbo lines
Fluid Compatibility Reference
| Fluid | SS Braided (NBR) | PTFE Braided | Nylon Braided | Push-On | Silicone |
|---|---|---|---|---|---|
| Petrol / Gasoline | ? | ? | ? | ? (return only) | ? |
| E85 / High Ethanol | ? Check | ? | ? Check | ? | ? |
| Methanol / Race Fuel | ? Swells NBR | ? | ? | ? | ? |
| Engine / Gear Oil | ? | ? | ? | ? (return only) | ? |
| Coolant / Water | ? (EPDM liner) | ? | ? (EPDM) | ? | ? |
| DOT 3/4/5.1 Brake Fluid | ? | ? | ? | ? | ? |
| DOT 5 (Silicone Brake Fluid) | ? | ? | ? | ? | ? |
| Power Steering Fluid | ? | ? | ? Check | ? | ? |
| Nitrous Oxide (N2O) | ? Check liner | ? | ? | ? | ? |
| Turbo Compressed Air | ? | ? | ? | ? | ? |
| Acetone / Ketones | ? | ? | ? | ? | ? |
Sizing & Flow Rate Guidelines
Hose sizing is critical for fuel systems in particular. An undersized feed line starves the fuel pump, causing lean conditions and engine damage under load. Use this as a starting guide – always verify with your fuel pump's flow curve at your intended fuel pressure.
| Dash Size | I.D. | Max Flow (fuel) | Suitable for (HP) | Typical Use |
|---|---|---|---|---|
| -4 | 6.3mm | ~70 L/hr | Up to 200 hp NA | Small carb returns, sensors, gauges |
| -6 | 9.5mm | ~170 L/hr | Up to 500 hp | Main fuel feed (NA), oil pressure, coolant |
| -8 | 12.7mm | ~340 L/hr | 500–900 hp | Main fuel feed (forced induction), oil cooler |
| -10 | 15.9mm | ~520 L/hr | 900–1,500 hp | High-power forced induction fuel, large oil lines |
| -12 | 19mm | ~750 L/hr | 1,500 hp+ | Fuel cell feed, large dry sump lines, remote filters |
Flow rates above are approximate at 3 psi pressure drop, straight run, with petrol/gasoline at standard density. Adding bends, length, and fitting restrictions reduces effective flow. For high-power builds, always consult your fuel pump manufacturer's flow curves.
Assembly Notes by Hose Type
Stainless braided (rubber)
- •Use a proper hose cutter – not a hacksaw which frays the braid.
- •For reusable ends: back-thread the socket CCW (left-hand thread) onto the braid before inserting the nipple.
- •Lubricate the inside of the socket and hose end nipple with clean oil or the system fluid before assembly.
- •Vinegar soak (30 min) will brighten oxidised stainless braid before use on show cars.
PTFE braided
- •Cut with a sharp rotary cutter or fine hacksaw – never scissors.
- •Inspect the cut end for any PTFE flare/fins – trim cleanly with a blade.
- •Some reusable PTFE ends require the inner PTFE tube to be slightly flared with a flaring tool – follow the specific fitting manufacturer's instructions.
- •Do not exceed minimum bend radius – kinks are permanent damage.
Nylon braided
- •Cut cleanly with scissors or snips – the nylon braid cuts cleanly.
- •Same reusable end assembly as stainless braided.
- •Do not expose to temperatures above 150°C – the outer braid will discolour and weaken.
Push-on
- •Push firmly onto the AN push-on barb until seated to the shoulder.
- •Secure with a push-on hose clamp or safety wire for under-bonnet applications (vibration can back push-on hose off barbs at elevated temperatures).
- •Maximum 250 psi – do not use on pressurised fuel supply regardless of how "tight" the hose feels on the barb.
Common Mistakes
Using rubber-lined hose on brake lines
Use PTFE-lined stainless braided only. Glycol brake fluids attack rubber liners, causing liner degradation and internal blockages that cause uneven brake bias.
Confusing working pressure with burst pressure
Always design to working pressure with headroom. Burst pressure is a lab metric, not an operating limit.
Bending PTFE hose below minimum radius
A kinked PTFE liner cannot be repaired. Replace the hose section. Reroute with an angled fitting to avoid tight bends.
Using NBR-lined hose with high-ethanol fuels (E85+)
Ethanol-blended fuels above E50 can cause NBR to swell and degrade. Use PTFE-lined hose for E85, E100, or methanol applications.
Not supporting long hose runs
Unsupported braided hose vibrates against chassis edges and wears through surprisingly quickly. Clamp every 300–400mm, protect contact points with split conduit.
Browse Hose & Fittings
Stainless braided, PTFE, nylon, and push-on hose with matching AN ends – all in stock.