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Braided Or Rubber Brake Hoses

Duncan
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Duncan Grand Master

Duncan

Posted
Posted

For all those that have been thinking about getting braided brake lines to reduce the expansion rubber hoses can have under big brake pressure, there is an interesting article on Autospeed this week http://autospeed.com/cms/A_2679/article.html

"Well, the first hose we tested was an old and worn rubber hose (which appears to be the original part from a ’65 Ford Mustang). In static conditions, this hose had an OD of 10.76mm and, when pressurised, it expanded to 11.02mm. An increase of 2.4 percent.

Next, we tested a brand new rubber hose. The new hose had a 10.47mm OD which expanded to 10.65mm when pressurised. An increase of 1.7 percent.

The final test was a new braided steel brake line. In static conditions, the braided line had an OD of 6.45mm and expanded to 6.49mm when pressurised. An increase of less than 1 percent."

0.7% difference in exansion between rubber and braided lines at 3500psi (about twice what you could actually generate). Considering the price is about 3 - 4 times as much......just buy new rubber hoses.

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dangerous_daveo Grand Master

dangerous_daveo

Posted
Posted

Can I ask what might be a stupid question. Percentages are nice and all, but in real life what does that percentage mean, like, is that 0.5% in expansion a bit increase or not?

Also remember whatever it is its x4.

blind_elk Grand Master

blind_elk

Posted
Posted

3 - 4 times as much??? pffft. The braided hose we got from Maltech were marginally more expensive than Nissan hoses. They cost around $350 for a set of 4. I purchased a pair of genuine Nissan front hoses at $90 EACH.

3 - 4 times as expensive. PFFFTT!

Beer Baron Grand Master

Beer Baron

Posted
Posted

yeah the genuine rubber ones are more expensive these days. i bought a set of nismo braided lines for 10 000 yen (about $130). they were very nice too.

the expansion measurement as a percentage is interesting too. the fact is the old rubber expanded .26mm where as the braided line only expanded .04. that is quite a difference among 4 lines (well six really on the GTR).

Duncan Grand Master

Duncan

Posted
  • Author
Posted

well I lost the receipt for my rubber lines in the mountain of receipts I have. But any decent brake shop can make up brake lines for you much cheaper, you don't need to use the Nissan ones.

And I can assure you that my pedal feel is brilliant with the new rubber hoses :P

Beer Baron Grand Master

Beer Baron

Posted
Posted
the nismo ones, were they $130 a corner?

nah, $130 for all 6. they are really nice too. Teflon lines, covered with stainless braid, then sheathed in teflon (or it may be silicone) to protect them. Without something covering the braid you can get problems as over time bits of dirt and grit can work their way into the gaps in the braid then slowing wear away at the line inside.

edit: I should mention that i bought them in japan on the cheap. I think the retail in japan is about 15 000 yen, and over here they are probably about $300 a set. still a good deal i reckon even at that price. particulary if bens maltech ones were $500 :P

LuvDR Contributor

LuvDR

Posted
Posted

I had braided lines on my 32 when it arrived, though for compliance reasons had to take them off. MASSIVE difference in feel of pedal. Was quite shocked, i thought the brand new lines i got made up would be very similar. Will hopefully go back to braided lines at some stage. It cost excactly twice as much for braided lines as rubber ones when i got quote. PS Have set of HKS sports braided lines for sale.

cowie165 Veteran

cowie165

Posted
Posted

Guys please correct me if I have it wrong, but the way I see it, if hose A expands by 1.7% and hose B expands by 1%, then the conclusion is that hose A expands 70% more than B, not a .7% difference...?

So 1/1.7 = braided has only 60% of the expansion that rubber does?

GTS20X Enthusiast

GTS20X

Posted
Posted

Also keep in mind that the tests where probably done at room temperature not at the temperatures often seen by brake hoses (you should all know rubber gets softer with heat). Also with braided hoses being silver wouldn't they be less susceptible to transfering heat to the brake fluid.

Carlos

omrae Apprentice

omrae

Posted
Posted

I think it's just a case of the journalist having some space to fill in and not actually understanding what's going on.

I have been involved and done similar tests and i know how to manipulate percentages, just measuring the expansion of the hose is not good enough. If you are going to do this type of test you must ensure each hose is the same length and new (not like the rubber hose shown). Also the machine used to do the test as shown in the article is not adequate for this type of testing, it keeps pumping pressure until its reaches it set pressure, the way it should be done is see what force is required to reach a certain pressure this will tell you how much the pressure the hose is absorbing. I’m certain a braided hose will out perform a rubber hose anytime.

Duncan Grand Master

Duncan

Posted
  • Author
Posted

omrae it sounds like you know what you are talking about....

Now I agree in total braided lines will be better than rubber....the question is, how much better.

If a new rubber line really does increase only 0.7% more than a braided one does, I am willing to bet that no-one could actually tell the difference on the track :)

cowie165 Veteran

cowie165

Posted
Posted
If a new rubber line really does increase only 0.7% more than a braided one does, I am willing to bet that no-one could actually tell the difference on the track :)

I'll make up some number just for the sake of simplicity.

Assume the OD of the hose is 10mm.

If hose A expands to 11mm and hose B expands to 15mm:

Hose A has increased by 10%

Hose B has increased by 50%

Hose B has not increased 40% more than A, it has increased 5 times that of A.

What I'm getting at is, the rubber hose increased by 1.7%, braided >1.0%, therefore the rubber hose has increased by nearly twice what the braided line did.

Duncan Grand Master

Duncan

Posted
  • Author
Posted

cowie165 I agree mathematically 1.7% is almost twice the expansion of 1% but thats not really the point....the difference in total diameter is 1% or 1.7% which lets face it is bugger all as a percentage of total diameter.

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