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It's soil, not dirt!
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Discussion Starter · #1 ·
What are the differences in the brakes that use DOT vs. mineral oil?

Is it the type of seals or are there actual engineering differences in the way they are designed?

And is there any reason to prefer one over the other?
 

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its mostly in the seals that the differences lie, DOT type systems use EPDM rubber, while mineral oil ( commonly known as hydraulic fluid) use nitrile (NBR).

the main limiter is that the rubber types cannot be interchanged as the incompatible fluid will cause the seals to swell, initially causing sticking, and as the rubber weakens, they fail.

there will be other differences as to how the systems are designed, but they are likely to be very subtle relating to how the fluids behave when heated and pressurized.
 

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Surfing trails
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A lot of people prefer mineral oil over DOT because it is a non-toxic oil that won't harm your skin or your bike's finish if it spills or leaks. DOT is nasty stuff (a mixture of different chemicals) but as long as you wash your hands soon after messing with it there is no harm done. Personally, I use DOT simply because I like Hope brakes. I've spilled DOT on my bike's finish before but immediately wiped it up with a rag and never had any damage to the paint. :)
 

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Commit or eat sh!t
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It could be mainly design issues, but I like DOT brakes (Formulas, Avid and Hope) over mineral oil brakes (Shimano, Magura). More feel and modulation. DOT fluid doesn't bother me. Just wear gloves or wash your hands.

I have Formula Ones on my bikes. Best brakes out there.
 

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Tool
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Another difference is that mineral oil does not absorb water, while DOT does. This would probably never matter unless you went a really, really long time without changing your fluid AND the seals became compromised, but it is a differnce in the properties of the two fluids.

This is why it's essential to keep DOT containers sealed very tightly if you plan to store them for any length of time.

-Pete
 

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I prefer shimano brakes as most shops do and as a bonus I do not have to worry about croaking from liver failure as DOT fluid absorbed by the skin over a prolonged period is toxic, fact of life is if you do your own wrenching you will have to deal with DOT fluid ruining your bike paint and your health.XT/XTR the best and most reliable.....flat fact.
 

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HUZZA said:
I prefer shimano brakes as most shops do and as a bonus I do not have to worry about croaking from liver failure as DOT fluid absorbed by the skin over a prolonged period is toxic, fact of life is if you do your own wrenching you will have to deal with DOT fluid ruining your bike paint and your health.XT/XTR the best and most reliable.....flat fact.
Most shops do? please.

You would have to absorb quite a bit of DOT fluid to induce liver failure. Face it, anyone that gets brake fluid on their hands or spills it on a regular basis is a poor mechanic. I spent years as an auto mechanic bleeding brakes and never once got it on my hands, clothes, or customer's paint.

And XTR are not the best or most reliable. They are nice brakes tho (I have owned both).
 

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TLL said:
Most shops do? please.

You would have to absorb quite a bit of DOT fluid to induce liver failure. Face it, anyone that gets brake fluid on their hands or spills it on a regular basis is a poor mechanic. I spent years as an auto mechanic bleeding brakes and never once got it on my hands, clothes, or customer's paint.

And XTR are not the best or most reliable. They are nice brakes tho (I have owned both).
yea...ok, I work with many end stage cancer patients and quite often they wonder how they got to this point, what is generally suspected are toxins and/or genetic pre disposition.....mechanics and such are prone to cancer...hope that is not the case with you, mineral oil is rather benign.I meant liver cancer or cancer in general on earlier post:) yep most shops I know of ...shimano is very dependable even down to the LX level...just my opinion though, you cut through all the marketing crap and shimano is a good choice or high end magura.
 

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HUZZA said:
I prefer shimano brakes as most shops do and as a bonus I do not have to worry about croaking from liver failure as DOT fluid absorbed by the skin over a prolonged period is toxic, fact of life is if you do your own wrenching you will have to deal with DOT fluid ruining your bike paint and your health.XT/XTR the best and most reliable.....flat fact.
i heard if your body took in enough mineral oil it would make you poop.


Not to mention that at only 15 degrees higher than the dot 5.1 boiling point, mineral oil can spontaneously combust. Imagine that... you're screaming down a hill, grab the brakes, and the whole brake system catches fire!

mineral oil doesn't absorb water like DOT fluid does, so if enough water collects in your hydraulics, it could boil over and leave you with no brakes at all!

