BRT Motorsport supplies AN fittings, AN hose and AN hose ends from AN3 to AN12, for brake, clutch, fuel, oil, power steering and coolant lines. We hold the full range in stock, crimp and swage fittings in our own UK workshop, and make lines up to your specification. Most orders are made up the same or the next working day.
What does AN mean?
AN is a thread and sizing standard originally developed for military aircraft (Army-Navy), now the common standard for motorsport fluid lines. The number is a dash size: it describes the nominal bore in sixteenths of an inch, and it comes with a matching male thread. So AN6 — also written -6, dash 6 or 6AN — is a 3/8" bore, because six sixteenths is three eighths.
The important point when ordering: the dash size fixes the thread as well as the bore. An AN6 hose end will always mate with an AN6 adaptor, whoever made it. That is the whole value of the standard.
AN size chart — bore and thread
| Size | Bore | Male thread | Typical use |
|---|---|---|---|
| AN3 (-3) | 3/16" | 3/8" x 24 UNF | Brake and clutch lines. The correct size for braided brake hose — do not go larger |
| AN4 (-4) | 1/4" | 7/16" x 20 UNF | Small fuel feeds, turbo oil feeds, gauge and sender lines |
| AN6 (-6) | 3/8" | 9/16" x 18 UNF | Fuel feed and return on most engine swaps and track builds. Power steering. The most common size we sell |
| AN8 (-8) | 1/2" | 3/4" x 16 UNF | Fuel returns on higher-power builds, oil return lines, coolant |
| AN10 (-10) | 5/8" | 7/8" UNF | Oil cooler lines, higher-flow oil return, coolant circuits, dry sump |
| AN12 (-12) | 3/4" | 1-1/16" UNF | Oil drain lines, dry sump plumbing, oil tanks, large-bore coolant |
Rule of thumb: AN3 for brakes and clutch, AN6 for fuel, AN8 upward for oil and coolant. If you need more flow than AN6 gives on a fuel system, step up to AN8 or AN10 rather than running two smaller lines.
All AN hose ends use a 37° JIC flare seat, which is what makes the standard interchangeable between manufacturers. Do not mate an AN fitting to a 45° flare — the seats will not seal.
Browse by size
- AN3 — Braided Brake Hose & Brake Fittings — hose, banjo and female ends, P-clips and locators
- AN4 Hose & Fittings
- AN6 Hose & Fittings — our widest range, including reusable PTFE hose ends
- AN8 Hose & Fittings
- AN10 Hose & Fittings
- AN12 Hose & Fittings
- Push-On / Push-Lok Hose & Fittings — AN6 to AN12, no crimping tool needed
Which hose goes with AN fittings?
The choice is about pressure, temperature and how the line is assembled.
- Smooth bore PTFE with a stainless steel braid — the motorsport standard. AN10 runs 2,000 PSI operating, 6,000 PSI burst. PTFE does not swell under pressure the way rubber does, so brake pedal feel stays firm and fuel lines stay dimensionally stable. Compatible with petrol, E85, VP Racing fuels, oil and coolant. Takes reusable or swaged ends.
- Convoluted PTFE — far more flexible for tight routing, 500 PSI maximum operating. For oil, fuel and breather runs where bend radius matters more than pressure.
- High-temperature polymer braid — the lightest option, 250 PSI, rated −54°C to +200°C. Used for fuel cell internals, breathers and vent lines.
- Push-on (push-lok) hose — a barbed fitting grips the hose inner, so no crimping tool and no clamps in most applications. The easiest route if you are assembling at home. Use hose clamps above 70°C.
- Rubber OEM-style hose with crimped fittings — for matching a factory line, mainly power steering. See Power Steering Hose & Fittings.
Reusable or swaged ends?
- Reusable ends can be undone and refitted, so a line can be shortened or re-routed without buying new fittings. Choose these for a build still changing.
- Swaged or crimped ends are pressed on permanently for a sealed assembly. Choose these for a finished installation.
Adaptors — getting AN onto a metric port
Most vehicles do not have AN threads from the factory, so an adaptor converts the component's thread to AN. We stock AN to M14 x 1.5, M16 x 1.5 and M18 x 1.5 metric O-ring, AN to imperial inverted flare, NPT adaptors, banjo adaptors, bulkheads, tees and blanking plugs.
See Brake Line Adaptors & Fittings for brake and clutch threads, and the size collections above for fuel and oil.
Passing a line through a panel? Each AN bulkhead fitting takes a matching lock nut — 3/4" UNF for AN8, 7/8" UNF for AN10, 1-1/16" UNF for AN12.
Don't forget the consumables: banjo bolts and copper washers. Copper washers are single-use — a reused one is the commonest cause of a weeping joint.
We can make the line up for you
Tell us the length, the fitting type and angle at each end, and the threads on your components, and we will build it. See Custom Hose Building for what we need from you.