Question about braided lines

[Chrislost]

Is it better to have seperate lines from the master cylinder to each caliper, or to have one line down and one accross to the other caliper?

Both my bikes have 2 lines down and i favour this method, howeveri have noticed a few late model standard bikes have one down and one accross.

[cs363]

Interesting question and it will be interesting to see what replies get thrown up.

My immediate thought would be that individual lines to each caliper would give the best result and that the modern sportbike line routing is probably done to save on costs.

However, I must emphasise that I am purely speculating.

[bogan]

cos they are hydraulic lines, with very little fluid flow, i doubt it would make much difference at all.

[cs363]

Sounds like bogan may be onto it, given the comments on this page regarding pressure:http://www.h-e-l.co.uk/brake-doctor/index.htm

No doubt the reduced cost of running extra brake hoses does come into it as well though.


Though it's interesting to note that looking at all the pics of current WSB & Moto GP bikes that I can find, they all appear to be running the individual hoses from master cylinder to calipers.

[Shaun]

I have always made and used 2 lines WHY, because I believe it is easier to work with some thing that is direct, and not about direct?

Banjo's and T Joints CAN also be a point where AIR can be trapped, so eliminating one more potentuall problem has got to be good?

I always include a bleed nipple into the master and lines up top ( If not there in the first place) as AIR is supposed to rise!


O and a TEE Joint is about $45 RT as well, so about the same cost for Dual or single/Duel

[NZsarge]

I would lean toward separate line to each caliper.
If your set up is in series as in one down then across over to the next it makes sense to me that it would have to begin pushing one set of pads onto the disc before the line pressured up to move the last set onto the disc, then again I don't know anything about fluid dynamics so..
It would also stand to reason there would be equal pressure to each caliper with separate lines too would'nt it?

[CookMySock]

I would use one line down, and keep the line to the second caliper as short as possible. I would use braided-over-flexible hose where I was forced to, or else I would use solid steel lines everywhere else. I would use the smallest possible diameter of each.

Steve

[Two Smoker]

I have always made and used 2 lines WHY, because I believe it is easier to work with some thing that is direct, and not about direct?

Banjo's and T Joints CAN also be a point where AIR can be trapped, so eliminating one more potentuall problem has got to be good?

I always include a bleed nipple into the master and lines up top ( If not there in the first place) as AIR is supposed to rise!


O and a TEE Joint is about $45 RT as well, so about the same cost for Dual or single/Duel

Agree with Shaun... Apparently he knows what he is talking about... most of the time hehehe.

Another reason that racers use individual lines to each caliper is so that the hoses are out in the airflow to aid in cooling and reduce overheating. thus improving brakng...

[98tls]

Two smoker probably has a valid point re cooling but apart from that i cant possibly see how it can make one iota of difference if the lines are properly bleed,was dicussed on the TL website awhile back and i followed a few links etc and those that supposedly know these things agreed it makes not one bit of difference.

[Pixie]

I would lean toward separate line to each caliper.
If your set up is in series as in one down then across over to the next it makes sense to me that it would have to begin pushing one set of pads onto the disc before the line pressured up to move the last set onto the disc, then again I don't know anything about fluid dynamics so..
It would also stand to reason there would be equal pressure to each caliper with separate lines too would'nt it?

You're correct-you don't know anything about fluidics

[Pixie]

Agree with Shaun... Apparently he knows what he is talking about... most of the time hehehe.

Another reason that racers use individual lines to each caliper is so that the hoses are out in the airflow to aid in cooling and reduce overheating. thus improving brakng...

Fluid in a braking system is effectively static.So heat transfer via the brake lines is negligible

[cs363]

You're correct-you don't know anything about fluidics

Yeah, I think people aren't reading the applicable section in that link I posted, so here's a cut and paste:

Pressure - Is a constant in the hydraulic system. If you put 10 psi into a system hydraulic laws state that this 10 psi will act on all surfaces within the system equally. Pressure In = Pressure Out.

I know it does tend to go against what our gut feeling is about how this would work, but a facts a fact! :)

[AllanB]

Yeah, I think people aren't reading the applicable section in that link I posted, so here's a cut and paste:

Pressure - Is a constant in the hydraulic system. If you put 10 psi into a system hydraulic laws state that this 10 psi will act on all surfaces within the system equally. Pressure In = Pressure Out.

