Magura Brake Fluid

[ScotchDave]

Try breathing water, Wayne? The oxygen is covalently bonded to the hydrogen, so it's not like you have hydrogen at one end of your hoses and oxygen at the other.

Equally, at 20°C, the density of water is 0.99820g/cm^3, compared to 1.08 for Dot fluid. A massive 0.07g/cm^3 max difference. That means there's less than 7% difference, and that was comparing it to a super high quality Dot fluid (can't remember the exact difference). When compared to a regular mineral oil (according to google), you're comparing the 0.99820g/cm^3 of water to 0.914g/cm^3. If you think that's how small the difference in density of the two materials is, just try and think of how close the difference is going to be between the two for compressibility (or whatever the tech term is)? There's f**k all difference, which is - funnily enough - why so many hundreds of people on here, OTN, people I've met on rides and so on all use water with no trouble.

Right, the propblem heres is not the density of the fluids in question but the viscosity, some liquids have very strong inter molecular bonds and therefore are highly viscous, this is not related to the mass of the moleculce, though the size of the electric forces between the molecules are also involved.

Basically the density of the fluids is not the be all and end all.

[Bionic Balls]

you forgot about the interactions between the hose material and the fluid...

in fact...that must be much more important than the viscosity, since viscosity is a measure of a materials resistance to plastic deformation,and here you aren't deforming anything as such, simply pushing something down a tube...

i'm sure it has an effect somewhere along the line though...

adam

Edited May 20, 2006 by ad101

[ScotchDave]

Pushing the fluid is deforming it, all the molecules move relative to each other when you push on the fluid.

[Waynio]

"General" water out of a TAP as everyone uses (as they dont boil it!!!) has more air in it. and if you can prove to me it does not then fair play. dave85 i HAVE run water and when the brake locks I got a "spongy" effect, which was the water compressing more, thats why when i have a go on peoples bikes with water in you have to pull it "firmly" to make sure it does lock up before the water starts compressing, NO SCIENCE here, its general knowledge, i dont need to get into all the formula's you lot are gettiing into like this:

"if you boil your water to 55 degrees it will be perfect and all the air will be out"

why????

H2O Hydrogen & Oxygen make water. its a fact. or wait a minute? is some trials rider on here telling me that when i went to school to going to school now water changed? im not argueing or putting people correct im stating a TRUE fact, and giving advice.

FOR ALL THE PEOPLE THAT WANT THIS INFO:

I use "DIESEL" in my brakes. Now run along to the petrol station fill a jerry can up and all bleed your brakes when you come back and say "WOW!!! it returns mega fast, locks well and pulls on really easily" il enjoy people using waters comment on it

i have a diesel car, im not saying to go "Syphoning" out of your mum or dads car, ok diesel is expensive @ mo, but getting a couple of litres and filling a couple of jars up with it, then puttin the rest in your mum or dads car. Tell em its a present for all the tripping around they do for you

"NOTE: there is soon to be a diesel shortage for people "youths" filling jerry cans up with diesel" that would be funny.

Waynio..............................

diesel in my brake doesnt feel to have air in, it also is "oil" based therefore lubricates the seals hasnt caused me any problems yet. feel free to try it.

[Bionic Balls]

if you boil your water to 55 degrees it will be perfect and all the air will be out

don't even go there guys...

think that's enough about the whole air thing now? but wayne..oxygen is air is very different from than in water- just as iron is very different when it's in it's ore...

diesel ey? that's definitely a new one

adam

[nmt_oli]

diesel is an interesting one, it is an oil distilate so will be better than water, but is very thin so while being nice and quick returning and all that, it wont lubricate the inside of your brake as much as proper fluid, or a shock oil like i use.

doesnt make much difference as your likely to damage the brake enough to warrant a new one before you wear the piston significantly enough due to a less lubricating fluid.

I would do a water bleed in an old brake, but mine is brand spanking new, and i want it to stay feeling like that, not go all horrible.