The risk doesn't end when you get off the hill,mineral oil can cause pneumonia, cramps, vomiting, and it may cause dermatitis People downplay the danger of mineral oil compared to DOT fluid, but DOT fluid can be rendered inert with water, while there's no easy solution to the mineral oil threat.

Really.... both fluids are pretty harmless. Get a little DOT fluid on you and it makes your skin dry out a little, just don't bathe or drink the stuff. Get the brakes you like the feel of most.
 

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The plough
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Mineral oil with a different melting point is commonly sold in most shops on the planet with a label: "Vaseline"

No, it will not kill you and yet it will indeed make you poop if you eat enough of it.

MSDS sheet is correct, but you will not be inhaling the mineral oil in order to get pneumonia, you will also not be drinking it down in large quantities - if you do you may indeed get cramps just before a bout of explosive diarrhea, and everything and anything can cause dermatitis.

DOT is dangerous, depending on who you ask. Here is the MSDS for the popular ATE DOT 4. Spilling DOT on your skin will not kill you, drinking it may, and apparently no authority claims that it causes cancer.

Lastly, for fire you need air.

V.
 

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ballbuster
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Most bikes aren't painted...

HUZZA said:
I prefer shimano brakes as most shops do and as a bonus I do not have to worry about croaking from liver failure as DOT fluid absorbed by the skin over a prolonged period is toxic, fact of life is if you do your own wrenching you will have to deal with DOT fluid ruining your bike paint and your health.XT/XTR the best and most reliable.....flat fact.
Most bikes are powder coated (or anodized). Waaay more chemical resistant. Some high end bikes from small handmade type builders are actually painted. Paint is much more candy-like in finish, but chips easily. Powder coat is really durable.

The health issue isn't really a problem unless you work on them day in and day out without gloves. I don't always wear gloves, but I always wear goggles in case something squirts.

BTW, my 4 pot XTs felt great, but dragged all the time. Pistons would not retract reliably. That isn't going to stop me from trying another set in the future. I'm just saying Shimanos aren't 100% reliable. I've had bad luck with Maguras, but good luck with two sets of Hopes.

How bout some punctuation?
 

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Meh.
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pimpbot said:
Most bikes are powder coated (or anodized). Waaay more chemical resistant. Some high end bikes from small handmade type builders are actually painted. Paint is much more candy-like in finish, but chips easily. Powder coat is really durable.
False.

Paint doesn't have to be more candy-like. Powder coat can be candy too.

Many paints are a one-stage. Most bikes are painted, some are powder coated. Fewer are anodized.

My XTR m965 brakes and groupset worked like crap. It howled and had very little power. My 755s work just fine. I took the time to face my mounts and center it properly and they don't rub. My 965 caliper paired to an 08 XT caliper works alright. My old LX brakes worked okay. My old Deores worked fine too.
 

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Perhaps I should just edit my previous post, but then no one will find it. What do you people think? And yes I prefer mineral oil simply b/c it is almost completely benign. I just wanted to know what my options were. I have used Avid J5, Hayes (of the older variety which worked very reliably for ages), shimano xtr m965 (which worked perfectly for me), and xt 765 which worked for about two years without bleeding, just changing pads, but just recently have started to have some issues so I probably need to try bleeding them. (My fork was leaking a bit of oil on the rotor though so I wasn't sure where the problem was coming from for sure).

Updated:

Mineral Oil
Shimano
Magura
Tektro
Gatorbrake

DOT
Hayes
Avid
Formula
Hope
 

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HUZZA said:
yea...ok, I work with many end stage cancer patients and quite often they wonder how they got to this point, what is generally suspected are toxins and/or genetic pre disposition.....mechanics and such are prone to cancer...hope that is not the case with you, mineral oil is rather benign.I meant liver cancer or cancer in general on earlier post:) yep most shops I know of ...shimano is very dependable even down to the LX level...just my opinion though, you cut through all the marketing crap and shimano is a good choice or high end magura.
I knew you were referrring to liver cancer.

The thing is, the exact etiology or certain types of cancers is unknown . . is it environmental factors, genetic predisposition, old age, or ??? And I am not sure that mechanics are more prone to certain types of cancer, though I do not have any stats in front of me---perhaps you do have stats and could share, as I'm actually interested in the subject.

Again, Shimano does make a great brake, no argument there.
 
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