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| Mr.Everready |
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 Mr.Everready World Chat Champion

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 Ichy World Chat Champion

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| Bishbash |
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 Bishbash World Chat Champion

Joined: 09 Jan 2006 Karma :   
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 Posted: 17:46 - 18 Mar 2009 Post subject: |
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IMO I really don't see the point in getting braided hoses added, there is such a small difference under hard breaking. Is it a look thing? I really don't get the whole attraction to them.  ____________________ My current bikes are - YZF-R1 & GS 500 E
Trackday videos - https://www.youtube.com/user/bishbash13 |
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 ..... Quote Me Happy
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| Bishbash |
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 Bishbash World Chat Champion

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| Kickstart |
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 Kickstart The Oracle

Joined: 04 Feb 2002 Karma :     
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 Posted: 18:00 - 18 Mar 2009 Post subject: |
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Hi
Not sure they really do last longer. Suspect more that the makers of them are less paranoid that the bike makers.
They are more easily damaged. They can expand (checked a load of hoses with some measuring calipers while pulling the brake lever hard, the standard fit braided hoses on Charlottes Thunderbird expanded the most, FAR more than the 10+ year old rubber hoses on my RS125).
Suspect for most people the reason they find an advantage from using braided steel hoses is that it forces them to bleed the brakes properly.
All the best
Keith ____________________ Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing |
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| Bishbash |
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 Bishbash World Chat Champion

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 Posted: 18:08 - 18 Mar 2009 Post subject: |
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I cant find any evidence of them making any significant difference, I found one site with some testing on them;
Quote;
Well, the first hose we tested was an old and worn rubber hose. 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.
And that is under 3500psi
Their conclusion;
Well, yes, a braided steel brake line does give less expansion under pressure than a rubber hose - but the margin is extremely small. And keep in mind that these tests were conducted at more than double the pressure you might generate in a real-world situation. So the difference between braided steel and rubber brake hoses is extremely, extremely small...
Just sounds like a waste of money to me. ____________________ My current bikes are - YZF-R1 & GS 500 E
Trackday videos - https://www.youtube.com/user/bishbash13 |
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| Ichy |
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 Ichy World Chat Champion

Joined: 15 Jul 2005 Karma :     
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 Posted: 19:26 - 18 Mar 2009 Post subject: |
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I buy them for two very simple reasons. The first is that they are cheaper than OEM when I need to replace the hoses on my older bikes. The second is that I ocasionally need custom lengths of hose, for instance I've just fitted different, bigger, bars to my bike.
Many people suggests it improves the feel. No idea how you quantify this or even if its true, it might be, as Keith said, just because they've bled and refilled with new fluid. ____________________ https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/ |
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| Bikeless |
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 Bikeless World Chat Champion
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| Pete. |
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 Pete. Super Spammer

Joined: 22 Aug 2006 Karma :     
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 Posted: 22:08 - 18 Mar 2009 Post subject: |
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| Bishbash wrote: | I cant find any evidence of them making any significant difference, I found one site with some testing on them;
Quote;
Well, the first hose we tested was an old and worn rubber hose. 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.
And that is under 3500psi
Their conclusion;
Well, yes, a braided steel brake line does give less expansion under pressure than a rubber hose - but the margin is extremely small. And keep in mind that these tests were conducted at more than double the pressure you might generate in a real-world situation. So the difference between braided steel and rubber brake hoses is extremely, extremely small...
Just sounds like a waste of money to me. |
It's quite conceivable that you can displace more oil through thinning the walls of the non-braided fat-walled hose than expanding the OD of the braided thin-walled one. Simply measuring the OD increase doesn't make for a fair test. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good  |
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| Kickstart |
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 Kickstart The Oracle

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| pyx_e |
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 pyx_e World Chat Champion

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| Kickstart |
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 Kickstart The Oracle

Joined: 04 Feb 2002 Karma :     
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 Posted: 12:46 - 19 Mar 2009 Post subject: |
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Hi
I suspect that any pump you use would be unlikely to be accuratly calibrated enough to get a consistant 1000psi.
Suspect it would be FAR easier to measure the force put on the lever or the piston. For a full rig you could put a small pressure sensor between the lever and piston and compare the output with that of a hydraulic pressure sensor in the line. Or compare it against the pressure exerted on a piston.
For a cheap test put a pressure sensor in the hydraulic system somewhere and then just pull the lever with a spring balance mounted at a fixed position on the lever. Pull the lever with X amount of force (you would need to pull at a fixed angle) and check the pressure in the hydraulics.
However rubber hoses have a thick protective coating, so this should be far less likely to occur than with a braided steel hose.
All the best
Keith ____________________ Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing |
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| sickpup |
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 sickpup Old Timer

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 Kickstart The Oracle

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| Ichy |
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 Ichy World Chat Champion

Joined: 15 Jul 2005 Karma :     
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 Posted: 17:19 - 19 Mar 2009 Post subject: |
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If you wanted to prove it on the bike you would need to machine up a brake lever replacement with marked datums or fixing points to insure you use the same position each time.
To the lever connect a load cell and a transducer to measure applied force and lever deflection.
connect a calibrated gauge directly to the master cylinder or via a steel tube, operate it loads of times and take the average to give a nominal value for applied force at a repeated deflection.
Do the same with the hose attached and either measure the output pressure at the same deflection and force or measure the amount of force and deflection required to achieve the same output pressure.
In the real world you would just use a comparator. ____________________ https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/ |
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| Pete. |
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 Pete. Super Spammer

Joined: 22 Aug 2006 Karma :     
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 Posted: 18:43 - 20 Mar 2009 Post subject: |
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Braided hoses don't make any difference to the pressure in the system. If you squeeze the lever with rubber hoses the same as with braided hoses then the pressure produced is the same. Something would have to give for it not to be. If either of the types of hose could not handle the pressure then the lever would hit the bars.
The benefit you get with braided hoses s that there's less 'give' in them than in all-rubber ones (which are actually fibre reinfocrd internally just theat you can't see it). You can feel this by having a 'firmer' lever when you fit braided hoses. Of course, if you fitted new rubber hoses you'd also get a firmer lever than with the old hoses and since they are a service item they should be changed periodically anyway.
If you want a good DIY test bleed up a system with split hoses that has one braided and one rubber going to each caliper. Put a clamp on the bottom end of the rubber hose and on the top of the braided one and try to squeeze the lever. It won't move much (once the return port is covered). Now swap the hose clamps so the rubber hose is clamped at the top and the braided one at the bottom. Squeeze the lever and it won't move at all because the braided ones expand only a negligable amount.
It's all a bit academic anyway because almost all of any lever movement is down to the calipers. Take just about any system that has excessive lever travel and clamp the hoses off at the calipers and your lever travel will go solid. ____________________ a.k.a 'Geri'
132.9mph off and walked away. Gear is good, gear is good, gear is very very good  |
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Old Thread Alert!
The last post was made 17 years, 177 days ago. Instead of replying here, would creating a new thread be more useful? |
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