[Mark W]

The fact there is oxygen in the chemical make up of water does not mean that it is full of air, Wayne. Hydrogen is a gas too, so why direct all your hate on oxygen

I know that this is suggesting that you may have done something wrong, but in that my water bleed feels stiff and responsive, maybe you somehow did a not-so-great bleed? My brake feels great, I know other people with water bleeds who've done it well, and it's fine. Yes, you don't like it or whatever, but I don't really give a f**k, and I can't really be bothered going into it more.

[ScotchDave]

don't even go there guys...

think that's enough about the whole air thing now? but wayne..oxygen is air is very different from than in water- just as iron is very different when it's in it's ore...

diesel ey? that's definitely a new one

adam

Sorry to burst your bubbles boys, but all water has air dissolved in it, not chemically bonded like in the water molecule but as small bubbles of gas in between the water molecules. The reason liquids compress so little distance between the molecules, now when you shove a great big squishy bubble of gas in between these molecules the water will compress more.

[Bionic Balls]

okies...i can see how air could be in the water- it's like that milky looking tap water, it's just full of tiny air bubbles...but surely they eventually rise to the surface and leave the water because of the difference in densities? or at least reach some kind of equilibrium with a <very> small amount of bubbles in the liquid?

adam

[nmt_oli]

gases can dissolve quite easily in water (think fizzy drink).

this happens with tap water. If you bleed your brake with water like this, even if there is no visible air in it (just dissolved air) over time, the water will come out of solution and return to its gaseous state, allowing the brake to compress more, giving the squidgey feeling.

the only way of solving this is a new bleed.

The advantage of oils is it is much harder for gases to dissolve in them, giving a lower compressability.

[Tomm]

Sorry to burst your bubbles boys, but all water has air dissolved in it, not chemically bonded like in the water molecule but as small bubbles of gas in between the water molecules. The reason liquids compress so little distance between the molecules, now when you shove a great big squishy bubble of gas in between these molecules the water will compress more.

Yes.

I was going to say everything you've said already in this thread, but you keep getting there first Fish breathe air (well, oxygen I suppose) that is dissolved in the water. Not from the water molecules breaking up. Whether or not the gas content of water has anything to do with the compressibility I don't know, but water is more compressible than other liquids.

Although I had another thought. Maybe in maguras the difference is that water is runnier so it's harder to get a good bleed and you end up with more air in your brake anyway... Whatever, like I said before, there's really no substitute for practical experience. There are far too many variables for anyone to come up with a definitive answer so we could probably leave it.

Water works OK

Mineral oil works OK

Vegetable oil works OK

Wayne says Diesel is OK

DOT oil is BAD (for seals, apparently)

[JT!]

JT why the you fool?(Mr T style FOOL) did you go to skool???? H2O is HYDROGEN & OXYGEN!!!!! hahahhahaha and THAT is what water is or is it JUST a H????? or did i miss something????

School boy errors!!!! hence the SH!T advice people give.

Waynio........................

I'm still at school doing A-level physics, maybe not doing great at it but still...

Water is h2o, yes. But if you mix hydrogen and oxygen in a container it doesn’t just magically make water, you need to go though some sort of chemical reaction to combine the atoms. Hence, water doesn’t contain air just because it’s made up of h2o.

Yes, water may compress a bit more than other fluids, but not because it 'contains air', but because of it's chemical makeup maybe, or maybe because it holds more tiny air bubbles (and I mean microscopic) which would make it compress more than other fluids. I’m not sure, but I’ll look into it.

Any liquid is usually considered uncompressible, on a mechanical scale, it dosn’t compress, the more water you have the more it will compress, you’d need a lot of water to actually see any kind of compression going on.

But on a hs33 scale, which is only a few milliliters, it really really wouldn't matter.

Also, you have the hose expanding, rubber compression in the pads, frame flex and the plastic bending in the leaver, which would collectivly have much more of an effect than the difference of compression between water and mineral oil.

I know i'm pritty much repeating what Mark said, but when someone thinks "Becuase water is H20, it contains air, and therefor compresses" and "Didn't you goto school?" It needs to be re-stated. Especially when you spell school 'skool'.

Edited May 21, 2006 by JT!

