# Brake line size question **URL:** \ **Category:** NYSpeed Automotive\ **Created:** [June 4, 2009, 7:17am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742 "2009-06-04T07:17:12Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![newman](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/newman/32/7569_2.png) [@newman](https://forums.speedlife.net/u/newman)\ **Post date:** [June 4, 2009, 7:17am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/1 "2009-06-04T07:17:12Z")
1/4" or 3/16" I can think of a few pros and cons to each, but would like to hear more input. My gut leans me toward 3/16… but the 1/4" stainless lines and fittings are all **_free_**. ---
**Author:** ![drvnkd](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/drvnkd/32/109615_2.png) [@drvnkd](https://forums.speedlife.net/u/drvnkd)\ **Post date:** [June 4, 2009, 7:19am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/2 "2009-06-04T07:19:47Z")
What are the pros/cons? Brake fluid does not really flow right? ---
**Author:** ![Jskrapper](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/jskrapper/32/7570_2.png) [@Jskrapper](https://forums.speedlife.net/u/Jskrapper)\ **Post date:** [June 4, 2009, 7:20am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/3 "2009-06-04T07:20:18Z")
.25 line and you are pushing more fluid. From what I understand you need a bigger cylinder then. 3/16 is fine for almost all apps. edit: now that I think about that it really might not make logical sense. ---
**Author:** ![ILC](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilc/32/5337_2.png) [@ILC](https://forums.speedlife.net/u/ILC)\ **Post date:** [June 4, 2009, 7:20am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/4 "2009-06-04T07:20:48Z")
Go with the free I doubt you will notice the difference ---
**Author:** ![Southtowns27](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/southtowns27/32/5002_2.png) [@Southtowns27](https://forums.speedlife.net/u/Southtowns27)\ **Post date:** [June 4, 2009, 7:22am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/5 "2009-06-04T07:22:40Z")
What’s the application? 1/4" can be a PITA if every fitting on the vehicles brake components (master cyl, wheel cyls, calipers, etc) is sized for 3/16" ---
**Author:** ![newman](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/newman/32/7569_2.png) [@newman](https://forums.speedlife.net/u/newman)\ **Post date:** [June 4, 2009, 7:23am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/6 "2009-06-04T07:23:09Z")
You will be displacing the same amount of fluid, there is just more of it. Pros: more volume = lower temps Cons: more volume = more fluid to absorb water I’m sure there are more… ---
**Author:** ![newman](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/newman/32/7569_2.png) [@newman](https://forums.speedlife.net/u/newman)\ **Post date:** [June 4, 2009, 7:23am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/7 "2009-06-04T07:23:56Z")
> [@Southtowns27](#): > > What’s the application? 1/4" can be a PITA if every fitting on the vehicles brake components (master cyl, wheel cyls, calipers, etc) is sized for 3/16" Master is 3/16. Calipers are 1/8npt Either way i am going to need adapters. ---
**Author:** ![Southtowns27](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/southtowns27/32/5002_2.png) [@Southtowns27](https://forums.speedlife.net/u/Southtowns27)\ **Post date:** [June 4, 2009, 7:25am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/8 "2009-06-04T07:25:32Z")
More adapters are more opportunities for leaks. If you’re worried about water absorption go with silicone brake fluid. Just be sure you flush ALL of the old fluid out or you will hate life. ---
**Author:** ![newman](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/newman/32/7569_2.png) [@newman](https://forums.speedlife.net/u/newman)\ **Post date:** [June 4, 2009, 7:25am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/9 "2009-06-04T07:25:58Z")
Another con is that there is more area for the fluid to act on = softer feel. However, the 3/16 would probably be mild steel, 1/4 would be stainless. ---
**Author:** ![ILC](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilc/32/5337_2.png) [@ILC](https://forums.speedlife.net/u/ILC)\ **Post date:** [June 4, 2009, 7:30am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/10 "2009-06-04T07:30:09Z")
Lotus? Or bimmer? ---
