Page 1 of 3 1 2 3 LastLast
Results 1 to 25 of 57
  1. #1
    It's soil, not dirt!
    Reputation: jhitch's Avatar
    Join Date
    Mar 2008
    Posts
    129

    DOT fluid vs. mineral oil

    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?

  2. #2
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    190
    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.

  3. #3
    Surfing trails
    Reputation: Nevegal's Avatar
    Join Date
    Feb 2006
    Posts
    208
    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.

  4. #4
    mtbr member
    Reputation:
    Join Date
    Nov 2005
    Posts
    868
    What is the break down of which brands use what?

    Mineral Oil
    Shimano
    magura?

    Dot

    Hayes
    Avid

  5. #5
    It's soil, not dirt!
    Reputation: jhitch's Avatar
    Join Date
    Mar 2008
    Posts
    129
    You can add Formula to the DOT list.

  6. #6
    Surfing trails
    Reputation: Nevegal's Avatar
    Join Date
    Feb 2006
    Posts
    208
    Magura and Shimano are the only companies I know of that use mineral oil.

    The rest use DOT brake fluid.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Apr 2007
    Posts
    190
    all the tektro hydraulics I have seen use mineral oil. ( actually an ok brake too at that pricepoint)

  8. #8
    mtbr member
    Reputation:
    Join Date
    Nov 2005
    Posts
    868
    Well then

    Mineral Oil
    Shimano
    Magura
    Tektro

    DOT
    Hayes
    Avid
    Formula

  9. #9

  10. #10
    Commit or eat sh!t
    Reputation: Cable0guy's Avatar
    Join Date
    Jun 2007
    Posts
    2,366
    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.

  11. #11
    Tool
    Reputation: Pedalphile's Avatar
    Join Date
    Aug 2008
    Posts
    1,977
    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
    I can barely get my mouth around it.

  12. #12
    banned
    Reputation:
    Join Date
    Aug 2008
    Posts
    151
    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.

  13. #13
    TLL
    TLL is offline
    mtbr member
    Reputation: TLL's Avatar
    Join Date
    Apr 2008
    Posts
    3,063
    Quote Originally Posted by HUZZA
    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).
    Hadley rear hub service here and here.

  14. #14
    banned
    Reputation:
    Join Date
    Aug 2008
    Posts
    151
    Quote Originally Posted by TLL
    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.

  15. #15
    mbtr member
    Reputation: scottzg's Avatar
    Join Date
    Sep 2006
    Posts
    2,590
    Quote Originally Posted by HUZZA
    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.
    Last edited by scottzg; 09-04-2008 at 11:29 PM.
    Hell is eternally climbing manzanita trail on your singlespeed.

  16. #16
    The plough
    Reputation: vmajor's Avatar
    Join Date
    Oct 2007
    Posts
    662
    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.

  17. #17
    ballbuster
    Reputation: pimpbot's Avatar
    Join Date
    Dec 2003
    Posts
    12,475

    Most bikes aren't painted...

    Quote Originally Posted by HUZZA
    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?

  18. #18
    Meh.
    Reputation: XSL_WiLL's Avatar
    Join Date
    Nov 2004
    Posts
    17,516
    Quote Originally Posted by pimpbot
    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.

  19. #19
    mtbr member
    Reputation:
    Join Date
    Nov 2005
    Posts
    868
    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

  20. #20
    TLL
    TLL is offline
    mtbr member
    Reputation: TLL's Avatar
    Join Date
    Apr 2008
    Posts
    3,063
    Quote Originally Posted by HUZZA
    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.
    Hadley rear hub service here and here.

  21. #21
    banned
    Reputation:
    Join Date
    Aug 2008
    Posts
    151
    Quote Originally Posted by vmajor
    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.
    It freaks me out to think about how little toxin skin absorbtion it would take to give one cancer, if I can easily avoid a toxic substance..if their are options as this is the case then thats great.Corporations have much to lose by actively stating the toxic effects of their products, many people simply ignore the danger, cancer is a horrible price to pay..be careful? If I were racing downhill events the DOT may be worth the risk,,mineral oil has notgiven me any problems for trail riding.

  22. #22
    paps
    Reputation: paps's Avatar
    Join Date
    Feb 2004
    Posts
    108
    all dots are seriously more toxic to the environment than minerals!
    and i really think this is more imp than fine differences that they may (or may not have). we should all push through our demand even more companies having mineral oil fluids i think!

  23. #23
    banned
    Reputation: Jerk_Chicken's Avatar
    Join Date
    Oct 2005
    Posts
    16,480
    Oh yeah, try using this so called "mineral oil" instead of DOT in your car, or other high temp apps.

    Then of course, there's the issue of what mineral oil really is. People think they can simply dump mineral oil into the sewer or drink it and it's great. Think again.

    When handled properly, even the most toxic items pose little to no risk. Stop being such a baby.

  24. #24
    paps
    Reputation: paps's Avatar
    Join Date
    Feb 2004
    Posts
    108
    surely it's not ok to just dump mineral into the washer, but surely it's less toxic than dot! my opinion is that the differences between them (in bikes at least) does not outweigh the dots higher degree of toxicity. i'd be ok with a little decrease (which i doubt personally, maguras are excellent brakes) in performance over no toxic dot fluids.

  25. #25
    banned
    Reputation: Jerk_Chicken's Avatar
    Join Date
    Oct 2005
    Posts
    16,480
    I still don't believe you're making your point. I said if handled properly, DOT isn't a problem. Hell, I've been getting it on my hands since I was a kid bleeding brakes and clutches on cars.

Page 1 of 3 1 2 3 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •