Motorcycle Oils....

Walk into any motorcycle dealership parts department and you are virtually guaranteed to see prominent
displays of oils produced specifically for use in motorcycle engines. Since dealers are not about to waste
valuable floor or counter space on a product unless it produces a decent profit, it is obvious that motorcy-
cle-specific oils have become one of the premier parts department cash cows of the 1990s.

Of course advances in lubrication technology have resulted in some fairly expensive premium, synthetic
and synthetic-blend products for automobiles also. But as you can see from our pricing research at a half-
dozen auto parts and cycle parts stores, the average purchase price for the motorcycle-specific lubricants
runs about 120 percent higher for petroleum products and 185 percent higher for synthetic products than
do their automotive counterparts.

The companies marketing these high-priced motorcycle lubricants would have us believe that their prod-
ucts are so superior to the automotive oils as to justify paying two and three times the price. But are we
really getting the added protection promised when we purchase these products? MCN decided to look be-
yond the advertising-hype, specifically to see if the claims of prolonged and superior viscosity retention
could be verified. What we found may very well change your mind about what should go into your motorcy-
cle's crankcase in the future.
So The Story Goes ...
Many motorcyclists have long doubted the need to pay the inflated prices asked for most motorcycle-
specific engine oils. An even larger number of us have harbored at least some degree of skepticism about
the claims made for motorcycle oils, but have been reluctant to turn away from them, for fear of damaging
our precious machines if the claims should happen to be true. Most of this fear comes from very successful
marketing campaigns mounted by the manufacturers and distributors of motorcycle-specific lubricants.

For example, a monthly trade publication for motorcycle dealers recently published an article suggesting,
"negative selling techniques" to "educate customers" against purchasing automotive oil for their bikes. The
example in the article begins with the benevolent dealer looking the poor, dumb customer in the eye and
asking, in an incredulous voice, "You're not really using that in your motorcycle, are you?"
The idea, of course, is not so much to educate as to frighten the customer into paying for the more expen-
sive motorcycle oil that only guess-who sells. Such techniques have played on our fears with great effect,
to the point where high-priced, motorcycle-specific lubricants have become staple profit producing items in
the majority of motorcycle dealership parts departments throughout the country.

The campaigns promoting motorcycle-specific oils have successfully indoctrinated an entire Generation of
motorcycle riders and mechanics. The doctrine is now so ingrained in the industry that questioning its ve-
racity instantly marks you as an ill-educated outsider. Even MCN has fallen victim to the hype, espousing
the superiority of such products in these very pages. Our own technical experts from the American Motor-
cycle Institute have repeatedly advised our readers against the dangers of straying from the straight and
narrow path.
 
What we, as well as the AMI, your local mechanic and all the other motorcycling publications have been
doing is simply repeating what we have been carefully taught to believe over the years. The only problem
with this approach is that our only source of information has been the people who stand to profit from our
faith in the superiority of motorcycle-specific oils.

STRETCHING THE TRUTH - JUST A BIT
Motorcycle oil producers make a multitude of claims for their products, some of which are extremely
difficult to substantiate, and others which are simply outdated and no longer applicable. This is not to
say that all claims made for the superiority of motorcycle oils are necessarily false, only that the ac-
tual differences between them and their automotive counterparts may be considerably less than we
have been lead to believe. For example:
Claim - Since the introduction of catalytic converters in automobiles, the best anti-wear
agents have been limited by law to the amount that can be used in automotive oils. but
are present in greater concentration in motorcycle oils.
Fact - Phosphorous deteriorates the catalyst in converters and is therefore restricted to a
very small percentage in automotive oils. Phosphorous is also an essential element in
one of the best anti-wear agents, ZDDP (zinc dialkyldithiophosphate), which is a primary
component of such over-the-counter engine additives as STP Engine Treatment.
While it is true that slightly increased concentrations of ZDDP are found in some motorcycle oils
(such as Spectro products), it is also true that these concentrations still fall under the governmental
limits, otherwise these oils could not be used in the new converter-equipped motorcycles from BMW
and Yamaha. Also, it should be noted that ZDDP is a "last line of defense"-type additive, generally
only coming into play under extremely severe conditions where actual metal-to-metal contact occurs
within an engine, something that should never happen under normal operating conditions.
Claim - Motorcycle engines run hotter and rev higher than automobile engines, therefore
requiring oils with more expensive, shear-stable polymers and additives than automotive
oils.
Fact - This is one of those statements that was much more true in the 1970s than in the
1990s. The big, slow-revving Detroit automobile engines of the past have mostly been
replaced with smaller, higher-revving four-cylinder and six-cylinder engines that have
much more in common with their counterparts running on two wheels. Keeping pace with
the development of the small, high-revving, automobile engine, automotive oils have im-
proved considerably, to the point where the newer, SG-rated automotive oils are nearly
identical to motorcycle oils.
In most cases where motorcycle oil producers show comparisons between their products and auto-
motive oils, you will find them using SE- or SF-rated oils as the "automotive standard." These are
oils that were designed and rated for the cars of 10 to 20 years ago. We have yet to see a motorcy-
cle oil compared in testing to the 1990's standard, SG-rated premium automotive oils.

THE VISCOSITY-RETENTION CLAIM
By far the loudest and most-believed claim made for motorcycle oils is that they retain their viscosity
longer than automotive oils when used in a motorcycle. The standard claim made in most advertis-
ing is that motorcycle-specific oils contain large amounts of expensive, shear-stable polymers that
better resist the punishment put on the oil by the motorcycle's transmission, thus retaining their vis-
cosity longer and better than automotive oils would under the same conditions.

