Oil! What's A Unit? What Is Light, Medium, Heavy?


Well-Known Member
This is posted here with permission of the original poster, Aloarjr810, who posted it on BR:

Here's the info I've collected on what's considered light, medium, or heavy oil.
(Basically there is no carved in stone definition, What's heavy oil for one person is medium for someone else.)

OIL! What's a Unit?

and what makes a lane condition light, medium, or heavy.

What is the definition of a unit of oil?

The term “Unit” has been around for years and frankly most bowlers had no idea what a Unit of oil was, other than that the more Units there were, The oilier the lanes generally were.

A "unit" of oil was defined by the American Bowling Congress (ABC) and Women's International Bowling Congress (WIBC) as 0.0167 cubic centimeters of oil evenly spread over a 1 sq. ft. surface, which equates to a film of oil about 7 millionths of an inch thick. (This information can be found in the USBC "Computerized Lane Inspection Program Manual" aka: The “Clip” manual)

Most look at a Unit as a measurement of volume, When it really is more a measurement of how deep or thick a layer of oil is on the lane.

In USBowler Magazine Vol.2, No.3 Spring 2007 Page 12 Coach's Corner, There is a article "Everything you wanted to know about lane conditions" where they give a example of the thickness.

Example: a piece of typing paper is about 400 units thick.
(.000007*400=.0028", A piece of 16# bond paper is about .0032" thick. So that's pretty close.)

So how many Units were considered Heavy or Light oil?
At the time a layer of oil 100-plus units would have been considered "Heavy oil" and anything less then 50 units probably would be "Light oil.

But the term “Unit” is a old term and is becoming outdated. While you can still find it being used, what you are more likely to see today is “Oil Volume” which is expressed in “milliliters of oil”

So what makes a lane condition light, medium, or heavy?
Basically there isn't a exact, straight forward, answer to this question. A lot of the time in other source's you find them defining light, medium, or heavy in terms of length.

Like in the book "Revolutions 2" they define it this way,
Oil (long oil) were lanes oiled 35 to 45 feet.
Med. were lanes oiled 25 to 35 feet.
Dry (very short oil) was 18 to 25 feet.

In USBowler Magazine Vol.2, No.3 Spring 2007 Page 12 Coach's Corner ,The article "Everything you wanted to know about lane conditions" they define it as,
Long oil as 40 feet or longer
Medium oil as 35' to 45' feet or more
Short oil 35 feet or less

In Bowling This Month magazine they rate ball's for Oil, Medium and Dry, the current issue (at the time of this writing) is showing these patterns being used.
Oily is a 44' oil (High Street)
Medium 41' oil (Main Street)
Dry 38' oil (Easy Street)

High Street, Main Street and Easy Street are in the Kegel Navigation Recreation Series of patterns. you can see them here. http://www.kegel.net/v3/PatternLibrary.aspx

Also in a past issue of BTM (Bowling This Month). They had a article about sport shots, They had a chart showing 6 patterns made of combination's of these, with ball and drilling recommendation's for them.

Pattern Length: Short (34' or shorter), Medium (35' to 40'), Long (41' or longer)
Oil Volume: Light to Medium (20ml. or less), Medium to Heavy (More than 20ml.)

As you can see here we see “Oil Volume” in “milliliters of oil” being used,

Here Kegel listed a basic definition by Oil Volume (including a basic ball recommendation).

Light to Heavy:
Less than 18 ml use a weaker cover ball
18 - 21 ml use a weak to medium cover
21 - 25 ml use a medium to strong cover
More than 25 ml use an aggressive coverstock

Mo Pinel said in reference to light, medium, or heavy that he defines it by Oil Volume.

QUOTE: “I do it by volume.”
< 21 mls of oil = light oil
21 to 25 mls of oil = medium oil
>25 mls = heavy oil

After all is said and done, it's not how much oil on the lane, but where it's at. Pattern's can be adjusted to make short ones appear long and long ones appear short.

Heres a quote from a article called- "Lane Pattern Basics: An Overview of Blend, Taper & Application".

"the overall volume of the shot probably has the least affect, as the length that the conditioner is applied can make the "volume" almost meaningless."

When it comes to Oil and Oil patterns there are many factor's that come into play about lane condition's and how to play them.

The amount of oil is one of the smaller factor's involved.