What Brake Fluid do you guys use with Downhill

Avid, Hayes and the like use Dot 4 or Dot 5 fluid

Shimano, Magura and some others use Mineral Oil

Are u asking about type or Brands of fluid used ?
 
Thanks guys
I use Saint M800, so I would have to use Mineral fluid then is that right?
If so is there one brand more popular than another?
So really there is no one popular type of Fluid it all comes down to what brakes you have and find the right fluid for them.
Have I got it right,
Thanks guys
 
Brake fluid is a non issue. As stated above, just use the right type for your brand of brake, and change it once a year or so, and bleed them properly. In your case with Shimano use mineral oil, just get the Shimano branded stuff.
 
Most brakes use DOT 4 or 5.1 - which is different to DOT 5. Get the numbers right.

For Shimano, use the Shimano stuff unless you know what you're doing with alternative fluids.

- Joel
 
Avid, Hayes, Hope and Formula all use DOT 3, DOT4 or DOT5.1, all of which are interchangeable - fwiw, DOT5.1 is said to be the "highest performance" in terms of boiling point, but DOT 4 is in my experience the easiest to get the air bubbles out of as it has a slightly different viscosity. You can use standard automotive DOT 3/4/5.1 in any of these brakes.

All Shimano, Magura (and I think Tektro) brakes use mineral oil. Use only the respective manufacturer's brake fluids for these brakes, as "mineral oil" is loosely defined compared to DOT fluid, and the boiling points, hygroscopic capacity etc vary significantly between one oil and another.

Do NOT under ANY circumstances put DOT fluid in a brake designed for mineral oil or vice versa - you will write all the seals off!
 
Hi guys,

I went out to buiy standard DOT4 as I was told (like mentioned above!!!) any brand fluid will do, just the type ie DOT4 or DOT 5.1 etc has to be right.

I bought some Shell DOT 4, and it was blue!!! I'm like what da F*** I've neva seen blue brake fluid, has always been the yellow greenish colour.
I was told it doesn't matter. It is just so that when you completely change your fluid, it is easier to tell if it has been completely changed if you switch from yellow/green to blue and them back when you do your next change.

I didn't want to put or mix funny blue fluid with the standard color though, kinda felt strange, so I got more standard colour DOT4.

What do you guys think? Would you mix it? Wouldn't you feel strange if you opened your brakes and found partly yellow and partly blue fluid???
 
With your brake fluid, never mix different brands or types (ie dot4 with dot 5.). Make sure you keep the lid securely on the bottle. Brake fluid absorbs moisture and once it does, it reduces its ability to be stable at high temperatures. Really, if you're only changing/topping up once a year, throw the bottle away. As it won't be the same fluid in 12 months time.

Do people actually get problems with fluid boiling?

If they do, Castrol make a Race fluid that will probably stop it. It is expensive, but it's arguably the best on the market. You probably know about it, but just thought I'd throw it out there.
 
Yellm said:
Hi guys,

I went out to buiy standard DOT4 as I was told (like mentioned above!!!) any brand fluid will do, just the type ie DOT4 or DOT 5.1 etc has to be right.

I bought some Shell DOT 4, and it was blue!!! I'm like what da F*** I've neva seen blue brake fluid, has always been the yellow greenish colour.
I was told it doesn't matter. It is just so that when you completely change your fluid, it is easier to tell if it has been completely changed if you switch from yellow/green to blue and them back when you do your next change.

I didn't want to put or mix funny blue fluid with the standard color though, kinda felt strange, so I got more standard colour DOT4.

What do you guys think? Would you mix it? Wouldn't you feel strange if you opened your brakes and found partly yellow and partly blue fluid???
Click to expand...

Colour is just dye. As much as I'm tempted to mock you, I shall decline the fabulous offer. Most commercial chemical products are dyed. Even our petrol. Usually so you can tell what it is though. In this case, just a brands choice(I'm fairly certain if it is dot 4).
 
Hey No skid marks,

that was my point. It is just dyed. So really it doesn't matter a single bit what colour it is. So you'd mix different colour brake fluid, provided it was the same type then?

@Muvro why would you not mix brands? As long as it is the same type. DOT 4 from Castrol should e the same as DOT4 from Shell.

If I open up a brake, I don't generally know what brand the original owner put in it... right?
 
Yellm said:
Hey No skid marks,

that was my point. It is just dyed. So really it doesn't matter a single bit what colour it is. So you'd mix different colour brake fluid, provided it was the same type then?

@Muvro why would you not mix brands? As long as it is the same type. DOT 4 from Castrol should e the same as DOT4 from Shell.

If I open up a brake, I don't generally know what brand the original owner put in it... right?
Click to expand...

I don't know the exact reasoning behind it, and people mix fluids in road cars to little if any detriment, race cars however are a different story. Any mixed fluid or bad quality fluid will usually result in the pedal not feeling as good as it did at the start of the day. However, it's recommended not to mix. It might be that certain brands have different additives and some may clash? Not sure. But if you're using it to extreme and the fluids maximum potential, it could be the difference between a solid lever at the end of a run and a soft lever.

The DOT specs are simply specs that are required for it to comply. So each brakefluid can and most probably is different so long as it meets the certain requirements for that specific DOT catagory. It's the same as motor oil.

If you don't know what's in it, pump it right through and flush out the old stuff.
 
S. said:
Avid, Hayes, Hope and Formula all use DOT 3, DOT4 or DOT5.1, all of which are interchangeable - fwiw, DOT5.1 is said to be the "highest performance" in terms of boiling point, but DOT 4 is in my experience the easiest to get the air bubbles out of as it has a slightly different viscosity. You can use standard automotive DOT 3/4/5.1 in any of these brakes.

All Shimano, Magura (and I think Tektro) brakes use mineral oil. Use only the respective manufacturer's brake fluids for these brakes, as "mineral oil" is loosely defined compared to DOT fluid, and the boiling points, hygroscopic capacity etc vary significantly between one oil and another.

Do NOT under ANY circumstances put DOT fluid in a brake designed for mineral oil or vice versa - you will write all the seals off!
Click to expand...


nice write up, thanks
 
For my Shimano brakes, I just get Shimano branded mineral oil.
That's what they came with from the factory, so that's what I replace it with.

I could probably research the chemical characteristics of all the different mineral oils out there and find something better, but I am basing my trusting nature to shimanos (IMO) reliability, and the fact that they spend millions of $ a year on dudes in white lab coats to do that job for me.

Never had a problem with the stuff yet.

Shimano%20Mineral%20Oil.JPG
 
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