**Author:** ![Southtowns27](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/southtowns27/32/5002_2.png) [@Southtowns27](https://forums.speedlife.net/u/Southtowns27)\ **Post date:** [June 4, 2009, 7:31am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/11 "2009-06-04T07:31:02Z")
The size of the line shouldn’t have much of an effect on pedal feel. As long as the ratio of the surface area of the master cylinder piston stays constant with the surface area of all the caliper pistons/wheel cylinder pistons the mechanical advantage stays the same. ---
**Author:** ![newman](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/newman/32/7569_2.png) [@newman](https://forums.speedlife.net/u/newman)\ **Post date:** [June 4, 2009, 7:38am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/12 "2009-06-04T07:38:05Z")
This is a totally scratch built system. It’s in a BMW using a honda master cylinder, with wilwood superlite calipers at all 4 corners. More adapters are more room for leaks, but it’s only an issue of adding two adapters. ---
**Author:** ![LUKE\_L](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/luke_l/32/7462_2.png) [@LUKE\_L](https://forums.speedlife.net/u/LUKE_L)\ **Post date:** [June 4, 2009, 8:50am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/13 "2009-06-04T08:50:03Z")
If you ran the 1/4 inch line I would consider upgrading your master cyl. In theory by going from a 3/16 line to 1/4 you essentially add ~40% more volume. Area of 3/16: .028 in^2 Area of 1/4: .049 In^2 The cylinder may have an adverse affect and you could loose braking power, yes? Which is cheaper better master cylinder or SS 3/16 lines? ---
**Author:** ![nitroinsane](https://avatars.discourse-cdn.com/v4/letter/n/d26b3c/32.png) [@nitroinsane](https://forums.speedlife.net/u/nitroinsane)\ **Post date:** [June 4, 2009, 8:55am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/14 "2009-06-04T08:55:11Z")
3/16ths is perfect . ---
**Author:** ![Carnut](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/carnut/32/7590_2.png) [@Carnut](https://forums.speedlife.net/u/Carnut)\ **Post date:** [June 4, 2009, 8:57am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/15 "2009-06-04T08:57:00Z")
3/16 ---
**Author:** ![rdandy5875](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/rdandy5875/32/7511_2.png) [@rdandy5875](https://forums.speedlife.net/u/rdandy5875)\ **Post date:** [June 4, 2009, 9:01am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/16 "2009-06-04T09:01:59Z")
I would probably go with the 1/4", building shit beefier (and getting materials free) appeals to me over the complications I might run into by using bigger parts. ---
**Author:** ![nelstoys](https://avatars.discourse-cdn.com/v4/letter/n/48db29/32.png) [@nelstoys](https://forums.speedlife.net/u/nelstoys)\ **Post date:** [June 4, 2009, 9:04am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/17 "2009-06-04T09:04:48Z")
Id go with free 1/4 line, in a proj like your bmw i bet $ its just eating at your wallet so free works as much as you can get it . At least on my 68 camaro every time I get ahead im set back another 40 dollars here and 150 there for little things. ---
**Author:** ![boardjnky4](https://avatars.discourse-cdn.com/v4/letter/b/96bed5/32.png) [@boardjnky4](https://forums.speedlife.net/u/boardjnky4)\ **Post date:** [June 4, 2009, 9:05am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/18 "2009-06-04T09:05:00Z")
just because it is 1/4 lines, doesn’t make it any beefier or more durable/longlasting/ ---
**Author:** ![Fry](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fry/32/7284_2.png) [@Fry](https://forums.speedlife.net/u/Fry)\ **Post date:** [June 4, 2009, 9:09am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/19 "2009-06-04T09:09:52Z")
The bigger the line, the more material to flex/deflect/stretch. I’d expect the 3/16" to give a firmer pedal feel. Wait, are we talking all metal tubing? If so then I’d bet you’d never feel a difference. Wait, you already brought this up in post #9. OK then. Free + Stainless \> oversized + two fittings. IMO. ---
**Author:** ![neonglh](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/neonglh/32/4951_2.png) [@neonglh](https://forums.speedlife.net/u/neonglh)\ **Post date:** [June 4, 2009, 9:27am UTC](https://forums.speedlife.net/t/brake-line-size-question/68742/20 "2009-06-04T09:27:07Z")
The temperature difference of the fluid is almost certainly negligible between the two! [Next page](https://forums.speedlife.net/t/brake-line-size-question/68742.md?page=2)