how often do your brakes need new pads or bleeding

Anonymous

And as said before, it's highly likely it actually doesn't need a bleed at all. Most people's crappy brakes are due to a lot of other reasons before it ever gets to needing to bleed.

delcol

curious now,,, so here comes my silly question :roll:

Brake fluid does have gas in it, that's why you degas it by de-pressurising it

how come you dont have to degas the fluid when bleeding other brakes there is no mention of degassing in formulas bleed manual nor on my hope tech 2's
see vid.
http://www.youtube.com/watch?v=QzGQpS6fd3E

:? :? :?

nicklouse

and it is amazing how much better your brakes feel if you do. you dont have to with avids as they will work fine.

cars dont mention it as the volumes are greater and the pressures are as well.

The Rookie

Neal_ wrote:

We could both be wrong

Brake fluid does have gas in it, that's why you degas it by de-pressurising it and the opposite is true so if you pressurise it air will dissolve into it. The best plan is to bleed them properly so there's no air in the system and you don't need to try tricks like holding the lever down overnight.

You don't depressurise (gauge) you create a vacuum, this makes the bubbles that aleady exist bigger and they come out easier, it doens't mean they weren't already there though......

I think you've fallen into the 'assumption' trap, something you assume is the case you believe is the case as it fits your theory rather than fact.....

Simon

Neal_

The Beginner wrote:

You don't depressurise (gauge) you create a vacuum, this makes the bubbles that aleady exist bigger and they come out easier, it doens't mean they weren't already there though......

I think you've fallen into the 'assumption' trap, something you assume is the case you believe is the case as it fits your theory rather than fact.....

Simon

De-pressurise/pressure reduction/vacuum degassing, it's all the same thing regardless of what you call it. I think it is you who has fallen into that trap, read and learn.

wiki wrote:

Degasification is the removal of dissolved gases from liquids, especially water or aqueous solutions, in the fields of science and engineering.

Pressure reduction

The solubility of gas obeys Henry's law, that is, the amount of a dissolved gas in a liquid is proportional to its partial pressure. Therefore, placing a solution under reduced pressure makes the dissolved gas less soluble. Sonication and stirring under reduced pressure can usually enhance the efficiency. This technique is often referred to as Vacuum degasification. Specialized vacuum chambers, called vacuum degassers, are used to degas materials through pressure reduction.

The Rookie

Dissolved air doesn't give spongey brakes unless you heat it up and it comes out.

Most Hydraulic systems are open, not sealed, bikes are sealed so will not have anywhere near the dissolved air (and brake fluid is better than most hydraulic fluids due to the application requirements anyway) simply put, tying the levers back fixes a different problem.

Simon

Neal_

Anonymous

Far too much analysis.

1 - Your brakes probably don't need a bleed
2 - If you really think they do, just bleed them
3 - Regardless of 1 and 2, just ride. Chances are you'll find they improve as you ride and brake, then you wonder what the fuss was about.

With the exception of course of:
Juicys - bin and buy new brakes :P

Actually they do stop the bike, it's just they can be quite spongy feeling on the levers, the pistons don't reset well, they pull to the bar sometimes for no apparent reason, plus the spring clips annoyingly catch on the disc and the pads are fiddly to fit. Most of the issues aren't to do with needing a bleed. Did my old Juicys again before I got fed up with them and virtually no bubbles in the system. They're just crap brakes.

mrmonkfinger

deadkenny wrote:

Actually they do stop the bike, it's just they can be quite spongy feeling on the levers, the pistons don't reset well, they pull to the bar sometimes for no apparent reason, plus the spring clips annoyingly catch on the disc and the pads are fiddly to fit.

They sound great, where can I buy some?

pigeontoes

Pads need replacing 3 times a day.................................if you were doing the Kielder 100 this year.

Anonymous

mrmonkfinger wrote:

They sound great, where can I buy some?

Can have my old Juicys if you want. I take no responsibility if you decide to rip them off and garrote someone with the hose out of frustration.