I know it does tend to go against what our gut feeling is about how this would work, but a facts a fact! :)

Excellent - so you just pick the setup that you think looks the coolest ;)

[cs363]

Excellent - so you just pick the setup that you think looks the coolest ;)

Lol, well it does seem to point to that! :laugh:

[Pussy]

Brian Bernard once told me that the main reason for using two lines from the master cylinder is ease of fitting calipers quickly.
I have stock pattern Goodridge lines on my sem fiddy... I chose them to keep a relatively stock look. They perform very well

[Max Preload]

2 lines = less banjos = cheaper. Pressure differential is non-existant. Cooling difference is negligible.

[R6_kid]

Fluid in a braking system is effectively static.So heat transfer via the brake lines is negligible

That may rule out convection in the lines, but what about heat conduction/transfer. Even if the fluid in the line is static it would act more like a metal does when heated - transferring the heat energy by conduction and not convection.

[cowpoos]

Agree with Shaun... Apparently he knows what he is talking about... most of the time hehehe.

Another reason that racers use individual lines to each caliper is so that the hoses are out in the airflow to aid in cooling and reduce overheating. thus improving brakng...
and a little more volume of fluid in two lines will help with heat dissipation

[LBD]

I would use one line down, and keep the line to the second caliper as short as possible. I would use braided-over-flexible hose where I was forced to, or else I would use solid steel lines everywhere else. I would use the smallest possible diameter of each.

Steve

Wot he said but he doesn't say why so I will....

The advantage of braided lines or steel lines is that they do not swell under pressure as much as the conventional hoses did. Therefore you get better feedback/more accurate control of your braking.

However braided lines still swell. The longer the lines the more volume of fluid is lost in the swelling of the lines. With Steves layout above, you will get better feel/control than with twin lines, because you have a shorter total length of hose to swell.

[Two Smoker]

Fluid in a braking system is effectively static.So heat transfer via the brake lines is negligible

Heat rises... and what R6 Kid said... The calipers heat up, thus heating the fluid in the calipers... This transfers up the brake lines through the fluid. Keeping them in the airflow cools them...

[cowpoos]

Heat rises... and what R6 Kid said... The calipers heat up, thus heating the fluid in the calipers... This transfers up the brake lines through the fluid. Keeping them in the airflow cools them...
+ 1

sorry pixie...heat energy is transfered. something I thought was obvious :)

[Two Smoker]

+ 1

sorry pixie...heat energy is transfered. something I thought was obvious :)

OI! Piker! Where were you last night!?

[LBD]

When the brakes are applies and released the fuild in the lines may move 25 mm back and forth, tops under braking when the heat is generated, the fluid is static until the brake is released, and any warm fluid enters the bottom of the synthetic braided hose remains very close to the caliper end of the line.

Point 1) If heat was an issue then we would not be using synthetic lines that insulate, we would have metal lines that conduct the heat out to the atmosphere.

Point 2) The inside of the hose is about 4.5mm (ish) way to small for convection circulation to work and overcome friction losses in the tube.

Point 3) Any heat that is in the caliper end of the line would be cooled within a few inches of the bottom of the line well before reaching any fork required with a single line system.

Point 4) The cooling on the greatest volume of fluid is carried out by the aluminum caliper housing where 95% of any warm fluid resides, the surface area of the caliper is far greater than the small surface area of a line, the caliper is made of aluminum, a great thermal conductor, and if cooling the brake fluid was at all a concern the Aluminum Caliper would have fins to increase the radiating surface area and would inprove the cooling where it is most needed..close to the friction.

My Conclusion) The cooling affect of the lines has no bearing on the single or twin brake line debate.

Twin lines are only of value in a conventional system, if a twin master cylinder system is used at the top, giving effectively two completely seperate controlled brakes with one lever....a 50% redundancy fail safe system. IMO

[imdying]

Didn't read all the posts, but... no, it doesn't make a difference. As far as bleeding goes, fucktards that can't bleed brakes properly will muck it up no matter how the lines are routed... and bleeding them is a piece of piss in any case. As far as cooling goes... hahahahahah.

Just whatever floats your boat will be fine... twin lines generally looks nicer.

[Mikkel]

Have a look on page 39 of Galfer's catalogue (http://www.galferusa.com/VIP/Galfer%20Catalog.pdf) for different line configurations.

They don't mention any benefits of either system... I'd go for a symmetric system - not because it's likely to have any noticable advantages, but from a pedantic point of view there should be no possibility of imbalance in the performance of either caliper.

The crossover kit makes sense as a cheaper option since you use a shorter length of brake line...

As for cooling - you'd have to be getting those lines very hot indeed for that to be noticable...

[boman]

I modified my Sv 1000, from 1 line down and across, in rubber. To two lines down in braid. The difference is very noticable. Much better feel and better bite too, due to less deflection in the braid.

:yes: