[Closed] Braided brake hose question

There will be no increase in overall power. It might alter the feel and might alter the initial bite but as it does not change the leverage ratios it cannot alter the power

Dont they say it prevents slight loss of power due to bulging in ordinary hose?
I just squeeze a bit harder.

Depends how you measure power, but if the hose bulges there'll be more volume for the fluid to occupy and therefore there wont be as greater force on the pistons pushing the pads together.

So I'd say that they should increase the available power. By how much, would vary depending on length and type of original hose at least.

I thought this was just bling on a mountain bike. The advantages of non-bulging hoses might be greater on a motor bike.

I've had both braided and non-braided on my bike and never been able to tell any difference. But then maybe I'm just not sensitive enough?

geoff - the pressure at the lever end and the caliper end of the hose will be the same hence the power will be the same.

a bulging hose does not reduce the pressure - just means more lever travel but not lever force to get the same line pressure

TJ - no. When the hose bulges you are effectively increasing the surface area that the fluid is acting on. As pressure is force per unit area, by increasing the area, you are reducing the pressure at the piston.

EDIT: Actually, braded hoses can't increase the braking power, but they can help to reduce a loss in braking power due to bulging hoses. Is that what you meant TJ?

geoff - nope. Teh pressure remains the same. More fluid is displaced thus lever travel is longer but the pressure remains the same for the same amount of force at the lever.

With standard hoses a pull of N newtons on the lever produces a pressure of P newtons per square inch in the master cylinder, the same pressure at the lever end of the hose and the same pressure at teh caliper end of the hose

With braided hoses a pull of N newtons still produces the same pressure in the master cylinder and thus at the lever end of the hose - although the lever travel will be less as less fluid needs to be displaced. Therefore there will be teh same pressure in the caliper end. therefore the same power.

What will be different is the feel - the lever will travel less for the same force and the initial bite will improve as the pressure will rise more quickly but once steady state is reached the power is the same.

Surely if the hose is bulging, its slightly elastic and therefore cannot transmit the full pressure from end to the other?

TJ aren't you assuming that the hose can only deform a set amount with your explanation?
Regardless of the actual physics involved, braided hoses should give a more positive "bite" coompared to standard hoses.

When the hose bulges you are effectively increasing the surface area that the fluid is acting on. As pressure is force per unit area, by increasing the area, you are reducing the pressure at the piston.

Yeah, that makes sense to me. I guess on the bike, the rider would compensate by pulling the lever further and/or harder & guess it's only noticeable when switching between bikes.

I'm going to throw another thing into the mix here (I'm not just s**t stirring...honest!). Last year, my wife and I both had Orange Fives in the same size, with exactly the same brakes. Both came with plastic hoses, but in some circumstances the brakes felt a bit weedy. So, I changed the hoses for 'Hel' braided on my bike, and Goodrich on hers. Both bikes had new fluid from the same bottle and were bled in the same way. Now, to me this is quite a strange one - with the plastic hoses, the brake power & modulation felt exactly the same, but with the braided, my bikes brakes (Hel hoses) felt much sharper and very slightly more powerful. The only obvious difference was that the Hel hoses appear to have a smaller diameter than the Goodrich. I'm sure there is definate difference - so, I'd wondered whether its the smaller diameter of the hose?

p.s. for any braided hose doubters - IMO, they're a worthwhile upgrade if you want to improve your brakes performance (not just bling), but can't afford to shell out £400+ on some really nice new Formulas or Maguras (hint hint...nearly Xmas 😉 .......some hope!)

Braided hoses make brakes feel very slightly less spongy.

But they're really for posing - they look nice - the difference is negligible and won't actually make your brakes 'better' in the real world.
People who say that changing to braided hoses improved their brakes are forgetting that the new hoses meant getting the brakes bled and it's the fresh brake fluid that's caused the improvement.

Oh, I have some bikes with braided hoses, some without depending on what I've bought second hand or bargains (eg CRC flood sale). One bike even has one of each. There's really no real world difference.

bigyinn - yes the initial bite will be greater as the pressure will rise to maximum quicker

Once steady state is reached tho the braking force will be the same.

Focrce x area is correct - but in the master cylinder. Teh same force at teh lever will produce the same pressure regardless of what the hose does. Othewise wheree do you think the pressure goes?

p.s. took me so long to write my last reply that I missed TJ's explanation of pressure & lever feel............oops! Yeah, what you've said is what I think is reflected in my back to back on-bike testing. Difference in power between Hel & Goodrich is extremely close, and I wonder if the actual difference is down to 'sharper' feel at lever.

It's the efficiency that is improved, not the power. You need to move the lever less to attain the (same) force you are applying (via the system) to the caliper. It's nothing to do with bite point, though; the lines won't begin to expand (considerably) until the pads have already clamped down on the rotor.

...although the lever travel will be less as less fluid needs to be displaced.

What do you mean by 'displaced'? Where is the fluid displaced from?

I use Goodrich on Shimano brakes as it 'firms' them up a bit, and I've always found shimano brakes a bit soft. but in terms of stopping power, it makes no difference. Look nice though.

TJ the pressure(force) goes in to expanding the hose. You are still considering that the expansion of the hose is finite. X pressure created at lever, y of that pressure expands hose thefore x-y at caliper.

fluid is displaced from the master cylinder into the hose and thus into the slave cylinder. If the hose bulges more fluid has to move to get the same pressure. Ie a softer lever feel

Initial bite of the pads onto the disc sas the pressure starts to build not bite point where the pads touch the disc in terms of travel.

Fatlassess - I am sure its that. You will get a sharper lever feel and more initial bite but power once steady state is reached will be the same

Same force on the lever will provide the same force on the pads irrespective of the hoses or any flex but you'll have to pull the lever further to get that force. More work done (force x distance remember) though and if they're spongy enough, the levers will hit the bar before you get the braking force you want.

Michael Bowden - Member

TJ the pressure(force) goes in to expanding the hose. You are still considering that the expansion of the hose is finite. X prssure created at lever. y of that pressure expands hose thefore x-y at caliper.

Nope - basic physics. If you have x pressure at one end of the hose you have x pressure at the other end [i]once steady state is reached[/i] It takes y pressure to expand the hose but at steady state it is pressing back with y pressure

every action has an equal and opposite reaction. newton and all that

Think about a spring on a set of scales. Put a weight on 1 kilo on teh spring what is registered on the scale - 1 kg even tho the spring has compressed

IOts the same thing

Think about it this way then TJ. If you replaced a 10cm length of hose (regular will do just fine and dandy) with a section of balloon. Assume its all sealed properly. Would you still expect to be able to get the force at the piston end to be as large as at the lever end?

Geoff - Yes, but only if you had huge/near unlimited lever travel and the balloon was very strong so that it didn't burst - as a balloon expands the pressure inside rises so eventually (and with enough fluid and lever travel), the pressure in the balloon would be sufficient to move the pistons with enough force to brake. It'd look very funny though 🙂

Of course in the real world, the lever would hit the bars and the caliper wouldn't move at all.

fluid is displaced from the master cylinder into the hose and thus into the slave cylinder.

The brake line and caliper are disconnected from the master cylinder when then lever is applied. They are only reconnected after the lever is released and returned to its neutral position.

The softness of the lever is due to the same amount of fluid having to apply force via an ever expanding tube. If the tube can not expand - if it was a solid metal pipe, for example - the force applied to the fluid would be transferred directly to the caliper. A hose with minimal expansion, like a braided hose, is similar to a solid pipe but with the advantages of being more flexible (along its length).

three fish - the reservoir is disconnected not the master cylinder. The master cylinder is the bit with the piston in in the lever assembly
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the reservoir is disconnected not the master cylinder. The master cylinder is the bit with the piston in in the lever assembly

Indeed, and I beg your pardon - I'd confused terms. You are correct, and I agree with you; I just thought you meant something different because you said that the amount of fluid displaced is less with a braided line. How can a different amount of fluid be displaced if the source (reservoir) is disconnected from the rest of the system immediately upon the lever being pulled?

IME, theres little difference in performance between stock plastic and braided hose.

The biggest difference is crash resistance and flexibility IMO. Saved me a fortune in crimped/folded hoses over the years I reckon.

You pay the price not just in cash, but weight too.

"Everyone" is right, just nobody has stated their assumptions properly (which you learn about doing in GCSE physics!)

TJ (and the other power doesn't increase people) are assuming the hose expansion is finite and limited. I.e. you press the hose, the hose expands to its max and from then on all force is applied to the lever.

The "power increases" people have assumed the hose can continue to expand throughout the braking process and therefore the system never reaches steady state as the volume increase continuously.

The reality is probably somewhere in the middle and will make **** all difference to your brakes.

The reality is probably somewhere in the middle

😆 Is that from GCSE Physics as well?

TJ (and the other power doesn't increase people) are assuming the hose expansion is finite and limited. I.e. you press the hose, the hose expands to its max and from then on all force is applied to the lever.

Nope! The hose expands to a point where it is providing an equal reaction to the force in the fluid - just like blowing up a balloon with a fixed pressure. If you added more pressure, the hose would expand more (or burst)