[Mark W]

Word. Pretty much what I'd have said, had I been bothered enough (although I guess I covered it in that post waaaay back, to some extent).

[Joe_Elding]

1 litre of water compresses by 0.1% approx. (according to my chem. teacher) assuming there is about 20ml of water in a magura (30ml syringe, don't use all of it) then it will compress 0.02ml, and to achieve it compressing that much you have to exert 16 atmospheric pressures (basically 16 times the strength of gravity). So basically unless you are the hulk and/or chuck norris you will not be able to make your water compress any noticable amount.

[Heatsink]

Diesel is an interesting one!

In high pressure applications (oil pressurised by pumps not your hand), I've come across something called the 'Diesel effect'. Maybe this could be the secret to your explosive riding Wayne!

What is the 'diesel effect'?

The diesel effect occurs in a hydraulic cylinder when air is drawn past the rod seals, mixes with the hydraulic fluid and explodes when pressurized.

Steve

[Janson]

haha, I can see it in front of me, wayne's brake exploding.

windshield wiper fluid is the way forwards by the way. it's blue and it smells good!

[Biff...]

Just use water for the summer can't really beat it, but when the days start to get colder, i would advise to either put a little bit of antifreez in your brake, or just buy some magura or genral minral oil from your local autospare shop.

Edited May 21, 2006 by Kyle Hinchcliffe

[Waynio]

windscreen wiper fluid sounds like it would smell nice too

i was stating a "science" fact then mark gives me a science equation, i left school after year 11, couldnt be bothered with it, would rather work and learn stuff to do with bikes. when i have had water in my brake form what I can feel and pretty much with everyone elses brake, the water compresses and im sorry if you can not feel that, but i do. weather its just me i dont know. but iv ridden magura brakes for 4years. if thats not long enough i dont know what is.

i was only stating what water is. yes ok if you boil it or whatever it will work (i dont know this im going off what you lot have said) but who gets their pan out and boils water while street riding???

people wanted to know what i used, i told them, mine feels good to me, but when people start using diesel and it dunt freeze and it feels better than water as it has similar properties, (ok maybe not) but for me it has worked loads better and for about 15/16 other people i ride with who have had Diesel in their brakes too.

haha i would laugh if my brake exploded

my explosive riding???? iv got a can of diesel inside not NOS diesel works better, and my cars run off it.

i knew you would pick up on the spelling "skool" and as i was writing it yesterday feeley was stood next to me and literally said "haha they will pick up on your spelling on skool instead of SCHool"

Waynio..........................

[OD404]

With Hydrogen being a gaseous element, like oxygen, and Diesel, like many fuels being made up of Carbon-Hydrogen (with a little Sulphur too), does this not mean, by some of the arguments going on here that this magical new fluid actually contains hydrogen gas in the same way that water supposedly contains "air"?

I've used various different fluid in my maggies, none of which have broken and to be honest i'll use what I can get my hands on, and that is water more often than not. To me it feels better than maggie fluid, and has never caused me issues with the seals. I can also say that I've never noticed any added compression when using water, but then maybe I'm not good enough to...

Also, seeing as I'm in a pedantic mood right now:

Air contains about 78.09% Nitrogen and only around 20.95% Oxygen, along with traces of other elements like Argon and Carbon Dioxide etc. Therefore water does not in any way contain air as part of its chemical make up.

[mat hudson]

wayne. if you have ever blead brakes according to the avid instructions you'll see how much air is in oil.

basically you plug the end of the syringe and yank the plunger back (creating a vacum) and loads of trapped air appears. you can do this with water too. just stop being so patronising to everyone.

Edited May 21, 2006 by mat hudson

[Mark W]

i was stating a "science" fact then mark gives me a science equation, i left school after year 11, couldnt be bothered with it, would rather work and learn stuff to do with bikes. when i have had water in my brake form what I can feel and pretty much with everyone elses brake, the water compresses and im sorry if you can not feel that, but i do. weather its just me i dont know. but iv ridden magura brakes for 4years. if thats not long enough i dont know what is.

