Walk into any motorsport parts store and you'll see shelves of "stainless braided hose" — but that label tells you about the outside of the hose, not the inside. The inner liner is what actually matters for fluid compatibility, pressure rating, and longevity. Get it wrong and you're looking at swollen hose, contaminated fluid, or a failure under load.
This guide breaks down the real differences between PTFE and rubber-lined braided hose, and tells you exactly which to use for fuel, oil, brake, and coolant applications.
What Is PTFE Hose?
PTFE stands for polytetrafluoroethylene — the same material as Teflon. As a hose liner it's chemically inert, has an extremely smooth bore, and handles a wide temperature range of -65°C to +260°C.
PTFE hose can be used bare (smooth bore only, low pressure) or sleeved with a stainless steel or nylon braid for pressure resistance. In motorsport, PTFE-lined stainless braided hose is the standard for fuel, oil, and brake lines.
Key properties:
- Chemically compatible with petrol, diesel, E85, methanol, race fuels, brake fluid, and most oils
- Smooth bore reduces flow restriction and makes flushing easy
- Does not swell, degrade, or absorb fluid over time
- Requires specific PTFE-compatible hose end fittings
AN6 straight swivel PTFE hose end in blue/red anodised — the inner liner is smooth bore PTFE, the outer braid is stainless steel.
What Is Stainless Steel Braided Hose?
The stainless steel braid is the outer protective layer — it provides burst pressure resistance, abrasion protection, and a clean appearance. The braid itself doesn't determine fluid compatibility; the inner liner does.
Most performance stainless braided hose uses a PTFE inner liner. Lower-cost options use a rubber liner, which has lower chemical resistance and a narrower temperature range. Always check the liner specification before buying.
- Stainless braid + PTFE liner: high performance, wide chemical compatibility, motorsport standard
- Stainless braid + rubber liner: lower cost, suitable for general coolant and low-risk applications only
- Nylon braid + PTFE liner: lighter, more flexible, good for tight routing — lower abrasion resistance than stainless
AN8 straight PTFE hose end in black anodised — paired with stainless braided hose for oil feed and return lines.
Key Differences at a Glance
| Property | PTFE + Stainless Braid | Rubber + Stainless Braid |
|---|---|---|
| Chemical resistance | Excellent | Good (not E85/methanol) |
| Pressure rating | High | High |
| Flexibility | Moderate | High |
| Temperature range | -65°C to +260°C | -40°C to +150°C |
| Brake fluid compatibility | Yes | No |
| E85 / race fuel compatible | Yes | No |
| Weight | Medium | Medium |
| Cost | Medium–High | Low–Medium |
Which Hose for Which Application?
Fuel Lines
PTFE-lined stainless braided hose is the only correct choice for performance fuel systems — especially if you're running E85, methanol, or any race fuel blend. Rubber-lined hose degrades with ethanol content over time, causing swelling, contamination, and eventual failure.
- Standard petrol up to ~300bhp: -6AN PTFE braided
- Forced induction or high-flow: -8AN PTFE braided feed, -6AN return
- E85 or methanol: PTFE only, no exceptions
Oil Lines (Feed, Return, Cooler)
Turbo oil feed and return lines run extremely hot. PTFE handles this comfortably; rubber-lined hose at the same temperature will harden and crack over time. Use -8AN for standard applications, -10AN for high-volume engines or long runs.
For sizing guidance, see our AN Fitting Size Guide.
AN8 45° PTFE swivel hose end — ideal for turbo oil feed and return lines where a straight fitting won't clear surrounding components.
Brake Lines
PTFE stainless braided only. Rubber brake hose expands under pressure, creating a spongy, inconsistent pedal feel. PTFE does not expand, giving a firm, progressive pedal. Always use -3AN for brake lines — do not upsize.
Coolant Lines
Both PTFE braided and silicone hose work well for coolant. Silicone is more flexible and better suited to larger diameter runs (-16AN to -20AN). PTFE is preferred where coolant contacts aluminium fittings long-term, as it won't react or corrode the seating surface.
Power Steering
PTFE stainless braided — power steering fluid is aggressive and runs at high pressure. Rubber-lined hose is not suitable for long-term use in power steering applications.
Smooth Bore vs Convoluted PTFE
PTFE hose comes in two inner bore profiles:
- Smooth bore: better flow rate, easier to flush, preferred for fuel, oil, and brake lines — the correct choice for AN plumbing in almost all cases
- Convoluted (corrugated): more flexible, tighter bend radius — used where routing is very restricted and flow rate is less critical
For performance AN plumbing, always specify smooth bore unless you have a specific routing constraint that requires convoluted.
AN6 90° PTFE swivel hose end — the 90° angle handles tight routing without needing to bend the hose itself, preserving flow rate.
What to Check Before You Buy
- Liner specification: confirm PTFE, not rubber — especially on lower-cost hose
- Pressure rating: check against your system's operating pressure (brake lines run high; oil returns run low)
- Temperature rating: turbo oil feed lines can exceed 150°C — rubber-lined hose will not cope
- Hose end compatibility: PTFE hose requires PTFE-specific hose ends — the internal geometry is different from rubber hose ends and they are not interchangeable
- Dash size: match to your fittings — see our AN Fitting Size Guide if unsure
AN6 45° PTFE swivel hose end in blue/red — note the PTFE-specific internal geometry; these are not compatible with standard rubber hose ends.
Common Mistakes
- Using rubber-lined hose for E85 or race fuel: the liner will swell and degrade — PTFE only for ethanol blends
- Pairing PTFE hose with rubber-spec hose ends: the crimp geometry is different — this will leak under pressure
- Choosing convoluted PTFE for fuel lines: the corrugated bore increases turbulence and reduces flow — use smooth bore
- Not pressure testing after assembly: always bench test before fitting to the car
- Assuming all braided hose is equal: the braid is cosmetic — always check the liner spec
Ready to Build?
For fuel, oil, and brake lines in any performance build, PTFE-lined stainless braided hose is the correct choice in almost every case. It's chemically compatible, temperature resistant, and gives you a firm, reliable system that won't degrade over time.
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