On Thu, 25 Feb 2021 16:38:37 -0800 (PST), Tom Kunich
wrote:
By the way, I just looked up mineral oil as opposed to DOT 5.1
and it has better properties in all cases. The only difference
appears to be that the DOT brake fluid doesn't absorb as much
moisture which can damage the antilock braking systems on a car.
But mineral oil is almost as good as they claim it to have the
same properties. But DOT5.1 was specifically formulated to
protect the ABS systems on a car. What ABS system do you have
on your bike?
Look again. Wikipedia has a nice description of the differences
between various brake fluid formulation:
https://en.wikipedia.org/wiki/Brake_fluid
As I see it:
DOT 2 Castor oil based
DOT 3 Glycol based
DOT 4 Glycol based
DOT 5 Silicone based
DOT 5.1 Glycol based
Cut-n-pasted:
DOT 5.1 is the non-silicone version of DOT 5, defined by
FMVSS 116 as being less than 70% silicone. Above that
threshold makes it DOT 5.
In other words, it's possible to buy DOT 5.1 with both glycol and
silicon oil in the recipe.
In chart at:
https://en.wikipedia.org/wiki/Brake_fluid#Boiling_point
note that the "Citroën LHM mineral oil" has about 4 times the
viscosity as the other DOT flavors. It's main advantage is corrosion
resistance and little else.
Also note that
Lack of acceptance of silicone-based fluids led to the
development of DOT 5.1...
For details, see:
https://en.wikipedia.org/wiki/Brake_fluid#Viscosity
TRW Brake Fluid Brochu
https://www.trwaftermarket.com/globalassets/en/trw_fluid_brochure_en.pdf
(23.6MBytes). Probably more than you wanted to know, but does have
readable graphs and charts with various brake fluid characteristics.
See Pg 8 for DOT 4 vs DOT 5.1 ESP viscosity/temperature graph. Notice
that TRW does not make DOT 5 brake fluid. I would guess(tm) that TRW
is one of the companies that didn't provide "acceptance" for DOT 5
(silicone).
I have no idea why bicycle hydraulic brake system manufacturers would
specify DOT 5.1 except possibly better performance at -40C (-40F).
Actually, a water/antifreeze mix works as well as DOT X:
EB15: Brake Force One H2O disc brake trades mineral oil for water
https://bikerumor.com/2015/08/29/eb15-brake-force-one-h2o-disc-brake-trade-mineral-oil-for-water/
Mo
https://www.google.com/search?q=brake+force+one+hto
Soon, everyone will be riding bicycles with water brakes.
Wow. The Brake Force One H2O video in 3D is really cool looking:
https://www.youtube.com/watch?v=IeWtoSxu8XY (2:56)
Buy yourself some anaglyph 3D red/blue glasses and try it out. The
cardboard version is fine and works nicely with prescription glasses:
https://www.ebay.com/sch/i.html?_nkw=anaglyph+3d+glasses+cardboard
Soon, everyone will be watching product demonstrations in 3D.
--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558