Q: What is the difference between a well-dressed bicyclist and a poorly dressed unicyclist?
A: Attire!

Explanation: Let’s start with some vocabulary:

• Well-dressed means to wear nice clothing (it is the opposite of poorly dressed);
• A bicyclist is a person who rides a bike;
• A unicyclist is a person who rides a unicycle;
• A unicycle is like a bicycle (bike) but it only has one wheel.

If you are well-dressed it means you are wearing nice clothing.  Clothing and attire can be used as synonyms, but attire is typically used to mean nice clothing, formal clothing.

Attire also sounds the same as a tire.  A bike has two wheels, that is, two tires; a unicycle has only one wheel, one tire.  Wheel and tire are synonyms.  (Well, people use them as synonyms.  The tire is really the rubber part of the wheel, the part that touches the street.)

This joke is funny because it plays with the the word attire: well dressed or a tire, a wheel.  So if you are well dressed on a bicycle you have both good attire, and a tire (one tire) more than the unicyclist.

If you want to learn to ride a unicycle, take a look at Finnovation: