Fact Check

Which Tire?

In the parlance of today's students, one might call this instructor's move a "sick burn."

Published Mar 24, 2000

 (Wikimedia Commons)
Image Via Wikimedia Commons
Students who offer a flat tire as an excuse for missing an exam are given a special make-up exam.

This story of cheaters outsmarted by a wiser instructor has been circulating for several years in a version that names a specific class, instructor, and school: the Introductory Chemistry class taught by Professor James F. Bonk at Duke University.

Example:  [Collected on the Internet, 1995]

Introductory Chemistry at Duke has been taught for about a zillion years by Professor Bonk (really), and his course is semi-affectionately known as 'Bonkistry'. He has been around forever, so I wouldn't put it past him to come up with something like this. Anyway, one year there were these two guys who were taking Chemistry and who did pretty well on all of the quizzes and the midterms and labs, etc., such that going into the final, they had a solid A.

These two friends were so confident going into the final that the weekend before finals week (even though the Chem final was on Monday), they decided to go up to UVirginia and party with some friends up there. So they did this and had a great time. However, with their hangovers and everything, they overslept all day Sunday and didn't make it back to Duke until early monday morning.

Rather than taking the final then, what they did was to find Professor Bonk after the final and explain to him why they missed the final. They told him that they went up to UVa for the weekend, and had planned to come back in time to study, but that they had a flat tire on the way back and didn't have a spare and couldn't get help for a long time and so were late getting back to campus. Bonk thought this over and then agreed that they could make up the final on the following day. The two guys were elated and relieved.

So, they studied that night and went in the next day at the time that Bonk had told them. He placed them in separate rooms and handed each of them a test booklet and told them to begin. They looked at the first problem, which was something simple about molarity and solutions and was worth 5 points. "Cool" they thought, "this is going to be easy." They did that problem and then turned the page. They were unprepared, however, for what they saw on the next page. It said:

(95 points) Which tire?

Professor Bonk was rather circumspect when asked whether he ever actually gave such a test:

Date: Thu, 15 Feb 1996
From: James F. Bonk

I would have to classify the story as being somewhere between UL and fact. It is based on a real incident, but it has been embellished. For instance, I have only been teaching at Duke for 37 years, not zillions of years!

The incident happened long enough ago that I am not able to recall accurately the exact details anymore. This version is such a good story that I have decided to "let the legend grow". The story has been on Internet about 3 years now and I have been informed that well over 5000 people have seen it.

A number of people have contacted me about the story. It has been a fun and educational experience for me to be involved. For instance, I recently received a non-traditional analysis of the probabilities that the students will pick the same tire.

Thanks for your interest. Best wishes.

Jim Bonk

The legend of a 'Which tire?' question being used to catch fibbers is an old one, antedating Professor Bonk and his chemistry class. It has been told for many years as a joke, with varying participants: a teacher and students who cut class, a manager and players who show up late for practice or miss a curfew, or a boss and employees who report late for work — all of which confirm the person of authority to be wiser than the underlings who try to pull a fast one on him.

We found this telling of it in a 1979 collection of anecdotes:

Down in Jackson, Mississippi, three boys arrived in school late. It was as late as 10:00 a.m. They had been fishing. For their excuse they stated that they were delayed because of a flat tire. The teacher decided to give them a test immediately, so she had them seated apart from one another. She said, "This test will have only one question, and I will give you thirty seconds to put down your answer." The question was, "Which tire?"

The teacher was pretty sharp. There is no question as to the result of the test. The boys were shown to be liars.   — Maurice Dametz

In 2004 it surfaced in Reader's Digest presented as having happened to a teacher at an unnamed community college.

Four students walked in halfway through American history test my father was giving at the local community college. "Sorry," they said, "we had a flat tire." An understanding man, Dad said that if they could answer just one question correctly, he would give them each an 'A" for the exam. The students agreed. So my father handed each one a piece of paper, placed them in four separate corners and said, "Write down which tire was flat."   — Kurt Smith

This legend is actually least plausible in its academic form. What if the students got the tire question right, either because they were cagey enough to work out the details in advance or because they actually had a flat tire? Would they really be awarded top marks without having to take a real final? Wouldn't that be unfair to the other students? Yes, we know: this was just a scare the professor pulled on his students to let them know they weren't fooling anyone before he gave them the real exam.

A similar biblical tale of lying conspirators exposed through separate questioning can be found in the Bible's story of Susanna, one of the books of the Apocrypha.


  • The number of students involved in the scheme varies (usually between two and four).
  • The reason for the students' missing their exam also varies: They were out drinking and overslept; they forgot about the exam; or they were doing poorly in the class anyway and decided to skip the final but later changed their minds.
  • In many versions 'Which tire?' is the single test question.


Carroll, Jon.   "Will This Be on the Final?"     The San Francisco Chronicle.   4 April 1994   (p. E10).

Heberlein, Greg.   "Ha Ha! Contest Is No Joke, But These Are."     The Seattle Times.   24 December 1995   (Business; p. 1).

Tan, Paul Lee.   Encyclopedia of 7700 Illustrations.     Rockville, Maryland: Assurance Publishers, 1979.   ISBN 0-88469-100-4   (p. 562).

Reader's Digest.   "All in a Day's Work."     November 2004   (p. 63).  

David Mikkelson founded the site now known as snopes.com back in 1994.

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