This quote comes directly from the back of a bottle of Spectro 4 motorcycle oil, and is similar to th
advertising line used by nearly all motorcycle oils: Because of its special polymers, Spectro 4
maintains its viscosity, whereas the shearing action of motorcycle gears quickly reduces the vis-
cosity of automotive oils. We've all heard it a thousand times before. Our transmissions are the cu
prits that force us to buy special, $6-a-quart motorcycle oil instead of the 99 cent special at Pep
Boys. We hate to have to do it, but we all know that it's true--or is it?

The question begged an answer, so MCN went looking for evidence that motorcycle oils really are
more shear-stable than their automotive counterparts.
HELP FROM THE SCIENTIFIC QUARTER
About the same time we began looking into the oil viscosity retention question, we received a lette
from John Woolum. a professor of physics at California State University - and a motorcyclist - who
noted that he was investigating in the same area on his own. Not being ones to look a gift horse in
the mouth, we contacted Dr. Woolum and encouraged him to expand his research on our behalf.

Later in this article Dr. Woolum explains the laboratory procedures he used to generate the statis-
tics used in this article. but for the mean-time let's just take a look at the bottom line when five
popular oils (three automotive and two motorcycle) were compared for relative viscosity retention
after use in the same motorcycle.

As can be seen from the figures, the best-performing oil of the group tested was Mobil 1 automo-
tive oil, a fully synthetic product. In today's market, virtually all oils sold are to some extent para-
synthetic, since even standard petroleum products usually contain at least some synthetic-derived
additives. However, for the sake of simplicity in this article we have listed the products as petro-
leum if the primary components are from basic petroleum stock. Those listed as synthetics have
their primary components derived from basic synthetic stocks, and may or may not contain any ad
ditives derived from petroleum products.

PRELIMINARY CONCLUSIONS

The results of these tests seem to support some of the long-standing theories about oils while
casting serious doubt on others. Going by these tests it would seem logical to assume that:
1.The viscosity of synthetic-based oils generally drops more slowly than that of petro-
leum-based oils in the same application.
2.Comparing these figures to viscosity retention for the same oils when used in an auto-
mobile (see later text by Prof. Woolum) would indicate that motorcycles are indeed
harder on oils than cars.
3.The fastest and most significant drop in the viscosity of petroleum-based oils used in
motorcycles occurs during the first 800 miles (or less) of use.
All of these results (1-3) agree with everything the oil companies have been telling us all
along. However, the same test data also indicates that: 
4.The viscosity of petroleum-based oils, whether designed for auto or motorcycle applica-
tion, drop at approximately the same rate when used in a motorcycle.
5.There is no evidence that motorcycle-specific oils out-perform their automotive counter-
parts in viscosity retention when used in a motorcycle.
These last two results (4-5) definitely do not agree with what the motorcycle oil producers have been
telling us. In fact the test results not only indicate the two motorcycle oils being outperformed in vis-
cosity retention by the two automotive synthetic products. but even by the relatively inexpensive Cas-
trol GTX, which is a petroleum product. This directly contradicts the advertising claims made by the
motorcycle oil producers.

 
THE OIL COMPANIES REPLY
At Spectro Oils we talked to three different company spokesmen, all of whom were helpful and pro-
vided us with a great deal of information about their products. Unfortunately, despite our repeated re-
quests for the testing data on which their advertising claims were based, the 15 pages of "Lubrication
Data" they supplied us contained nothing that could not be found in their regular advertising and mar-
keting packages. No verifiable testing data has been forthcoming.

The Spectro spokesmen were not pleased when informed of our test results, but when pressed, none
could come up with a valid reason why their product should have scored the lowest, either. The only
comment we got was, "We only wish you had tested our Golden Spectro synthetic instead of the pe-
troleum-based Spectro 4."

Undoubtedly the Golden Spectro would have outscored the regular Spectro in our tests, though how
well in comparison to the Mobil 1 and Castrol products we can only guess at this point.

When asked why the Spectro 4 petroleum product sold for $5.00 a quart when comparable automo-
tive oils could be found at less than $1.50 a quart, a Spectro spokesman insisted theirs was "a supe-
rior, premium petroleum product, with expensive, shear-stable additives that should outperform auto-
motive oils." That being the case, it should have been the perfect product for our testing.

We made a half-dozen calls to several different divisions within American Honda, but could find no
one willing to make any statement regarding their HP4 motorcycle oil. All of the Honda employees we
reached were friendly, and tried to help as much as they could, but you must keep in mind that
Honda is a huge conglomerate and sometimes the person with the right answers to a question is diffi-
cult to track down through the corporate maze. Their Accessories Product Management Division
noted that they had a lubrication expert that might be able to help us, but also that he was out of the
country on vacation for the next month and could not be reached before this article went to press.
Should someone from Honda wish to comment at a later date, we will certainly make room in a later
issue.

Spokesmen at both Mobil and Castrol were a bit surprised at our questions, since neither makes any
claims for their products in a motorcycling context. However, when we explained the test results, nei-
ther company spokesman seemed the least bit surprised, both noting that automotive oils in general
had made a quantum leap in viscosity retention technology in the past five or six years. Both compa-
nies claimed to be using the very latest in shear-stable polymers for viscosity retention, and while
claiming no knowledge of the motorcycle-specific oils' formula, expressed serious doubt that they
could contain some type of additive that was superior in this context to that already being used in
their automotive oils. Our test results support their assertion.