Question: How do smaller gaps between tread cause a regular tire in the mud to resemble a slick tyre?
Context: Paddle tires are mainly used on off road vehicles, specifically designed for use in sand and mud.  They consist of a smooth tire core which has a series of large rubber cups (or paddles) attached to it.  The volume inside of a paddle is much larger than the void of a knobby tire, so it is unlikely to clog up with sand/mud.  A street legal mud tire is a more or less normal tire, but with extra large gaps or "voids" between each tread block (called "lugs") to allow centrifugal force to "self-clean" or fling the mud out of the gap.  Smaller gaps trap the mud in between the tire lugs, which turns the tire into something resembling a "slick" with no tread at all, which will have no traction in mud.  A paddle tire is an even more extreme version of this, optimized for mud or sand.  The paddle provides superior traction in the sand, in part, because the paddles dig into the sand and push off from the buried sand, not just the surface, and in mud, the gigantic "voids" give no place for mud to stick.  They work something like a paddle wheel on a paddle-steamer.  Street legal mud tires are a compromise between large voids and a smooth rolling shape for on-road use.  The more "extreme" a mud tire (such as a "Super Swamper") is, the harsher and louder it is on a hard surface.  A "tractor tire" on a farm tractor is a somewhat more mild version of a paddle tire, only the voids are smaller to allow for limited use on hard surfaces, and the "lugs" are angled to give lateral traction.  A paddle tire is so optimized for mud that the shape is of no use on anything other than a soft surface, since the vibration and lack of control of the tire would render a vehicle almost unusable.  One other way the paddle tire is a specialized-application-only is that it gives only forward/rearward traction.  This means that it is used on a wheel that drives a vehicle to push it forward, but gives little "lateral" (side-to-side) traction.  For that reason, the tires of the vehicle that steer it are generally more "normal" tires, since a paddle tire on a steering wheel will just slide sideways rather than pulling the vehicle with it.  So many 4WD vehicles will use paddle tires only on the rear, although the front wheels are powered as well.  On a 2WD or a motorbike, the rear wheel is the only drive wheel, and so putting a paddle tire on the front wheels is useless or worse, since steering performance will be negatively impacted. A racing slick (also known as a "slick tyre") is a type of tyre that has a smooth tread used mostly in auto racing.  The first production "slick tyre" was developed by M&H Tires in the early 1950s for use in drag racing.  By eliminating any grooves cut into the tread, such tyres provide the largest possible contact patch to the road, and maximize traction for any given tyre dimension.  Slick tyres are used on road or oval track racing, where steering and braking require maximum traction from each wheel, but are typically used on only the driven (powered) wheels in drag racing, where the only concern is maximum traction to put power to the ground. A spare tire or spare tyre (or stepney) is an additional tire (or tyre - see spelling differences) carried in a motor vehicle as a replacement for one that goes flat, a blowout, or other emergency.  "Spare tire" is generally a misnomer, as almost all vehicles actually carry an entire wheel with a tire mounted on it as a spare rather than just a tire, as fitting a tire to a wheel would require a motorist to carry additional, specialized equipment.  However, some spare tires ("space-saver" and "donut" types) are not meant to be driven long distances.  Space-savers have a maximum speed of around 50 mi/h . Forensic tire tread evidence records and analyzes impressions of vehicle tire treads for use in legal proceedings to help prove the identities of persons at a crime scene.  Every tire will show different amounts of tread wear, and different amounts of damage in the form of tiny cuts and nicks.  These unique characteristics will also show on the impression left by the tire. The tread of a tire or track refers to the rubber on its circumference that makes contact with the road or the ground.  As tires are used, the tread is worn off, limiting its effectiveness in providing traction.  A worn tire can often be retreaded. Rain tyres or Wet tyres ("tires" in American English, commonly shortened to wets) are special tyres used in motorsport in wet weather as opposed to a slick tyre used in dry conditions.  They are very similar in many ways to the tyres found on normal road cars. A flat tire (British English: flat tyre) is a deflated pneumatic tire, which can cause the rim of the wheel to ride on the tire tread or the ground potentially resulting in loss of control of the vehicle or irreparable damage to the tire.  The most common cause of a flat tire is puncturing of the tire by a sharp object, such as a nail, letting air escape.  Depending on the size of the puncture, the tire may deflate slowly or rapidly. A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases.  There are several geological processes that may cause the formation of mud volcanoes.  Mud volcanoes are not true igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity.  The Earth continuously exudes a mud-like substance, which may sometimes be referred to as a "mud volcano".  Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide.  Smaller mud exudations are sometimes referred to as mud-pots.  The largest (man made) mud volcano is "Lusi" in Java, Indonesia, which is 10 km in diameter. Tire maintenance for motor vehicles is based on several factors.  The chief reason for tire replacement is friction from moving contact with road surfaces, causing the tread on the outer perimeter of tires to eventually wear away.  When the tread depth becomes too shallow (less than 0.125in. /3.2mm), the tire is worn out and should be replaced.  The same wheels can usually be used throughout the lifetime of the car.  Other problems encountered in tire maintenance include: JK Tyre & Industries Ltd is an Automotive Tyre, Tubes and flaps manufacturing company based in Delhi, India.  The name JK is derived from the initials of Kamlapatji (1884–1937) and his father Seth Juggilal (1857–1922).  The company is the market leader in Truck/Bus Radial tire in India and is the only tyre manufacturer offering the entire range of 4 wheeler radials for Trucks, Buses and Cars.  JK Tyre has a worldwide customer base in over 80 countries across all 6 continents.  It is a part of J. K. Organisation group of Companies.  JK Tyre acquired Mexican tyre major – Tornel in 2008.  With production facilities in all 9 plants, total production capacity is almost 20 million tyres p.a.
Answer: Smaller gaps trap the mud in between the tire lugs