350Z and G35

370Z and G37

Camaro 2010+

Caprice/Impala '71-'76

Charger, Challenger, Magnum, 300C

Chevy Colorado

Cobalt and HHR

Contour and Cougar

Corvette C2&C3

Corvette C4

Corvette C5, Z06

Corvette C6, Z06

Corvette C7

Countryman/Paceman by MINI

Crown Vic- Panther


Dodge RAM 1500

Eclipse 1G

Eclipse 2G

F150 (2010+)


Focus 00-'07

Focus 2012+

Ford Ranger

Fusion '13+

Impala SS 94-96

Jeep Cherokee


Lancia Scorpion

Lightning, Harley F150 99-04


Mazda 3

Mazda 6

Mazda RX8

MINI 01-06

MINI 07-13

MINI 2014+

Mustang 05-13

Mustang 2015-

Mustang 94-04


SHO '89-95

SHO, Flex, Explorer, MKS 2010+



Subaru WRX 08+

Subaru WRX 99-05

Super Duty 1999-2004

Super Duty 2005-2012

Super Duty 2013+



XXX Customs

TCE Performance Products

TCE Glossery of Random References

A dumping ground for helpful and basic info to aide buyers and builders with some simple cross reference information. Use at your own risk.


What is a Single Flare, an Inverted Flare and a Bubble Flare?

  • Single flares are simply hardline being opened up to fit over a male flare fitting. Effective in many applications where dedicated JIC or "AN" fittings are used. This is a single flare with a back up compression sleeve and b-nut that threads onto the 37 degree end of an AN3 fitting such as a bulkhead tee. For more info on these style end please visit Summit or Speedway where you can view the many AN3 options. For most reading this the next two are your more common types.
  • Inverted flares (sometimes called "double flares") are more production car style fittings and common on older US vehicles (3/8-24 IF it's called) and M10-1.0 on many imports. The tubing is flared one time and then rolled into itself creating a convex look. This seat mirrors that of the chassis fitting. 
  • Bubble Flares (BF) are common on many European vehicles; BMW, VW, AUDI and more. Here the tubing is swelled on the end creating a mushroom looking end that then compresses into the conical seat of the chassis fitting. Beware: by nature these have been proven to "swell" the ends of the threaded sleeve a bit (GM..) and may require a light dressing with a file to get them started into the female ends of many ss flex lines. Not'll go. 
  • How can you identify them? IF fittings are a cone shape, BF have more of a mushroom head. Which one is right for you? Unless you plan on re-plumb your car stick with the factory fittings. Much easier.  If you are plumbing a race car with a roll of steel hardline basic single flares are quick and effective- if you use the right adapters. Restoration of American Iron will require the use of 3/8IF fittings usually - 3/8  being 3/8", 24 thread ends, not the size of the steel hardline; that's 3/16",  which are still found on some new cars today. M10 fittings are more common on Asian imports and are similar to the 3/8IF fitting but have M10-1.0 threaded ends- again the M10 being the diameter of the thread, the 1.0 the "pitch" or distance from crown to crown of the thread. Nothing to do with the size of the steel line. 
  • Keeping it right! It's imperative that you use the correct fitting with your car and hose. 3/8-24 and M10-1/0 are VERY similar but will not correctly seal. To that end; crushing your bubble flare into the seat of an inverted flare might seal up...or not...but you have permanently damaged the hardline if you do so. 
  • In addition to these images and references there are more sizes and threads such as: 7/16-24, M10-1.25, M12 and more... this is the basic info here. Google more if you want to learn more.

Here in order:

  • Single flare; for use with AN style chassis adapters
  • Next:; Single, Bubble, Inverted.  
  • Then; comparing IF vs Bubble.
  • Lastly; notice the seats these ends thread into are very different.



Metric vs Imperial Thread adapters and hose ends..what the hell?

Ok so you know there are some difference and crossing things up will go way wrong. You sunk $150 into the fancy ss flex hose kit but you're not sure what you really got. Or maybe you're installing said fancy flex hose kit and something doesn't "feel right" about how it's threading. STOP! Take time to verify what you have before you continue. Luckily the hose industry is here to help. Did you know hose ends and chassis adapters are referenced for metric ends?? 

  • Imperial or SAE threads: commonly 3/8-24, maybe 71/6-24 or possibly larger on say... your master cylinder. Most of the time these adapters are clean six sided hexes and that's good.
  • Metric ends; be it IF or Bubble flare are often indicated by an additional machine marking on the six sided hex making ID very simple. 

On the left: we have Imperial 3/8-34 chassis fittings, flare nuts and banjo bolts.  

On the right; we have the same items but in metric thread. See those little marks?  Now you know!  (*not all brands have this)













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