This is my Diamondback El Oso fat tire mountain bike, and well, it’s not exactly what you
would call svelte.
The tires are almost 5 inches wide which is like 3 normal mountain bike wheels side by
side.
We already know these tires are massive enough to use the bike as a floatation device.
And once you get them spinning, they sound like tie fighters.
Yet, even at that speed you can stop these massive wheels from spinning with the flick
of a finger thanks to some run of the mill hydraulic brakes.
These are similar to what you’d find on the majority of mountain bikes sold today,
and indeed they came on my fat bike.
But they didn’t come with baby oil in the rear brake.
You see, the front lever, hose, and caliper are filled with Shimano brand hydraulic brake
oil just like factory.
But just over a year ago we purged the rear brake, and refilled it with baby oil.
Here we are a year later, and it’s still in there.
And I’ve been using this bike.
The question is, why do this?
Well, you can find forum posts and comments spanning a decade, from those claiming that
baby oil can be used in place of brake oil—on certain brands.
Namely, those that use mineral oil blends like Shimano, TRP, and Magura.
So the questions we’re attempting to answer today are:
1. is baby oil the same as brake oil?
2.
Is baby oil easier to obtain?
3.
Does baby oil work as well as brake oil?
4.
Is it cheaper?
5.
Will it damage your brakes?
6.
Is baby oil safe for the rider?
7.
Is brake oil safe for infants?
Well maybe we’ll pass on that last one.
I still don’t fully understand why you need to fill babies with oil.
But before we answer the first six questions I need to reiterate that we only filled one
model of one brand with baby oil, and that’s not science.
So this video is just for your entertainment.
With that being said, let’s move on to the first question:
Is baby oil the same as brake oil?
No.
The only thing baby oil shares in common with any of these brand specific blends is that
it’s based on mineral oil, but even pure mineral oil has a different viscosity and
boiling point than any one of these solutions.
Not to mention all of these blends have different properties than each other.
And baby oil smells like diaper.
So these aren’t the same thing.
Next question: is baby oil easier to obtain?
Yes.
Baby oil or straight mineral oil can be obtained at the grocery store.
You can get it 24/7.
Meanwhile some bike shops don’t even sell brake oil, keeping it on hand only for service.
Usually you’ll need to order bleed supplies online, so yes Baby Oil is much easier to
obtain.
But does it work as well as brake oil?
Well that question’s not as easy to answer, but in the case of my fat bike, It seemed
to work just as well.
But again that’s only a test on one brake on this bike, in this climate, at this elevation.
We can assume that reputable manufacturers perform torture tests on their brakes where
they burn through a full set of pads in only minutes.
So perhaps in really demanding situations where the pistons heat up, we would see different
results.
We can also assume that when engineers design brakes, they’re plugging numbers into formulas
that correspond to the properties of their own in-house oil.
Since brakes are designed around the fluid they’ll be using, it’s hard to argue they’ll
work exactly the same using something, but to what degree is up for debate.
Next question: Is replacing brake oil with baby oil cheaper?
That depends.
For argument’s sake let’s assume that baby oil works just as well as the real thing.
Then yes, it would save you money.
Name brand baby oil is about $1 per ounce, and if we use the cheap stuff it’s $0.25
per ounce.
Shimano oil costs $1.30 per ounce which is clearly more expensive.
But that’s just the cost of the oil.
Should you send your diaper scented brakes in for a warranty claim, you may be denied,
and that would cost you money.
Also the cost of legit brake oil is actually less than brake cables.
An entire purge and refill of your front and rear brakes would cost under $1 using Shimano
oil, and most riders don’t even do that yearly.
Next question: Will baby oil damage your brakes?
Before making this video I went to Sauatch bikes in Brevard North Carolina, to get the
opinion of a professional bike mechanic.
Pat purged these brakes, took them apart, and removed the seals so we could examine
the most vulnerable parts under a microscope.
Again, the front lever was filled with legitimate Shimano brake oil, while only the rear was
filled with baby oil, making the front lever a control.
We examined the seals and o-rings side by side, looking for differences between the
two levers.
To make a long story short, we could not see any difference.
Given that there’s nothing but rubber and aluminum inside of brake levers and calipers,
it’s hard to imagine there would be.
After all, baby oil is not exactly what you’d call a harsh chemical.
With all that said.
We still don’t know how baby oil affects brakes exposed to high heat, lofty elevations,
or long term abuse.
So is it safe to use on your brakes?
It was in my case, but but we can’t comment on other brakes being used in different ways,
for different periods of time.
As for the rider...
Well, I slept just fine knowing my brakes were filled with baby oil, but I can’t recommend
that others do the same.
Brakes are just too important, and this was at most an unscientific test.
Now I know some of you were rootin’ for the baby oil.
It’s fun to think you can get something from the diaper isle to run your brakes on.
And I would love nothing more than to expose brake manufacturers for ripping off their
customers, while simultaneously providing a cheap alternative to their kool aid filled
brake fluid.
But that’s just not the case.
Brake oil is far from expensive.
And there are no compelling reasons to use something else, unless you simply have no
choice.
So unless you’re in some theoretical Apollo 13 situation where you’ll die in space without
a brake oil substitute—you might want to order the right stuff for your brand, or at
the very least something designed for brakes.
Speaking of which, this test has left my brakes completely devoid of any oil, so we need to
fill ‘em up.
If only I could find that big jug of shimano oil…
Thanks for riding with me today and I’ll see you next time.