That's why I picked up on it though, in that you were wrong about the "o" of "h2o" making water have 'air' in it, which isn't right. Equally, like that guy up there said, water compresses by such a tiny amount you wouldn't be able to feel it with a decent bleed, similarly to how my brake feels solid to me ('cept for a tiny amount of frame flex, pesky 2-bolt booster). Oh, and 4 years for me too

Anyway, we'll all use whatever I guess. Could probably have put that as like second post and this thread would've gone by now

[ScotchDave]

Yes.

I was going to say everything you've said already in this thread, but you keep getting there first Fish breathe air (well, oxygen I suppose) that is dissolved in the water. Not from the water molecules breaking up. Whether or not the gas content of water has anything to do with the compressibility I don't know, but water is more compressible than other liquids.

Although I had another thought. Maybe in maguras the difference is that water is runnier so it's harder to get a good bleed and you end up with more air in your brake anyway... Whatever, like I said before, there's really no substitute for practical experience. There are far too many variables for anyone to come up with a definitive answer so we could probably leave it.

Water works OK

Mineral oil works OK

Vegetable oil works OK

Wayne says Diesel is OK

DOT oil is BAD (for seals, apparently)

We do our best to please.

1 litre of water compresses by 0.1% approx. (according to my chem. teacher) assuming there is about 20ml of water in a magura (30ml syringe, don't use all of it) then it will compress 0.02ml, and to achieve it compressing that much you have to exert 16 atmospheric pressures (basically 16 times the strength of gravity). So basically unless you are the hulk and/or chuck norris you will not be able to make your water compress any noticable amount.

With Hydrogen being a gaseous element, like oxygen, and Diesel, like many fuels being made up of Carbon-Hydrogen (with a little Sulphur too), does this not mean, by some of the arguments going on here that this magical new fluid actually contains hydrogen gas in the same way that water supposedly contains "air"?

I've used various different fluid in my maggies, none of which have broken and to be honest i'll use what I can get my hands on, and that is water more often than not. To me it feels better than maggie fluid, and has never caused me issues with the seals. I can also say that I've never noticed any added compression when using water, but then maybe I'm not good enough to...

Also, seeing as I'm in a pedantic mood right now:

Air contains about 78.09% Nitrogen and only around 20.95% Oxygen, along with traces of other elements like Argon and Carbon Dioxide etc. Therefore water does not in any way contain air as part of its chemical make up.

Read my last post, it explains this.

1 litre of water compresses by 0.1% approx. (according to my chem. teacher) assuming there is about 20ml of water in a magura (30ml syringe, don't use all of it) then it will compress 0.02ml, and to achieve it compressing that much you have to exert 16 atmospheric pressures (basically 16 times the strength of gravity). So basically unless you are the hulk and/or chuck norris you will not be able to make your water compress any noticable amount.

That is only under STP as a pure liquid and also with no gasses dissolved within it. That is not a real world value I'm afraid, for normal tap water you can probably triple that as a minimmum.

That's why I picked up on it though, in that you were wrong about the "o" of "h2o" making water have 'air' in it, which isn't right. Equally, like that guy up there said, water compresses by such a tiny amount you wouldn't be able to feel it with a decent bleed, similarly to how my brake feels solid to me ('cept for a tiny amount of frame flex, pesky 2-bolt booster). Oh, and 4 years for me too

Anyway, we'll all use whatever I guess. Could probably have put that as like second post and this thread would've gone by now

See above quote.

Also everyone lay off Wayne, he's right water out of the tap has air dissolved with in it, he may be a bit confused about the exact science of it, but he is right.

[OD404]

Read my last post, it explains this.

I'm not contesting your last post, which by all account is completely correct, I am merely pointing out certain flaws in the "H2O has an O in it therefore it contains air" argument. My guess is, about 1% of all people who have read this thread were remotely aware of what you talked about.

[ScotchDave]

Yeah probably, but it's good revision for my exam.

The thing about the H2O argument is that water molecules do occasionally fission randomly, not often but sometimes. But the main factor is as I say the dissolved gasses.

I'm sorry if I sounded like I was having a go but I though you had just missed the post. :$