How To Choose Between Knobby and Slick Bicycle Tires

Selecting the right tires for your bike can make a major difference in performance, whether you ride on the street or off-road. To pick the best tires, you need to consider tire size, valves, and the type of tire tread.

Bike tires come with one of four types of tread:

  • knobby
  • inverted
  • semi-slick
  • slick

Slick and knobby tires are the most common choices but are suited for different types of riding. So, should you ride on knobby or slick bicycle tires? Here’s what you need to know.

The difference between knobby and slick bicycle tires

Knobby and slick refer to the tread of the tires. A knobby tire has more tread, which provides more grip and resistance. Slick tires have less tread. The surface of the tires is smoother and grips the road less.

As the name suggests, knobby tires have “knobby” protrusions. The knobs form a pattern or rows and come in a variety of shapes, including squares and hexagons. The knobs provide more resistance and grip on terrain with loose material, such as gravel or dirt.

Knobby rear tire of a mountain bike as a rider goes down the trail
The protrusions on a knobby tire make them great for off-road riding.

Slick bike tires have less tread. The surface of the tire is smooth, but you may notice impressions in the rubber, such as the manufacturer’s logo or a pattern. The impressions may resemble treads but are only included for aesthetics.  The smooth surface of a slick tire ensures that it grips pavement and cement, making it the preferred choice for riding on the road.

Cyclist rides a road bike with slick tires on dry pavement
The smooth tread of a slick tire provides little resistance, making it the preferred choice of road and racing cyclists. (© Simon Connellan on Unsplash)

Advantages of knobby tires

Knobby tires offer several benefits, depending on the riding conditions:

  • Better traction on loose material
  • Safety on hazardous terrain
  • Fewer air leaks

Mountain bikes are often equipped with knobby tires, as the knobs provide better performance on loose surfaces. You will likely want knobby tires when riding on dirt, gravel, and snow. Knobby tires are also a safer option compared to slick tires when riding on icy roads. However, specialized winter tires such as metal studded tires offer the best stability on icy roads.

Knobby tire of a bike lightly dusted in snow
A knobby tire gives you a chance to stay upright in the snow.

Overall, knobby tires work well on more hazardous terrain than on pavement. Dirt, grass, sand, and other off-road environments are softer compared to roads and sidewalks. Knobby tires press into off-road surfaces, which improves traction.

Knobby tires also help protect the tube from punctures. The knobby protrusions decrease the risk of nails and other sharp objects puncturing the bicycle tire and the tube.

Advantages of slick tires

Slick tires provide a few advantages over knobby tires. However, these advantages apply only to specific situations:

  • Increased efficiency
  • Better grip on clear roads
  • Faster speeds

People tend to assume that slick tires offer less grip compared to knobby tires. However, the smooth rubber on the tires provides a better grip on the road. Pavement is not a soft surface, which allows slick tires to provide better traction.

Resting road bike with slick tires
© Hilary Travers on Unsplash

Riding on a slick road tire also means less rolling resistance. Rolling resistance is the energy needed to maintain a consistent speed. With less rolling resistance and better grip, you can achieve faster speeds and exert less energy. While estimates vary, you may receive a 10 to 15 per cent increase in efficiency when switching from knobby tires to slick tires.

When to use knobby tires

Knobby tires are recommended when riding on loose or unstable terrain. Snow, ice, dirt, gravel, and most off-road conditions increase the risk of slipping on small debris or slick surfaces. The extra tread on the tires helps maintain stability when rolling over loose terrain. Knobby tires are also typically wider and pumped with lower air pressure, which increases traction and rolling resistance.

Knobby tires are also the preferred choice for muddy terrain, the knobs press into the soft surface to provide better grip, which is why knobby tires are sometimes called mud tires. Use a mud tire with widely spaced knobs to keep the mud from clogging up the treads.

Mountain biker with knobby tires cuts through the mud in a forest

When to use slick tires

Slick tires are well-suited for cycling on roads and flat surfaces. As slick tires offer less resistance, you can travel more efficiently. Bike commuters may prefer reaching work without having to break a sweat.

Despite having less tread, slick tires do not significantly increase your risk of slipping on wet roads. The tires have a thick, smooth layer of rubber that provides a good grip on flat surfaces, including wet pavement.

Yet, if you live in an area that gets freezing temperatures, you may want something with more tread before winter arrives. Icy roads are more hazardous and require more traction.

What are semi-slick tires?

Semi-slick tires provide a compromise between slick and knobby tires. The surface is mostly smooth, especially along the center. The outer edges of the tire have deeper treads to improve cornering.

Semi-slick bike tires provide a balance for those who feel safer with more tread compared to the smooth surface of slick tires. You still have a smooth center for achieving faster speeds on asphalt, along with side treads for gripping the terrain. However, knobby tires still perform best in strictly off-road conditions due to the tread pattern across the center and sides of the tires.

What is an inverted tread?

Inverted tread tires have indents, resulting in a smooth surface when rolling over flat terrain, such as city roads. Yet, the indents provide traction when you come across loose gravel, pebbles, or crumbling concrete.

Inverted tread bicycle tire closeup, with grooves cutting into the surface
A tire with an inverted tread.

The choice between knobby vs. slick bicycle tires depends on the riding conditions. Stick with slick tires on roads. If you need something with a little more traction for rough city roads or dirt roads, consider using semi-slick or inverted tread tires. Use knobby tires for off-road or hazardous terrain.

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